title: Antimicrobial resistance of non-typhoidal Salmonella isolates from egg layer flocks and egg shells.
abstract: This study was conducted to examine the antimicrobial resistance (AMR) of Salmonella spp. isolated from commercial caged layer flocks in New South Wales and South Australia. All Salmonella isolates (n=145) were subjected to phenotypic and genotypic characterisation of AMR and carriage of integrons. The majority of Salmonella isolates (91.72%) were susceptible to all antimicrobials tested in this study. Limited resistance was observed to amoxicillin and ampicillin (5.51%), tetracycline (4.13%), cephalothin (2.06%) and trimethoprim (0.68%). None of the isolates were resistant to cefotaxime, ceftiofur, ciprofloxacin, chloramphenicol, gentamycin, neomycin or streptomycin. A low frequency of Salmonella isolates (4.83%) harboured antimicrobial resistance genes and a class 1 integron. The most commonly detected AMR genes among the Salmonella isolates were blaTEM (2.07%), tet A (1.38%) and dhfrV (0.69%). Overall, Salmonella enterica isolates exhibited a low frequency of AMR and represent a minimal public health risk associated with the emergence of multidrug resistant Salmonella spp. from the Australian layer industry.
authors.affiliation: School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA 5371, Australia.
authors.forename: Vivek V
authors.initials: VV
authors.lastname: Pande
authors.affiliation: School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA 5371, Australia.
authors.forename: Vaibhav C
authors.initials: VC
authors.lastname: Gole
authors.affiliation: School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA 5371, Australia.
authors.forename: Andrea R
authors.initials: AR
authors.lastname: McWhorter
authors.affiliation: School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA 5371, Australia.
authors.forename: Sam
authors.initials: S
authors.lastname: Abraham
authors.affiliation: School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA 5371, Australia. Electronic address: kapil.chousalkar@adelaide.edu.au.
authors.forename: Kapil K
authors.initials: KK
authors.lastname: Chousalkar
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001315:Australia; D002645:Chickens / Q000382:microbiology*; D004352:Drug Resistance, Microbial / Q000235:genetics; D004528:Egg Shell / Q000382:microbiology*; D032023:Integrons / Q000235:genetics; D008826:Microbial Sensitivity Tests; D012475:Salmonella / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D019779:Salmonella enterica / Q000235:genetics; D013021:South Australia
chemical_list: D000890:Anti-Infective Agents
keywords: Antimicrobial resistance; Eggs; Layer; Salmonella