Prevalence of Campylobacter spp. by cdtB gene-based multiplex PCR in chicken meat, lettuce and drinking water from Bangkok and suburb area.

Abstract

Campylobacter is a bacterium mainly causing diarrhea illness and leading to fatal in humans. It is indicated as the health problems and poor hygienic practice. The aim of this study was to determine the prevalence of Campylobacter spp. contamination in a total of 180 samples, consisting of chicken meat, lettuce and drinking water, 60 samples for each. The samples from 25 g of chicken, 50g of lettuce and 2 L of drinking water filtrated with a membrane size of 0.45 micron were inoculated into Bolton broth at 37°C in an atmosphere with a gas mixture (5% O₂, 10% CO₂ and 85% N₂) for 24 hours. Then bacterial suspensions were prepared for DNA extraction and inoculated on modified cefoperazone charcoal deoxycholate agar (mCCDA) agar plates. The plates were incubated at 37° C in the same atmosphere with the gas mixture for 48 hours. Colonies grown on plates were swept from the first and second streak planes for DNA extraction. The DNAs extracted from Bolton broth and colonies were used for detecting Campylobacter by cdtB gene-based multiplex PCR. Using the direct Bolton broth, Campylobacter spp. were detected in 9 samples,  5 samples from chicken (8.3%), 2 samples from lettuce (3.3%), and 2 samples from drinking water (3.3%). Of the 9 samples, 6 samples (3.3 %) were identified as C. coli and 3 samples (1.7%) were C. jejuni. The results from colonies revealed that Campylobacter spp. were detected in 18 samples comprising 8 samples of chicken (13.33%), 8 samples of lettuce (13.3%) and 2 samples of drinking water (3.3%).  Of the 18 samples, 11 samples (6.1%) were identified as C. coli, 6 samples (3.3%) were C. jejuni and 1 sample (0.6 %) was C. fetus. Our study revealed the contamination of Campylobacter in chicken meat, lettuce and drinking water. With cdtB gene-based multiplex PCR method, 50% of Campylobacter could be detected from colony, more than those detected from the Bolton broth directly. This result demonstrates that Campylobacter spp. is contaminated in food and water, and thus the risks of these infections in both humans and animals. In addition, cdtB gene-based multiplex PCR method can be used to detect this bacterium in food and drinking water, and simultaneously identify the species level of Campylobacter which is the main cause of pathogen.