Antimicrobial resistance profiles in bacterial species isolated from fecal samples of free-ranging long-tailed macaques (Macaca fascicularis) living in Lopburi Old Town, Thailand

Background and Aim: At present, increasing in long-tailed macaques (Macaca fascicularis) population in Lopburi old town caused several problems in its community, in particular with sanitation problem. The present study aimed to explore species distribution and antimicrobial resistance patterns in bacteria isolated from feces of the free-ranging long-tailed macaques (Macaca fascicularis) in Lopburi Old Town, Thailand. Materials and Methods: Fresh fecal samples were collected from October 2018 to July 2019 from seven troops of macaques. Bacterial colonies were identified based on Gram stain and standard biochemical techniques. Sensitivity toward eight different antibiotics, including amoxicillin, amoxicillin-clavulanate, cephalexin, clindamycin, doxycycline, enrofloxacin, erythromycin, and gentamicin, was analyzed using the disk diffusion method. Results: A total of 1050 fecal samples were collected. Five unique bacterial species were identified, including Escherichia coli, Enterobacter spp., Proteus spp., Salmonella Group B, and Citrobacter spp. in 100%, 25.71%, 18%, 1.71%, and 0.57% of the fecal specimens, respectively. Among 70 distinct isolates of E. coli, 63 (93%) were resistant to multiple drugs, including amoxicillin, cephalexin, clindamycin, and erythromycin; one isolate (6%) was resistant to clindamycin only. Furthermore, 17 isolates (94%) of Salmonella Group B were resistant to both clindamycin and erythromycin. Five of the six Citrobacter spp. isolates (83%) were also multidrug-resistant (to cephalexin, clindamycin, and erythromycin); the one remaining Citrobacter spp. isolate (6%) was resistant to both clindamycin and erythromycin. However, a high percentage of E. coli, Salmonella Group B and Citrobacter spp. remained susceptible to amoxicillin-clavulanate, enrofloxacin, and doxycycline. Conclusion: Our findings provide the basic information for the selection of empirical therapy and for the evaluation of the scale of antibiotic resistance associated with macaques living in Lopburi Old Town.