Prevalence of Staphylococcus aureus among Clinical Isolates and their Responses to Selected Antibiotics at Centre Hospitalier Universitaire de Kigali (CHUK) (original) (raw)
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Periodic monitoring of Staphylococcus aureus characteristics in a locality is imperative as their drug-resistant variants cause treatment problem. In this study, antibiograms, prevalence of toxin genes (sea-see, seg-ser, seu, tsst-1, eta, etb, and etd), PFGE types, accessory gene regulator (agr) groups, and ability to form biofilm of 92 S. aureus Thailand clinical isolates were investigated. They were classified into 10 drug groups: groups 1-7 (56 isolates) were methicillin resistant (MRSA) and 8-10 (36 isolates) were methicillin sensitive (MSSA). One isolate did not have any toxin gene, 4 isolates carried one toxin gene (seq), and 87 isolates had two or more toxin genes. No isolate had see, etb, or tsst-1; six isolates had eta or etd. Combined seg-sei-sem-sen-seo of the highly prevalent egc locus was 26.1%. The seb, sec, sel, seu, and eta associated significantly with MSSA; sek was more in MRSA. The sek-seq association was 52.17% while combined sed-sej was not found. Twenty-three PFGE types were revealed, no association of toxin genes with PFGE types. All four agr groups were present; agr group 1 was predominant (58.70%) but agr group 2 strains carried more toxin genes and were more frequent toxin producers. Biofilm formation was found in 72.83% of the isolates but there was no association with antibiograms. This study provides insight information on molecular and phenotypic markers of Thailand S. aureus clinical isolates which should be useful for future active surveillance that aimed to control a spread of existing antimicrobial resistant bacteria and early recognition of a newly emerged variant. BioMed Research International cytokines and T-cell stimulating factors leading to toxic shock syndrome which may be fatal [8, 9]. The enterotoxicity and superantigenicity are distinct properties of the toxin molecule [6]. SEs are classified into two types based on their emetic activity in the toxin fed modeled primate. Toxins that induce vomiting in the primate are placed in the classical SE type while those that lack the emetic activity or have not been tested are allocated in the SE-like (SEls) type [10, 11]. Members of the classical SEs are SEA-SEE and the more recently recognized SEG, SEH, SEI, SER, SES, and SET. The SEls members include SElJ, SElK, SElL, SElM, SElN, SElO, SElP, SElQ, SElU, SElU2 or SEW, and SElV [11]. The staphylococcal enterotoxin F (SEF) which lacks emetic activity but is associated with toxic shock syndrome is presently called toxic shock syndrome toxin-1 (TSST-1) [12]. The SEs and the TSST-1 as well as the bacterial resistance to drugs are encoded by genes on the mobile genetic elements including prophages, plasmids, pathogenicity islands, genomic islands, and antibiotic resistance cassette [13]; thus they are transmitted horizontally rather easily. Expression of S. aureus virulence factors and metabolism of metabolic pathways during growth are coordinated/regulated by a quorumsensing operon named accessory gene regulator (agr) [14, 15]. Based on the amino acid sequence polymorphisms of the agr-encoding autoinducing peptides and their responding receptors, S. aureus strains can be divided into four major agr groups (groups 1-4) [16]. During the last five decades, S. aureus clones that resist methicillin (methicillin-resistant S. aureus, MRSA) disseminated and caused medical and public health problem worldwide [17, 18]. These strains are not only resistant to methicillin, but also resistant to all other-lactams, such as cephalosporin [18, 19]. In Thailand, MRSA infections were reported from 23 hospitals from 1988 to 1998 [20, 21]. The proportions of MRSA to MSSA in the northeast, central, and southern regions of the country during the studied period increased from 11 to 23.4%, 16 to 30.5%, and 21 to 30.3%, respectively [22]. Moreover, methicillin-resistant S. aureus with reduced susceptibility to vancomycin was recognized [23]. However, data on genotypic characteristics and other attributes of the S. aureus isolates in Thailand are relatively rare. Therefore, this study investigated the prevalence of virulence toxin genes coding for enterotoxins (sea-see, seg-ser, and seu), toxic shock syndrome toxin-1 (tsst-1), and exfoliative toxins (eta, etb, and etd) among S. aureus Thailand clinical isolates. Molecular diversity of the isolates regarding their endonuclease-restricted patterns of genomic DNA (PFGE), agr types, and antimicrobial susceptibility as well as their ability to produce biofilm were also investigated.
https://www.ijrrjournal.com/IJRR\_Vol.9\_Issue.8\_Aug2022/IJRR-Abstract01.html, 2022
Introduction: Staphylococcus aureus (S. aureus) is a Gram-positive cocci arranged in grape like clusters, non-motile, non-sporing, non-capsulated, that causes nosocomial infections, severe blood infections, bacteremia, food poisoning, cutaneous infections, toxic shock syndrome. Objectives: To isolate and identify S. aureus from blood samples. To perform antimicrobial susceptibility testing of S. aureus. To find prevalence of bacteremia caused due to S. aureus. Material & Methods: The study was carried out from October 2021 to March 2022, A total 1,270 samples were received in Bacteriology section from patients admitted in various ICUs & EMR of AIMSR hospital. S. aureus was identified on the basis of colony characteristics, gram staining morphology and biochemical tests. Antimicrobial susceptibility testing was done by automated method, Vitek 2 compact machine using P628AST card. Results: The prevalence of S. aureus in culture positive blood samples was 2.83%. Maximum S. aureus were obtained from CCU department and minimum from NICU & PICU. S. aureus isolation was slightly more in males 25(69.4%) than females 11 (30.6%) and was found to be same in the age group of 21-40 & 41-60 years (30.60%) as compared to other age groups. S. aureus isolates were highly sensitive to teicoplanin, vancomycin, tigecycline, doxycycline, minocycline (100%). Sensitivity towards linezolid was recorded as (96%), Tetracycline (86.1%) and Daptomycin (77.7%). However, they showed resistance to Benzylpenicillin, & Oxacillin (100%), Ciprofloxacin & Levofloxacin (83.3%), Erythromycin (69.5%), Cotrimoxazole (52.8%), Clindamycin (41.7%), Gentamicin (38.9%), Daptomycin (22.3%), Tetracycline(13.9%), Rifampicin (5.6%), Linezolid (3%). Conclusion: S. aureus bacteremia causes a health burden, particularly in low and middle income countries. S. aureus infections are a significant clinical problem in medical practice as the organism shows resistance to the commonly used first line drugs.
Staphylococcus aureus Bacteremia: Epidemiology, Pathophysiology, and Management Strategies
This supplement is based on the proceedings of a Novartis-sponsored session at the 9th International Symposium of Modern Concepts in Endocarditis and Cardiovascular Infections, June 2007; for sponsorship details, see p. S235. Staphylococcus aureus is a major cause of bacteremia, and S. aureus bacteremia is associated with higher morbidity and mortality, compared with bacteremia caused by other pathogens. The burden of S. aureus bacteremia, particularly methicillin-resistant S. aureus bacteremia, in terms of cost and resource use is high. The risk of infective endocarditis and of seeding to other metastatic foci increases the risk of mortality and raises the stakes for early, appropriate treatment. The incidence of S. aureus bacteremia and its complications has increased sharply in recent years because of the increased frequency of invasive procedures, increased numbers of immunocompromised patients, and increased resistance of S. aureus strains to available antibiotics. This changing epidemiology of S. aureus bacteremia, in combination with the inherent virulence of the pathogen, is driving an urgent need for improved strategies and better antibiotics to prevent and treat S. aureus bacteremia and its complications.
Staphylococcus aureus bacteraemia: a major cause of mortality in Australia and New Zealand
The Medical journal of Australia, 2009
To document the types of, and mortality from, Staphylococcus aureus bacteraemia in Australia and New Zealand, and determine factors associated with mortality. Prospective observational study in 27 independent or hospital pathology laboratories in Australia (24) and New Zealand (3), employing a web-based database to prospectively record demographic features, selected risk factors, principal antibiotic treatment and mortality data on all patients with positive blood cultures for S. aureus from June 2007 to May 2008. 30-day all-cause mortality. 1994 episodes of S. aureus bacteraemia were identified, and complete 30-day follow-up data were available for 1865. Most episodes had their onset in the community (60.8%; 95% CI, 58.7%-63.0%). Methicillin-resistant S. aureus (MRSA) caused 450 episodes (24.1%; 95% CI, 22.2%-25.9%), and 123 of these (27.3%) had a susceptibility profile consistent with community-associated MRSA. All-cause mortality at 30 days was 20.6% (95% CI, 18.8%-22.5%). On uni...
Staphylococcus aureus belongs to the genus Staphylococcus and the family Staphylococcaceae. It is a non-motile, fermentative, and non-spore-forming bacterium that is facultative anaerobic. They develop quite large yellow or white colonies on nutrient rich agar media and are typically found in clusters that resemble a bunch of grapes when observed under a light microscope after Gram staining. Staphylococcus aureus is a desiccation and high osmotic condition tolerant bacteria that may thrive in potentially dry and stressful conditions. Human nares are the principal niche and greatest reservoir of Staphylococcus aureus; cows may be the second largest. The virulence factors produced by Staphylococcus aureus are essential for successful human and animal infection. It is one of the most significant bacteria in veterinary medicine, and it is widely known as a major cause of intramammary infections. Staphylococcus aureus is a common human pathogen that can cause a wide range of clinical infections, from minor skin infections to life-threatening infections. Staphylococcus aureus is a highly adaptable bacterium that develops resistance to the majority of antibiotics on the market. Drug resistance in Staphylococcus aureus has gradually risen over the last few decades as the pathogen have evolved and antibiotics have been abused. The treatment is ineffective; instead, control and prevention of Staphylococcus aureus should be prioritized. Eliminating conditions that expose the teat ends to bacteria and reducing the probability of cow-to-cow transmission are the most effective ways to prevent new infection and control Staphylococcus aureus in dairy animals. Contact precautions and adequate infection control techniques are used to prevent the spread of Staphylococcus aureus infection in humans.