Multidrug resistant Salmonella enterica isolated from conventional pig farms using antimicrobial agents in preventative medicine programmes

Abstract

A longitudinal study was conducted to investigate the presence of multidrug antimicrobial resistance (multi-AR) in Salmonella enterica in pigs reared under conventional preventative medicine programmes in Spain and the possible association of multi-AR with ceftiofur or tulathromycin treatment during the pre-weaning period. Groups of 7-day-old piglets were treated by intramuscular injection with ceftiofur on four farms (n=40 piglets per farm) and with tulathromycin on another four farms (n=40 piglets per farm). A control group of untreated piglets (n=30 per farm) was present on each farm. Faecal swabs were collected for S. enterica culture prior to treatment, at 2, 7 and 180days post-treatment, and at slaughter. Minimal inhibitory concentrations of 14 antimicrobial agents, pulsed-field gel electrophoresis and detection of resistance genes representing five families of antimicrobial agents were performed. Plasmids carrying cephalosporin resistant (CR) genes were characterised. Sixty-six S. enterica isolates were recovered from five of eight farms. Forty-seven isolates were multi-AR and four contained bla genes harboured in conjugative plasmids of the IncI1 family; three of these isolates were recovered before treatment with ceftiofur. The most frequent AR genes detected were tet(A) (51/66, 77%), sul1 (17/66, 26%); tet(B) (15/66, 23%) and qnrB (10/66, 15%). A direct relation between the use of ceftiofur in these conditions and the occurrence of CR S. enterica was not established. However, multi-AR was common, especially for ampicillin, streptomycin, sulphonamides and tetracycline. These antibiotics are used frequently in veterinary medicine in Spain and, therefore, should be used sparingly to minimise the spread of multi-AR.

Antimicrobial resistance profile and prevalence of extended-spectrum beta-lactamases (ESBL), AmpC beta-lactamases and colistin resistance (mcr) genes in Escherichia coli from swine between 1999 and 2018

“…In addition, an increase of these MDR frequencies was observed in 2017 and 2018, being amoxicillin and tetracycline the antimicrobials with the highest levels of resistance (98.5 and 94.5% respectively). Similar resistance levels to these antibiotics have been previously described in enterobacteria from pig farms of Catalonia in 2002 [9,10]. According to the EMA [11], tetracycline was the most sold antibiotic family for animal production in Spain from 2010 to 2015 and is still highly used in pigs and other species.…”

“…One hundred and sixty pathogenic E. coli strains isolated from swine enteric clinical cases were randomly recovered from the strain collection of the Infectious Diseases Laboratory of the Veterinary Faculty of Barcelona (Spain) between 1999 and 2014 (8)(9)(10)(11)(12)(13)(14)(15)(16) strains per year). Those cases came from farms of different counties of Spain with neonatal or post-weaning diarrhoea problems.…”

Antimicrobial Resistance of Common Zoonotic Bacteria in the Food Chain: An Emerging Threat

“…The ranges of FQ resistance, however, varied extremely among the countries and even regions. In Spain, for example, isolates from pigs in Catalonia (50%) [28] and humans in Extremadura (35%) [29] exhibited much higher levels of FQ resistance than reported by EFSA/ECDC for Spain (7 and 14.8%, respectively).…”

Putting the microbiota to work: Epigenetic effects of early life antibiotic treatment are associated with immune-related pathways and reduced epithelial necrosis following Salmonella Typhimurium challenge in vitro

“…It is an important cause of food-borne zoonoses worldwide, being associated with millions of cases of gastroenteritis and bacteremia in humans every year [1]. Pigs are an important infection source for humans, as they can shed the pathogen without clinical signs or become chronic carriers, increasing the risk of carcass contamination [2,3]. S. enterica serovars lead to fibrinonecrotic enterocolitis, diarrhea and dehydration in pigs.…”