scholarly journals Staphylococcus aureus—A Known Opponent against Host Defense Mechanisms and Vaccine Development—Do We Still Have a Chance to Win?

2022 ◽  
Vol 23 (2) ◽  
pp. 948
Author(s):  
Urszula Wójcik-Bojek ◽  
Barbara Różalska ◽  
Beata Sadowska

The main purpose of this review is to present justification for the urgent need to implement specific prophylaxis of invasive Staphylococcus aureus infections. We emphasize the difficulties in achieving this goal due to numerous S. aureus virulence factors important for the process of infection and the remarkable ability of these bacteria to avoid host defense mechanisms. We precede these considerations with a brief overview of the global necessitiy to intensify the use of vaccines against other pathogens as well, particularly in light of an impasse in antibiotic therapy. Finally, we point out global trends in research into modern technologies used in the field of molecular microbiology to develop new vaccines. We focus on the vaccines designed to fight the infections caused by S. aureus, which are often resistant to the majority of available therapeutic options.

1963 ◽  
Vol 118 (1) ◽  
pp. 13-26 ◽  
Author(s):  
P. F. Bartell ◽  
I. S. Thind ◽  
T. Orr ◽  
W. S. Blakemore

Staphylococcus bacteriophage 81 is capable of in vivo interaction with Staphylococcus aureus, Type 80/81. This is immediately made evident by increased levels of bacteriophage and concomitant survival of 81 per cent infected mice. The reaction is dependent upon the use of active, type-specific bacteriophage. The maximal protective effect is observed at a bacteriophage to bacteria ratio of 1:2 and decreased quantities of bacteriophage result in decreased protection. Time and sequence of administration are also determining factors. It is evident that bacteriophage administered intravenously is capable of interaction with the infecting bacterial cell at the site of infection. In vivo produced bacteriophage is apparently eliminated or otherwise rendered nondetectable fairly rapidly, occurring within a period of 5 to 10 days. However, it appears that host defense mechanisms are stimulated in the process and actively play a protective role against subsequent challenge inocula administered up to 3 weeks later.


mSphere ◽  
2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Mariane Pivard ◽  
Karen Moreau ◽  
François Vandenesch

ABSTRACT Staphylococcus aureus is both a commensal and a pathogenic bacterium for humans. Its ability to induce severe infections is based on a wide range of virulence factors. S. aureus community-acquired pneumonia (SA-CAP) is rare and severe, and the contribution of certain virulence factors in this disease has been recognized over the past 2 decades. First, the factors involved in metabolism adaptation are crucial for S. aureus survival in the lower respiratory tract, and toxins and enzymes are required for it to cross the pulmonary epithelial barrier. S. aureus subsequently faces host defense mechanisms, including the epithelial barrier, but most importantly the immune system. Here, again, S. aureus uses myriad virulence factors to successfully escape from the host’s defenses and takes advantage of them. The impact of S. aureus virulence, combined with the collateral damage caused by an overwhelming immune response, leads to severe tissue damage and adverse clinical outcomes. In this review, we summarize step by step all of the S. aureus factors implicated in CAP and described to date, and we provide an outlook for future research.


2021 ◽  
Vol 12 ◽  
Author(s):  
Bahman Mirzaei ◽  
Ryhaneh Babaei ◽  
Habib Zeighami ◽  
Maryam Dadar ◽  
Ali Soltani

Since the 1960s, the frequency of methicillin-resistant Staphylococcus aureus as a recurrent cause of nosocomial infections has increased. Since multidrug-resistant Staphylococcus has overcome antimicrobial treatment, the development of putative vaccines based on virulence factors could be a great help in controlling the infections caused by bacteria and are actively being pursued in healthcare settings. This mini-review provides an overview of the recent progress in vaccine development, immunogenicity, and therapeutic features of some S. aureus macromolecules as putative vaccine candidates and their implications against human S. aureus-related infections. Based on the reviewed experiments, multivalent vaccines could prevent the promotion of the diseases caused by this bacterium and enhance the prevention chance of S. aureus infections.


1999 ◽  
Vol 67 (8) ◽  
pp. 4106-4111 ◽  
Author(s):  
Olga Shamova ◽  
Kim A. Brogden ◽  
Chengquan Zhao ◽  
Tung Nguyen ◽  
Vladimir N. Kokryakov ◽  
...  

ABSTRACT We purified three proline-rich antimicrobial peptides from elastase-treated extracts of sheep and goat leukocytes and subjected two of them, OaBac5α and ChBac5, to detailed analysis. OaBac5α and ChBac5 were homologous to each other and to bovine Bac5. Both exhibited potent, broad-spectrum antimicrobial activity under low-concentration salt conditions. While the peptides remained active againstEscherichia coli, Pseudomonas aeruginosa,Bacillus subtilis, and Listeria monocytogenesin 100 mM NaCl, they lost activity against Staphylococcus aureus and Candida albicans under these conditions. ChBac5 was shown to bind lipopolysaccharide, a property that could enhance its ability to kill gram-negative bacteria. Proline-rich Bac5 peptides are highly conserved in ruminants and may contribute significantly to their innate host defense mechanisms.


2021 ◽  
Vol 11 (12) ◽  
pp. 217-219
Author(s):  
Ruvin Haidar

For a pathogenic microbe to cause disease in a susceptible host, it must gain access to that host first. The pathogenicity of a microbe is determined by the virulence factors alongside other innate mechanisms. Apart from the initiation of infection, these virulence factors also enable the pathogenic microorganism to survive in the new environment within the susceptible host. They also enable the pathogenic microorganism to invade the host, colonize, and evade the host defense mechanisms. These virulence factors include; invasins, capsules, siderophores, adhesins, enzymes, endotoxins, and exotoxins. Key words: Pathogenicity factors and Pathological effect on cells.


1998 ◽  
Vol 66 (10) ◽  
pp. 4947-4949 ◽  
Author(s):  
Christine Lawrence ◽  
Charles Nauciel

ABSTRACT Peptidoglycan (PG), a component of the bacterial cell wall, has various immunomodulating activities, including the capacity to induce delayed-type hypersensitivity reactions to antigens administered in Freund’s adjuvant. We report that PG induces interleukin-12 (IL-12) mRNA production and IL-12 secretion by mouse macrophages. The capacity of PG to induce IL-12 production, like its previously reported immunomodulating activities, was dependent on the structure of its peptide subunit. PG from Bacillus megaterium andStaphylococcus aureus induced IL-12 production, whereas PG from Micrococcus luteus and Corynebacterium poinsettiae did not. The ability of most bacterial PGs to induce IL-12 production suggests that they play an important role in triggering host defense mechanisms against bacterial infections.


2001 ◽  
Author(s):  
Lorraine Sordillo ◽  
Don Wojchowski ◽  
Gary Perdew ◽  
Arthur Saran ◽  
Gabriel Leitner

Staphylococcus aureus is a major cause of mastitis in dairy cattle. The organism is able to adhere to and penetrate mammary epithelium, forming deep seated abscesses that result in chronic infections. This study was based on the observation that certain genotypes of S. aureus are isolated more frequently from field cases of bovine mastitis than others and the most prevalent genotypes of S. aureus have an increased ability to resist neutrophil phagocytosis and killing compared to the rare variants. It was hypothesized that these predominating genotypes differentially express virulence factors that allow them to overcome or suppress essential host defense mechanisms and successfully colonize mammary parenchyma. The overall objective of this study was to determine the mechanisms by which predominating S. aureus genotypes were able to resist mammary gland defense mechanisms. The following specific aims were accomplished to address the overall objectives of this project: 1. Analyze and compare cell surface and secreted protein profiles of common and rare S. aureus genotypes isolated from field cases of bovine mastitis. 2. Purify and sequence selectively synthesized proteins unique to the most prevalent genotypes of S. aureus . 3. Determine the in vitro effects of isolated proteins on essential host defense mechanisms. Results from each specific aim showed that these redominating genotypes differentially express factors that may allow them to overcome or suppress essential host defense mechanisms and successfully colonize mammary parenchyma. Using complementary approaches, both the US and Israeli teams identified differentially expressed S. aureus factors that were positively correlated with virulence as determined by the ability to modify host immune cell responses and increase disease pathogenesis. Several candidate virulence factors have ben identified at both the molecular (US team) and protein (Israeli team) levels. Components of the phosphotransferase system were shown to be differentially expressed in prevalent strains of S. aureus and to modify the growth potential of these strains in a milk microenvironment. Evidence provided by both the Israeli and US teams also demonstrated a potential role of Staphylococcal enterotoxins in the pathogenesis of mastitis. Certain enterotoxins were shown to directly affect neutrophil bactericidal activities which can profoundly affect the establishment of new intramammary infections. Other evidence suggests that S. aureus superantigens can suppress mammary defenses by enhancing lymphoid suppressor cell activity. Collectively, these data suggest that unique factors are associated with predominating S. aureus genotypes that can affect in vitro and in vivo virulence as related to the pathogenesis of bovine mastitis. The potential development of a subunit mastitis vaccine which incorporates only relevant antigenic determinants has not been investigated in depth. Experiments outlined in this proposal has identified putative virulence factors which contribute to the pathogenesis of S. aureus mastitis and which may be used to formulate an efficacious subunit mastitis vaccine. Results from these studies may lead to the development of new methods to prevent this costly disease, providing a viable alternative to less effective mastitis control procedures based on chemotherapy.


2017 ◽  
Vol 6 (05) ◽  
pp. 5373
Author(s):  
Prabha Ponnusamy* ◽  
Radhika Katragadda ◽  
Thyagarajan Ravinder

Asymptomatic bacteriuria (ASB), most common during pregnancy is endangering as it may lead to maternal and fetal complications. Various organisms causing ASB combats the host defense mechanisms through virulence factors exhibited by them. In order to understand the pathogenesis and sequelae of infections, virulence factors like hemolysin production, gelatinase production, haemagglutination, biofilm production and many more should be identified. Hence, we aimed at studying the distribution of virulence factors among each organism causing asymptomatic bacteriuria in pregnant females attending a tertiary care hospital. Materials and Methods: This cross-sectional study was conducted in Department of Microbiology over a period of one year and six months (January 2014 to June 2015) at a tertiary care teaching hospital. A total of 1000 urine samples were included in study taken from pregnant women with asymptomatic bacteriuria. Isolation, identification of organisms was done according to standard microbiological techniques and virulence factors for individual organisms by phenotypic method were tested. Results: Out of 1000 samples screened for ASB, organisms were isolated in following frequency distribution: Escherichia coli, the commonest 54/118 (45.76%), Klebsiella pneumoniae 21/118 (17.80%), Staphylococcus aureus 19/118 (16.10%), Staphylococcus saprophyticus 10/118 (8.45%), Enterococcus faecalis 9/118 (7.63%), Pseudomonas aeruginosa 3/118 (2.54%) and Proteus mirabilis 2/118 (1.69%). Virulence factors for individual organisms and biofilm detection for all organisms were done. Conclusion: Multifactorial mechanisms determine the pathogenicity of an organism and it needs to be explored by analyzing each virulence factor and mechanism of invasion in combating the host defense systems. Hence analyzing the phenotypic expression of each virulence factor helps in better understanding about the complications of ASB.


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