Molecular characterization of Campylobacter isolated from chickens and humans in northern Thailand.

A study was conducted in northern Thailand to characterize Campylobacter spp isolated from chickens at farms, slaughterhouse, and chicken meat at fresh markets, and stools from chicken farmers as well as neighboring crop farmers who served as controls. The Campylobacter isolates were collected during the rainy months of the years 2000, 2001, and 2002. Standard methods were used for primary isolation and identification of Camplobacter and the resulting isolates were frozen and stored in 30% glycerol with Mueller-Hinton broth at -70 degrees C until used in 2003. A multiplex PCR assay was used for differentiation of the Campylobacter spp. A total of 415 Campylobacter spp were isolated from 849 (48.9%) samples from chickens at the farm, slaughter house and fresh chicken meat market. Campylobacter spp were isolated from 5 of the 129 (3.9%) chicken farmers but none from the 100 neighboring crop farmers. C. jejuni was the most prevalent (42.5%) at the farm, followed by C. coli (39.1%) and other species (8.0%). In contrast, C. coli was the most prevalent at the slaughter house (72.4%) while C. jejuni was only 17.2% and others 3.4%. Similarly, at the fresh chicken market, C. coli was the most prevalent (54.4%) while C. jejuni was 26.5% and others were 13.2%. Campylobacter spp isolated from the chicken farmers were predominantly (75%) C. coli and the rest (25%) were C. jejuni. The results of the study show that both C. coli and C. jejuni are highly prevalent in chickens, along the chicken production system and in chicken farmers in northern Thailand. Critical control points for exposure and contamination of the chicken meat supply should be identified so that methods can be developed to protect human exposure to Campylobacter spp.

Prevalence of Salmonella and E. coli, and their resistance to antimicrobial agents, in farming communities in northern Thailand.

A cross-sectional pilot study was conducted in Chiang Mai, Thailand, to determine the prevalence of Salmonella and Escherichia coli in swine, broiler chickens and human workers from farms and abattoirs in northern Thailand, and compare their antimicrobial resistance profiles. Fecal samples and cloacal swabs were collected from 150 swine and 150 chickens at the farm. Fecal samples from swine, cloacal swabs from chickens, and carcass swabs from both animals were collected from 100 swine and 100 chickens at the abattoir. Stool samples were collected from 15 swine farm workers and seven chicken farm workers. Primary isolation and identification of Salmonella and E. coli were conducted using standard methods. In vitro susceptibility testing of Salmonella and E. coli was conducted using the broth microdilution method, based on the United States National Committee for Clinical Laboratory Standards (NCCLS) guidelines. The prevalence of Salmonella from swine and chicken samples ranged from 2% to 25%. The prevalence of E. coli in chickens and swine ranged from 36.8% to 47.6%. In humans, the prevalence of Salmonella was 15%, and the prevalence of E. coli ranged from 51% to 53%. Resistance in Salmonella was found for tetracycline (84.7%), nalidixic acid (27.1%), florfenicol (18.6%), ampicillin (13.6%), and ceftiofur (3.4%), and in E. coli for tetracycline (91.5%), nalidixic acid (67.4%), ampicillin (61.6%), florfenicol (51.8%), enrofloxacin (28.7%), ciprofloxacin (12.5%), ceftiofur (4.9%) and ceftriaxone (1.5%).