Evaluation and Characterization of Salmonella and Shigella Species from Abattoir Effluents and Receiving Watersheds in Ikpoba River, Benin City, Nigeria

Abstract

This study aimed at assessing abattoir effluents and receiving
water bodies for the presence of Salmonella and Shigella species
as well as biofilm formation potential and antibiotic
susceptibility profile. A total of 24 samples were collected from
different sampling points (point of slaughter, discharge point,
200-M upstream and 200-M downstream) between July and
December 2018. The samples were evaluated for Salmonella
and Shigella species using standard culture-based techniques
and an analytical profile index (API 20E) was used to identify
the respective bacteria isolates. Antibiotic resistance profile was
determined using the disc diffusion method and biofilm
formation was evaluated using the microtitre plate method. The
occurrence of Salmonella and Shigella isolates in this study is
as follows: point of slaughter [13(22.03%), 11(24.44%)];
discharge point [22(37.28%), 15(33.33%)]; 200-M upstream
[8(13.56%), 7(15.56%)] and 200-M downstream [16(27.12%),
12(26.67%)] respectively. Biofilm formation profile of the
Salmonella and Shigella species in this study is as follows:
strong biofilm formation [22(37.29%), 9(20%)]; moderate
biofilm formation [20(33.89%), 22(48.89%)]; weak biofilm
formation [9(15.25%), 14(31.11%)] and those negative for
biofilm formation [8(13.56%), 14(31.11%)] respectively. The
resistance profile of Salmonella and Shigella species for
ampicillin [25(42.4%), 12(20.3%)]; amoxicillin-clavulanate
[13(22.0%), 5(8.5%)]; azithromycin [27(45.8%), 13(22.0%)];
tetracycline [15(25.4%), 6(10.2%)]; chloramphenicol
[31(52.5%), 15(25.4%)]; fosfomycin [27(45.8%), 11(18.6%)]
and gentamicin [10(16.9%), 3(5.1%)] respectively. Findings
from this study could be used as a baseline study to investigate
pathogenic and multi-drug resistant Salmonella and Shigella
isolates in abattoir environments.