Profiling resistance pattern and assessing toxicity of coliform bacteria on the developmental stages of Artemia salina isolated from drinking water of northern part of Bangladesh

Abstract

Objectives: Scarcity of safe drinking water is a major health concern in Bangladesh. In this context, both commercially and locally available drinking water in the northern part of Bangladesh were assessed. Materials and Methods: Coliform bacteria were isolated on MacConkey agar media and morphological, physiological, biochemical, molecular characterization were also done. Antibiotic resistance pattern was tested through disc diffusion method. Acute toxicity assay was performed on stationary and exponential stages of Artemia salina development as well as significant variation was analyzed by Duncan multiple range test (DMRT) using statistical analysis software (SAS, version 9.1.3). Additionally, LC50 value was evaluated through probit mortality software against Artemia salina. Results: Among twelve samples, on MacConkey agar screening illustrated highest number of coliform colonies in Sample 1 (Isolate A)> Sample 7 (Isolate B)> Sample 9 (Isolate C) and were selected on the basis of colony number and morphology for microbiological and toxicological profiling. Molecular identification using 16S rRNA gene sequencing showed isolate A, B and C as Aeromonas sp. with 76%, Enterobacter sp. and Escherichia sp. with 96% homogeneity, respectively. Aeromonas sp. and Escherichia sp. were multi-drug resistant against penicillin, ceftazidime, doxycycline and cefuroxime. Among three isolates, Escherichia sp. showed highest toxicity on both stages of Artemia salina with abnormal organ formation (atypical head width, swimming leg missing, deformed ovary) and no Artemia salina survival was found in exponential phase after 8 hour. tD50 values were 6, 7 and 4 hour for Aeromonas sp., Enterobacter sp. and Escherichia sp., respectively. Moreover, highest toxic LC50 value was 48.32 0.17 ml for Escherichia sp. among three isolates. Conclusion: The present study is the first considerable evidence of coliform bacterial toxicity on Artemia salina development which indicates detrimental conseque