Antibiotic Resistance and Diversity of Salmonella enterica Serovars Associated with Broiler Chickens

Abstract

The objective of this study was to analyze the antibiotic resistance phenotype and genotype of Salmonella isolated from broiler production facilities. A total of 193 Salmonella isolates recovered from commercial farms in British Columbia, Canada, were evaluated. Susceptibility to antibiotics was determined with the Sensititre system. Virulence and antibiotic resistance genes were detected by PCR assay. Genetic diversity was determined by pulse-field gel electrophoresis (PFGE) typing. Seventeen serovars of Salmonella were identified. The most prevalent Salmonella serovars were Kentucky (29.0% of isolates), Typhimurium (23.8%), Enteritidis (13.5%), and Hadar (11.9%); serovars Heidelberg, Brandenburg, and Thompson were identified in 7.7, 4.1, and 3.6% of isolates, respectively. More than 43% of the isolates were simultaneously resistant to ampicillin, amoxicillin-clavulanic acid, ceftiofur, cefoxitim, and ceftriaxone. This β-lactam resistance pattern was observed in 33 (58.9%) of the Salmonella Kentucky isolates; 2 of these isolates were also resistant to chloramphenicol, streptomycin, sulfisoxazole, and tetracycline. Genes associated with resistance to aminoglycosides (aadA1, aadA2, and strA), β-lactams (blaCMY-2, blaSHV, and blaTEM), tetracycline (tetA and tetB), and sulfonamide (sul1) were detected among corresponding resistant isolates. The invasin gene (invA) and the Salmonella plasmid virulence gene (spvC) were found in 97.9 and 25.9% of the isolates, respectively, with 33 (71.7%) of the 46 Salmonella Typhimurium isolates and 17 (65.4%) of the 26 Salmonella Enteritidis isolates carrying both invA and spvC. PGFE typing revealed that the antibiotic-resistant serovars were genetically diverse. These data confirm that broiler chickens can be colonized by genetically diverse antibiotic-resistant Salmonella isolates harboring virulence determinants. The presence of such strains is highly relevant to food safety and public health.

Isolation, serotype diversity and antibiogram of Salmonella enterica isolated from different species of poultry in India

“…In the present study, antibiogram results revealed high resistance to beta-lactam antibiotics (oxacillin, penicillin, ampicillin) and clindamycin followed by colistin, nalidixic acid and tetracycline. Diarra et al reported in their study the similar pattern of resistance against beta-lactam antibiotics like ampicillin, amoxicillin-clavulanic acid, ceftiofur, cefoxitin and ceftriaxone [35] . Growing resistance towards beta-lactam antibiotics has been prevalent worldwide among members of Enterobacteriaceae from animal origin, especially in Salmonella sp.…”

The antibiotic resistome: what's new?

“…Mobile elements carrying antibiotic resistance genes are prevalent in food-borne bacteria we consume [16][17][18][19], and are potential sources of resistance genes for the human microbiome. These genes are enriched by the use of antibiotics in agriculture, which can impact the prevalence, diversity and mobility of antibiotic resistance genes.…”

Utilization of Pyrosequencing to Monitor the Microbiome Dynamics of Probiotic Treated Poultry (<i>Gallus gallus domesticus</i>) during Downstream Poultry Processing

“…For example, Campylobacter was found to be increasingly resistant to antibiotics such as fluoroquinolones and macrolides that are used as antimicrobials for the treatment of campylobacteriosis [11]. Additionally, the development of resistance to antibiotics by Salmonella has also been reported [12]. Hence, there is an increased necessity not only to minimize AGP use but also to develop novel non-antibiotic-based alternative treatments.…”