Potential of Surface Water Gram-negative Bacterial Flora as a Reservoir of Heterogeneous Plasmid and Multi-drug Resistance Phenomenon
Fatema Akter
Department of Microbiology, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh and Department of Microbiology, Primeasia University, Banani, Dhaka 1213, Bangladesh
Md. Ishtiak Rashid
Department of Microbiology, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh
Sourav Biswas
Department of Microbiology, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh and Department of Microbiology, Gono Bishwabidyalay, Mirzanagar, Savar, Dhaka 1344, Bangladesh
Nazneen Jahan
Department of Microbiology, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh and Department of Mathematics and Natural Science, BRAC University, Mohakhali, Dhaka 1212, Bangladesh
Zia Uddin Ahmed
Department of Microbiology, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh
M. Hasibur Rahman *
Department of Microbiology, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh
*Author to whom correspondence should be addressed.
Abstract
Aims: Present study highlights the diversity of Gram-negative bacterial community at surface water and their potential as a reservoir of antibiotic resistance genes. We also explore the potential of this heterogeneous community to host plasmids of diverse origin.
Place and Duration of Study: The study was carried out at the Department of Microbiology, Jahangirnagar University, Bangladesh during a period from July 2016 to June 2017.
Methodology: Water samples were cultured onto MacConkey plates for selective isolation of Gram-negative bacteria and identified according to Bergey’s Manual of Systematic Bacteriology. Antimicrobial susceptibility was done by disc-diffusion method followed by determination of MIC assay by agar dilution method. Plasmid extraction was done according to the hot alkaline method.
Results: A total of 197 representative isolates from 310 water sample culture, 110 were identified as E. coli and 87 as non- E. coli belonged to 14 different species of the genera Escherichia, Enterobacter, Citrobacter, Klebsiella, Serratia, Proteus, Kluyvera, Obesumbacterium and Yersinia. Susceptibility test showed highest incidence of resistance phenomenon against amoxicillin (66.5%), followed by cefixime (56.8%), sulfamethoxazole-trimethoprim (33.5%), ciprofloxacin (20.3%), tetracycline (19.79%) and gentamicin (18.78%). A notable proportion of the isolates (33.9%) showed multi-antibiotic resistance (MAR) phenomenon. The occurrence of MAR phenotype was almost twice (42%) as much as in E. coli population in compared to non-E. coli (22%) population. Plasmid extraction revealed that majority (57%) of the isolates contained plasmids with 59 different profile, incidence and diversity being higher in E. coli population.
Conclusion: The study indicates that surface-water Gram-negative bacterial flora is a reservoir of plasmids and multidrug resistance gene. E. coli population seems to be more potential in compared to non- E. coli population as a reservoir of both multi-antibiotic resistance genes and heterogeneous plasmids.
Keywords: Plasmid, multidrug resistance, gram-negative bacteria