Plasmid mediated extended spectrum beta-lactamase producing strains of enterobacteriaceae isolated from diabetic foot infections in Egypt

Background: Extended spectrum beta-lactamases (ESBLs) are heterogeneous group of plasmid mediated β-lactamases enzymes that confer resistant to oxyimino cephalosporins, monobactam (aztreonam) and usually show co-resistance to other classes of antibiotics. The present was done to identify and characterize the most common plasmid-mediated ESBL genes associated with diabetic foot infections in Egypt.Methods and findings: A total of 135 Gram negative bacterial isolates were re- covered from 91 diabetic foot ulcers specimens of patients attending governmental hospitals and private clinics in Cairo, Egypt. The antibiogram analysis revealed a remarkable high resistance pattern towards different classes of the tested antimi- crobial agents. Based on CLSI, a total of 114 isolates out of 135 were considered potential ESBLs producer by using disc diffusion and broth microdilution screening assays followed by double disc synergy test (DDST). 58 out of 114 isolates were ESBLs producers and almost 14% (8 out of 58), were plasmid-mediated as deter- mined by plasmid extraction and transformation experiments. The majority of the tested plasmids (6 out of 8) carried 2 or more genes on the same plasmid. The most common combination was blaCTX-M and blaTEM (n=3/8; 37.5%), followed by blaSHV and blaCTX-M(n=2/8; 25%) and blaCTX-M+ blaTEM+ blaSHV (n=1/8;12.5%). One E.coli isolate harbored a plasmid (pECDF16) coding for the three ESBLs genes. The final nucleotide sequences of blaTEM1 and blaSHV-8 were submitted to the GenBank database under accessions coder JX976326, and JX976327, respectively.Conclusion: High prevalence of plasmid-mediated ESBLs was detected among DFIs in Egypt. Therefore, new guidelines should be undertaken in Egypt to limit or prevent the misuse and abuse of antimicrobial agents.

Author(s): Kamel Noha A., Aboshana Khaled M., Abouelwafa Mohammad M., El-tayeb Wafaa N.

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