Cemil Kürekci

Characterisation of Phenotypic and Genotypic Antibiotic Resistance Profile of Enterococci from Cheeses in Turkey.

The aim of this study was to determine the prevalence of enterococci in cheese samples and to characterize their antimicrobial resistance profiles as well as the associated resistance genes. A total of 139 enterococci were isolated from 99 cheese samples, the isolates were identified as E. faecalis (61.2%), E. faecium (15.1%), E. gallinarum (12.9%), E. durans (5.0%), E. casseliflavis (2.9%) and E. avium (2.9%). The most frequent antimicrobial resistance observed in enterococci isolates was to lincomycin (88.5%), followed by kanamycin (84.2%), gentamycin (low level, 51.1%), rifampin (46.8%) and tetracycline (33.8%). Among the isolates, the frequencies of high level gentamycin and streptomycin resistant enterococci strains were 2.2% and 5.8%, respectively. Apart from the mentioned antibiotics, low levels of resistance to ciprofloxacin, erythromycin and chloramphenicol were found. Moreover no resistance was observed against penicillin and ampicillin. The antimicrobial resistance genes including tetM, tetL, ermB, cat, aph(3’)-IIIa, ant(6)-Ia and aac(6’)-Ieaph(2”)-Ia were found in enterococci from Turkish cheese samples. In the current study, we provided data for antibiotic resistance and the occurrence of resistance genes among enterococci. Regulatory and quality control programs for milk and other dairy products from farms to retail outlets has to be established and strengthened to monitor trends in antimicrobial resistance among emerging food borne pathogens in Turkey.

Antimicrobial susceptibility pattern and SCCmec types of methicillin-resistant coagulase-negative staphylococci from subclinical bovine mastitis in Hatay, Turkey

Abstract Eighty-nine isolates of coagulase-negative staphylococci (CoNS) of eight species from subclinical bovine mastitis were screened for the phenotypic and genotypic methicilline-resistance. In addition, all methicillin-resistant (MR) isolates indicating the mecA gene were examined by PCR for the antimicrobial susceptibility patterns, and staphylococcal cassette chromosome mec (SCCmec) types were also determined by multiplex PCR. A total of 21 (23.6%) CoNS isolates were found to be resistant to oxacillin in broth microdilution assay. All isolates phenotypically resistant to oxacillin did not have the mecA gene, which was only found in 14.6% (13) of the isolates. Most MR-CoNS isolates were highly resistant to erythromycin (92.3%), fusidic acid (84.6%), penicillin (76.9%), and rifampycin (61.5%), and susceptible to mupirocin (100%), tetracycline (100%), vancomycin (100%), clindamycin (92.3%), and sulfamethoxazole-trimethoprim (69.2%). In conclusion, a high rate of antimicrobial resistance among MR-CoNS isolated from food producing animals emphasises the need for periodic surveillance of their resistance.

Characterization of extended spectrum β -lactamase (ESBL)-producing Escherichia coli in Asi (Orontes) River in=Turkey

In this study, the presence of extended spectrum β-lactamase (ESBL)-producing Escherichia coli in aquatic environments (the Orontes River and an urban wastewater) was investigated. Fifty-four E. coli strains resistant to cefotaxime were isolated from the river waters and nearby waste water treatment plant and screened for ESBL gene variants, different classes of integrons and sulfonamide resistance genes. The ESBL-producing E. coli strains were further characterized by PhP-typing system, phylogenetic grouping and antimicrobial susceptibility testing. Of the 54 ESBL-producing strains, 14 (25.9%) belonged to four common PhP types and the remaining were of single types. CTX-M type ESBL genes were identified in 68% of the isolates. The most predominant specific CTX-M subtype identified was blaCTX-M-15 (n = 36), followed by blaCTX-M-1 (n = 1). None of the isolates were SHV and OXA positive. Most of the ESBL positive isolates (n = 37; 68.5%) were harboring sul gene. This study indicates a widespread distribution of CTX-M-15 producing E. coli strains in the surface waters in part of Turkey, suggesting an aquatic reservoir for ESBL genes.

Characteristics of ciprofloxacin resistant Campylobacter spp. isolated from chicken meat in Turkey

The objective of the current study was to investigate mutations in the gyrA and 23S rRNA gene fragments the high level ciprofloxacin resistant (HL-CipR) Campylobacter isolates (C. jejuni n = 6 and and C. coli n = 9) obtained from chicken meat samples, in Turkey. PCR-based restriction fragment length polymorphism (RFLP) was used to characterize these isolates. In addition, the presence of several virulence traits among these isolates was also examined. Of the 15 HL-CipRCampylobacter strains, there were eight unique RFLP banding patterns. All HL-CipRCampylobacter strains had mutations in codon 86 (Thr-86 to Ile) in the gyrA gene. Four C. jejuni isolates had missense mutation of Asp-203 to Ser, whereas one C. jejuni strain also presented a change at Ala-40 to Ser. A2075G substitution in the 23S rRNA gene was identified in five isolates (C. coli n = 3 and C. jejuni n = 2), whereas none of the isolates had A2074G substitution. The tetO gene conferring resistance to tetracycline were observed among five Campylobacter isolates. Of Campylobacter strains, 13 (86.6 %) were found to be positive for one or more virulence factors, the cdt genes being the most detected. The results of the current study extends the current knowledge about molecular mechanisms for erythromycin and ciprofloxacin resistance as well as virulence traits by investigation of HL-CipRCampylobacter isolates from chicken meat sold in Turkey.