Enteropathogenic bacteria; Escherichia coli, Shigella spp. and Salmonella spp. in the gut of Decapterus russelli (Indian scad mackerel) from the coastline of western province, Sri Lanka
Date
2024-11-01
Authors
Alahakoon, A. S. S.
Imthikab, A. I. A.
George, G. D. N.
Polgolla, A. M. V. S. S.
Journal Title
Journal ISSN
Volume Title
Publisher
Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka
Abstract
Though fish is a common food source for humans, fish gut can harbour pathogenic bacteria such as Salmonella spp., Shigella spp., and Escherichia coli, which may pose health risks. Decapterus russelli (Indian scad mackerel) is a common fish found in the Indian Ocean and along the coastal waters of Sri Lanka. This study investigated the presence of human pathogenic bacteria in the gut of D. russelli, their antibiotic resistance, and the association between the presence of pathogens and sampling sites. A total of 15 D. russelli individuals were collected to represent five from each of the three locations; Negombo, Beruwala, and Muthuwella. Extracted fish guts were homogenized separately, and 100 μL of each sample was cultured on MacConkey agar. After incubation at 37 °C for 24 hrs., 42 colonies with different morphologies were selected and sub-cultured. These colonies were subjected to further analysis with IMViC tests: Sulfideindole-motility (SIM) agar, Methyl red-Vogues Proskauer (MR-VP) broth and Simmon’s citrate agar to determine different characteristics of Enterobacteriaceae. The suspected species were cultured on differential media. The study yielded seven Salmonella species, two Shigella species, and two enteropathogenic E. coli (EPEC) isolates. The antibiotic susceptibility test performed using Ampicillin, Erythromycin, and Chloramphenicol on Mueller-Hinton agar revealed that all seven Salmonella species, both Shigella species, and both EPEC samples were resistant to Ampicillin and Erythromycin. In contrast, two Salmonella species, and both EPEC isolates, were susceptible to Chloramphenicol while Shigella species showed an intermediate susceptibility. Salmonella species were found in all three locations and EPEC was present in both Beruwala and Negombo. However, Shigella species were exclusively found in the Beruwala samples. A Chi-square analysis (p > 0.05, likelihood ratio = 5.597) indicated no significant association between sample collection location and the presence of pathogenic bacteria.
Description
Keywords
EPEC , Fish gut , Indian scad , Salmonella species , Shigella species
Citation
Proceedings of the Postgraduate Institute of Science Research Congress (RESCON) -2024, University of Peradeniya, P 131