A cross-sectional survey on the prevalence and antimicrobial resistance of Salmonella in commercial and backyard chicken farms in Bangladesh

Abstract

A cross-sectional survey was conducted to find out the prevalence of
Salmonella in chicken farms in Chittagong by analyzing the fecal samples from
May to November 2009. Isolation and identification of Salmonella from fecal
samples were done according to the conventional methods and all the isolates
of Salmonella were tested for their sensitivity patterns to 9 antimicrobials. For farm prevalence of Salmonella, three categories of chicken farms were
targeted: commercial layer, commercial broiler and backyard. Seroprevalence
of Salmonella Pullorum was also done, having retrieved blood serum samples
from the serum bank maintained at the Department of Microbiology,
Chittagong Veterinary and Animal Sciences University (CVASU). This serum
bank was made, having collected serum samples from chickens of the
Participatory Livestock Development Project (PLDP) and Smallholder Livestock
Development Project-2 (SLDP-2) areas. The results showed that the farmprevalence of Salmonella in backyard and commercial layer farms were almost identical- 28 vs 23% (P=0.517), but a significant lower prevalence of Salmonella was observed in commercial broiler farms compared with backyard (P= 0.008) and layer (P=0.062) farms. Of the 288 serum samples tested 37 (9.5%) were seropositive for Salmonella Pullorum. However, there was no significant difference between seroprevalence of SP in the backyard chickens in two different areas (P=0.980). All the isolates were resistant to 4 antimicrobials tested, namely colistin sulphate, co-trimoxazole, oxytetracycline and penicillin. The antimicrobial sensitivities of the isolates of different production categories
varied widely