scholarly journals Characterization of Methicillin Resistance Staphylococcus aureus isolated from chicken and human

2017 ◽  
Vol 32 (1) ◽  
pp. 132-137
Author(s):  
Ashraf Abd El-Tawab ◽  
Fatma Hofy ◽  
Sahar Mohamed ◽  
Sohila Amin
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance

scholarly journals Characterization of Passage-Selected Vancomycin-Resistant Staphylococcus aureus Strains of Diverse Parental Backgrounds

2000 ◽  
Vol 44 (2) ◽  
pp. 294-303 ◽  
Author(s):  
Richard F. Pfeltz ◽  
Vineet K. Singh ◽  
Jennifer L. Schmidt ◽  
Michael A. Batten ◽  
Christopher S. Baranyk ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Walls ◽  
Methicillin Resistance ◽  
Surface Hydrophobicity ◽  
Whole Cell ◽  
Transmission Electron ◽  
Vancomycin Mics ◽  
Vancomycin Resistant ◽  
Doubling Times

ABSTRACT A series of 12 Staphylococcus aureus strains of various genetic backgrounds, methicillin resistance levels, and autolytic activities were subjected to selection for the glycopeptide-intermediate S. aureus (GISA) susceptibility phenotype on increasing concentrations of vancomycin. Six strains acquired the phenotype rapidly, two did so slowly, and four failed to do so. The vancomycin MICs for the GISA strains ranged from 4 to 16 μg/ml, were stable to 20 nonselective passages, and expressed resistance homogeneously. Neither ease of acquisition of the GISA phenotype nor the MIC attained correlated with methicillin resistance hetero- versus homogeneity or autolytic deficiency or sufficiency. Oxacillin MICs were generally unchanged between parent and GISA strains, although the mec members of both isogenic methicillin-susceptible and methicillin-resistant pairs acquired the GISA phenotype more rapidly and to higher MICs than did their susceptible counterparts. Transmission electron microscopy revealed that the GISA strains appeared normal in the absence of vancomycin but had thickened and diffuse cell walls when grown with vancomycin at one-half the MIC. Common features among GISAs were reduced doubling times, decreased lysostaphin susceptibilities, and reduced whole-cell and zymographic autolytic activities in the absence of vancomycin. This, with surface hydrophobicity differences, indicated that even in the absence of vancomycin the GISA cell walls differed from those of the parents. Autolytic activities were further reduced by the inclusion of vancomycin in whole-cell and zymographic studies. The six least vancomycin-susceptible GISA strains exhibited an increased capacity to remove vancomycin from the medium versus their parent lines. This study suggests that while some elements of the GISA phenotype are strain specific, many are common to the phenotype although their expression is influenced by genetic background. GISA strains with similar glycopeptide MICs may express individual components of the phenotype to different extents.

scholarly journals Study of Antibiotics Sensitivity Pattern And Molecular Characterization of Staphylococcus Aureus Isolated From Human And Animal Pyogenic Cases

2021 ◽  
Author(s):  
Jayshree Singh ◽  
Amit Kumar ◽  
Sharad K. Yadav ◽  
Ritika Yadav ◽  
Vinod K. Singh
Keyword(s):  
Staphylococcus Aureus ◽  
Molecular Characterization ◽  
Drug Sensitivity ◽  
Methicillin Resistance ◽  
Phenotypic Characterization ◽  
Resistance Pattern ◽  
Sensitivity Pattern ◽  
Drug Resistance Pattern ◽  
Animal Isolates

Abstract Staphylococcus aureus has been described as the most common cause of human and animal diseases and has emerged as superbug due to multidrug resistance. Considering these, a total of 175 samples were collected from pyogenic cases of humans (75) and animals (100), to establish the drug resistance pattern and also for molecular characterization of human and animal isolates. Thermonuclease (nuc) gene amplification was used to confirm all presumptive S. aureus isolates and then antibiotic sensitivity and slide coagulase tests were used for phenotypic characterization of isolates. Following that, all of the isolates were subjected to PCR amplification to detect the existence of the methicillin resistance (mecA) and coagulase (coa) genes. Lastly, typing was done by using the Randomly Amplified Polymorphic DNA-PCR. The overall prevalence of S. aureus in human and animal samples was found to be 39.4%. Drug sensitivity revealed the highest resistance against the β-lactam antibiotics such as ampicillin (94.8%) and penicillin (90.6%), followed by cephalosporin (cefixime-67.7%) and quinolone (ciprofloxacin-52.1%) group of drugs. The drug sensitivity was the highest against antibiotics like chloramphenicol (95%) followed by gentamicin (90%). Among the 69 S. aureus isolates, the overall presence of MRSA was 40.5% (27.5% and 50% in human and animal isolates respectively). Total 33 isolates exhibited coa genes amplification of more than one amplicons and variable in size of 250, 450, 800, and 1100 bp. The RAPD typing revealed amplification of 5 and 6 different band patterns in humans and animals, respectively, with two common patterns suggesting a common phylogenetic profile.

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.

scholarly journals Molecular Characterization and Pathogenicity of Staphylococcus aureus Isolated from Benin-City, Nigeria

2020 ◽  
Vol 8 (6) ◽  
pp. 912 ◽  
Author(s):  
Osahon Obasuyi ◽  
JoAnn McClure ◽  
Francis E. Oronsaye ◽  
John O. Akerele ◽  
John Conly ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Molecular Epidemiology ◽  
Molecular Characterization ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Developed Countries ◽  
Small Degree ◽  
Local Conditions ◽  
Benin City

While numerous studies examine the epidemiology and molecular characterization of Staphylococcus aureus in most developed countries, the detailed molecular characterization and molecular epidemiology of S. aureus strains and clones in Africa is lacking. We determined the molecular epidemiology and virulence of 81 non-duplicate isolates of S. aureus from Benin-City, Nigeria, collected during January–July 2016, and compared with global strains. Forty-seven isolates (58.0%) were found to be methicillin-sensitive Staphylococcus aureus (MSSA), while 34 (42.0%) were methicillin-resistant Staphylococcus aureus (MRSA). ST152-MSSA (24.7%) and ST7-MRSA-V (19.8%) were the dominant groups identified, which were not genetically related to global predominant strains, but rather exhibited regional dominance. An interesting finding of the study was the presence of highly related strains in the region, which differed primarily in their methicillin resistance gene carriage, staphylococcal cassette chromosome mec (SCCmec), with 99.4–99.7% relatedness between the genomes of the strains within the MRSA–MSSA pairs. This suggests that the strains within a pair are experiencing gain or loss of SCCmec within local conditions, with evolution continuing to diversify the strains to a small degree. This study represents the most comprehensive genetic and virulence study of S. aureus in Nigeria.

scholarly journals Isolation, Detection and Molecular Characterization of Staphylococcus aureus from Postoperative Infections

2020 ◽  
pp. 63-67
Author(s):  
Ritya Mary Jibu ◽  
R. V. Geetha ◽  
T. Lakshmi
Keyword(s):  
Staphylococcus Aureus ◽  
Wound Infection ◽  
Molecular Characterization ◽  
Methicillin Resistance ◽  
Healthcare Associated Infection ◽  
Postoperative Infections ◽  
Coagulase Negative Staphylococci ◽  
Mrsa Strains ◽  
Healthcare Associated

Post operative infections that occur after surgical procedures can cause a lot of complications like sepsis, organ failure or even death. These are the third most commonly reported healthcare associated infection. The most common cause of wound infection regardless of procedure performed remains gram-positive cocci which comprise more than 50% of all infections. Specifically, Staphylococcus aureus and coagulase-negative staphylococci are the most frequent organisms isolated from a wound infection. There has been an increasing incidence of MRSA strains reported in hospitals across the globe. The main aim of our study is isolation, detection and molecular characterization of Staphylococcus aureus from postoperative infections.  Samples were collected from post operative patients with infected wounds. The area around the wound was cleaned. Exudates were collected from the wound with a sterile swab stick. The samples were inoculated on different solid culture mediums and the plates were incubated in the presence of oxygen at 37°C overnight. There were many standard procedures done in which tube coagulase was taken as the main criteria. Antibiotic susceptibility testing was done by Kirby Bauer method following Clinical and Laboratory Standards Institute (CLSI) guidelines using commercially available cefoxitin (30 μg) disc (HiMedia) and the results were compared with Staphylococcus aureus ATCC 25923 and MRSA ATCC 43300 control strains. The MRSA strains were identified and detection of Mec A gene that codes for methicillin resistance is done using PCR technique.

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