The epidemiological relationship between Salmonella enterica serovar typhimurium and Salmonella enterica serovar 4,[5],12:i:- isolates from humans and swine in Thailand.

A total of 138 isolates of S. Typhimurium and S. 4,[5],12:i:- from humans and swine in Thailand during 2003-2006, were evaluated for antimicrobial sensitivity by the disk diffusion method against 10 antimicrobial drugs and pulsed-field gel electrophoresis (PFGE) with endonuclease Xbal to investigate the epidemiological relationship among isolates. It was found that all isolates were classified into 27 antimicrobial resistance patterns, and 80% of S. Typhimurium and 95.4% of S. 4,[5],12:i:- isolates were resistant to three or more antimicrobial agents. By PFGE testing, the 84 PFGE patterns were categorized into A to Z patterns. Eighty percent of S. Typhimurium and 71.3% of S. 4,[5],12:i:- isolates in 7 major PFGE patterns had close clonal relationships (_85% similarity). Our studies indicate the spread of genetically identical clones of S. Typhimurium and S. 4,[5],12:i:- in humans and swine in Thailand.

Detection of Campylobacter in duck using standard culture method and multiplex polymerase chain reaction.

In 2005, total of 140 samples of duck meat and intestine from slaughterhouses in Nakhon Pathom Province, Thailand, were analyzed for Campylobacter spp. Twenty-eight samples (20%) were positive for Campylobacter spp using the standard culture method (SCM) with 21 samples of C. jejuni and the other 7 C. coli. Forty-four samples (31%) were positive using multiplex polymerase chain reaction, with 34 samples of C. jejuni and 10 of C. coli. This is the first report of Campylobacter contamination in duck in Thailand.

Recovery of Salmonella using a combination of selective enrichment media and antimicrobial resistance of isolates in meat in Thailand.

From November 2004 to March 2005, 50 samples (chicken, pork and beef) of registered meat and non-registered meat were purchased from supermarkets and retail markets located in Bangkok, Thailand. Each sample was evaluated for Salmonella spp by a conventional method using combination of selective enrichment media (RV+MSRV) and compared with selective enrichment medium alone (DIASALM). Our study revealed the performance of RV+MSRV for the detection of Salmonella spp was significantly better than those of DIASALM alone since the recovery of Salmonella spp in both groups of meat was high using RV+MSRV, particularly in the registered meat. In addition, the recovery of serovars in registered meat was significantly higher than those in non-registered meat. Antimicrobial resistance of 62 Salmonella isolates in both groups of meat was determined for 10 antimicrobial drugs using the disk diffusion method. The results show that 100% of isolates from both groups were susceptible to amoxicillin/clavulanic acid, ciprofloxacin, cefotaxime and norfloxacin and 50-60% of isolates from both groups were resistant to tetracycline, streptomycin and ampicillin. Sixty percent of Salmonella isolates from meat showed multiresistance antimicrobial patterns.

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.