Antibiotic Sensitivity Profiling and Virulence Potential of Campylobacter jejuni Isolates from Estuarine Water in the Eastern Cape Province, South Africa

is a zoonotic microbe and a major causative organism of diarrheal infection in humans that often has its functional characteristics inactivated in stressed conditions. The current study assessed the correlation between recovered and water quality parameters and the drug sensitivity patterns of the pathogen to frontline antibiotics in human and veterinary medicine. Water samples ( = 244) from rivers/estuarines were collected from April⁻September 2016, and physicochemical conditions were recorded on-site. was isolated from the samples using standard microbiological methods and subjected to sensitivity testing to 10 antibiotics. Mean counts were between 1 and 5 logs (CFU/mL). Ninety-five isolates confirmed as by PCR showed varying rates of resistance. Sensitivity testing showed resistance to tetracycline (100%), azithromycin (92%), clindamycin (84.2%), clarithromycin and doxycycline (80%), ciprofloxacin (77.8%), vancomycin (70.5%), erythromycin (70%), metronidazole (36.8%) and nalidixic acid (30.5%). Virulence encoding genes were detected in the majority 80/95, 84.2%) of the confirmed isolates from ; 60/95 (63.2%) from ; 49/95 (51.6%) from ; 45/95 (47.4%) from ; 30/95 (31.6%) from , and 0/95 (0%) from . A multiple resistance ABC active efflux pump system was present in 69/95 (72.6) isolates. The presence of was positively correlated with temperature ( = 0.17), pH ( = 0.02), dissolved oxygen ( = 0.31), and turbidity ( = 0.23) but negatively correlated with salinity ( = −0.39) and conductivity ( = −0.28). The detection of multidrug resistant strains from estuarine water and the differential gene expressions they possess indicates a potential hazard to humans. Moreover, the negative correlation between the presence of the pathogen and physicochemical parameters such as salinity indicates possible complementary expression of stress tolerance response mechanisms by wild-type strains.