Simple Search:

Genotypic and phenotypic characterization of methicillin resistance determinants and β-lactamase in Staphylococcus species


Citation

Abdul Rachman, Abdul Rahim and Mat Azis, Norhidayah and Pung, Hui Ping and Suhaili, Zarizal and Amin Nordin, Syafinaz and Othman, Zulkefley and Mohd Desa, Mohd Nasir (2017) Genotypic and phenotypic characterization of methicillin resistance determinants and β-lactamase in Staphylococcus species. Malaysian Journal of Microbiology, 13 (4). pp. 308-317. ISSN 1823-8262; ESSN: 2231-7538

Abstract / Synopsis

Aims: To characterize the genotypic distribution of mec complex, bla complex, methicillin-resistance level (cefoxitinMIC) and β-lactamase activity in carriage methicillin-resistant Staphylococcus species for a potential correlation. Methodology and results: Biochemical test, 30 µg cefoxitin diffusion disc test, cefoxitin E-test, mec and bla complexes distributions, Pbp2a and β-lactamase assays were conducted to characterize phenotypic and genotypic of MRSA and MRCoNS in our collection. Phylogenetic tree was constructed using MEGA6 software to trace the diversity of blaZ gene of MRSA and MRCoNS. Sixteen MRSA and nineteen MRCoNS were identified by biochemical tests followed by 30 µg cefoxitin antibiotic disc susceptibility test and mecA gene screening. Twenty nine isolates carry complete mecA genes (2.1 kb), incomplete mec regulator (negative or truncated) and positive Pbp2a assay for both MRSA and MRCoNS. Only MRCoNS SC177 isolate with cefoxitin MIC of 32 µg/mL carries complete mec complex. Thirty-one of thirty-five isolates carry complete bla complex (blaZ, blaRI, blaI) with 10 MRSA produce strong β-lactamase and cefoxitin MIC of ≥12 µg/mL. Only 4 MRCoNS with cefoxitin MIC of ≤8 µg/mL produce strong β-lactamase. The diversity of blaZ gene was demonstrated by phylogenetic analysis and unusual amino acid mutation at position 145 for MRSA SA60 isolate may compromise its β-lactamase activity with low cefoxitin MIC level (2 µg/mL). Conclusions, significance and impact of the study: Isolates that carry complete complete mecA gene were largely consistent with the expression of Pbp2a. Nevertheless, there is no clear correlation of mec regulator genes in relation to cefoxitin-MIC in both methicillin resistant (MR) Isolates that carry Staphylococcus species. On the other hand, various expression level of β-lactamase may correlate with cefoxitin-MIC level in MRSA as compared to MRCoNS.


Download File

[img]
Preview
PDF (Abstract)
Genotypic and phenotypic characterization of methicillin resistance determinants and β-lactamase in Staphylococcus species.pdf

Download (63kB) | Preview

Additional Metadata

Item Type: Article
Divisions: Faculty of Medicine and Health Science
Halal Products Research Institute
Publisher: Malaysian Society for Microbiology
Keywords: Cefoxitin-MIC; Mec complex; Bla complex; β-lactamase; MR Staphylococcus
Depositing User: Nabilah Mustapa
Date Deposited: 08 Jun 2018 00:25
Last Modified: 08 Jun 2018 00:25
URI: http://psasir.upm.edu.my/id/eprint/63943
Statistic Details: View Download Statistic

Actions (login required)

View Item View Item