Phenotypic and genetic characterization of antimicrobial resistance in salmonella isolates from different sources in Turkey


Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Gıda Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2015

Öğrenci: SİNEM ACAR

Danışman: YEŞİM SOYER

Özet:

Salmonella enterica subsp. enteric serovars are responsible for causing the highest number of bacterial foodborne infections in the world. Antimicrobial resistance (AR) and virulence of Salmonella isolates play a critical role in systemic infections and they impose great concern to human health in severe salmonellosis cases when multidrug resistance interferes with treatment. Also, antimicrobial resistance genes might be shared with closely related human pathogens. Therefore, antimicrobial susceptibility monitoring of isolates from farm/field to fork is very crucial. The objective of this study was to determine the phenotypic and genetic variations of the AR among Salmonella isolates from different sources (i.e., animal, human, and foods). Disk diffusion and MIC methods were used for phenotypic characterization of AR in Salmonella isolates. For genotyping characterization, beta-lactam, chloramphenicol, aminoglycoside, sulfonamide and tetracycline resistance coding genes were studied. At the end, 21 regions of known antimicrobial resistant coding genes (blaTEM-1, blaPSE-1, blaCMY-2, ampC, cat1 ,cat2, flo, cmlA, aadA1, aadA2, strA, strB, aacC2, aphA1-Iab, dhfrI, dhfrXII, sulI, sulII, tetA, tetB, tetG) were amplified to determine genetic variation of AR. The co-presence of some antimicrobial resistance genes had raised the question of mobile genetic elements presence, thus occurrence of plasmids and class 1 integrons on the isolates were analyzed. To investigate the virulence characteristics, ctdB, gatC, gogB, hlyE, pefA, ssek3, sseI, sspH, sodC, sopE, STM 2759, tcfA genes were screened on the isolates. The results were analyzed according to the source of isolate (food, animal, and human), the type of serovar. Our study fills the gap of limited relevant study about the antibiotic susceptibility profile of Salmonella isolates from farm/field to fork. Our study has the potential of being a progressive work conducted in the pathogenicity area.