Microorganisms

15 pages, 1273 KiB

Open AccessArticle

Leishmania and the Model of Predominant Clonal Evolution

by Michel Tibayrenc and Francisco J. Ayala

Microorganisms 2021, 9(11), 2409; https://doi.org/10.3390/microorganisms9112409 - 22 Nov 2021

Cited by 5 | Viewed by 2104

As it is the case for other pathogenic microorganisms, the respective impact of clonality and genetic exchange on Leishmania natural populations has been the object of lively debates since the early 1980s. The predominant clonal evolution (PCE) model states that genetic exchange in [...] Read more.

As it is the case for other pathogenic microorganisms, the respective impact of clonality and genetic exchange on Leishmania natural populations has been the object of lively debates since the early 1980s. The predominant clonal evolution (PCE) model states that genetic exchange in these parasites’ natural populations may have a high relevance on an evolutionary scale, but is not sufficient to erase a persistent phylogenetic signal and the existence of bifurcating trees. Recent data based on high-resolution markers and genomic polymorphisms fully confirm the PCE model down to a microevolutionary level. Full article

(This article belongs to the Special Issue Inter- and Intraspecific Variation between Leishmanial Parasites)

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11 pages, 1527 KiB

Open AccessCommunication

Combined Therapy with microRNA-Expressing Salmonella and Irradiation in Melanoma

by Wonsuck Yoon, Yongsung Park, Seunghyun Kim, Yongkeun Park and Chul Yong Kim

Microorganisms 2021, 9(11), 2408; https://doi.org/10.3390/microorganisms9112408 - 22 Nov 2021

Cited by 7 | Viewed by 2337

Abstract

Anticancer treatment strategies using bacteria as a vector are currently expanding with the development of anticancer drugs. Here, we present a research strategy to develop anticancer drugs using bacteria that contain miRNAs. We also present a strategy for the development of novel bacterial [...] Read more.

Anticancer treatment strategies using bacteria as a vector are currently expanding with the development of anticancer drugs. Here, we present a research strategy to develop anticancer drugs using bacteria that contain miRNAs. We also present a strategy for the development of novel bacterial anticancer drugs in combination with radiation. Salmonella strains expressing miRNA were produced by modifying the miRNA expression vector encoding INHA, a radiation-resistant gene developed previously. The anticancer effect of INHA was confirmed using skin cancer cell lines. We also tested a combination strategy comprising bacteria and radiation for its anticancer efficacy against radiation-resistant mouse melanoma to increase the efficacy of radiation therapy as a novel strategy. The recombinant strain was confirmed to promote effective cell death even when combined with radiation therapy, which exerts its cytotoxicity by enhancing reactive oxygen species production. Moreover, a combination of bacterial and radiation therapy enhanced radiotherapy efficacy. When combined with radiation therapy, bacterial therapy exhibited effective anti-cancer properties even when administered to animals harboring radiation-resistant tumors. This strategy may promote the secretion of cytokines in cells and more effectively reduce the number of bacteria remaining in the animal. Thus, this study may lead to the development of a strategy to improve the effectiveness of radiation therapy using Salmonella expressing cancer-specific miRNA for intractable cancers such as those resistant to radiation. Full article

(This article belongs to the Special Issue Microbial Regulation of Cancer Treatment and Response)

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16 pages, 3671 KiB

Open AccessArticle

New Insights into the Host–Pathogen Interaction of Mycoplasma gallisepticum and Avian Metapneumovirus in Tracheal Organ Cultures of Chicken

by Nancy Rüger, Hicham Sid, Jochen Meens, Michael P. Szostak, Wolfgang Baumgärtner, Frederik Bexter and Silke Rautenschlein

Microorganisms 2021, 9(11), 2407; https://doi.org/10.3390/microorganisms9112407 - 22 Nov 2021

Cited by 8 | Viewed by 3159

Abstract

Respiratory pathogens are a health threat for poultry. Co-infections lead to the exacerbation of clinical symptoms and lesions. Mycoplasma gallisepticum (M. gallispeticum) and Avian Metapneumovirus (AMPV) are two avian respiratory pathogens that co-circulate worldwide. The knowledge about the host–pathogen interaction of [...] Read more.

Respiratory pathogens are a health threat for poultry. Co-infections lead to the exacerbation of clinical symptoms and lesions. Mycoplasma gallisepticum (M. gallispeticum) and Avian Metapneumovirus (AMPV) are two avian respiratory pathogens that co-circulate worldwide. The knowledge about the host–pathogen interaction of M. gallispeticum and AMPV in the chicken respiratory tract is limited. We aimed to investigate how co-infections affect the pathogenesis of the respiratory disease and whether the order of invading pathogens leads to changes in host–pathogen interaction. We used chicken tracheal organ cultures (TOC) to investigate pathogen invasion and replication, lesion development, and selected innate immune responses, such as interferon (IFN) α, inducible nitric oxide synthase (iNOS) and IFNλ mRNA expression levels. We performed mono-inoculations (AMPV or M. gallispeticum) or dual-inoculations in two orders with a 24-h interval between the first and second pathogen. Dual-inoculations compared to mono-inoculations resulted in more severe host reactions. Pre-infection with AMPV followed by M. gallispeticum resulted in prolonged viral replication, more significant innate immune responses, and lesions (p < 0.05). AMPV as the secondary pathogen impaired the bacterial attachment process. Consequently, the M. gallispeticum replication was delayed, the innate immune response was less pronounced, and lesions appeared later. Our results suggest a competing process in co-infections and offer new insights in disease processes. Full article

(This article belongs to the Topic Veterinary Infectious Diseases)

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4 pages, 210 KiB

Open AccessEditorial

Special Issue: Role of Bacterial Chromatin in Environmental Sensing, Adaptation and Evolution

by Remus T. Dame

Microorganisms 2021, 9(11), 2406; https://doi.org/10.3390/microorganisms9112406 - 22 Nov 2021

Viewed by 1564

Abstract

A typical bacterial cell is micron-sized and contains a genome several million base pairs in length [...] Full article

(This article belongs to the Special Issue Role of Bacterial Chromatin in Environmental Sensing, Adaptation and Evolution)

10 pages, 1134 KiB

Open AccessArticle

Evidence of Borrelia theileri in Wild and Domestic Animals in the Kafue Ecosystem of Zambia

by Yongjin Qiu, David Squarre, Yukiko Nakamura, Alice C. C. Lau, Lavel Chinyama Moonga, Naoko Kawai, Aiko Ohnuma, Kyoko Hayashida, Ryo Nakao, Junya Yamagishi, Hirofumi Sawa, Boniface Namangala and Hiroki Kawabata

Microorganisms 2021, 9(11), 2405; https://doi.org/10.3390/microorganisms9112405 - 22 Nov 2021

Cited by 11 | Viewed by 2813

Abstract

Members of the genus Borrelia are arthropod-borne spirochetes that are human and animal pathogens. Vertebrate hosts, including wild animals, are pivotal to the circulation and maintenance of Borrelia spirochetes. However, information on Borrelia spirochetes in vertebrate hosts in Zambia is limited. Thus, we [...] Read more.

Members of the genus Borrelia are arthropod-borne spirochetes that are human and animal pathogens. Vertebrate hosts, including wild animals, are pivotal to the circulation and maintenance of Borrelia spirochetes. However, information on Borrelia spirochetes in vertebrate hosts in Zambia is limited. Thus, we aimed to investigate the presence of Borrelia spirochetes in wild animals and cattle in Zambia. A total of 140 wild animals of four species and 488 cattle DNA samples from /near the Kafue National Park were collected for real-time PCR screening, followed by characterization using three different genes with positive samples. Five impalas and 20 cattle tested positive using real-time PCR, and sequence analysis revealed that the detected Borrelia were identified to be Borrelia theileri, a causative agent of bovine borreliosis. This is the first evidence of Borrelia theileri in African wildlife and cattle in Zambia. Our results suggest that clinical differentiation between bovine borreliosis and other bovine diseases endemic in Zambia is required for better treatment and control measures. As this study only included wild and domestic animals in the Kafue ecosystem, further investigations in other areas and with more wildlife and livestock species are needed to clarify a comprehensive epidemiological status of Borrelia theileri in Zambia. Full article

(This article belongs to the Special Issue Borrelia Ecology and Evolution: Ticks and Hosts and the Environment)

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17 pages, 3746 KiB

Open AccessArticle

The Effect of Lactiplantibacillus plantarum BX62 Alone or in Combination with Chitosan on the Qualitative Characteristics of Fresh-Cut Apples during Cold Storage

by Qian Zhao, Shihua Tang, Xiang Fang, Zhuo Wang, Yu Jiang, Xusheng Guo, Jianning Zhu and Ying Zhang

Microorganisms 2021, 9(11), 2404; https://doi.org/10.3390/microorganisms9112404 - 22 Nov 2021

Cited by 10 | Viewed by 2578

Abstract

In order to explore whether beneficial lactic acid bacteria (LAB) could prolong the shelf life and improve the quality of fresh-cut apples, Lactiplantibacillus plantarum BX62, which was isolated from traditional fermented yak yogurt, and chitosan (CT), were applied to fresh-cut apples, subsequently stored [...] Read more.

In order to explore whether beneficial lactic acid bacteria (LAB) could prolong the shelf life and improve the quality of fresh-cut apples, Lactiplantibacillus plantarum BX62, which was isolated from traditional fermented yak yogurt, and chitosan (CT), were applied to fresh-cut apples, subsequently stored at 4 °C. On days 0, 2, 4, 6, and 8, apple slices were taken for physicochemical, microbiological analysis, and sensory evaluation. The results showed that apple slices coated with L. plantarum BX62 (8 log CFU/mL) presented lower weight loss and browning rate, higher DPPH scavenging capacity, and achieved more effective inhibition of polyphenol oxidase (PPO) and peroxidase (POD) activities compared to the control samples. The application of CT alone or in combination with L. plantarum BX62 resulted in a significant reduction in aerobic mesophilic bacteria (AMB), aerobic psychrophilic bacterial (APB), yeast and molds (YAMs) counts (2.31 log CFU/g for AMB, 2.55 for APB, and 1.58 for YAMs). In addition, L. plantarum BX62 coated apples showed acceptable sensory properties in terms of color, flavor, taste, texture, and overall visual quality during 8 d of storage. On this basis, L. plantarum BX62 could be used as an excellent bio-preservative to extend the shelf life and improve the quality of fresh-cut apples. Full article

(This article belongs to the Special Issue Studies on Lactic Acid Bacteria: Metabolism, Genomics and Applications)

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Graphical abstract

11 pages, 253 KiB

Open AccessArticle

Effects of Additives on Silage Fermentation Characteristic and In Vitro Digestibility of Perennial Oat at Different Maturity Stages on the Qinghai Tibetan

by Ping Li, Xiaolong Tang, Chaosheng Liao, Maoya Li, Liangyin Chen, Guangrou Lu, Xiaokang Huang, Chao Chen and Wenlong Gou

Microorganisms 2021, 9(11), 2403; https://doi.org/10.3390/microorganisms9112403 - 22 Nov 2021

Cited by 9 | Viewed by 1959

Abstract

To effectively use local grass resources to cover the winter feed shortage on the Qinghai-Tibetan Plateau, the silage fermentation and in vitro digestibility of perennial oat (Helictotrichonvirescens Henr.) were investigated. Perennial oat was harvested at the heading/flowering stage, wilted under sunny [...] Read more.

To effectively use local grass resources to cover the winter feed shortage on the Qinghai-Tibetan Plateau, the silage fermentation and in vitro digestibility of perennial oat (Helictotrichonvirescens Henr.) were investigated. Perennial oat was harvested at the heading/flowering stage, wilted under sunny conditions, chopped, vacuumed in small bag silos, and stored at ambient temperatures (5–15 °C) for 60 days. The silages were treated without (CK) or with local lactic acid bacteria (LAB) inoculant (IN1), commercial LAB inoculant (IN2), and sodium benzoate (BL). Control silages of perennial oat at early heading stage showed higher (p < 0.05) lactate and acetate contents and lower (p < 0.05) final pH, butyrate, and ammonia-N contents than those at the flowering stage. High levels of dry matter recovery (DMR) and crude protein (CP) were observed in IN1- and BL-treated silages, with high in vitro gas production and dry matter digestibility. Compared to CK, additives increased (p < 0.05) aerobic stability by inhibiting yeasts, aerobic bacteria, and coliform bacteria during ensiling. In particular, the local LAB inoculant increased (p < 0.05) concentrations of lactate, acetate and propionate, and decreased concentrations of butyrate and ammonia-N in silages. This study confirmed that local LAB inoculant could improve the silage quality of perennial oat, and this could be a potential winter feed for animals such as yaks on the Qinghai Tibetan Plateau. Full article

(This article belongs to the Topic Development of Agricultural and Food By-Product Resources and Animal Production to Achieve Food Sustainability)

20 pages, 1402 KiB

Open AccessReview

Gut Microbiota Parameters Potentially Useful in Clinical Perspective

by Francesco Di Pierro

Microorganisms 2021, 9(11), 2402; https://doi.org/10.3390/microorganisms9112402 - 22 Nov 2021

Cited by 30 | Viewed by 4418

Abstract

Interest in gut microbiota analyses is at an all-time high. Gut microbiota is thought to relate to an increasing range of diseases of interest to physicians and nutritionists. Overweight, obesity, response to diet, metabolic syndrome, low grade inflammation, diabetes and colon neoplasms could [...] Read more.

Interest in gut microbiota analyses is at an all-time high. Gut microbiota is thought to relate to an increasing range of diseases of interest to physicians and nutritionists. Overweight, obesity, response to diet, metabolic syndrome, low grade inflammation, diabetes and colon neoplasms could maybe be observed in microbiota if affordable markers were available. Possible biomarkers like the Firmicutes/Bacteroidetes ratio, the Gram-positive/Gram-negative ratio, the Prevotella/Bacteroides ratio, and the Fusobacterium nucleatum/Faecalibacterium prausnitzii ratio are here reviewed in a narrative way in the attempt to highlight their possible future role in routine practice and clinically relevant diagnostics. Full article

(This article belongs to the Special Issue Gut Microbioma Structure and Functions in Human Health and Disease 2.0)

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25 pages, 749 KiB

Open AccessArticle

Disinfectant and Antimicrobial Susceptibility Studies of Staphylococcus aureus Strains and ST398-MRSA and ST5-MRSA Strains from Swine Mandibular Lymph Node Tissue, Commercial Pork Sausage Meat and Swine Feces

by Ross C. Beier, Kathleen Andrews, Michael E. Hume, Muhammad Umar Sohail, Roger B. Harvey, Toni L. Poole, Tawni L. Crippen and Robin C. Anderson

Microorganisms 2021, 9(11), 2401; https://doi.org/10.3390/microorganisms9112401 - 22 Nov 2021

Cited by 5 | Viewed by 2910

Abstract

Staphylococcus aureus (S. aureus) causes gastrointestinal illness worldwide. Disinfectants are used throughout the food chain for pathogenic bacteria control. We investigated S. aureus bioavailability in swine Mandibular lymph node tissue (MLT) and pork sausage meat (PSM), established susceptibility values for S. [...] Read more.

Staphylococcus aureus (S. aureus) causes gastrointestinal illness worldwide. Disinfectants are used throughout the food chain for pathogenic bacteria control. We investigated S. aureus bioavailability in swine Mandibular lymph node tissue (MLT) and pork sausage meat (PSM), established susceptibility values for S. aureus to disinfectants, and determined the multilocus sequence type of MRSA strains. Antimicrobial and disinfectant susceptibility profiles were determined for 164 S. aureus strains isolated from swine feces (n = 63), MLT (n = 49) and PSM (n = 52). No antimicrobial resistance (AMR) was detected to daptomycin, nitrofurantoin, linezolid, and tigecycline, while high AMR prevalence was determined to erythromycin (50.6%), tylosin tartrate (42.7%), penicillin (72%), and tetracycline (68.9%). Methicillin-resistant S. aureus (MRSA) strains, ST398 (n = 6) and ST5 (n = 1), were found in the MLT and PSM, 4 MRSA in MLT and 3 MRSA strains in the PSM. About 17.5% of feces strains and 41.6% of MLT and PSM strains were resistant to chlorhexidine. All strains were susceptible to triclosan and benzalkonium chloride, with no cross-resistance between antimicrobials and disinfectants. Six MRSA strains had elevated susceptibilities to 18 disinfectants. The use of formaldehyde and tris(hydroxylmethyl)nitromethane in DC&R was not effective, which can add chemicals to the environment. Didecyldimethylammonium chloride and benzyldimethylhexadecylammonium chloride were equally effective disinfectants. ST398 and ST5 MRSA strains had elevated susceptibilities to 75% of the disinfectants tested. This study establishes susceptibility values for S. aureus strains from swine feces, mandibular lymph node tissue, and commercial pork sausage against 24 disinfectants. Since it was demonstrated that S. aureus and MRSA strains can be found deep within swine lymph node tissue, it may be beneficial for the consumer if raw swine lymph node tissue is not used in uncooked food products and pork sausage. Full article

(This article belongs to the Section Food Microbiology)

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2 pages, 167 KiB

Open AccessEditorial

In Silico Novel Drug Design Targeting the Oral Microbiome: Endodontic and Periodontal Pathogenic Bacteria

by Maurilio D’Angelo, Alessio Zanza, Luca Testarelli, Federico Valenti Obino and Andrea Cicconetti

Microorganisms 2021, 9(11), 2400; https://doi.org/10.3390/microorganisms9112400 - 22 Nov 2021

Cited by 1 | Viewed by 1540

Abstract

The oral cavity is composed of about 300 million species of bacteria that occupy various ecological niches [...] Full article

(This article belongs to the Special Issue In Silico Novel Drug Design Targeting the Oral Microbiome)

9 pages, 858 KiB

Open AccessArticle

Susceptibility to Bismuth(III) of Aquaculture Bacterial Pathogens: Effectiveness of Bismuth–Deferiprone Therapy against Vibrio anguillarum Infection in Fish

by Miguel Balado, Diego Rey-Varela, Ana M. Albela and Manuel L. Lemos

Microorganisms 2021, 9(11), 2399; https://doi.org/10.3390/microorganisms9112399 - 21 Nov 2021

Viewed by 1997

Abstract

Bismuth is a heavy metal with antibacterial properties that has a long history of medicinal use. The results reported here suggest that bismuth(III) (chelated with deferiprone) could be used in aquaculture systems to treat bacterial disease outbreaks, greatly reducing antibiotic use. We tested [...] Read more.

Bismuth is a heavy metal with antibacterial properties that has a long history of medicinal use. The results reported here suggest that bismuth(III) (chelated with deferiprone) could be used in aquaculture systems to treat bacterial disease outbreaks, greatly reducing antibiotic use. We tested bismuth susceptibility in a collection of aquaculture bacterial pathogens. In the presence of bismuth concentrations ranging from 1.3 to 13 µM, most bacteria started showing a drastic decrease in their growth ability, although with high inter- and intraspecific variability. The minimal inhibitory concentrations of bismuth ranged from 13 to more than 780 µM, depending on bacterial species and strain. The results of in vivo assays suggest that low concentrations of bismuth could be especially effective to treat vibriosis caused by Vibrio anguillarum, since bismuth greatly reduced mortality in experimentally infected fish without any observable side effects. A bismuth therapy, alone or combined with other antimicrobials, could contribute to reduce the use of antibiotics in aquaculture. Full article

(This article belongs to the Special Issue Advances in Bacterial Fish and Shellfish Diseases in Aquaculture)

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15 pages, 762 KiB

Open AccessArticle

Agronomic Biofortification of Cayenne Pepper Cultivars with Plant Growth-Promoting Rhizobacteria and Chili Residue in a Chinese Solar Greenhouse

by Ibraheem Olamide Olasupo, Qiuju Liang, Chunyi Zhang, Md Shariful Islam, Yansu Li, Xianchang Yu and Chaoxing He

Microorganisms 2021, 9(11), 2398; https://doi.org/10.3390/microorganisms9112398 - 21 Nov 2021

Cited by 9 | Viewed by 2589

Abstract

Agronomic biofortification of horticultural crops using plant growth-promoting rhizobacteria (PGPR) under crop residue incorporation systems remains largely underexploited. Bacillus subtilis (B1), Bacillus laterosporus (B2), or Bacillus amyloliquefaciens (B3) was inoculated on soil containing chili residue, while chili residue without PGPR (NP) served as [...] Read more.

Agronomic biofortification of horticultural crops using plant growth-promoting rhizobacteria (PGPR) under crop residue incorporation systems remains largely underexploited. Bacillus subtilis (B1), Bacillus laterosporus (B2), or Bacillus amyloliquefaciens (B3) was inoculated on soil containing chili residue, while chili residue without PGPR (NP) served as the control. Two hybrid long cayenne peppers, succeeding a leaf mustard crop were used in the intensive cultivation study. Net photosynthesis, leaf stomatal conductance, transpiration rate, photosynthetic water use efficiency, shoot and root biomass, and fruit yield were evaluated. Derivatives of folate, minerals, and nitrate contents in the pepper fruits were also assessed. B1 elicited higher net photosynthesis and photosynthetic water use efficiency, while B2 and B3 had higher transpiration rates than B1 and NP. B1 and B3 resulted in 27–36% increase in pepper fruit yield compared to other treatments, whereas B3 produced 24–27.5% and 21.9–27.2% higher 5-methyltetrahydrofolate and total folate contents, respectively, compared to B1 and NP. However, chili residue without PGPR inoculation improved fruit calcium, magnesium, and potassium contents than the inoculated treatments. ‘Xin Xian La 8 F1’ cultivar had higher yield and plant biomass, fruit potassium, total soluble solids, and total folate contents compared to ‘La Gao F1.’ Agronomic biofortification through the synergy of Bacillus amyloliquefaciens and chili residue produced better yield and folate contents with a trade-off in the mineral contents of the greenhouse-grown long cayenne pepper. Full article

(This article belongs to the Section Plant Microbe Interactions)

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12 pages, 2828 KiB

Open AccessArticle

Production of Hydroxycarboxylic Acid Receptor 3 (HCA₃) Ligands by Bifidobacterium

by Takuma Sakurai, Ayako Horigome, Toshitaka Odamaki, Takashi Shimizu and Jin-Zhong Xiao

Microorganisms 2021, 9(11), 2397; https://doi.org/10.3390/microorganisms9112397 - 21 Nov 2021

Cited by 13 | Viewed by 3203

Abstract

Hydroxycarboxylic acid receptor 3 (HCA₃) was recently identified in the genomes of humans and other hominids but not in other mammals. We examined the production of HCA₃ ligands by Bifidobacterium spp. In addition to 4-hydroxyphenyllactic acid, phenyllactic acid (PLA), and [...] Read more.

Hydroxycarboxylic acid receptor 3 (HCA₃) was recently identified in the genomes of humans and other hominids but not in other mammals. We examined the production of HCA₃ ligands by Bifidobacterium spp. In addition to 4-hydroxyphenyllactic acid, phenyllactic acid (PLA), and indole-3-lactic acid (ILA), we found that LeuA was produced by Bifidobacterium as an HCA₃ ligand. The four ligands produced were the mixtures of enantiomers, and D-ILA, D-PLA, and D-LeuA showed stronger activity of the HCA₃ ligand than their respective L-isomers. However, there was no difference in AhR activity between the two ILA enantiomers. These results provide new insights into the HCA₃ ligands produced by Bifidobacterium and suggest the importance of investigating the absolute stereo structures of these metabolites. Full article

(This article belongs to the Special Issue Dialogue of Probiotics with the Host)

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13 pages, 1683 KiB

Open AccessReview

Biomineralization Induced by Cells of Sporosarcina pasteurii: Mechanisms, Applications and Challenges

by Yang Wu, Huimin Li and Yang Li

Microorganisms 2021, 9(11), 2396; https://doi.org/10.3390/microorganisms9112396 - 21 Nov 2021

Cited by 24 | Viewed by 6168

Abstract

Biomineralization has emerged as a novel and eco-friendly technology for artificial mineral formation utilizing the metabolism of organisms. Due to its highly efficient urea degradation ability, Sporosarcina pasteurii(S. pasteurii) is arguably the most widely investigated organism in ureolytic biomineralization studies, with wide [...] Read more.

Biomineralization has emerged as a novel and eco-friendly technology for artificial mineral formation utilizing the metabolism of organisms. Due to its highly efficient urea degradation ability, Sporosarcina pasteurii(S. pasteurii) is arguably the most widely investigated organism in ureolytic biomineralization studies, with wide potential application in construction and environmental protection. In emerging, large-scale commercial engineering applications, attention was also paid to practical challenges and issues. In this review, we summarize the features of S. pasteurii cells contributing to the biomineralization reaction, aiming to reveal the mechanism of artificial mineral formation catalyzed by bacterial cells. Progress in the application of this technology in construction and environmental protection is discussed separately. Furthermore, the urgent challenges and issues in large-scale application are also discussed, along with potential solutions. We aim to offer new ideas to researchers working on the mechanisms, applications and challenges of biomineralization. Full article

(This article belongs to the Section Microbial Biotechnology)

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19 pages, 4271 KiB

Open AccessArticle

Bioplastic Production by Bacillus wiedmannii AS-02 OK576278 Using Different Agricultural Wastes

by Amal W. Danial, Shereen M. Hamdy, Sulaiman A. Alrumman, Sanaa M. F. Gad El-Rab, Ahmed A. M. Shoreit and Abd El-Latif Hesham

Microorganisms 2021, 9(11), 2395; https://doi.org/10.3390/microorganisms9112395 - 21 Nov 2021

Cited by 23 | Viewed by 6915

Abstract

Polyhydroxybutyrates (PHBs) are macromolecules synthesized by bacteria. Because of their fast degradability under natural environmental conditions, PHBs were selected as alternatives for the production of biodegradable plastics. Sixteen PHB-accumulating strains were selected and compared for their ability to accumulate PHB granules inside their [...] Read more.

Polyhydroxybutyrates (PHBs) are macromolecules synthesized by bacteria. Because of their fast degradability under natural environmental conditions, PHBs were selected as alternatives for the production of biodegradable plastics. Sixteen PHB-accumulating strains were selected and compared for their ability to accumulate PHB granules inside their cells. Isolate AS-02 was isolated from cattle manure and identified as Bacillus wiedmannii AS-02 OK576278 by means of 16S rRNA analysis. It was found to be the best producer. The optimum pH, temperature, and incubation period for the best PHB production by the isolate were 7, 35 °C, and 72 h respectively. PHB production was the best with peptone and glucose as nitrogen and carbon sources at a C/N ratio of (2:1). The strain was able to accumulate 423, 390, 249, 158, and 144 mg/L PHB when pretreated orange, mango, banana, onion peels, and rice straw were used as carbon sources, respectively. The extracted polymer was characterized by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and GC-MS spectroscopy, which confirmed the structure of the polymer as PHB. The isolate B. wiedmannii AS-02 OK576278 can be considered an excellent candidate for industrial production of PHB from agricultural wastes. Full article

(This article belongs to the Section Environmental Microbiology)

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19 pages, 1851 KiB

Open AccessArticle

Cross-Border Investigations on the Prevalence and Transmission Dynamics of Cryptosporidium Species in Dairy Cattle Farms in Western Mainland Europe

by Pedro Pinto, Cláudia A. Ribeiro, Sumaiya Hoque, Ourida Hammouma, Hélène Leruste, Sébastien Détriché, Evi Canniere, Yvonne Daandels, Martine Dellevoet, Janine Roemen, Anne Barbier Bourgeois, Martin Kváč, Jérôme Follet and Anastasios D. Tsaousis

Microorganisms 2021, 9(11), 2394; https://doi.org/10.3390/microorganisms9112394 - 20 Nov 2021

Cited by 18 | Viewed by 4608

Abstract

Cryptosporidium is an apicomplexan parasitic protist, which infects a wide range of hosts, causing cryptosporidiosis disease. In farms, the incidence of this disease is high in animals such as cows, leading to extensive economic loss in the livestock industry. Infected cows may also [...] Read more.

Cryptosporidium is an apicomplexan parasitic protist, which infects a wide range of hosts, causing cryptosporidiosis disease. In farms, the incidence of this disease is high in animals such as cows, leading to extensive economic loss in the livestock industry. Infected cows may also act as a major reservoir of Cryptosporidium spp., in particular C. parvum, the most common cause of cryptosporidiosis in these animals. This poses a risk to the trading of livestock, to other farms via breeding centres, and to human health. This study is a part of a global project aimed at strategies to tackle cryptosporidiosis. To reach this target, it was essential to determine whether prevalence was dependent on the studied countries or if the issue was borderless. Indeed, C. parvum occurrence was assessed across dairy farms in certain regions of Belgium, France, and the Netherlands. At the same time, the animal-to-animal transmission of the circulating C. parvum subtypes was studied. To accomplish this, we analysed 1084 faecal samples, corresponding to 57 dairy farms from all three countries. To this end, 18S rRNA and gp60 genes fragments were amplified, followed by DNA sequencing, which was subsequently used for detection and subtyping C. parvum. Bioinformatic and phylogenetic methods were integrated to analyse and characterise the obtained DNA sequences. Our results show 25.7%, 24.9% and 20.8% prevalence of Cryptosporidium spp. in Belgium, France, and the Netherlands respectively. Overall, 93% of the farms were Cryptosporidium positive. The gp60 subtyping demonstrated a significant number of the C. parvum positives belonged to the IIa allelic family, which has been also identified in humans. Therefore, this study highlights how prevalent C. parvum is in dairy farms and further suggests cattle as a possible carrier of zoonotic C. parvum subtypes, which could pose a threat to human health. Full article

(This article belongs to the Special Issue Evolution and Genetic Diversity of Gut Protozoan Parasites)

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9 pages, 799 KiB

Open AccessArticle

Use of Sedatives and Neuromuscular-Blocking Agents in Mechanically Ventilated Patients with COVID-19 ARDS

by Amédée Ego, Lorenzo Peluso, Julie Gorham, Alberto Diosdado, Giovanni Restuccia, Jacques Creteur and Fabio Silvio Taccone

Microorganisms 2021, 9(11), 2393; https://doi.org/10.3390/microorganisms9112393 - 20 Nov 2021

Cited by 7 | Viewed by 2239

Abstract

Objectives: To assess differences in the use of analgesics, sedatives and neuromuscular-blocking agents (NMBA) in patients with acute respiratory distress syndrome (ARDS) due to COVID-19 or other conditions. Methods: Retrospective observational cohort study, single-center tertiary Intensive Care Unit. COVID-19 patients with ARDS (March–May [...] Read more.

Objectives: To assess differences in the use of analgesics, sedatives and neuromuscular-blocking agents (NMBA) in patients with acute respiratory distress syndrome (ARDS) due to COVID-19 or other conditions. Methods: Retrospective observational cohort study, single-center tertiary Intensive Care Unit. COVID-19 patients with ARDS (March–May 2020) and non-COVID ARDS patients (2017–2020) on mechanical ventilation and receiving sedation for at least 48 h. Results: A total of 39 patients met the inclusion criteria in each group, with similar demographics at baseline. COVID-19 patients had a longer duration of MV (median 22 (IQRs 16–29) vs. 9 (6–18) days; p < 0.01), of sedatives administration (18 (11–22) vs. 5 (4–9) days; p < 0.01) and NMBA therapy (12 (9–16) vs. 3 (2–7) days; p < 0.01). During the first 7 days of sedation, compared to non-COVID patients, COVID patients received more frequently a combination of multiple sedative drugs (76.9% vs. 28.2%; p < 0.01) and a higher NMBA regimen (cisatracurium: 3.0 (2.1–3.7) vs. 1.3 (0.9–1.9) mg/kg/day; p < 0.01). Conclusions: The duration and consumption of sedatives and NMBA was significantly increased in patients with COVID-19 related ARDS than in non-COVID ARDS. Different sedation strategies and protocols might be needed in COVID-19 patients with ARDS, with potential implications on long-term complications and drugs availability. Full article

(This article belongs to the Special Issue The COVID-19 Pandemic and Bacterial Infections: Microbiological and Clinical Aspects)

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25 pages, 1846 KiB

Open AccessReview

Neutrophils in Streptococcus suis Infection: From Host Defense to Pathology

by Marêva Bleuzé, Marcelo Gottschalk and Mariela Segura

Microorganisms 2021, 9(11), 2392; https://doi.org/10.3390/microorganisms9112392 - 20 Nov 2021

Cited by 12 | Viewed by 3366

Abstract

Streptococcus suis is a swine pathogen and zoonotic agent responsible for economic losses to the porcine industry. Infected animals may develop meningitis, arthritis, endocarditis, sepsis and/or sudden death. The pathogenesis of the infection implies that bacteria breach mucosal host barriers and reach the [...] Read more.

Streptococcus suis is a swine pathogen and zoonotic agent responsible for economic losses to the porcine industry. Infected animals may develop meningitis, arthritis, endocarditis, sepsis and/or sudden death. The pathogenesis of the infection implies that bacteria breach mucosal host barriers and reach the bloodstream, where they escape immune-surveillance mechanisms and spread throughout the organism. The clinical manifestations are mainly the consequence of an exacerbated inflammation, defined by an exaggerated production of cytokines and recruitment of immune cells. Among them, neutrophils arrive first in contact with the pathogens to combat the infection. Neutrophils initiate and maintain inflammation, by producing cytokines and deploying their arsenal of antimicrobial mechanisms. Furthermore, neutrophilic leukocytosis characterizes S. suis infection, and lesions of infected subjects contain a large number of neutrophils. Therefore, this cell type may play a role in host defense and/or in the exacerbated inflammation. Nevertheless, a limited number of studies addressed the role or functions of neutrophils in the context of S. suis infection. In this review, we will explore the literature about S. suis and neutrophils, from their interaction at a cellular level, to the roles and behaviors of neutrophils in the infected host in vivo. Full article

(This article belongs to the Special Issue Epidemiology and Pathogenicity of Animal-Adapted Streptococci)

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13 pages, 2192 KiB

Open AccessArticle

Composition and Biological Activity of Vitis vinifera Winter Cane Extract on Candida Biofilm

by Zdeněk Kodeš, Maria Vrublevskaya, Markéta Kulišová, Petr Jaroš, Martina Paldrychová, Karolína Pádrová, Kristýna Lokočová, Andrea Palyzová, Olga Maťátková and Irena Kolouchová

Microorganisms 2021, 9(11), 2391; https://doi.org/10.3390/microorganisms9112391 - 19 Nov 2021

Cited by 10 | Viewed by 2287

Abstract

Vitis vinifera canes are waste material of grapevine pruning and thus represent cheap source of high-value polyphenols. In view of the fact that resistance of many pathogenic microorganisms to antibiotics is a growing problem, the antimicrobial activity of plant polyphenols is studied as [...] Read more.

Vitis vinifera canes are waste material of grapevine pruning and thus represent cheap source of high-value polyphenols. In view of the fact that resistance of many pathogenic microorganisms to antibiotics is a growing problem, the antimicrobial activity of plant polyphenols is studied as one of the possible approaches. We have investigated the total phenolic content, composition, antioxidant activity, and antifungal activity against Candida biofilm of an extract from winter canes and a commercially available extract from blue grapes. Light microscopy and confocal microscopy imaging as well as crystal violet staining were used to quantify and visualize the biofilm. We found a decrease in cell adhesion to the surface depending on the concentration of resveratrol in the cane extract. The biofilm formation was observed as metabolic activity of Candida albicans, Candida parapsilosis and Candida krusei biofilm cells and the minimum biofilm inhibitory concentrations were determined. The highest inhibition of metabolic activity was observed in Candida albicans biofilm after treatment with the cane extract (30 mg/L) and blue grape extract (50 mg/L). The composition of cane extract was analyzed and found to be comparatively different from blue grape extract. In addition, the content of total phenolic groups in cane extract was three-times higher (12.75 g_GA/L). The results showed that cane extract was more effective in preventing biofilm formation than blue grape extract and winter canes have proven to be a potential source of polyphenols for antimicrobial and antibiofilm treatment. Full article

(This article belongs to the Special Issue Diagnosis, Resistance and Treatment of Infections by Candida Species)

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16 pages, 2581 KiB

Open AccessArticle

Leaky Gut Syndrome Is Associated with Endotoxemia and Serum (1→3)-β-D-Glucan in Severe Dengue Infection

by Wiwat Chancharoenthana, Asada Leelahavanichkul, Wassawon Ariyanon, Somratai Vadcharavivad, Suphasit Phatcharophaswattanakul, Supitcha Kamolratanakul, Pornsawan Leaungwutiwong, Weerapong Phumratanaprapin and Polrat Wilairatana

Microorganisms 2021, 9(11), 2390; https://doi.org/10.3390/microorganisms9112390 - 19 Nov 2021

Cited by 17 | Viewed by 2778

Abstract

The hallmark of severe dengue infection is the increased vascular permeability and hemodynamic alteration that might be associated with an intestinal permeability defect. However, the mechanisms underlying the gastrointestinal-related symptoms of dengue are not well characterized. A prospective observational study was conducted on [...] Read more.

The hallmark of severe dengue infection is the increased vascular permeability and hemodynamic alteration that might be associated with an intestinal permeability defect. However, the mechanisms underlying the gastrointestinal-related symptoms of dengue are not well characterized. A prospective observational study was conducted on patients with dengue who were categorized according to: (i) febrile versus critical phase and (ii) hospitalized patients with versus without the warning signs to evaluate the gut barrier using lactulose-to-mannitol excretion ratio (LEMR). Serum endotoxins, (1→3)-β-D-glucan (BG), and inflammatory parameters were measured. A total of 48 and 38 patients were enrolled in febrile illness and critical phase, respectively, while 22 and 64 patients presented with or without the warning signs, respectively. At enrollment, a positive LEMR test was found in 20 patients (91%) with warning signs, regardless of phase of infection. Likewise, serum endotoxins and BG, the indirect biomarkers for leaky gut, prominently increased in patients who developed severe dengue when compared with the non-severe dengue (endotoxins, 399.1 versus 143.4 pg/mL (p < 0.0001); BG, 123 versus 73.8 pg/mL (p = 0.016)). Modest impaired intestinal permeability occurred in dengue patients, particularly those with warning signs, and were associated with endotoxemia and elevated BG. Thus, leaky gut syndrome might be associated with severity of dengue infection. Full article

(This article belongs to the Special Issue Gut Microbiota-Host Interactions under Inflammatory Conditions)

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19 pages, 1304 KiB

Open AccessArticle

Diversity and Hydrocarbon-Degrading Potential of Deep-Sea Microbial Community from the Mid-Atlantic Ridge, South of the Azores (North Atlantic Ocean)

by Maria Paola Tomasino, Mariana Aparício, Inês Ribeiro, Filipa Santos, Miguel Caetano, C. Marisa R. Almeida, Maria de Fátima Carvalho and Ana P. Mucha

Microorganisms 2021, 9(11), 2389; https://doi.org/10.3390/microorganisms9112389 - 19 Nov 2021

Cited by 10 | Viewed by 3963 | Correction

Abstract

Deep-sea sediments (DSS) are one of the largest biotopes on Earth and host a surprisingly diverse microbial community. The harsh conditions of this cold environment lower the rate of natural attenuation, allowing the petroleum pollutants to persist for a long time in deep [...] Read more.

Deep-sea sediments (DSS) are one of the largest biotopes on Earth and host a surprisingly diverse microbial community. The harsh conditions of this cold environment lower the rate of natural attenuation, allowing the petroleum pollutants to persist for a long time in deep marine sediments raising problematic environmental concerns. The present work aims to contribute to the study of DSS microbial resources as biotechnological tools for bioremediation of petroleum hydrocarbon polluted environments. Four deep-sea sediment samples were collected in the Mid-Atlantic Ridge, south of the Azores (North Atlantic Ocean). Their autochthonous microbial diversity was investigated by 16S rRNA metabarcoding analysis. In addition, a total of 26 deep-sea bacteria strains with the ability to utilize crude oil as their sole carbon and energy source were isolated from the DSS samples. Eight of them were selected for a novel hydrocarbonoclastic-bacterial consortium and their potential to degrade petroleum hydrocarbons was tested in a bioremediation experiment. Bioaugmentation treatments (with inoculum pre-grown either in sodium acetate or petroleum) showed an increase in degradation of the hydrocarbons comparatively to natural attenuation. Our results provide new insights into deep-ocean oil spill bioremediation by applying DSS hydrocarbon-degrading consortium in lab-scale microcosm to simulate an oil spill in natural seawater. Full article

(This article belongs to the Special Issue Oil Biodegradation and Bioremediation in Cold Marine Environment)

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21 pages, 2574 KiB

Open AccessArticle

Bacterial Communities in the Embryo of Maize Landraces: Relation with Susceptibility to Fusarium Ear Rot

by Alessandro Passera, Alessia Follador, Stefano Morandi, Niccolò Miotti, Martina Ghidoli, Giovanni Venturini, Fabio Quaglino, Milena Brasca, Paola Casati, Roberto Pilu and Davide Bulgarelli

Microorganisms 2021, 9(11), 2388; https://doi.org/10.3390/microorganisms9112388 - 19 Nov 2021

Cited by 8 | Viewed by 3458

Abstract

Locally adapted maize accessions (landraces) represent an untapped resource of nutritional and resistance traits for breeding, including the shaping of distinct microbiota. Our study focused on five different maize landraces and a reference commercial hybrid, showing different susceptibility to fusarium ear rot, and [...] Read more.

Locally adapted maize accessions (landraces) represent an untapped resource of nutritional and resistance traits for breeding, including the shaping of distinct microbiota. Our study focused on five different maize landraces and a reference commercial hybrid, showing different susceptibility to fusarium ear rot, and whether this trait could be related to particular compositions of the bacterial microbiota in the embryo, using different approaches. Our cultivation-independent approach utilized the metabarcoding of a portion of the 16S rRNA gene to study bacterial populations in these samples. Multivariate statistical analyses indicated that the microbiota of the embryos of the accessions grouped in two different clusters: one comprising three landraces and the hybrid, one including the remaining two landraces, which showed a lower susceptibility to fusarium ear rot in field. The main discriminant between these clusters was the frequency of Firmicutes, higher in the second cluster, and this abundance was confirmed by quantification through digital PCR. The cultivation-dependent approach allowed the isolation of 70 bacterial strains, mostly Firmicutes. In vivo assays allowed the identification of five candidate biocontrol strains against fusarium ear rot. Our data revealed novel insights into the role of the maize embryo microbiota and set the stage for further studies aimed at integrating this knowledge into plant breeding programs. Full article

(This article belongs to the Special Issue Beneficial Microbiomes in Agriculture and Human Health: The Food Connection)

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13 pages, 1414 KiB

Open AccessArticle

Development of Plant–Fungal Endophyte Associations to Suppress Phoma Stem Canker in Brassica

by Davood Roodi, James P. Millner, Craig R. McGill, Richard D. Johnson, Shen-Yan Hea, Jenny J. Brookes, Travis R. Glare and Stuart D. Card

Microorganisms 2021, 9(11), 2387; https://doi.org/10.3390/microorganisms9112387 - 19 Nov 2021

Cited by 4 | Viewed by 2541

Abstract

Endophytic microorganisms are found within the tissues of many plants species, with some conferring several benefits to the host plant including resistance to plant diseases. In this study, two putative endophytic fungi that were previously isolated from wild seeds of Brassica, identified [...] Read more.

Endophytic microorganisms are found within the tissues of many plants species, with some conferring several benefits to the host plant including resistance to plant diseases. In this study, two putative endophytic fungi that were previously isolated from wild seeds of Brassica, identified as Beauveria bassiana and Pseudogymnoascus pannorum, were inoculated into cultivars of three Brassica species—Brassica napus, Br. rapa and Br. oleracea. Both fungal endophytes were reisolated from above- and below-ground tissues of inoculated plants at four different plant-growth stages, including cotyledon, one-leaf, two-leaf, and four-leaf stages. None of the plants colonised by these fungi exhibited any obvious disease symptoms, indicating the formation of novel mutualistic associations. These novel plant–endophyte associations formed between Brassica plants and Be. bassiana significantly inhibited phoma stem canker, a devastating disease of Brassica crops worldwide, caused by the fungal pathogen Leptosphaeria maculans. The novel association formed with P. pannorum significantly suppressed the amount of disease caused by L. maculans in one out of two experiments. Although biological control is not a new strategy, endophytic fungi with both antiinsect and antifungal activity are a highly conceivable, sustainable option to manage pests and diseases of economically important crops. Full article

(This article belongs to the Special Issue Microbial Endophytes: Functional Biology and Applications)

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22 pages, 1921 KiB

Open AccessArticle

Role of Maturation of Lipoproteins in the Pathogenesis of the Infection Caused by Streptococcus suis Serotype 2

by Servane Payen, David Roy, Anaïs Boa, Masatoshi Okura, Jean-Philippe Auger, Mariela Segura and Marcelo Gottschalk

Microorganisms 2021, 9(11), 2386; https://doi.org/10.3390/microorganisms9112386 - 19 Nov 2021

Cited by 5 | Viewed by 2187

Abstract

Streptococcus suis serotype 2 is an important porcine bacterial pathogen associated with multiple pathologies in piglets. Bacterial lipoproteins (LPPs) have been described as playing important roles in the pathogenesis of the infection of other Gram-positive bacteria as adhesins, pro-inflammatory cell activators and/or virulence [...] Read more.

Streptococcus suis serotype 2 is an important porcine bacterial pathogen associated with multiple pathologies in piglets. Bacterial lipoproteins (LPPs) have been described as playing important roles in the pathogenesis of the infection of other Gram-positive bacteria as adhesins, pro-inflammatory cell activators and/or virulence factors. In the current study, we aimed to evaluate the role of the prolipoprotein diacylglyceryl transferase (Lgt) and lipoprotein signal peptidase (Lsp) enzymes, which are responsible for LPP maturation, on the pathogenesis of the infection caused by two different sequence types (STs) of S. suis serotype 2 strains (virulent ST1 and highly virulent ST7). Through the use of isogenic Δlgt, Δlsp and double Δlgt/Δlsp mutants, it was shown that lack of these enzymes did not influence S. suis adhesion/invasion to porcine respiratory epithelial cells. However, in the absence of the Lsp and/or Lgt, a significant reduction in the capacity of S. suis to activate phagocytic cells and induce pro-inflammatory mediators (in vitro and in vivo) was observed. In general, results obtained with the double mutant did not differ in comparison to single mutants, indicating lack of an additive effect. Finally, our data suggest that these enzymes play a differential role in virulence, depending on the genetic background of the strain and being more important for the highly virulent ST7 strain. Full article

(This article belongs to the Special Issue Epidemiology and Pathogenicity of Animal-Adapted Streptococci)

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12 pages, 881 KiB

Open AccessReview

Assessment of Oral Microbiome Changes in Healthy and COVID-19-Affected Pregnant Women: A Narrative Review

by Andrea Butera, Carolina Maiorani, Annalaura Morandini, Manuela Simonini, Arianna Colnaghi, Stefania Morittu, Stefania Barbieri, Maria Ricci, Gaetano Guerrisi, Daniela Piloni, Roberta Cimarossa, Barbara Fusaro, Antonia Sinesi, Ambra Bruni and Andrea Scribante

Microorganisms 2021, 9(11), 2385; https://doi.org/10.3390/microorganisms9112385 - 19 Nov 2021

Cited by 10 | Viewed by 3859

Abstract

During pregnancy, there are several metabolic changes and an alteration in the composition of microorganisms that inhabit the oral cavity, with an increase in pathogenic bacteria that promote the onset of gingival diseases. This review is based on research in reference to the [...] Read more.

During pregnancy, there are several metabolic changes and an alteration in the composition of microorganisms that inhabit the oral cavity, with an increase in pathogenic bacteria that promote the onset of gingival diseases. This review is based on research in reference to the PICO model (Problem/Intervention/Comparison/Outcome), related to changes in the oral microbiome of pregnant women and possible oral consequences in patients with COVID-19. The results showed a growth of some pathogenic bacteria in pregnant women, including Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum, and the selective growth of the Prevotella intermedia, Porphyromonas gingivalis and Tannerella species, probably due to the fact that these bacteria use progesterone as a source of nutrition. These same bacteria are implicated in the development of periodontal disease. Periodontal pockets have bidirectional interactions between the oral cavity and the systemic circulatory system through the peripheral gingival blood vessels. The affinity of the SARS-CoV-2 virus to specific membrane receptors is now clear, and could involve the internal and external epithelial lining or the fibroblasts of the periodontal ligament. According to the results of the present review, the control of oral microbiome changes during pregnancy would be welcomed. The use of probiotics could help clinicians manage pregnant patients, reducing inflammatory indexes. Future studies should focus not only on changes in the level of the oral microbiome in pregnancy or the correlation between periodontal disease and COVID-19, but also on oral changes induced by both clinical situations. Full article

(This article belongs to the Special Issue Microbiology of Oral Diseases)

12 pages, 463 KiB

Open AccessArticle

Relationship between the Biofilm-Forming Capacity and Antimicrobial Resistance in Clinical Acinetobacter baumannii Isolates: Results from a Laboratory-Based In Vitro Study

by Matthew Gavino Donadu, Vittorio Mazzarello, Piero Cappuccinelli, Stefania Zanetti, Melinda Madléna, Ádám László Nagy, Anette Stájer, Katalin Burián and Márió Gajdács

Microorganisms 2021, 9(11), 2384; https://doi.org/10.3390/microorganisms9112384 - 18 Nov 2021

Cited by 30 | Viewed by 3341

Abstract

The relationship between the multidrug-resistant (MDR) phenotype and biofilm-forming capacity has been a topic of extensive interest among biomedical scientists, as these two factors may have significant influence on the outcomes of infections. The aim of the present study was to establish a [...] Read more.

The relationship between the multidrug-resistant (MDR) phenotype and biofilm-forming capacity has been a topic of extensive interest among biomedical scientists, as these two factors may have significant influence on the outcomes of infections. The aim of the present study was to establish a possible relationship between biofilm-forming capacity and the antibiotic-resistant phenotype in clinical Acinetobacter baumannii (A. baumannii) isolates. A total of n = 309 isolates were included in this study. Antimicrobial susceptibility testing and the phenotypic detection of resistance determinants were carried out. The capacity of isolates to produce biofilms was assessed using a crystal violet microtiter-plate-based method. Resistance rates were highest for ciprofloxacin (71.19%; n = 220), levofloxacin (n = 68.61%; n = 212), and trimethoprim-sulfamethoxazole (n = 66.02%; n = 209); 42.72% (n = 132) of isolates were classified as MDR; 22.65% (n = 70) of tested isolates were positive in the modified Hodge-test; the overexpression of efflux pumps had significant effects on the susceptibilities of meropenem, gentamicin, and ciprofloxacin in 14.24% (n = 44), 6.05% (n = 19), and 27.51% (n = 85), respectively; 9.39% (n = 29), 12.29% (n = 38), 22.97% (n = 71), and 55.35% (n = 170) of isolates were non-biofilm-producing and weak, moderate, and strong biofilm producers, respectively. A numerical, but statistically not significant, difference was identified between the MDR and non-MDR isolates regarding their biofilm-forming capacity (MDR: 0.495 ± 0.309 vs. non-MDR: 0.545 ± 0.283; p = 0.072), and no association was seen between resistance to individual antibiotics and biofilm formation. Based on numerical trends, MER-resistant isolates were the strongest biofilm producers (p = 0.067). Our study emphasizes the need for additional experiments to assess the role biofilms have in the pathogenesis of A. baumannii infections. Full article

(This article belongs to the Special Issue Structure and Composition of Biofilms of Cutaneous and Environmental Microorganisms)

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20 pages, 3714 KiB

Open AccessArticle

CsrA Regulates Swarming Motility and Carbohydrate and Amino Acid Metabolism in Vibrio alginolyticus

by Bing Liu, Qian Gao, Xin Zhang, Huizhen Chen, Ying Zhang, Yuehong Sun, Shan Yang and Chang Chen

Microorganisms 2021, 9(11), 2383; https://doi.org/10.3390/microorganisms9112383 - 18 Nov 2021

Cited by 10 | Viewed by 2715

Abstract

Vibrio alginolyticus, like other vibrio species, is a widely distributed marine bacterium that is able to outcompete other species in variable niches where diverse organic matters are supplied. However, it remains unclear how these cells sense and adjust metabolic flux in response [...] Read more.

Vibrio alginolyticus, like other vibrio species, is a widely distributed marine bacterium that is able to outcompete other species in variable niches where diverse organic matters are supplied. However, it remains unclear how these cells sense and adjust metabolic flux in response to the changing environment. CsrA is a conserved RNA-binding protein that modulates critical cellular processes such as growth ability, central metabolism, virulence, and the stress response in gamma-proteobacteria. Here, we first characterize the csrA homolog in V. alginolyticus. The results show that CsrA activates swarming but not swimming motility, possibly by enhancing the expression of lateral flagellar associated genes. It is also revealed that CsrA modulates the carbon and nitrogen metabolism of V. alginolyticus, as evidenced by a change in the growth kinetics of various carbon and nitrogen sources when CsrA is altered. Quantitative RT-PCR shows that the transcripts of the genes encoding key enzymes involved in the TCA cycle and amino acid metabolism change significantly, which is probably due to the variation in mRNA stability given by CsrA binding. This may suggest that CsrA plays an important role in sensing and responding to environmental changes. Full article

(This article belongs to the Special Issue Bacterial Responses to Environmental Stress and Their Specific Contribution to Escherichia coli and Vibrio spp. Survival and Virulence 2.0)

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10 pages, 1068 KiB

Open AccessArticle

Challenging the Conventional Interpretation of HCMV Seronegativity

by Shelley Waters, Silvia Lee, Ashley Irish and Patricia Price

Microorganisms 2021, 9(11), 2382; https://doi.org/10.3390/microorganisms9112382 - 18 Nov 2021

Cited by 4 | Viewed by 2155

Abstract

The majority of adults in the world (around 83%) carry antibodies reactive with HCMV and are thought to retain inactive or latent infections lifelong. The virus is transmitted via saliva, so infection events are likely to be common. Indeed, it is hard to [...] Read more.

The majority of adults in the world (around 83%) carry antibodies reactive with HCMV and are thought to retain inactive or latent infections lifelong. The virus is transmitted via saliva, so infection events are likely to be common. Indeed, it is hard to imagine a life without exposure to HCMV. From 45 seronegative individuals (13 renal transplant recipients, 32 healthy adults), we present seven cases who had detectable HCMV DNA in their blood and/or saliva, or a CMV-encoded homologue of IL-10 (vIL-10) in their plasma. One case displayed NK cells characteristic of CMV infection before her HCMV DNA became undetectable. In other cases, the infection may persist with seroconversion blocked by vIL-10. Future research should seek mechanisms that can prevent an individual from seroconverting despite a persistent HCMV infection, as HCMV vaccines may not work well in such people. Full article

(This article belongs to the Section Virology)

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21 pages, 2727 KiB

Open AccessArticle

Bacterial Morphotypes as Important Trait for Uropathogenic E. coli Diagnostic; a Virulence-Phenotype-Phylogeny Study

by Manuel G. Ballesteros-Monrreal, Margarita M. P. Arenas-Hernández, Edwin Barrios-Villa, Josue Juarez, Maritza Lizeth Álvarez-Ainza, Pablo Taboada, Rafael De la Rosa-López, Enrique Bolado-Martínez and Dora Valencia

Microorganisms 2021, 9(11), 2381; https://doi.org/10.3390/microorganisms9112381 - 18 Nov 2021

Cited by 16 | Viewed by 5016

Abstract

Urinary tract infections (UTIs) belong to the most common pathologies in Mexico and are mainly caused by Uropathogenic Escherichia coli (UPEC). UPEC possesses a wide diversity of virulence factors that allow it to carry out its pathogenesis mechanism in the urinary tract (UT). [...] Read more.

Urinary tract infections (UTIs) belong to the most common pathologies in Mexico and are mainly caused by Uropathogenic Escherichia coli (UPEC). UPEC possesses a wide diversity of virulence factors that allow it to carry out its pathogenesis mechanism in the urinary tract (UT). The development of morphotypes in UT represents an important feature of UPEC because it is associated with complications in diagnosis of UTI. The aim of this study was to determine the presence of bacterial morphotypes, virulence genes, virulence phenotypes, antibiotic resistant, and phylogenetic groups in clinical isolates of UPEC obtained from women in Sonora, Mexico. Forty UPEC isolates were obtained, and urine morphotypes were observed in 65% of the urine samples from where E. coli was isolated. Phylogenetic group B2 was the most prevalent. The most frequent virulence genes were fimH (100%), fliCD (90%), and sfaD/focC (72%). Biofilm formation (100%) and motility (98%) were the most prevalent phenotypes. Clinical isolates showed high resistance to aminoglycosides and β-lactams antibiotics. These data suggest that the search for morphotypes in urine sediment must be incorporated in the urinalysis procedure and also that clinical isolates of UPEC in this study can cause upper, lower, and recurrent UTI. Full article

(This article belongs to the Special Issue Virulence Factors and Antibiotic Resistance of Enterobacterales)

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14 pages, 2184 KiB

Open AccessArticle

Role of the Sortase A in the Release of Cell-Wall Proteinase PrtS in the Growth Medium of Streptococcus thermophilus 4F44

by Ahoefa Ablavi Awussi, Emeline Roux, Catherine Humeau, Zeeshan Hafeez, Bernard Maigret, Oun Ki Chang, Xavier Lecomte, Gérard Humbert, Laurent Miclo, Magali Genay, Clarisse Perrin and Annie Dary-Mourot

Microorganisms 2021, 9(11), 2380; https://doi.org/10.3390/microorganisms9112380 - 18 Nov 2021

Cited by 1 | Viewed by 2491

Abstract

Growth of the lactic acid bacterium Streptococcus thermophilus in milk depends on its capacity to hydrolyze proteins of this medium through its surface proteolytic activity. Thus, strains exhibiting the cell envelope proteinase (CEP) PrtS are able to grow in milk at high cellular [...] Read more.

Growth of the lactic acid bacterium Streptococcus thermophilus in milk depends on its capacity to hydrolyze proteins of this medium through its surface proteolytic activity. Thus, strains exhibiting the cell envelope proteinase (CEP) PrtS are able to grow in milk at high cellular density. Due to its LPNTG motif, which is possibly the substrate of the sortase A (SrtA), PrtS is anchored to the cell wall in most S. thermophilus strains. Conversely, a soluble extracellular PrtS activity has been reported in the strain 4F44. It corresponds, in fact, to a certain proportion of PrtS that is not anchored to the cell wall but rather is released in the growth medium. The main difference between PrtS of strain 4F44 (PrtS_4F44) and other PrtS concerns the absence of a 32-residue imperfect duplication in the prodomain of the CEP, postulated as being required for the maturation and correct subsequent anchoring of PrtS. In fact, both mature (without the prodomain at the N-terminal extremity) and immature (with the prodomain) forms are found in the soluble PrtS_4F44 form along with an intact LPNTG at their C-terminal extremity. Investigations we present in this work show that (i) the imperfect duplication is not implied in PrtS maturation; (ii) the maturase PrtM is irrelevant in PrtS maturation which is probably automaturated; and (iii) SrtA allows for the PrtS anchoring in S. thermophilus but the SrtA of strain 4F44 (SrtA_4F44) displays an altered activity. Full article

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