Investigation of the presence of plasmid replicone types among CTX-M-15 producing escherichia coli isolates from different sources

Recently, extended spectrum β-lactamase (ESBL) producing Escherichia coli has been frequently reported from human clinical samples. Foods of animal origin and water sources are found to be contaminated with this bacteria and is thefore recognised as possible reservuar. In this thesis, a total of 41 CTX-M-15 positive and epidemologically unrelated E. coli isolates were examined for the presence of plasmid replicon types by polymerase chain reaction (PCR). In addition, all the isolates were screened for the presence of phenotypic fosfomycin resistance and the plasmid-mediated fosA3 gene. The isolates included in the current study were obtained from various sources [chicken meat and raw milk, Sürk cheese, waste water (wwtp and Asi River)] and were already characterized. Human clinical isolates (n=8) were characterized for the presence of blaCTX-M-15 gene, clonal relationships and antimicrobial resistance profiles in this study. As a result, none of the isolate were found to be resistant to fosfomycin and FosA3 gene was not found in any isolate. Among the 30 replicon types examined, a total of 12 replicon types (FIA, FIB, FIBKN, FII, X1, A / C, U, N, HI2, I2, I1α and I1y) were found. The presence of FIA, FIB, FIB KN and FII among the replicon types found showed a statistically significant difference between the sources. FII replicon type was found in 22 isolates in total, and it was found that water and chicken meat isolates were statistically significantly more common (P˂0.05) than other isolates. FIB replicon type was found in %36.6 of the isolates from chicken meat, water and clinical samples, but not in isolates from raw milk and cheese samples. Similarly, the FIA replicon type was found in %29.2 of the isolates of water and clinical samples, and its presence was not found in any other isolates. However, unlike these results, FIB KN replicon type was found only in raw milk (n = 6) and Surk cheese isolates (n=4) (P = 0.001). To sum up, the majority of isolates harbored more than one replicon types and replicon types differed statistically amonst the source of isolates.