Bacterial fauna associating with chironomid larvae from lakes of Bengaluru city, India - A 16s rRNA gene based identification

Abstract

Chironomid larvae that inhabit in aquatic sediments play an important role as vector for bacterial pathogens. Its life cycle consists of four stages i.e. eggs, larvae, pupae and adult. In the present study we identified bacterial species associated with whole larvae of chironomids from 11 lake sediments of Bangalore region using 16s rRNA gene Sanger sequencing. We found that larvae from all lake sediments associated with bacterial species which include key pathogens. Totally we identified 65 bacterial isolates and obtained GenBank accession numbers (KX980423 - KX980487). Phylogenetic tree constructed using MEGA 7 software and tree analysis highlight the predominant bacterial community associated with larvae which include Enterobacteriaceae (43.08%; 28 isolates) and Aeromonas (24.62%; 16 isolates), Shewanella, Delftia, Bacillus (6.15%; 4 isolates each), Pseudomonas (4.62%; 3 isolates) and Exiguobacterium (3.08%; 2 isolates). Current findings state that among bacterial population Aeromonas, Enterobacter and Escherichia with serotypes are commonly associated with larvae in maximum lake points. In other hand Vibrio, Pseudomonas, Klebsiella, Shigella, Bacillus, and other bacterial species were identified moderately in all lakes. Interestingly, we identified first time Shigella Gram negative, rod shaped pathogenic organism of Enterobacteriaceae and Rheinheimera Gram negative, rod shaped organism associating chironomid larvae.

Keywords

• Chironomid larvae
• Bacterial species
• 16s rRNA gene
• Sanger sequencing
• MEGA 7 software
• Phylogenetic tree