Occurrence of qacE/qacEDelta1 genes and their correlation with class 1 integrons in salmonella enterica isolates from poultry and swine.

In this study, a total of 122 Salmonella enterica isolates from poultry and swine were assessed for susceptibility to clinically important antibiotics and to benzalkonium chloride (BKC). All isolates were examined for the presence of the antiseptic resistance genes qacE and qacEDelta1 and intl1 (class 1 integrase). The intl1-positive strains were further investigated for the presence of the 3' conserved region. The results demonstrated widespread distribution of qacEDelta1 (27%) but no isolate with qacE was observed. The intl1 gene was identified in 23 isolates (70%) with qacEDelta1. All of the intl1-postive strains carried qacEDelta1 in 3' conserved segment, confirming that the qacEDelta1 gene is linked to the integrons. Increased MIC value to BKC was independent of the presence of qacEDelta1, and multiple antibiotic-resistant bacteria were no more tolerant to BKC than the non-multidrugresistant strains, regardless of the presence of qacEDelta1.

Seroprevalence and risk factors associated with leptospirosis in dogs.

This study was done to determine the seroprevalence and risk factors of leptospirosis in dogs. From March to September 2004, a total of 210 dogs were randomly selected from the Small Animal Hospital, Faculty of Veterinary Medicine, Chiang Mai University. Dog sera were collected from the cephalic vein and kept at -20 degrees C until submitted to the National Institute of Health for a Microscopic Agglutination Test (MAT). Risk factors were analysed using logistic regression modelling. The prevalence of Leptospira antibodies was 11% (23/210). The most prevalent Leptospira serogroups were Bataviae 5.2% (11/210), Canicola 2.4% (5/210), Australis 1.4% (3/210), Icterohaemorrhagiae 1.4% (3/210), Ballum 0.5% (1/210), Djasiman 0.5% (1/210), Javanica 0.5% (1/ 210), Mini 0.5% (1/210), and Sejroe 0.5% (1/210). Risk factors, including signalment, environment and health status, were not significantly associated with leptospirosis antibodies. However, playing in sewage, staying outdoors >50% of the time, and consumption raw meat increased the risk of leptospirosis antibodies in dogs.

Serotypes and antimicrobial resistance of Campylobacter jejuni isolated from humans and animals in Thailand.

We investigated the serotypes, distributions, and antimicrobial resistance of Campylobacter jejuni isolates from humans and animals as a source of infection in poultry between 2002 and 2003. A total of 50 C. jejuni isolates from humans and 29 C. jejuni isolates from poultry were studied for serotype using the Penner serotyping scheme and the drug susceptibilities of the isolates which were determined for 7 antimicrobial drugs using the disk diffusion method. Serotype B (10%), serotype E (8%) and serotype R (8%) were found in humans isolates, while serotype A (27%) was most freguently isolated from poultry, followed by serotype K (21%) and serotype C (13%). Resistance in human isolates to cephalothin was high (100%). Resistance to trimethoprim/sulfamethoxazole, ciprofloxacin, and nalidixic acid were observed in 90, 82 and 78% of isolates, respectively. Most of the isolates (88%) were susceptible to erythromycin. High levels of resistance to drugs (ciprofloxacin and nalidixic acid) were observed in the isolates from poultry. These results indicate the importance of poultry as a reservoir of C. jejuni infection in Thailand is limited. In addition, a high proportion of the isolates were resistant to antimicrobial drugs, particularly the quinolone group.

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%).