Higher prevalence of multidrug-resistant extended-spectrum β-lactamases producing in unorganized pig farms compared to organized pig farms in Mizoram, India.

AIM

The present study was conducted to record the prevalence of multidrug-resistant (MDR), extended-spectrum β-lactamases (ESBLs) producing from pig population of organized and unorganized farms of Mizoram and to record the presence of ESBLs, non-ESBLs, and integrons.

MATERIALS AND METHODS

Fecal samples were collected from pigs under organized (n=40) and unorganized (n=58) farms of Mizoram. Samples were processed for isolation and identification of by conventional techniques, BD Phoenix™ automated bacterial system, and polymerase chain reaction (PCR) based confirmatory test. All the isolates were subjected to antimicrobial sensitivity test by disk diffusion assay and ESBLs production by double-disk synergy test (DDST). The ESBLs producing isolates were subjected to PCR for determination of ESBLs genes and all the isolates were screened for non-ESBLs genes and integrons by PCR.

RESULTS

A total of 258 was isolated and identified from organized (n=120) and unorganized farms (n=138). Majority of the isolates exhibited high level of resistance against amoxicillin (Ax) (81.78%), cefalexin (85.42%), co-trimoxazole (50.78%), sulfafurazole (69.38%), tetracycline (65.89%), and trimethoprim (TR) (51.94%). Statistically highly significant (p<0.01) variations in resistance among the isolates from organized and unorganized farms were recorded in case of Ax, ampicillin, cephalexin, ciprofloxacin, co-trimoxazole, gentamicin, piperacillin, and TR. By DDST, 65.89% isolates were recorded as ESBLs producer, of which 82/120 (68.33%) and 88/138 (63.77%) were from organized and unorganized farms, respectively. A total of 29/258 (11.24%) isolates were positive for at least one ESBLs gene. was most frequently (9.69%) gene, followed by -M (5.04%) and (0.78%). Altogether, 6 (5.00%), 4 (3.33%), and 2 (1.67%) isolates from the organized farms were positive for , , and genes, respectively. Similarly, 21 (15.22%) and 7 (5.07%) isolates from the unorganized farms were positive for and genes, respectively. None of them were positive for genes. Altogether 57 (22.09%), 9 (3.49%), 66 (25.58%), 78 (30.23%), 21 (8.14%), and 18 (6.98%) isolates were positive for , , , , , and genes, respectively. The prevalence of non-ESBLs genes was higher in the isolates from the unorganized farms than organized farms.

CONCLUSION

MDR and ESBLs producing are circulating among the pigs and their environment in Mizoram. Pigs under unorganized farms exhibited higher level of resistance against majority of the antimicrobials, including third-generation cephalosporins, which might be an indication of overuse or misuse of antibiotics under the unorganized piggery sectors in Mizoram.