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Microorganisms
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Staphylococcal Infections (Host and Pathogenic Factors) 3.0
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Staphylococcal Infections (Host and Pathogenic Factors) 3.0

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

Deadline for manuscript submissions: 31 July 2024 | Viewed by 4537

Special Issue Editor

Dr. Rajan P. Adhikari

E-Mail Website1 Website2
Guest Editor
Integrated Biotherapeutics, Inc., Rockville, MD, USA
Interests: bacterial toxins; host-pathogen interactions; bacterial pathogens; Staphylococcus aureus
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue is the continuation of our previous special issue "Staphylococcal Infections (Host and Pathogenic Factors) 1.0"  and "Staphylococcal Infections (Host and Pathogenic Factors) 2.0".

Although 30% of the healthy human population is colonized with various Staphylococcus spp., some staphylococcal strains, referred to as opportunistic pathogens, can cause minor to life-threatening diseases. The pathogenicity of these bacteria depends on their virulence factors and the robustness of the regulatory networks expressing these virulence factors. Virulence factors of pathogenic Staphylococcus spp. consist of numerous toxins, enterotoxins (some of which act as superantigens), enzymes, and proteins (cytoplasmic, extracellular, and surface) that are regulated by two-component (TC) and quorum-sensing (QS) regulatory networks. For example, based on their homology with quorum-sensing molecules/components, one Staphylococcus aureus species can alter the toxin/surface protein production of another S. aureus species either synergistically or antagonistically. To invade this niche, some other Staphylococcus species, such as Staphylococcus simulans, produce a potent endopeptidase called lysostaphin, which can lyse and eradicate the pathogenic S. aureus. Some other Staphylococcus species produce autolysins and cationic peptides to win the intra- and inter-species competition. The outcome of this microbial invasion depends not only on pathogenic factors but also on the host’s internal and external defense mechanisms, including a healthy skin microbiome. A healthy skin microbiome population consisting of Staphylococcus epidermidis can prevent colonization by other major pathogens. As normal host microflora, these commensals establish a complex relationship with the host as well as the surrounding microbial communities. This Special Issue of Microorganisms is focused on studies and recent advancements in our understanding of staphylococcal virulence mechanisms that enable Staphylococcus spp. either to successfully establish themselves as a colonizer or to overcome the host’s defense system to cause infection.

Dr. Rajan P. Adhikari
Guest Editor

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.

Keywords

  • S. aureus
  • S. epidermidis
  • Staphylococcus spp.
  • pore-forming toxins (hemolysins and leukotoxins)
  • quorum sensing (QS) and two component (TC) systems
  • colonization
  • biofilm formation
  • surface proteins
  • enterotoxins (superantigens)

Published Papers (3 papers)

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Research

30 pages, 9895 KiB  
Article
Validating Interactions of Pathogenic Proteins of Staphylococcus aureus and E. coli with Phytochemicals of Ziziphus jujube and Acacia nilotica
by Wen Zou, Iram Hassan, Bushra Akram, Huma Sattar, Awais Altaf, Amjad Islam Aqib, Hassaan Bin Aslam, Mikhlid H. Almutairi and Kun Li
Microorganisms 2023, 11(10), 2450; https://doi.org/10.3390/microorganisms11102450 - 29 Sep 2023
Viewed by 827
Abstract
This study focused on the assessment of the antimicrobial resistance of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) isolated from bovine mastitis milk samples and the revealing anti-mastitis potential of phytocompounds of Ziziphus jujube and Acacia nilotica [...] Read more.
This study focused on the assessment of the antimicrobial resistance of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) isolated from bovine mastitis milk samples and the revealing anti-mastitis potential of phytocompounds of Ziziphus jujube and Acacia nilotica through molecular docking analysis. The mastitis milk samples were collected from various dairy farms for the isolation of the bacteria (S. aureus and E. coli) and their response to antibiotics. Ethanolic extracts of both plants were prepared. Their antibacterial activity was evaluated, and they were processed for phytochemical analysis after which, molecular docking analysis with pathogenic proteins of the bacteria was carried out. Parametric and non-parametric statistical analyses were performed to reach the conclusions of this study. The findings of the study revealed a higher drug resistance (≥40%) of E. coli against ampicillin, amikacin, and vancomycin, while S. aureus exhibited the highest resistance to ampicillin, erythromycin, and ciprofloxacin. The ethanolic extracts of the Ziziphus jujube and Acacia nilotica plants produced a ZOI between 18 and 23 mm against multidrug-resistant S. aureus and E. coli. Gas chromatography–mass spectrophotometry (GC–MS) was used to explore 15 phytocompounds from Ziziphus jujube and 18 phytocompounds from Acacia nilotica. The molecular docking analysis of 2cyclopenten−1-one,3,4,4 trimethyl and Bis (2ethylhexyl) phthalate of Ziziphus jujube showed a binding affinity of −4.8 kcal/mol and −5.3 kcal/mol and −5.9 kcal/mol and −7.1 kcal/mol against the DNA Gyrase and toxic shock syndrome toxin-1 proteins of S. aureus and E. coli, respectively. The suberic acid monomethyl ester of Acacia nilotica showed a binding affinity of −5.9 kcal/mol and −5 kcal/mol against the outer membrane protein A and Topoisomerase IV protein of E. coli and −5.1 kcal/mol and −5.8 kcal/mol against the toxic shock syndrome toxin-1 and Enterotoxin B proteins of S. aureus. Similarly, 2,2,4-trimethyl-1,3-pentanediol di-iso-butyrate showed a binding affinity of −6.5 kcal/mol and −5.3 kcal/mol against the outer membrane protein A and Topoisomerase IV of E. coli and −5.2 kcal/mol and −5.9 kcal/mol against the toxic shock syndrome toxin-1 and Enterotoxin B proteins of S. aureus, respectively. The study concluded that there was an increasing trend for the antimicrobial resistance of S. aureus and E. coli, while the Ziziphus jujube and Acacia nilotica plant extracts expressed significant affinity to tackle this resistance; hence, this calls for the development of novel evidence-based therapeutics. Full article
(This article belongs to the Special Issue Staphylococcal Infections (Host and Pathogenic Factors) 3.0)
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17 pages, 6995 KiB  
Article
Celecoxib-Loaded Cubosomal Nanoparticles as a Therapeutic Approach for Staphylococcus aureus In Vivo Infection
by Samar Zuhair Alshawwa, Thanaa A. El-Masry, Mohamed Nasr, Ahmed Y. Kira, Hadil Faris Alotaibi, Al-Sayed Sallam and Engy Elekhnawy
Microorganisms 2023, 11(9), 2247; https://doi.org/10.3390/microorganisms11092247 - 06 Sep 2023
Cited by 1 | Viewed by 1442
Abstract
There is a great need for novel approaches to treating bacterial infections, due to the vast dissemination of resistance among pathogenic bacteria. Staphylococcus aureus are ubiquitous Gram-positive pathogenic bacteria and are rapidly acquiring antibiotic resistance. Here, celecoxib was encapsulated into cubosomal nanoparticles, and [...] Read more.
There is a great need for novel approaches to treating bacterial infections, due to the vast dissemination of resistance among pathogenic bacteria. Staphylococcus aureus are ubiquitous Gram-positive pathogenic bacteria and are rapidly acquiring antibiotic resistance. Here, celecoxib was encapsulated into cubosomal nanoparticles, and the particle morphology, size distribution, zeta potential, entrapment efficiency, and celecoxib release were evaluated in vitro. Also, a systemic infection model in mice elucidated the in vivo antibacterial action of the celecoxib cubosomes. Cubosomes are a nanotechnology-based delivery system which can adhere to the external peptidoglycan layers of Gram-positive bacteria and penetrate them. The size distribution investigation revealed that the prepared celecoxib-loaded cubosomes had a mean particle size of 128.15 ± 3.04 nm with a low polydispersity index of 0.235 ± 0.023. The zeta potential measurement showed that the prepared cubosomes had a negative surface charge of −17.50 ± 0.45, indicating a highly stable nanodispersion formation with little susceptibility to particle aggregation. The cubosomal dispersion exhibited an entrapment efficiency of 88.57 ± 2.36%. The transmission electron micrograph for the prepared celecoxib-loaded cubosomes showed a narrow size distribution for the cubosomal nanoparticles, which had a spherical shape and were non-aggregated. The tested cubosomes diminished the inflammation in the treated mice’s liver and spleen tissues, as revealed by hematoxylin and eosin stain and Masson’s trichrome stain. The immunostained tissues with nuclear factor kappa B and caspase-3 monoclonal antibodies revealed a marked decrease in these markers in the celecoxib-treated group, as it resulted in negative or weak immunostaining in liver and spleen that ranged from 4.54% to 17.43%. This indicates their inhibitory effect on the inflammatory pathway and apoptosis, respectively. Furthermore, they reduced the bacterial burden in the studied tissues. This is alongside a decrease in the inflammatory markers (interleukin-1 beta, interleukin-6, cyclooxygenase-2, and tumor necrosis factor-alpha) determined by ELISA and qRT-PCR. The IL-1β levels were 16.66 ± 0.5 pg/mg and 17 ± 0.9 pg/mg in liver and spleen, respectively. Also, IL-6 levels were 85 ± 3.2 pg/mg and 84 ± 2.4 pg/mg in liver and spleen, respectively. In conclusion, the current study introduced cubosomes as an approach for the formulation of celecoxib to enhance its in vivo antibacterial action by improving its oral bioavailability. Full article
(This article belongs to the Special Issue Staphylococcal Infections (Host and Pathogenic Factors) 3.0)
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17 pages, 3283 KiB  
Article
Alpha-Gal Bound Aptamer and Vancomycin Synergistically Reduce Staphylococcus aureus Infection In Vivo
by Matthew K. Doherty, Claire Shaw, Leslie Woods and Bart C. Weimer
Microorganisms 2023, 11(7), 1776; https://doi.org/10.3390/microorganisms11071776 - 08 Jul 2023
Cited by 1 | Viewed by 1329
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a pervasive and persistent threat that requires the development of novel therapies or adjuvants for existing ones. Aptamers, small single-stranded oligonucleotides that form 3D structures and can bind to target molecules, provide one possible therapeutic route, especially when [...] Read more.
Methicillin-resistant Staphylococcus aureus (MRSA) is a pervasive and persistent threat that requires the development of novel therapies or adjuvants for existing ones. Aptamers, small single-stranded oligonucleotides that form 3D structures and can bind to target molecules, provide one possible therapeutic route, especially when presented in combination with current antibiotic applications. BALB/c α-1, 3-galactosyltransferase (−/−) knockout (GTKO) mice were infected with MRSA via tail vein IV and subsequently treated with the αSA31 aptamer (n = 4), vancomycin (n = 12), or αSA31 plus vancomycin (n = 12), with split doses in the morning and evening. The heart, lungs, liver, spleen, and kidneys were harvested upon necropsy for histological and qPCR analysis. All mice treated with αSA31 alone died, whereas 5/12 mice treated with vancomycin alone and 7/12 mice treated with vancomycin plus αSA31 survived the course of the experiment. The treatment of MRSA-infected mice with Vancomycin and an adjuvant aptamer αSA31 reduced disease persistence and dispersion as compared to treatment with either vancomycin SA31 alone, indicating the combination of antibiotic and specifically targeted αSA31 aptamer could be a novel way to control MRSA infection. The data further indicate that aptamers may serve as a potential therapeutic option for other emerging antibiotic resistant pathogens. Full article
(This article belongs to the Special Issue Staphylococcal Infections (Host and Pathogenic Factors) 3.0)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

1. Topic: MRSA
Authors: Arnold S. Bayer, et al.
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