Relationship between MLSB resistance and the prevalent virulence genotypes among Bulgarian Staphylococcus aureus isolates

2020 ◽  
Author(s):  
Virna-Maria Tsitou ◽  
Ivan Mitov ◽  
Raina Gergova
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Genes ◽  
Methicillin Resistance ◽  
Macrolide Resistance ◽  
Clinical Isolates ◽  
Penicillin Resistance ◽  
Clinical Strains ◽  
Multiple Genes ◽  
Number Of Genes

AbstractThe aim of this study was to investigate the rate of resistance to macrolide-lincosamide-streptogramin B (MLSB) antibiotics, the mechanisms underlying this resistance and to evaluate their relationship with virulence genes profiles of 435 Bulgarian clinical isolates Staphylococcus aureus. The highest resistance was observed to penicillin (96.09%), followed by resistance to erythromycin and clindamycin (34.02 and 22.76%, respectively). Of the tested clinical strains of S. aureus, 96.09% contained the blaZ gene associated with penicillin resistance and 11.03%, the mecA gene responsible for methicillin resistance. The most prevalent were the erm genotypes associated with the presence mainly of ermA and ermC genes followed by ermB. The frequency rates of these genes, alone or in combinations were ermA 41.89%, ermB 27.70%, ermC 43.99%. The majority of Bulgarian macrolide resistant S. aureus exhibited cMLS phenotype, in 58.78% (P = 0.0036). The following virulence genotypes were present significantly more often in the macrolide resistant S. aureus isolates among the studied ones: hlg; hlg,seb; hlg,seb,sec; hlg,seb,seh; hlg,sec; hlg,sec,sei; hlg,sec,sei; hlg,sei; hlg,sei,sej; hlg,sej. This survey found correlation between the virulence profiles with a small number of genes and macrolide resistance among Bulgarian clinical S. aureus isolates, in contrast to sensitive strains, which possessed profiles predominantly with multiple genes.

scholarly journals Susceptibility of Clinical Isolates of Staphylococcus aureus to Ceftaroline

2021 ◽  
Author(s):  
Harsha Sreedharan ◽  
KB Asha Pai
Keyword(s):  
Staphylococcus Aureus ◽  
Tertiary Care Hospital ◽  
Methicillin Resistance ◽  
Descriptive Analysis ◽  
Tertiary Care ◽  
The United States ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Care Hospital

Introduction: Methicillin-Resistant Staphylococcus aureus(MRSA) infection is a major global healthcare problem, the prevalence of which varies from 25-50% in India. It is known to cause Skin and Soft tissue Infections (SSI), endovascular infections, endocarditis, pneumonia, septic arthritis, osteomyelitis, and sepsis. Vancomycin is the drug of choice for treating severe MRSA infections. Ceftaroline, a fifth-generation cephalosporin has been approved by the United States Food and Drug Administration (US FDA) for treating acute bacterial SSI caused by susceptible micro-organisms including MRSA, Community acquired respiratory tract infection, MRSA bacteremia and endocarditis. Aim: To assess the susceptibility of clinical isolates of S. aureusto ceftaroline, in a Tertiary Care Hospital. Materials and Methods: This prospective study was conducted in the Department of Microbiology of a Tertiary Care Hospital over a period of two months from June 2019 to July 2019. S.aureus isolates from various clinical samples were screened for methicillin resistance by disc diffusion method using cefoxitin disc and ceftaroline susceptibility of these isolates was assessed by E-strip method. The isolates were classified as ceftaroline susceptible, Susceptibility Dose Dependent (SDD) and ceftaroline resistant respectively as per CLSI guidelines. A descriptive analysis of the data was done and the results were presented as frequencies and percentages. Results: All the S.aureus isolates were found to be susceptible to ceftaroline. Methicillin Sensitive Staphylococcus aureus(MSSA) isolates had lower Minimum Inhibitory Concentration (MIC) when compared to MRSA. The highest MIC among MRSA was 0.5 μg/mL. Conclusion: Ceftaroline can be considered as an effective alternative for treatment of infections caused by MRSA.

scholarly journals Prevalence of Methicillin Resistant and Virulence Determinants in Clinical Isolates of Staphylococcus aureus

2018 ◽  
Vol 10 (1) ◽  
pp. 108-115
Author(s):  
Manjunath Chavadi ◽  
Rahul Narasanna ◽  
Ashajyothi Chavan ◽  
Ajay Kumar Oli ◽  
Chandrakanth Kelmani. R
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Morphology ◽  
Methicillin Resistance ◽  
Protein A ◽  
Clinical Isolates ◽  
Clinical Samples ◽  
Virulence Determinants ◽  
Methicillin Resistant ◽  
Alternative Medicines ◽  
Mrsa Strains

Introduction:Methicillin-resistantStaphylococcus aureus(MRSA) is the major threat that is a result of the uncontrolled use of antibiotics causing a huge loss in health, so understanding their prevalence is necessary as a public health measure.Objective:The aim of this study was to determine the prevalence of methicillin-resistant MRSA and virulence determinant among associatedS. aureusfrom the clinical samples obtained from various hospital and health care centers of the Gulbarga region in India.Materials and Methods:All the collected samples were subjected for the screening ofS. aureusand were further characterized by conventional and molecular methods including their antibiotic profiling. Further, the response of methicillin antibiotic on cell morphology was studied using scanning electron microscopy.Results:A total 126S. aureuswas isolated from the clinical samples which showed, 100% resistant to penicillin, 55.5% to oxacillin, 75.3% to ampicillin, 70.6% to streptomycin, 66.6% to gentamicin, 8.7% to vancomycin and 6.3% to teicoplanin. The selected MRSA strains were found to possessmecA(gene coding for penicillin-binding protein 2A) andfemA(factor essential for methicillin resistance)genetic determinants in their genome with virulence determinants such as Coagulase (coa) and the X region of the protein A (spa)gene. Further, the methicillin response in resistantS. aureusshowed to be enlarged and malformed on cell morphology.Conclusion:The molecular typing of clinical isolates ofS. aureusin this study was highly virulent and also resistant to methicillin; this will assist health professionals to control, exploration of alternative medicines and new approaches to combat Staphylococcal infections more efficiently by using targeted therapy.

Staphylococcus aureus strains differ in their in vitro responsiveness to human urokinase: evidence that methicillin-resistant strains are predominately nonresponsive to the growth-enhancing effects of urokinase

1996 ◽  
Vol 42 (10) ◽  
pp. 1024-1031 ◽  
Author(s):  
David A. Hart ◽  
Carol Reno ◽  
Thomas Louie ◽  
Wallace Krulicki
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Clinical Isolates ◽  
Growth Enhancement ◽  
Western Canada ◽  
Methicillin Resistant ◽  
Resistant Strains ◽  
The Uk ◽  
Regulation Of Growth

Clinical isolates of Staphylococcus aureus were found to exhibit strain-specific heterogeneity to the growth-enhancing effects of human urokinase (UK), a proteinase with plasminogen activator activity. Nine out of fourteen (64%) methicillin-sensitive strains of S. aureus were responsive to UK in "in vitro" cultures. In contrast, 3/29 (10%) methicillin-resistant strains were responsive to the proteinase. When only strains isolated from western Canada were considered, 6/11 methicillin-sensitive strains and 1/26 methicillin-resistant strains were responsive to UK. The single western Canadian methicillin-resistant strain (strain 456) responsive to UK was one of two isolated from the same patient, indicating that the two strains were phenotypically different. Strain 456, resistant to 32 μg mefhicillin/mL, was responsive to as little as 50 U UK/mL and enhancement of growth was evident by 9 h of incubation at 37 °C. This growth enhancement was specific to UK and not duplicated by equivalent concentrations of other proteins (bovine serum albumin, trypsin, plasminogen). The results presented indicate differences in the frequency of the UK-responsive phenotype between methicillin-sensitive and -resistant S. aureus. These findings indicate that the UK phenotype of S. aureus may have utility in both phenotyping clinical isolates, as well as providing insights into the regulation of growth in this clinically important organism.Key words: Staphylococcus aureus, growth, urokinase, methicillin resistance.

scholarly journals Genetic Basis of Resistance to Fusidic Acid in Staphylococci

2007 ◽  
Vol 51 (5) ◽  
pp. 1737-1740 ◽  
Author(s):  
A. J. O'Neill ◽  
F. McLaws ◽  
G. Kahlmeter ◽  
A. S. Henriksen ◽  
I. Chopra
Keyword(s):  
Staphylococcus Aureus ◽  
Fusidic Acid ◽  
Drug Target ◽  
Genetic Basis ◽  
Elongation Factor ◽  
The Other ◽  
Clinical Isolates ◽  
Staphylococcal Species ◽  
Clinical Strains ◽  
Resistant Strains

ABSTRACT Resistance to fusidic acid in Staphylococcus aureus often results from acquisition of the fusB determinant or from mutations in the gene (fusA) that encodes the drug target (elongation factor G). We now report further studies on the genetic basis of resistance to this antibiotic in the staphylococci. Two staphylococcal genes that encode proteins exhibiting ca. 45% identity with FusB conferred resistance to fusidic acid in S. aureus. One of these genes (designated fusC) was subsequently detected in all fusidic acid-resistant clinical strains of S. aureus tested that did not carry fusB or mutations in fusA, and in strains of S. intermedius. The other gene (designated fusD) is carried by S. saprophyticus, explaining the inherent resistance of this species to fusidic acid. Fusidic acid-resistant strains of S. lugdunensis harbored fusB. Thus, resistance to fusidic acid in clinical isolates of S. aureus and other staphylococcal species frequently results from expression of FusB-type proteins.

scholarly journals Epidemiology and microbiological characterization of clinical isolates of Staphylococcus aureus in a single healthcare region of the UK, 2015

2016 ◽  
Vol 145 (2) ◽  
pp. 386-396 ◽  
Author(s):  
C. HORNER ◽  
L. UTSI ◽  
L. COOLE ◽  
M. DENTON
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Current Data ◽  
Clinical Isolates ◽  
Dilution Method ◽  
Genes Encoding ◽  
Mupirocin Resistance ◽  
The Uk ◽  
Resistance Rates

SUMMARYWe investigated the epidemiology and characterization of isolates of Staphylococcus aureus within the Yorkshire and Humber (YH) region in the UK. In July 2015, each laboratory within YH (n = 14) was assigned two consecutive days during which all clinical isolates of S. aureus were collected. Isolates were tested for antibiotic susceptibilities and the presence of genes encoding methicillin resistance (mecA and mecC), Panton–Valentine leukocidin (PVL) (lukS-PV), and efflux-mediated chlorhexidine resistance (qacA); isolates were also characterized by spa-types. Minimum inhibitory concentrations (MICs) to chlorhexidine were determined by the broth dilution method. Of 520 isolates collected, 6·2% were methicillin-resistant S. aureus (MRSA, all mecA-positive) and mupirocin resistance was low [0·8%, 95% confidence interval (CI) 0·3–2·0] and only found in MRSA. Carriage of the qacA gene was identified in 1·7% (95% CI 0·8–3·3) of isolates and 3·5% (95% CI 2·2–5·4) had a chlorhexidine MIC of 4 mg/l. The PVL gene was infrequent (3·7%, 95% CI 2·4–5·6). Genotyping identified 234 spa-types that mapped to 22 clonal complexes. Comparison of these current data with previous work suggest that the widespread use of staphylococcal decolonization regimens over the past decade or more has not had an adverse impact on resistance rates, PVL carriage or the prevalence of specific S. aureus lineages.

Sign in / Sign up

Export Citation Format

Share Document