Isolation and Drug Resistance Analysis of Escherichia coli and Salmonella spp. in Pork from Sichuan Province

Abstract

Abstract: One hundred and twenty-six pork samples were collected in Sichuan province. Escherichia coli and Salmonella spp. were isolated using selective medium. The isolates were identified by morphological characteristics and confirmed by 16s rDNA sequence analysis. The susceptibility to seventeen antibiotics was performed according to the standard disk diffusion method recommended by the Clinical and Laboratory Standards Institute (CLSI). The results showed that 105 E. coli and 17 Salmonella spp. were obtained with detection frequency of 83.33% and 14.28%, respectively. Of 105 E. coli isolates, 55.3% and 52.3% were resistant to tetracycline and ampicillin, respectively. The resistance frequency to other antibiotics decreased in the following order: K (26.7%) > S (19.1%) > CIP (17.1%) > NOR (14.3%) > KF (11.5%) > SAM (4.8%) > CRO, CTX, ATM, CN (2.9%) > CAE (1.9%) > AMC (0.8%) > AK (0.1%) > IPM (0%), TZP (0%). There were 28 resistance profiles. Among these resistance profiles, AMP, TET and AMP/TET profiles were dominant. In addition, 55.5%, 38.9% and 27.8% of 17 Salmonella isolates were resistant to tetracycline, ampicillin and streptomycin, respectively. The resistance frequency to other antibiotics decreased in the following order: SAM, AMC (11.1%) > CTX, K, KF, CN, CIP, NOR (5.6%) > CRO, CAE, IPM, ATM, TZP and AK (0%). There were 13 resistance profiles. The isolates in pork from Sichuan province had appeared a certain drug-resistant frequency. Although the resistance frequency was lower than other reports, the multi-drug resistance was common in the isolates from pork, suggesting that the isolates from pork should be cautioned because they may constitute a reservoir of antibacterial resistance.

Key words: Sichuan province, pork, Escherichia coli, Salmonella spp., drug resistance

CLC Number:

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