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Phenotypic and molecular characteristics of methicillin-resistant Staphylococcus aureus isolates from Ekiti State, Nigeria.

Olowe OA, Kukoyi OO, Taiwo SS, Ojurongbe O, Opaleye OO, Bolaji OS, Adegoke AA, Makanjuola OB, Ogbolu DO, Alli OT - Infect Drug Resist (2013)

Bottom Line: The S. aureus isolates were resistant to penicillin (82.7%) and tetracycline (65.4%), but largely susceptible to erythromycin (78.8% sensitive), pefloxacin (82.7%), and gentamicin (88.5%).When compared to the mecA gene as the gold standard for MRSA detection, methicillin, oxacillin, and cefoxitin gave sensitivity rates of 70%, 80%, and 100%, and specificity rates of 76.2%, 69.1%, and 78.5% respectively.When compared with previous studies employing mecA polymerase chain reaction for MRSA detection, the prevalence of 19.2% reported in Ekiti State, Nigeria in this study is an indication of gradual rise in the prevalence of MRSA in Nigeria.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Microbiology and Parasitology, College of Health Sciences, Ladoke Akintola University of Technology, Ogbomoso, Nigeria.

ABSTRACT

Introduction: The characteristics and antimicrobial resistance profiles of Staphylococcus aureus differs according to geographical regions and in relation to antibiotic usage. The aim of this study was to determine the biochemical characteristics of the prevalent S. aureus from Ekiti State, Nigeria, and to evaluate three commonly used disk diffusion methods (cefoxitin, oxacillin, and methicillin) for the detection of methicillin resistance in comparison with mecA gene detection by polymerase chain reaction.

Materials and methods: A total of 208 isolates of S. aureus recovered from clinical specimens were included in this study. Standard microbiological procedures were employed in isolating the strains. Susceptibility of each isolate to methicillin (5 μg), oxacillin (1 μg), and cefoxitin (30 μg) was carried out using the modified Kirby-Bauer/Clinical and Laboratory Standard Institute disk diffusion technique. They were also tested against panels of antibiotics including vancomycin. The conventional polymerase chain reaction method was used to detect the presence of the mecA gene.

Results: Phenotypic resistance to methicillin, oxacillin, and cefoxitin were 32.7%, 40.3%, and 46.5%, respectively. The mecA gene was detected in 40 isolates, giving a methicillin-resistant S. aureus (MRSA) prevalence of 19.2%. The S. aureus isolates were resistant to penicillin (82.7%) and tetracycline (65.4%), but largely susceptible to erythromycin (78.8% sensitive), pefloxacin (82.7%), and gentamicin (88.5%). When compared to the mecA gene as the gold standard for MRSA detection, methicillin, oxacillin, and cefoxitin gave sensitivity rates of 70%, 80%, and 100%, and specificity rates of 76.2%, 69.1%, and 78.5% respectively.

Conclusion: When compared with previous studies employing mecA polymerase chain reaction for MRSA detection, the prevalence of 19.2% reported in Ekiti State, Nigeria in this study is an indication of gradual rise in the prevalence of MRSA in Nigeria. A cefoxitin (30 μg) disk diffusion test is recommended above methicillin and oxacillin for the phenotypic detection of MRSA in clinical laboratories.

No MeSH data available.


Related in: MedlinePlus

Agarose gel electrophoresis of PCR products of representative isolates.Notes: The mecA gene is indicated by the amplification of 533 base pair products. Lanes 6 and 9 are positive for mecA, as indicated by the 533 base pair PCR product. Lanes 1–5, 7, 8, 10–21, 24, and 25 were negative for mecA. Lane 22 was the MRSA-positive control (NCTC 119040), lane 23 was the negative control (water), and lane M was the molecular weight size marker.Abbreviations: PCR, polymerase chain reaction; MRSA, methicillin-resistant Staphylococcus aureus; NCTC, National Center for Type Cultures; M, molecular weight.
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f1-idr-6-087: Agarose gel electrophoresis of PCR products of representative isolates.Notes: The mecA gene is indicated by the amplification of 533 base pair products. Lanes 6 and 9 are positive for mecA, as indicated by the 533 base pair PCR product. Lanes 1–5, 7, 8, 10–21, 24, and 25 were negative for mecA. Lane 22 was the MRSA-positive control (NCTC 119040), lane 23 was the negative control (water), and lane M was the molecular weight size marker.Abbreviations: PCR, polymerase chain reaction; MRSA, methicillin-resistant Staphylococcus aureus; NCTC, National Center for Type Cultures; M, molecular weight.

Mentions: Figure 1 shows the agarose gel electrophoresis of PCR products of representative isolates with the mecA-positive isolate showing band at approximately 533 base pairs.


Phenotypic and molecular characteristics of methicillin-resistant Staphylococcus aureus isolates from Ekiti State, Nigeria.

Olowe OA, Kukoyi OO, Taiwo SS, Ojurongbe O, Opaleye OO, Bolaji OS, Adegoke AA, Makanjuola OB, Ogbolu DO, Alli OT - Infect Drug Resist (2013)

Agarose gel electrophoresis of PCR products of representative isolates.Notes: The mecA gene is indicated by the amplification of 533 base pair products. Lanes 6 and 9 are positive for mecA, as indicated by the 533 base pair PCR product. Lanes 1–5, 7, 8, 10–21, 24, and 25 were negative for mecA. Lane 22 was the MRSA-positive control (NCTC 119040), lane 23 was the negative control (water), and lane M was the molecular weight size marker.Abbreviations: PCR, polymerase chain reaction; MRSA, methicillin-resistant Staphylococcus aureus; NCTC, National Center for Type Cultures; M, molecular weight.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3753063&req=5

f1-idr-6-087: Agarose gel electrophoresis of PCR products of representative isolates.Notes: The mecA gene is indicated by the amplification of 533 base pair products. Lanes 6 and 9 are positive for mecA, as indicated by the 533 base pair PCR product. Lanes 1–5, 7, 8, 10–21, 24, and 25 were negative for mecA. Lane 22 was the MRSA-positive control (NCTC 119040), lane 23 was the negative control (water), and lane M was the molecular weight size marker.Abbreviations: PCR, polymerase chain reaction; MRSA, methicillin-resistant Staphylococcus aureus; NCTC, National Center for Type Cultures; M, molecular weight.
Mentions: Figure 1 shows the agarose gel electrophoresis of PCR products of representative isolates with the mecA-positive isolate showing band at approximately 533 base pairs.

Bottom Line: The S. aureus isolates were resistant to penicillin (82.7%) and tetracycline (65.4%), but largely susceptible to erythromycin (78.8% sensitive), pefloxacin (82.7%), and gentamicin (88.5%).When compared to the mecA gene as the gold standard for MRSA detection, methicillin, oxacillin, and cefoxitin gave sensitivity rates of 70%, 80%, and 100%, and specificity rates of 76.2%, 69.1%, and 78.5% respectively.When compared with previous studies employing mecA polymerase chain reaction for MRSA detection, the prevalence of 19.2% reported in Ekiti State, Nigeria in this study is an indication of gradual rise in the prevalence of MRSA in Nigeria.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Microbiology and Parasitology, College of Health Sciences, Ladoke Akintola University of Technology, Ogbomoso, Nigeria.

ABSTRACT

Introduction: The characteristics and antimicrobial resistance profiles of Staphylococcus aureus differs according to geographical regions and in relation to antibiotic usage. The aim of this study was to determine the biochemical characteristics of the prevalent S. aureus from Ekiti State, Nigeria, and to evaluate three commonly used disk diffusion methods (cefoxitin, oxacillin, and methicillin) for the detection of methicillin resistance in comparison with mecA gene detection by polymerase chain reaction.

Materials and methods: A total of 208 isolates of S. aureus recovered from clinical specimens were included in this study. Standard microbiological procedures were employed in isolating the strains. Susceptibility of each isolate to methicillin (5 μg), oxacillin (1 μg), and cefoxitin (30 μg) was carried out using the modified Kirby-Bauer/Clinical and Laboratory Standard Institute disk diffusion technique. They were also tested against panels of antibiotics including vancomycin. The conventional polymerase chain reaction method was used to detect the presence of the mecA gene.

Results: Phenotypic resistance to methicillin, oxacillin, and cefoxitin were 32.7%, 40.3%, and 46.5%, respectively. The mecA gene was detected in 40 isolates, giving a methicillin-resistant S. aureus (MRSA) prevalence of 19.2%. The S. aureus isolates were resistant to penicillin (82.7%) and tetracycline (65.4%), but largely susceptible to erythromycin (78.8% sensitive), pefloxacin (82.7%), and gentamicin (88.5%). When compared to the mecA gene as the gold standard for MRSA detection, methicillin, oxacillin, and cefoxitin gave sensitivity rates of 70%, 80%, and 100%, and specificity rates of 76.2%, 69.1%, and 78.5% respectively.

Conclusion: When compared with previous studies employing mecA polymerase chain reaction for MRSA detection, the prevalence of 19.2% reported in Ekiti State, Nigeria in this study is an indication of gradual rise in the prevalence of MRSA in Nigeria. A cefoxitin (30 μg) disk diffusion test is recommended above methicillin and oxacillin for the phenotypic detection of MRSA in clinical laboratories.

No MeSH data available.


Related in: MedlinePlus