Detection of carbapenem resistant Escherichia coli in cattle and pigs

The aim of this study was to detect the presence of carbapenem resistant Escherichia coli (E. coli) in cattle and pigs. Altogether, 100 samples were collected, 50 each from cattle and pigs including mastitic milk and faecal samples from healthy as well as diarrhoeic cattle and faecal samples and slaughter specimens from pigs. Bacteria were isolated from the samples and antibiotic sensitivity test was carried out. Eight isolates of E. coli were obtained from cattle and 15 isolates from pigs. The phenotypic resistance patterns against carbapenems (ertapenem, imipenem and meropenem) were analysed. In cattle, the four isolates from milk were observed to be sensitive to all the three carbapenems whereas, all the isolates obtained from faecal samples were resistant to all the three carbapenems. The four faecal and three intestinal isolates of E. coli from pigs showed sensitivity to all the three carbapenems. From a total of 10 faecal samples from pigs, four, three and one isolates showed resistance to ertapenem, imipenem and meropenem respectively. Among five isolates from intestine, one isolate showed resistance to ertapenem and imipenem and no isolate showed resistance to meropenem. Polymerase chain reaction (PCR) was carried out to find the presence of carbapenem resistance genes (blaSHV, blaCTX, blaTEM and blaNDM) in all the 23 isolates and the results revealed that seven (58.3 per cent) E. coli isolates carried blaSHV gene and four (33.3 per cent) contained blaCTX gene which encodes carbapenem resistant enzymes. Antibiogram using 14 commonly used antimicrobial agents revealed varied multidrug resistant patterns among the E. coli isolates.

Keywords: Antibiogram, carbapenem resistance, Escherichia coli, multidrug resistance