Occurrence, Phenotypic and Molecular Characteristics of Extended-Spectrum Beta-Lactamase-Producing in Healthy Turkeys in Northern Egypt.

Poultry is one of the most important reservoirs for zoonotic multidrug-resistant pathogens. The indiscriminate use of antimicrobials in poultry production is a leading factor for development and dissemination of antimicrobial resistance. This study aimed to describe the prevalence and antimicrobial resistance of isolated from healthy turkey flocks of different ages in Nile delta region, Egypt. In the current investigation, 250 cloacal swabs were collected from 12 turkey farms in five governorates in the northern Egypt. Collected samples were cultivated on Brilliance ESBL agar media supplemented with cefotaxime (100 mg/L). The isolates were identified using MALDI-TOF-MS and confirmed by a conventional PCR assay targeting 16S rRNA-DNA. The phenotypic antibiogram against 14 antimicrobial agents was determined using the broth micro-dilution method. DNA-microarray-based assay was applied for genotyping and determination of both, virulence and resistance-associated gene markers. Multiplex real-time PCR was additionally applied for all isolates for detection of the actual most relevant Carbapenemase genes. The phenotypic identification of colistin resistance was carried out using E-test. A total of 26 isolates were recovered from the cloacal samples. All isolates were defined as multidrug-resistant. Interestingly, two different strains were isolated from one sample. Both strains had different phenotypic and genotypic profiles. All isolates were phenotypically susceptible to imipenem, while resistant to penicillin, rifampicin, streptomycin, and erythromycin. None of the examined carbapenem resistance genes was detected among isolates. At least one beta-lactamase gene was identified in most of isolates, where TEM was the most commonly identified determinant (80.8%), in addition to CTX-M9 (23.1%), SHV (19.2%) and OXA-10 (15.4%). Genes associated with chloramphenicol resistance were R (65.4%) and A1 (46.2%). Tetracycline- and quinolone-resistance-associated genes A and S were detected in (57.7%) and (50.0%) of isolates, respectively. The aminoglycoside resistance associated genes A1 (65.4%), A2 (53.8%), A (50.0%), A (69.2%), and B (65.4%), were detected among isolates. Macrolide resistance associated genes and were also detected in (53.8%) and (34.6%). Moreover, colistin resistance associated gene -9 was identified in one isolate (3.8%). The class 1 integron integrase I1 (84.6%), transposase for the transposon ISEcp1 (34.6%) and OqxB -integral membrane and component of RND-type multidrug efflux pump B (7.7%) were identified among the isolates. The existing high incidence of ESBL/colistin-producing identified in healthy turkeys is a major concern that demands prompt control; otherwise, such strains and their resistance determinants could be transmitted to other bacteria and, eventually, to people via the food chain.