Antimicrobial resistance in Indian isolates of non typhoidal Salmonella of livestock, poultry and environmental origin from 1990 to 2017

A retrospective antimicrobial resistance study of nontyphoidal Salmonella enterica isolates from India during 1990-2017 was conducted to study the microbial susceptibility to antibiotics. A total of 271 Salmonella enterica isolates from poultry (n = 146), farm animals (n = 55) and environmental sources (n = 70) were tested for susceptibility using 15 antimicrobial drugs. The drug classes include aminoglycosides, phenicols, cephalosporins, penicillins, carbapenems, fluoroquinolones, and sulphonamide-trimethoprim. Study revealed that overall, 133 (49.08%) of 271 isolates were resistant to >= 1 antimicrobial drugs and 81 (29.89%) out of 271 isolates were multidrug resistant (resistance to >= 3 drugs). Majority (68.96%) of Typhimurium serovars (n = 87) were susceptible to all antibiotics tested, whereas only 5% Kentucky serovars (n = 40) were pan susceptible. All the drugs revealed decreasing trend of susceptibility from 1990 towards 2017 except cephalosporins and carbapenems. Statistical analysis of association between time period and antimicrobial resistance revealed a significance of < 0.05. Molecular detection of genetic determinants associated with antimicrobial resistance revealed the presence of genes like class I integrons, sul1, sul2, catIII, cmlA, dfrA, bla(TEM), bla(AmpC) in the resistant isolates. Furthermore, plasmid mediated quinolone resistant determinants like qnrD and qnrS were also reported in the current study.

Automated summary

The study conducted a retrospective analysis of antimicrobial resistance in non-typhoidal Salmonella enterica isolates from India between 1990 and 2017. Results showed that nearly half of the isolates (49.08%) were resistant to at least one antimicrobial drug, with almost a third (29.89%) being multidrug resistant. Typhimurium serovars demonstrated higher susceptibility compared to Kentucky serovars. The susceptibility to most antibiotics decreased over time, except for cephalosporins and carbapenems. Statistical analysis showed a significant association between time period and antimicrobial resistance. Genetic determinants associated with antimicrobial resistance were detected in resistant isolates, including genes like class I integrons, sul1, sul2, catIII, cmlA, dfrA, bla(TEM), bla(AmpC), as well as plasmid mediated quinolone resistant determinants qnrD and qnrS.