High level of contamination of antimicrobial drug resistant non-typhoidal Salmonella enterica in commercial poultry and its surroundings in Chitwan, Nepal

BackgroundAntimicrobial resistance (AMR) among bacterial pathogens is a fast-growing public health concern. AMR in non-typhoidal Salmonella species among food animals is of special concern as this may transmit resistant pathogens to humans during handling or consumption of animal products. In Nepal, the possibility of AMR Salmonella species among food animals is an important area of research, particularly in light of the rapidly growing poultry industry, lack of surveillance, and paucity of studies that have been conducted. MethodsTaking one health approach, a cross-sectional study was carried out in Chitwan district of Nepal between May and October 2017. Various environmental samples viz. farm litter, feed, water, poultry feces, vehicle swabs, farm swabs from 12 broiler poultry farms and various sections of poultry carcasses from 21 slaughter houses were aseptically collected. These were microbiologically assessed for the presence of non-typhoidal Salmonella and their phenotypic and genotypic indicators of antimicrobial resistance. ResultsOverall, Of 62 environmental samples collected, 31(50%) tested positive for Salmonella enterica serovars with environmental swabs (70%, 8/12) being the most culture positive sample types. Similarly, of 159 tissue samples collected from 24 carcasses, 79% (126/159) were culture positive for Salmonella enterica. Nearly 97% (153/157), 11% (17/157), 5% (8/157) and none of isolates showed resistance to tetracycline, ciprofloxacin, azithromycin and meropenem respectively. Some 83% (131/157), 40% (64/157), 8% (13/157) and 0.6% (1/157) of isolates tested positive for tetA, QrnS, mefA and VIM-1 AMR genes corresponding to the above antimicrobials respectively.ConclusionsThis study revealed gross contamination of farms and subsequent poultry meat samples with Salmonella enterica serovars that were resistant to several clinically applicable antimicrobials. This reinforces an urgent need to implement proper biosecurity approaches from farms to slaughter houses and strengthen policies to cease the rampant use of clinically important antimicrobials in poultry.