High Prevalence of Antibiotic Resistance in Escherichia coli Isolated from Fecal Sample of Cows and Assessment of Antibacterial Efficacy of Indigenous Medicinal Plants from Assam, India

Cow dung is the most common organic manure in agriculture in Assam, India. Escherichia coli were isolated from cow dung samples in between January to May, 2013. The isolates were tested for antibiotic sensitivity to multiple antibiotics and production of ESBLs as per the NCCLS guidelines, 2002 and genotypically through PCR for the presence of bla genes. E. coli were isolated in 80% of the total 100 samples, of which 15% showed resistance to multiple drugs. Of these 80 isolates, 59 (73.75%) were found to be resistant to at least one of the 3GCs. PCR data revealed blaTEM in 25/28 isolates, blaSHV in 6/28 isolates, blaCTX-M in 8/28 isolates and blaAmpC in 27/28 isolates; both blaTEM and blaSHV were present in 21.42%, blaTEM and blaCTX-M in 28.57%, blaSHV and blaCTX-M in 10.71%. ESBLs are the main cause of resistance to beta-lactam antibiotics in E. coli. ESBL mediating resistance to 3GC was found in 35% of isolates. The leaves of Holarhenna antidysenterica wall, and flowers of Woodfordia fructicosa (L.) Kurz were collected at the same time and its antibacterial activity was assessed against antibiotic resistant isolates. Methanolic crude extracts from these medicinal plants exhibited inhibitory activity against TEM+SHV encoding enteric isolates from cow. Detection of enteric ESBL producers in cows in Assam, India in high numbers imply the risk of dissemination of antibacterial resistance into the environment being relatively high and thus, warrant preventive measures.