Nipa Chokesajjawatee

Distribution and Genetic Profiles of Campylobacter in Commercial Broiler Production from Breeder to Slaughter in Thailand

Poultry and poultry products are commonly considered as the major vehicle of Campylobacter infection in humans worldwide. To reduce the number of human cases, the epidemiology of Campylobacter in poultry must be better understood. Therefore, the objective of the present study was to determine the distribution and genetic relatedness of Campylobacter in the Thai chicken production industry. During June to October 2012, entire broiler production processes (i.e., breeder flock, hatchery, broiler farm and slaughterhouse) of five broiler production chains were investigated chronologically. Representative isolates of C. jejuni from each production stage were characterized by flaA SVR sequencing and multilocus sequence typing (MLST). Amongst 311 selected isolates, 29 flaA SVR alleles and 17 sequence types (STs) were identified. The common clonal complexes (CCs) found in this study were CC-45, CC-353, CC-354 and CC-574. C. jejuni isolated from breeders were distantly related to those isolated from broilers and chicken carcasses, while C. jejuni isolates from the slaughterhouse environment and meat products were similar to those isolated from broiler flocks. Genotypic identification of C. jejuni in slaughterhouses indicated that broilers were the main source of Campylobacter contamination of chicken meat during processing. To effectively reduce Campylobacter in poultry meat products, control and prevention strategies should be aimed at both farm and slaughterhouse levels.

Distribution, quantitative load and characterization of Salmonella associated with swine farms in upper-northern Thailand.

This study was conducted to analyze the prevalence and quantitative loads of Salmonella spp. on pig farms in Chiang Mai, Lamphun, Thailand to assess loading levels before slaughtering. The serotype diversity, antimicrobial-resistance pattern and pulse-field type of Salmonella spp. were also characterized to assess the dynamic propagation of the pathogen. The Salmonella-positive prevalence was 246/805 (30.56%), and the quantitative loads varied from 1.48~4.04 Log10MPN/g, with a mean ± standard deviation of 2.11 ± 0.57. AMP/S/TE (ampicillin/streptomycin/tetracycline) was the highest frequency antimicrobial resistance pattern found in this study. In addition, Salmonella Rissen was the primary serotype in this region. PFGE results indicated the occurrence of infection by cross contamination among pig farms. Our study showed that pork is easily contaminated with this pathogen. Farm control programs must be based on strict biosecurity and hygienic measures, which could further reduce the contamination pressure at slaughterhouses or retail shops.

Determination of Sperm Sex Ratio in Bovine Semen Using Multiplex Real-time Polymerase Chain Reaction

Gender selection is important in livestock industries; for example, female calves are required in the dairy industry. Sex-sorted semen is commonly used for the production of calves of the desired gender. However, assessment of the sex ratio of the sorted semen is tedious and expensive. In this study, a rapid, cost effective and reliable method for determining the sex ratio was developed using a multiplex real-time polymerase chain reaction (PCR) assay. In this assay, the X and Y chromosome-specific markers, i.e., bovine proteolipid protein (PLP) gene and sex-determining region Y (SRY) were simultaneously quantified in a single tube. The multiplex real-time PCR assay was shown to have high amplification efficiencies (97% to 99%) comparable to the separated-tube simplex real-time PCR assay. The results obtained from both assays were not significantly different (p>0.05). The multiplex assay was validated using reference DNA of known X ratio (10%, 50%, and 90%) as templates. The measured %X in semen samples were the same within 95% confidence intervals as the expected values, i.e., >90% in X-sorted semen, <10% in Y-sorted semen and close to 50% in the unsorted semen. The multiplex real-time PCR assay as shown in this study can thus be used to assess purity of sex-sorted semen.

Climatic factors and prevalence of Campylobacter in commercial broiler flocks in Thailand

&NA; Campylobacter are bacteria associated with human foodborne disease worldwide. Poultry and poultry products are generally considered as a main source of these organisms. Compared to temperate zones, baseline information on Campylobacter in tropical regions is limited. Thus, the objectives of the present study were 1) to determine the prevalence of Campylobacter in Thai broiler flocks and 2) to investigate the association between climatic factors (i.e., rainfall, ambient temperature, and relative humidity) and Campylobacter colonization status of broiler flocks in Thailand. A total of 442 commercial broiler flocks reared in the central and northeastern regions of Thailand during 2012 to 2014 were investigated. Campylobacter positive status was identified in 252 examined flocks (57.01%; 95% CI 52.39 to 61.63%). Prevalence of Campylobacter in the northeastern region (54.46%; 95% CI 44.76 to 63.83%) was slightly lower than that of the central region (57.77%; 95% CI 52.47 to 62.90%). More than 65% of Campylobacter positive flocks in the central and northeastern regions had within‐flock prevalence higher than 75%. Generalized estimating equations (GEE) revealed that the increased rainfall and relative humidity were associated with the increase of Campylobacter colonization in broiler flocks (P ≤ 0.05), while no relationship between ambient temperature and Campylobacter colonization status was identified.

Repetitive sequence-based PCR fingerprinting and the relationship of antimicrobial-resistance characteristics and corresponding genes among Salmonella strains from pig production

Abstract Objective To investigate the relationship between antimicrobial resistance characteristics and corresponding genes, and to diversify repetitive element sequence-based PCR (rep-PCR) fingerprinting of three Salmonella serotypes: Rissen, Panama and Stanley, which were isolated from pig farms and slaughterhouses in Chiang Mai and Lumphun Provinces, Thailand. Methods A total of 90 Salmonella strains were identified using the Kauffman-White scheme. The Kirby-Bauer disk diffusion method was used to investigate resistance phenotypes of 10 antimicrobial agents. Conventional PCR was used to detect 10 antimicrobial resistance genes, additionally, rep-PCR typing method was applied to identify clonality among Salmonella isolates. Results The antimicrobial susceptibility testing found resistance to ampicillin (80.0%), streptomycin (65.6%), tetracycline (61.1%), sulfamethoxazole (53.3%), chloramphenicol (28.9%), nalidixic acid (6.7%) and cefotaxime (2.2%). All strains were sensitive to amoxicillin-clavulanic acid, ciprofloxacin and norfloxacin. The most common antimicrobial resistance patterns among the isolates were ampicillin, chloramphenicol, streptomycin, tetracycline, and sulfamethoxazole. The type and frequency of antimicrobial genes detected included bla TEM (100.0%), aad A2 (52.2%), cml A (45.6%), str A (38.9%), tet A(B) (16.7%), sul 1 (15.6%), bla OXA-2 (14.4%), bla PSE1 (6.7%), aph A1-lab (2.2%) and blaCMY-2 (1.1%). Conclusions Statistical analysis revealed no association between antimicrobial resistance genes and resistance profiles with the exception of cml A and chloramphenicol, sul 1 and sulfamethoxazole, aad A2 and streptomycin, and str A and streptomycin ( P Salmonella genotypes from farms and from slaughterhouses.