Molecular epidemiology of TEM and SHV type beta-lactamase genes encoded by plasmid in enterobacteria isolated from various clinical samples

8. SUMMARY Molecular epidemiology of the plasmids encoding TEM or SHV-types of $- lactamase enzymes in 133 of ampicillin resistant members of Enterobacteriaceae family isolated from various clinical materials obtained from both outpatients and inpatients into two months in Farabi Hospital of Karadeniz Technical University was investigated in this study. Among ampicillin resistant strains, it was determined that 26 isolates (19.54 %) and their transconjugants produced extended-spectrum P-lactamases (ESBL). In conjugation experiments, 9 E. coli, 9 Klebsiella spp. and 2 E. aerogenes isolates were detected to transfer their ESBL-encoding plasmids, ranging from 6.7 to 93.1 kb in molecular size, to a susceptible laboratory strain of E. coli J53-2. According to the results of Mütem and Z?/aSHv-specific PCRs, among 20 transconjugants encoding resistance of aminoglycoside, tetracycline and trimethoprim/sulfomethaxazole other than pMactam resistance, 30 % had SHV, 55 % had both TEM and SHV, and 15 % had non-TEM or non-SHV-derived genes. Only TEM-derived genes were not determined. According to the analysis of plasmids digested with EcoRI restriction enzyme and the results from Southern hybridization assays using Mötem and blaSH\ probes, conjugative plasmids were grouped as epidemic (A, B, C, D and E groups) and non-epidemic (F, G, H, I, J, K and L groups). Mutem and blaSuv probes hybridized to the same restriction fragments in the same groups of plasmids. Because the epidemic plasmids in this study were isolated from the enterobacteria which were the infectious agents of different patients in various units of our hospital, it was concluded that there were the epidemics of various conjugative plasmids with both TEM and SHV-derived ESBLs among enterobacteria in our hospital. It would be suggested that the hygiene of the hands be considered important by our hospital personels, and also it is urgent that such molecular epidemiological studies be spread around the country in order to moniterize ESBL-producing organisms with multiple-drug resistance. More importantly, control of this problem urgently requires coordinating antibiotic use strategies including the limitation of unnecessary antibiotic use around the country. Key Words: Enterobacteriaceae, ESBL, TEM and SHV.