title: Characterization of Virulence-Associated Genes, Antimicrobial Resistance Genes, and Class 1 Integrons in Salmonella enterica serovar Typhimurium Isolates from Chicken Meat and Humans in Egypt.
abstract: Foodborne pathogens are leading causes of illness especially in developing countries. The current study aimed to characterize virulence-associated genes and antimicrobial resistance in 30 Salmonella Typhimurium isolates of chicken and human origin at Mansoura, Egypt. The results showed that invA, avrA, mgtC, stn, and bcfC genes were identified in all the examined isolates, while 96.7% and 6.7% were positive for sopB and pef genes, respectively. The highest resistance frequencies of the isolates were to chloramphenicol and trimethoprim-sulfamethoxazole (73.3%, each), followed by streptomycin (56.7%), tetracycline and ampicillin (53.3%, each), and gentamicin (30%). However, only 2.7% of the isolates were resistant to cefotaxime and ceftriaxone each. Different resistance-associated genes, including blaTEM, aadB, aadC, aadA1, aadA2, floR, tetA(A), tetA(B), and sul1, were identified in Salmonella Typhimurium isolates with the respective frequencies of 53.3%, 6.7%, 23.3%, 46.7%, 63.3%, 73.3%, 60%, 20%, and 96.7%. None of the isolates was positive for blaSHV, blaOXA, and blaCMY genes. The results showed that the intI1 gene was detected in 24 (80%) of the examined Salmonella Typhimurium isolates. Class 1 integrons were found in 19 (79.2%) isolates that were intI1 positive. Seven integron profiles (namely: P-I to P-VII) were identified with P-V (gene cassette dfrA15, aadA2), the most prevalent profile. To the best of our knowledge, this is the first study to characterize the unusual gene cassette array dfrA12-OrfF-aadA27 from Salmonella Typhimurium isolates in Egypt.
authors.affiliation: 1 Department of Zoonoses, Faculty of Veterinary Medicine, Zagazig University , Zagazig, Egypt .
authors.forename: Heba A
authors.initials: HA
authors.lastname: Ahmed
authors.affiliation: 2 Department of Bacteriology, Immunology and Mycology, Faculty of Veterinary Medicine, Benha University , Benha, Egypt .
authors.forename: Fatma I
authors.initials: FI
authors.lastname: El-Hofy
authors.affiliation: 3 Department of Food Hygiene, Animal Health Research Institute , Mansoura, Egypt .
authors.forename: Saleh M
authors.initials: SM
authors.lastname: Shafik
authors.affiliation: 4 Department of Microbiology, Animal Health Research Institute , Mansoura, Egypt .
authors.forename: Mahmoud A
authors.initials: MA
authors.lastname: Abdelrahman
authors.affiliation: 3 Department of Food Hygiene, Animal Health Research Institute , Mansoura, Egypt .
authors.forename: Gamilat A
authors.initials: GA
authors.lastname: Elsaid
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D002645:Chickens; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004534:Egypt / Q000453:epidemiology; D005516:Food Microbiology; D005798:Genes, Bacterial / Q000235:genetics; D006801:Humans; D032023:Integrons / Q000235:genetics; D008460:Meat / Q000382:microbiology*; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D016133:Polymerase Chain Reaction; D011201:Poultry Diseases / Q000453:epidemiology / Q000382:microbiology; D012480:Salmonella Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D012481:Salmonella Infections, Animal / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents