Special Issue "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 1999

Special Issue Editors

Prof. Dr. Parviz Ahmad-Nejad
E-Mail Website
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
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

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Microorganisms is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.


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

Published Papers (1 paper)

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Interaction between Porcine Alveolar Macrophage-Tang Cells and Streptococcus suis Strains of Different Virulence: Phagocytosis and Apoptosis
Microorganisms 2023, 11(1), 160; https://doi.org/10.3390/microorganisms11010160 - 08 Jan 2023
Cited by 1 | Viewed by 1571
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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