Antibiogram signatures of non-cholera causing Vibrio species recovered from environmental niches in Eastern Cape, South Africa.

Abstract

Background: The use of antibiotics globally has helped reduce mortality and morbidity rate due to its ability to effectively treat bacterial infections in both humans and animals. However, the menace of antimicrobial resistance has become a challenge to public health due to its increased mortality and morbidity rate. This study determined the antibiogram pattern of non-cholera causing Vibrio species against a panel of 11 antibiotics that are wildly used for treatment. Multiple antibiotic resistance phenotype, multiple antibiotic resistant indices and minimum inhibitory concentration (MIC) of test antibiotics were also determined.Results: Polymerase chain reaction (PCR) was used to confirm 100 isolates of Vibrio parahaemolyticus, 82 and 46 isolates of Vibrio vulnificus and Vibrio fluvialis respectively, collected from the culture collections of the Applied and Environmental Microbiology Research Group (AEMREG), University of Fort Hare. Thereafter, disc diffusion method was used to determine the antibiogram pattern of target non-cholera causing Vibrio species against a panel of 11 antibiotics that are of clinical importance. The highest rate of Vibrio parahaemolyticus resistance was observed against tetracycline (22 %) and nalidixic acid (16 %). Vibrio fluvialis also displayed highest rate of resistance against tetracycline (28 %) and nalidixic acid (28 %), while Vibrio vulnificus isolates exhibited highest rate resistance against imipenem (40 %) and tetracycline (22 %). A total of 38 MARP patterns were observed and the MAR indices ranged between 0.3 and 0.8. Against the resistant Vibrio parahaemolyticus and Vibrio fluvialis isolates, minimum inhibitory concentration ranged from 16 µg/ml to 2048 µg/ml for both tetracycline and nalidixic acid, while against Vibrio vulnificus isolates, minimum inhibitory concentration ranged from 8 µg/ml to 256 µg/ml for both imipenem and nalidixic acid. Conclusions: Results obtained from this study is an indication that antibiotic resistant bacteria that could pose as threat to health of humans and animals are present in the environment.