Prevalence, antimicrobial resistance and staphylococcal toxin gene of blaTEM-1a-producing Staphylococcus aureus isolated from animals in Chongqing, China

Abstract

Background Livestock-associated Staphylococcus aureus is one of the most important etiological agents in both human and animals. It has been reported with high antimicrobial resistance and multiple staphylococcal superantigen genes in many countries and several provinces of China. However, large-scale investigation of this organism has not been documented in Chongqing, China. The aim of this study is to demonstrate the prevalence, antimicrobial susceptibility and some molecular characteristics of S. aureus acquired from animals in Chongqing. Results A total of 89 S. aureus isolates were cultured from 1371 samples picked up from March 2014 to December 2017. The isolates were originated from pigs (25), cattle (6), goats (10), rabbits (16) and chicken (32). Four MRSA strains were identified from 3 pig samples and 1 chicken sample. The isolates showed high resistance to penicillin (93.3%) and ampicillin (92.1%), but were more susceptible to amikacin and ofloxacin, since the resistance rates of these two drugs were less than 10%. Meanwhile, 74.2% isolates exhibited varying degree of MDR. Almost all strains, except for 3 chicken-originated isolates, were positive for blaTEM-1a, but did not harbor other ESBL genes. Nineteen staphylococcal SE/SEl/TSST-1 genes, except seq, were detected in isolates. The predominant genes were sei (58.4%), tst-1 (56.2%) and seg (51.7%). Conclusions The high antimicrobial resistance and prevalence of blaTEM-1a seriously reminded that it was urgent to standardize and cut down the usage of antimicrobials. The universal existence of staphylococcal toxin genes in isolated strains implied a potential threat of public health from animals to human through the food chain.

Global pathogenomic analysis identifies known and novel genetic antimicrobial resistance determinants in twelve species

“…TEM-116 was observed on three plasmids of which plasmid NZ_AJ437107.1 was observed in both GP and GN strains, suggesting a potential route of transfer. While blaTEM was only recently reported in S. aureus 50 , the S. aureus genomes we identified to harbor TEM-116 were isolated as early as 2009, suggesting that this transfer may be a much older phenomenon.…”