Title: Serotyping and determination of antimicrobial resistance patterns of Salmonella isolates from commercial birds and poultry environment in Mississippi
Authors: Pulido-Landinez M, Washington P, Thornton J, Zhang Y, Sanchez-Ingunza R, Banda A, Guard JY, Pinheiro Do Nascimen T, Magee D, Mauel MJ
Journal: Avian Dis
Accepted date: 2013 Oct 8
Interpretive summary: Intergenic sequence ribotyping (ISR) analyzes single nucleotide polymorphisms occurring around a 5s ribosomal gene to assign serotype to Salmonella enterica isolates. The purpose of this research was to compare the results obtained by ISR with those obtained with the traditional Kauffman-White-Le Minor (KWL) scheme for the characterization and serotyping of Salmonella enterica isolates from commercial birds and poultry environment, previously isolated at the Poultry Research and Diagnostic Laboratory, Mississippi State University. ISR assigned serotype to 50 Salmonella enterica isolates showing an almost perfect agreement ('=89.58) between ISR and KWL (43 out of 48 isolates). The ISR method was also able to detect possible mixtures of serotypes in the samples. The antimicrobial resistance patterns (ARPs) of 12 serotypes of S. enterica (Enteritidis, Typhimurium, Kentucky, Bredeney, Mbandaka, Saintpaul, Montevideo, Cubana, Lille, Senftenberg, Johanesburg and one serotype UN0094) were determined using the minimum inhibitory concentration values. The antibiograms demonstrated differences between Salmonella serotypes and among isolates of the same serotype. All isolates were 100% susceptible to enrofloxacin and trimethoprim/sulfamethoxazole. The number of antimicrobials to which the isolates were resistant ranged from 2 to 9. Twenty two different ARPs were identified. ARP1 was the most frequently observed with resistance to two antimicrobials (spectinomycin and sulfadimethoxine). Forty isolates (80%) were resistant to 3 or more antimicrobials meeting the criteria to be designated as multidrug resistant.