Enteric bacterial isolates and antimicrobial susceptibility patterns in captive non-human primates at Lwiro, Democratic Republic of Congo

Abstract

Lwiro Primates Rehabilitation Center (LPRC) is a home in Democratic Republic of Congo (DRC) for more than 85 chimpanzees and 105 monkeys of 11 different species, and who are victims (orphans) of pouching, illegal primate trading, agricultural expansion, road construction, logging among other Non-Human Primates (NHPs) population decreasing factors. The NHPs at LPRC regularly suffer from bacterial infections and are treated with various antibiotics. However, it was observed that the infections were persistent, and this suggested the possible emergence of antibiotic resistance at LPRC requiring further comprehensive investigation. The objective of the study was to characterize the enteric bacterial isolates and their antimicrobial susceptibility pattern in captive non-human primates in Lwiro, Democratic Republic of Congo. This was a cross-sectional study conducted in the sanctuary. Fresh fecal samples were collected, one sample from each primate during the study period between June and August of 2019. The collected samples were placed into sterile containers using sterile spatulas, with care to collect from the top of the samples to avoid ground contamination and they were immediately placed into enrichment medium at LPRC Laboratory and then transported chilled from LPRC to the Institute for Superior Medical Techniques (ISTM) laboratory for analysis. Bacteriological culture was performed, and isolates identified to species level morphologically and biochemically. Ten bacterial species associated with enteric bacterial infections in captive non-human primates (NHP) at Lwiro sanctuary were identified. Antimicrobial susceptibility of the bacterial isolates was tested against 14 commonly used antimicrobial agents in the sanctuary including amoxicillin, amoxicillin/clavulanic acid, imipenem, gentamycin, doxycycline, levofloxacin, meropenem, norfloxacin, oxacillin, tetracycline, ceftazidime, cefotaxime, amikacin, and ampicillin. In order of decreasing mean prevalence, the pathogens found in more than one NHP were: E. coli (33.8%), Enterobacter sp (22.3%), Staphylococcus sp. (18.9%), Staphylococcus aureus (17.3%), Klebsiella sp (13.7%), Citrobacter sp (4.1%), Serratia sp (2.0%), Enterobacter (1.8%), and Salmonella sp (1.4%). The bacterium Proteus sp. was only found in C. Ascanius at a prevalence of 4.3%. Most of the bacterial isolates were resistant to Amoxicillin, Imipenem, and Amoxicillin/Clavulanic Acid. Notably, Enterobacter sp and Proteus sp were 100% resistant to amoxicillin, gentamycin, and ceftazidime. Moderate resistance was observed against levofloxacin, ampicillin, doxycycline, norfloxacin and amikacin. The most effective drug was tetracycline. In conclusion, these results show that there are a number of enteric bacteria species in the primates within the sanctuary with widespread antimicrobial resistance against most of the tested antimicrobials. Most isolated bacteria have the potential to cause gastrointestinal diseases (mainly diarrhea and enteritis) in non-human primates and among caretakers in the sanctuary. Hence, it is recommended routine hygiene measures of the facilities and handwashing among the caretakers. Further, it is recommended conducting culture and sensitivity test for isolates from suspected gastrointestinal infections before any treatment is administered to NHP in the sanctuary.