Haydar Özpinar

Evaluation of pathogenic Escherichia coli occurrence in vegetable samples from district bazaars in Istanbul using real-time PCR.

In this study, a total of 180 vegetable samples collected from several district bazaars of Istanbul were investigated for the occurrence of Escherichia coli using a culture‐based method. The isolates were subjected to real‐time PCR detection of Shiga‐toxin–producing E. coli (STEC) using primers specific for the Shiga toxin (stx1 and stx2) and intimin (eae) virulence genes. The prevalences of E. coli in the samples were 93·3% in spinach, 93·3% in lettuce, 86·6% in parsley, 43·3% in carrot, 33·3% in cucumber and 13·3% in tomato. Of 180 samples, 13 contained STEC (six parsley, three carrots, three lettuces and one cucumber of 30 samples of each). Among 13 STEC‐positive isolates, presence of stx1, stx2 and eae was detected in only one sample, stx2 and eae in two samples, and stx2 in ten samples. Serotype O157 was found in parsley, lettuce and carrot; O26 in lettuce, parsley, cucumber and carrot; and O111 and O113 in parsley only. In conclusion, STEC was present in vegetable samples marketed in several district bazaars in Istanbul; this might represent a route of transmission of pathogenic STEC to humans and be harmful to public health.

Occurrence and characteristics of extended spectrum beta-lactamases-producing Enterobacteriaceae from foods of animal origin

Presence of extended spectrum beta-lactamases (ESBL) in bacteria is a growing health concern of global significance. The local, regional, national, and international epidemiological studies for extended spectrum beta-lactamases-producing Enterobacteriaceae and their encoding genes in foods are still incomplete. The objective of this study was to determine the occurrence of extended spectrum beta-lactamases-producing Enterobacteriaceae and the characteristics of their encoding genes from a total of 250 samples of various foods of animal-origin (100 raw chicken meat, 100 raw cow milk, and 50 raw cow milk cheese) sold in Turkey. Overall, 55 isolates were positive as extended spectrum beta-lactamases-producing Enterobacteriaceae. The most prevalent extended spectrum beta-lactamases-producing strain were identified as Escherichia coli (80%), followed by Enterobacter cloacae (9.1%), Citrobacter braakii (5.5%), Klebsiella pneumoniae (3.6%), and Citrobacter werkmanii (1.8%) by Vitek® MS. The simultaneous production of extended spectrum beta-lactamases and AmpC was detected in five isolates (9.1%) in E. coli (80%) and E. cloacae (20%). The frequency rates of blaTEM, blaCTX-M, and blaSHV were 96.4%, 53.7%, and 34.5%, respectively. The co-existence of bla-genes was observed in 82% of extended spectrum beta-lactamases producers with a distribution of blaTEM & blaCTX-M (52.7%), blaTEM & blaSHV (20%), blaTEM & blaCTX-M & blaSHV (12.7%), and blaSHV & blaCTX-M (1.8%). The most prevalent variant of blaCTX-M clusters was defined as blaCTX-M-1 (97.2%), followed by blaCTX-M-8 (2.8%). In summary, the analysed foods were found to be posing a health risk for Turkish consumers due to contamination by Enterobacteriaceae with a diversity of extended spectrum beta-lactamases encoding genes.