Pathogenicity and Virulence of the Major Gram-Positive Bacteria—Staphylococci and Enterococci

A special issue of Microorganisms (ISSN 2076-2607). This special issue belongs to the section "Molecular Microbiology and Immunology".

Deadline for manuscript submissions: closed (31 August 2023) | Viewed by 3320

Special Issue Editors


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Guest Editor
Institute for Medical Laboratory Diagnostics, Center for Clinical and Translational Research (CCTR), Helios University Hospital Wuppertal, Witten/Herdecke University, 42283 Wuppertal, Germany
Interests: laboratory diagnostics; clinical microbiology

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Co-Guest Editor
Center of Pediatrics, Helios University Hospital Wuppertal, Wuppertal, Germany
Interests: immunology and infectious diseases in pediatrics; proteomics in asthmatic children
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Special Issue Information

Dear Colleagues,

The aim of this Special Issue is to elucidate the molecular features of genes, plasmids, and clones of major Gram-positive bacteria, staphylococci, and enterococci.

Among multidrug-resistant (MDR) Gram-positive bacteria, and MRSA (methicillin-resistant Staphylococccus aureus and vancomycin-resistant enterococci (VRE), especially E. faecium) are a most pressing concern.

Staphylococci and enterococci are a significant cause of healthcare-associated infections. Vancomycin, a last-resort glycopeptide, is among the administered antimicrobial agents to fight these bacteria, but the emergence of resistance against such agents leaves some patients with few therapeutic options.

Therefore, surveillance of MDR Gram-positive bacteria and their virulence determinants are important for conducting epidemiological analysis of such factors, designing risk management, and strategically controlling their spread in the community and healthcare facilities because these data are highly relevant to public health. The agr system in S. aureus is a prototype regulator of pathogenesis and controls the expression of virulence factors and antimicrobial resistance genes. However, multiple factors associated with the staphylococci and their environments affect the evolution of antibiotic resistance and virulence.

In recent years, there has been an observed increase in VRE infections in invasive diseases globally and in particular nations. Few analyses suggest that nosocomial VRE infections significantly increase hospital costs compared to infections with vancomycin-susceptible enterococci (VSE). However, comparison of patients with VRE and VSE bacteremias revealed no significant differences in mortality, especially after controlling for factors such as age and APACHE II score. There is no evidence that VRE are more virulent than VSE strains of the same enterococcal spp. Indeed, it is not always easy to assess the clinical significance of VRE in routine cultures or to differentiate colonization from infection. This is especially true for urine or when VRE is part of a polymicrobial infection.

As Guest Editor of this Special Issue, I am delighted to invite colleagues investigating any of the pathogenic staphylococci and enterococci within the areas of their ecology, genetics, genomics, immunology, diagnostic detection, public health, and antimicrobial development to submit their manuscripts to this Special Issue in the form of original research, short communication, and reviews. This includes original clinical and laboratory-based research, together with reports of clinical trials and reviews dealing with the epidemiology, clinical diagnosis, treatment, and control of MDR—Gram-positive bacteria, including MRSA and VRE.

Prof. Dr. Parviz Ahmad-Nejad
Dr. Malik Aydin
Guest Editors

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Keywords

  • staphylococci
  • enterococci
  • virulence factor genes
  • pathogenicity
  • molecular epidemiology
  • antimicrobial resistance
  • new rapid diagnostic tools
  • MRSA
  • VRE
  • bacteremia
  • nosocomial and community-associated infections
  • allergic diseases

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Published Papers (1 paper)

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Research

14 pages, 3461 KiB  
Article
Interaction between Porcine Alveolar Macrophage-Tang Cells and Streptococcus suis Strains of Different Virulence: Phagocytosis and Apoptosis
by Siqi Li, Chunsheng Wang, Yan-Dong Tang, Lei Qin, Tianfeng Chen, Shanghui Wang, Yuanzhe Bai, Xuehui Cai and Shujie Wang
Microorganisms 2023, 11(1), 160; https://doi.org/10.3390/microorganisms11010160 - 8 Jan 2023
Cited by 2 | Viewed by 2772
Abstract
Streptococcus suis is an important swine bacterial pathogen that activates macrophages to secrete inflammatory cytokines. Primary porcine alveolar macrophages (PAMs) are inconvenient to obtain, but it is unknown whether immortalized PAM-Tang cells can replace them as a better cell model for the study [...] Read more.
Streptococcus suis is an important swine bacterial pathogen that activates macrophages to secrete inflammatory cytokines. Primary porcine alveolar macrophages (PAMs) are inconvenient to obtain, but it is unknown whether immortalized PAM-Tang cells can replace them as a better cell model for the study of the interaction between S. suis and macrophages. In this study, the phagocytic integrity, polarization, and pro-inflammatory cytokine secretion of PAM-Tang cells were confirmed by live-cell imaging, electron microscopy, confocal microscopy, and ELISA. Interestingly, the S. suis serotype 9 avirulent strain W7119 induced higher levels of adhesion and pro-inflammatory cytokines in PAM-Tang cells than the S. suis serotype 2 virulent strain 700794. Prolonged incubation with S. suis caused more cytotoxic cell damage, and the virulent strain induced higher levels of cytotoxicity to PAM-Tang cells. The virulent strain also induced higher levels of apoptosis in PAM-Tang cells, as shown by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) assay. In addition, it is the first report of virulent and avirulent S. suis inducing PAM-Tang polarization towards pro-inflammatory M1 macrophages and p53- and caspase-dependent apoptosis in PAMs. Taken together, this study contributes to a better understand of interactions between macrophages and S. suis isolates of different virulence, and confirms that PAM-Tang cells provide a long-term, renewable resource for investigating macrophage infections with bacteria. Full article
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