Integrons are mobile DNA elements that allow for acquisition and dissemination of antibiotic-resistance genes among pig farm-derived bacteria. Limited information is available on integrons of Staphylococcus aureus from pig farms. The aim of this study was to characterise and investigate the prevalence of class 1 and 2 integrons in multi-drug resistant (MDR) S. aureus isolates from pig farms. A total of 724 swabs were collected from 12 pig farms in Chongqing, China, and examined by conventional microbial and molecular methods. In total, 68 isolates were S. aureus, 57 of which were methicillin resistant (MRSA). All 68 isolates were MDR strains and carried integrons, of which 88.2% (60/68) harboured both class 1 and 2. In addition, 85.3% (58/68) of the class 2 integron-positive isolates carried the β-lactam resistance gene (blaTEM₋₁), and 66.7% (40/60) of the class 1 integron–positive isolates carried the aadA1c, aadA1 or dfrA1 gene for respective streptomycin and spectinomycin or trimethoprim resistance. Class 1 and 2 integrons are common among the pig farm-derived S. aureus isolates. On account of their significance for public health, the prevalence of the integrons and their associated resistance genes in pig farm-derived S. aureus isolates should be paid special attention.

The article describes the occurrence and phylogenetic relationship of Salmonella isolates found in subcutaneous abscesses of leopard geckos. The aim of the study was to determine the cause of the abscesses and to characterise isolated Salmonella strains. Samples of abscesses from five animals and internal organs (lungs, liver, and gut) of three of them were tested for Salmonella according to the PN-EN ISO 6579:2002/A1:2007 standard. The antimicrobial resistance was evaluated by minimal inhibitory concentrations and the genetic similarity of the isolates was assessed with pulsed field gel electrophoresis (PFGE). In total, seventeen Salmonella isolates belonging to five different serovars were found to be susceptible to all tested antimicrobials except streptomycin. The serovars were S. Hadar, S. Fluntern, S. Tennessee, S. enterica subsp. salamae 55:k:z₃₉, and S. Kentucky. Up to three serovars from different organs were isolated from the same individual. In two geckos, Salmonella were detected in the lungs. In three serovars, XbaI-PFGE typing revealed indistinguishable isolates from organs and abscesses. Multiple Salmonella serovars might be involved in abscess formation and infections. The occurrence of the same PFGE profiles of the isolates may testify to the role of opportunistic organisms in causing infection.

Salmonellosis is a zoonotic disease, and Salmonella spp. can sometimes be found in dogs and cats, posing a risk to human health. In this study, the prevalence and antimicrobial susceptibility of faecal Salmonella were investigated in pet dogs and cats in Xuzhou, Jiangsu Province, China. Faecal samples from 243 dogs and 113 cats, at seven pet clinics, were tested between March 2018 and May 2019. Each Salmonella isolate was characterised using serotyping and antimicrobial susceptibility tests. The prevalence of Salmonella was 9.47% in dogs and 1.77% in cats. Among the 25 isolates, eight serotypes of Salmonella enterica subsp. enterica were detected, S. Kentucky (n = 11), S. Indiana (n = 5), and S. Typhimurium (n = 4) predominating. S. Derby, S. Toucra, S. Sandiego, S. Newport, and S. Saintpaul all occurred singly. The 23 Salmonella strains found in dogs were from seven different serovars, while the two strains in cats were from two. The highest resistance rates were found for tetracycline (92%), azithromycin (88%), cefazolin (84%), nalidixic acid (80%), ampicillin (80%), ceftriaxone (80%), and streptomycin (76%). Resistance to three or more antimicrobial agents was detected in 24 (96%) isolates. Most of the S. Kentucky and S. Indiana isolates were multi-drug resistant to more than 11 agents. The carriage rate was far higher in dogs than in cats from Xuzhou. Some isolated strains were highly resistant to antimicrobials used to treat infections in humans and pets, which may raise the risk of humans being infected with multi-drug resistant Salmonella via close contact with pets.