Investigation of escherichia coli O157:H7 in Afyon kaymak sold in Afyonkarahisar

The aim of this study was to isolate the E. coli O157:H7/H- serotype from Afyon kaymak sold in Afyonkarahisar, investigate the Stx1, Stx2, ehlyA and eaeA genes in isolated strains by PCR and determine the antibiotic resistance of strains to some antibiotics commonly used in Turkey. For this purpose, a total of 100 kaymak samples sold in public bazaars located center town and villages of Afyonkarahisar were collected. E. coli O157 was isolated from 3 of 100 samples by using conventional culture methods and serological confirmation tests. The presence of Stx1, Stx2, ehlyA and eaeA genes in the isolated 3 strains was investigated by PCR. Multiplex PCR was used for the detection of Stx1, Stx2 and ehlyA genes and singleplex PCR was used for the detection of eaeA virulence gene. While all of 3 strains harboured the Stx1 and ehlyA genes, the Stx2 and eaeA genes were not found in the strains. The antibiotic resistance 3 E. coli O157 strains isolated from kaymak samples to some antibiotics was investigated by Kirby-Bauer disc diffusion test. While all of strains were resistant to cephazoline, cefoxitin and ceftiofur, the resistance was also determined in the strains to ampicillin (66.7%), cephalothin (66.7%), ceftriaxone (33.3%), nalidixic acid (33.3%) and trimethoprim/sulphamethoxazole (33.3%). To our knowledge, this is the first study showing the presence of E. coli O157 and its virulence genes in the kaymak samples in Turkey. Key words: E. coli O157, enterohemolysin, intimin, kaymak, Shiga toxin