Molecular Characterization Of Multidrug Resistant Salmonella Enterica Isolated From Poultry

In this study, Atotal of 180 samples from poultry meat: 60 fresh slaughtered poultry , 60 frozen poultry meat, 60 poultry organs (liver and gizzard) were obtained randomly from slaughter houses, restaurants and supermarkets at Sharqia governorate. The collected samples were examined for the presence of S.enterica. Biochemical and serological identification were applied, Biochemical and serological examination revealed that incidence of S.enterica was 8.3 % (15 isolates) from all samples. Molecular characterization using multiplex PCR technique was applied for confirming the serotyping of S.enterica. From these 15 isolates , S.typhiurium was the most isolated serovar represented in 9 of 15 isolates (60%), S.paratyphi A was 3 of 15 isolates (20%), S.enteritidis was 2 of 15 isolates (13.3%) and S.kentucky was 1 of 15 isolates (6.7%), Invitro sensitivity of S.enterica isolates to various antimicrobial agents revealed that the incidence of resistance to enrofloxacin was (1/15) (6.6%),streptomycin was (4/15) (26.6%), ceftriaxone (11/15) (73.3%), cefpodoxime was (11/15) ( 73.3%) , ceftazidime was (10/15) (66.7%), ampicillin was (12/15) (80%) , chloramphenicol was (0/15) (0%), cefotaxime was (12/15) ( 80%), tetracycline was (6/15) (40%), ciprofloxacin was (0/15)( 0%), nalidixic acid was (5/15) (33.3%) and amoxicillin-clavulanic acid was (9/15) ( 60%) ,The molecular characterization of β-lactamase resistance genes in MDR S.enterica isolates showed presence of blaCMY gene in 2 of 15 isolates (13.3%), blaCTX-M in 12 isolates (80%), blaTEM in 6 isolates (40%), where blaSHV and blaOXA genes could not be identified, Molecular characterization of plasmid mediated quinolone resistance genes in multidrug-resistant S.enterica isolates revealed the presence of qnrA in 7 of 15 isolates (46.7%),qnrB in 3 of 15 isolates (20%) and qnrS in 1 of 15 isolates (6.7%). Class 1 integron was detected in 2 of 15 MDR S.enterica (13.3%), DNA-sequencing results for the inserted gene cassettes identified 3 types of class 1 integrons. The identified antibiotic resistance genes were dihydrofolate reductase types : dfrA15 and dfrA17 which confer resistance to trimethoprim and aminoglycoside adenyltransferase type aadA2 which confer resistance to streptomycin and spectinomycin, All strains were negative for class 2 integrons.