Pig farm environment as a source of beta-lactamase or AmpC-producing Klebsiella pneumoniae and Escherichia coli

Abstract

The present study was undertaken to detect the occurrence of beta-lactamase-/AmpC-producing Klebsiella and Escherichia coli in healthy pigs, feed, drinking water, and pen floor or surface soil. The study also intended to detect the clonal relationship between the environmental and porcine isolates to confirm the route of transmission. Rectal swabs and environmental samples were collected from apparently healthy pigs kept in organized or backyard farms in India. The pigs had no history of antibiotic intake. Production of phenotypical beta-lactamase, associated genes, and class I integron gene was detected in E. coli and Klebsiella isolates. The phylogenetic relationship among the isolates was established on the basis of Random amplification of polymorphic DNA banding pattern. Beta-lactamase-producing Klebsiella were isolated from healthy pigs (20.0%), pen floor swabs/surface soil swabs (14.0%), and drinking water (100%). Escherichia coli isolated from healthy pigs (14.4%), pen floor/surface soil (8.0%), and drinking water (33.3%) were detected as beta-lactamase producers. Majority of beta-lactamase-producing isolates possessed blaCTX-M-9. Further, 35 (81%) Klebsiella and all the E. coli isolates were detected as AmpC beta-lactamase ACBL producers and possessed blaAmpC. Sixteen beta-lactamase-producing Klebsiella (37.20%) and 13 E. coli (86.67%) possessed class I integron. Few resistant isolates from environmental sources (surface soil swab and drinking water) and the studied pigs were detected within the same cluster of the dendrogram representing their similarities. The study indicated about the possible role of contaminated environment as a source of beta-lactamase/AmpC-producing Klebsiella and E. coli in pigs.