Antimicrobial resistance patterns of faecal E. coli and Salmonella in wild animals in eastern wildlife region of Sri Lanka

Resistance to antimicrobials is a worldwide problem in both human and veterinary medicine. Exposure to antimicrobials is commonly attributed to the maintenance of resistance in bacterial populations. Commensals like Escherichia coli (E. coli) can easily acquire and transfer resistance genes. The present study was conducted to identify antimicrobial resistance (AMR) profiles of E. coli and Salmonella isolated from faecal samples of wild animals. During the period of December 2015 to June 2016, samples were collected from 26 birds, 25 mammals and three reptiles within the Eastern Wildlife Health Region of Sri Lanka, which covers approximately 125,576 hectares. Isolation rates of E. coli and Salmonella from faecal samples were 37.03% (20/54) and 18.51% (10/54) respectively. Nine of the 20 E. coli isolates (45%) were resistant to ampicillin and 7 (35%) to trimethoprim+sulfamethoxazole and tetracycline. Two E. coli isolates were resistant to more than 6 antimicrobials tested. All 20 E. coli isolates were susceptible to amikacin and imipenem and 19 (95%) were susceptible to ceftriaxone and gentamicin. Out of the 10 Salmonella isolates, four were resistant to ampicillin and tetracycline, while 2 were resistant to trimethoprim+sulfamethoxazole. Ten percent resistance was observed against each nalidixic acid, streptomycin, and ciprofloxacin. Multiple Drug Resistant (MDR, i.e. not susceptible to at least one agent in at least three antimicrobial classes) E. coli and Salmonella were recovered from Jungle Cat (Felis chaus), Jungle Fowl (Gallus lafayetti), and Serpent Eagle (Spilornis cheela). These AMR and MDR patterns indicate a threat to wildlife and the necessity of conducting a detailed study to identify the possible sources of wildlifecontamination.