Molecular detection of extended-spectrum β-lactamase-producing Escherichia coli from bat caves on Lombok Island

Background: The discovery of antibiotic-resistant Enterobacteriaceae bacteria in wild animals is an indication of their potential for wildlife as a reservoir. Bats are natural reservoir hosts and a source of infection for several microorganisms and have the potential to become vectors for the spread of zoonotic diseases. Aim: A study was conducted based on these characteristics to identify and detect the blaTEM gene in Eschericia coli isolated from bat excrements in Tanjung Ringgit Cave, East Lombok. Methods: Bat fecal samples were firstly inoculated onto eosin methylene blue agar media. Recovered bacterial isolates were further characterized using standard microbiological techniques. Antimicrobial susceptibility testing was done using the Kirby-Bauer disc diffusion method. blaTEM gene detection was carried out using polymerase chain reaction (PCR). Results: Out of the 150 bat fecal samples obtained from Tanjung Ringgit cave, Lombok Island, Indonesia, 56 (37%) were positive for E. coli. Eight (8) out of the 56 E. coli isolates that underwent antimicrobial susceptibility testing using the disc diffusion method were confirmed to be multidrug-resistant as they exhibited resistance to at least three different classes of antibiotics. Out of the eight (8) multidrug resistance E. coli isolates recovered from fecal samples of bats, 2 (two) harbored the blaTEM gene. Conclusion: The discovery of the blaTEM gene in bat fecal samples indicates the potential for wild animals, especially bats, to spread ESBL resistance genes to the environment and to humans.