New Family of Multilevel Matrix Converters for Wind Power Applications: Final Report, July 2002 - March 2006

The goal of this project was to develop a new modular multilevel matrix converter for wind power applications and to demonstrate a working scale model in the laboratory

Characterization of Klebsiella pneumoniae complex isolates from pigs and humans in farms in Thailand: population genomic structure, antibiotic resistance and virulence genes

Objectives: To define characteristics of Klebsiella pneumoniae complex (hereafter KP) isolates from healthy pigs, farm workers and their householdmembers in Thailand.Methods: A total of 839 individual rectal swabs from pigs on 164 farms and 271 faecal samples of humans working on pig farms and persons living in the same household in Khon Kaen, Thailand were screened for gut colonization by KP. Genomic sequenceswere investigated for antibiotic resistance and virulence genes. Phylogenetic analyseswere performed in addition to comparison with isolates from previous studies from Thailand.Results: KP was detected in approximately 50% of pig and human samples. In total, 253 KP isolates were obtained: 39% from pigs, 34% from farmers and 26% from individuals living on the same farm but without animal contact. MLST revealed high genetic diversity with 196 different STs distributed over four phylogroups (Kp1 to Kp4). Low prevalence of ESBL-KP (7.5%) and colistin-resistant KP (3.2%) was observed among pigs and humans. Remarkably, four convergent MDR and hypervirulent strains were observed: one from pigs (ST290) and three from humans [ST35, ST3415 (strain 90CP1), ST17 (strain 90CM2)]. Sharing of KP clones among pigs and humans was identified for some STs including ST4788, ST661, ST3541 and ST29.Conclusions: The study indicated a low prevalence of ESBL and mcr genes among KP isolated from pigs and healthy humans in Thailand and suggested the possibility of zoonotic transmission for a subset of circulating KP clones

OXA-48-positive carbapenem-resistant Enterobacteriaceae in a farrow-to-finish pig farm: First report in Thailand

Carbapenem-resistant Enterobacteriaceae (CRE) have emerged as an urgent threat to public health. This study aimed to determine the occurrence of CRE and the carbapenemase genes in a farrow-to-finish pig farm, and to investigate carriage proportion and maintenance of CRE during the pig production cycle. We conducted a cross-sectional study by collecting 200 rectal swabs from healthy pigs of 5 groups: gilts, sows, piglets, weaners, and fatteners. In the longitudinal study, 20 healthy pigs were followed from 2 to 26 weeks old, and rectal swabs were collected from each pig for 5 times. Samples were screened for CRE using MacConkey agar supplemented with meropenem at 0.5 µg/mL. Identification and antimicrobial susceptibility pattern of the recovered isolates were determined using an automated system. PCR was used to detect carbapenemase genes. The occurrence of Enterobacteriaceae isolates with the carbapenem resistant phenotype and/or harboring the blaOXA-48 gene was 3% (6/200) in the cross-sectional study. Groups of sows and piglets had the same occurrence rate at 5% (2/40), while weaner and fattener groups had 2.5% (1/40). In the longitudinal study, CRE were not detected in pigs at an early age; however, two isolates were detected at the age of finishing. This study is the first report of Enterobacteriaceae with a carbapenem resistant phenotype and/or carrying blaOXA-48 gene in pigs in Thailand. Finding CRE in pigs at all age categories including finisher in the study farm underscores the need for active monitoring and surveillance studies to determine the occurrence of CRE in pig farms in Thailand

Exploring the Antibiotic Resistance Burden in Livestock, Livestock Handlers and Their Non-Livestock Handling Contacts: A One Health Perspective

Antibiotics are freqeuently used in the livestock sector in low- and middle-income countries for treatment, prophylaxis, and growth promotion. However, there is limited information into the zoonotic prevalence and dissemination patterns of antimicrobial resistance (AMR) within these environments. In this study we used pig farming in Thailand as a model to explore AMR; 156 pig farms were included, comprising of small-sized (= 100 sows) farms, where bacterial isolates were selectively cultured from animal rectal and human fecal samples. Bacterial isolates were subjected to antimicrobial susceptibility testing (AST), and whole-genome sequencing. Our results indicate extensive zoonotic sharing of antibiotic resistance genes (ARGs) by horizontal gene transfer. Resistance to multiple antibiotics was observed with higher prevalence in medium-scale farms. Zoonotic transmission of colistin resistance in small-scale farms had a dissemination gradient from pigs to handlers to non-livestock contacts. We highly recommend reducing the antimicrobial use in animals' feeds and medications, especially the last resort drug colistin

Prevalence, genetic characterization, and antimicrobial resistance of Salmonella isolated from meat goats in the Northeastern region of Thailand

This study aimed to determine the prevalence, genotypic diversity, and antimicrobial resistance pattern of Salmonella isolated from meat goats in the Northeastern region of Thailand. A total of 1,014 rectal swabs were collected from 30 meat goat farms during April to November, 2018. Salmonella was isolated and identified according to the International Organization for Standardization protocol (ISO-6579:2002/AMD:2017) and serotyped using a slide agglutination test following the Kauffmann-White scheme. An antimicrobial susceptibility test to determine minimal inhibitory concentration (MIC) of 12 antimicrobial agents was performed using a broth microdilution method following the CLSI protocol (2017). Pulsed-field gel electrophoresis (PFGE) of XbaI digested chromosomal DNA was used to determine genotypic diversity of the isolates. The overall prevalence of Salmonella in the meat goats was 1.28%. A total of 13 Salmonella isolates recovered from the meat goats belonged to 4 serovars includings. Weltevreden (n=4), S. Bovismorbificans (n=4), S. Paratyphi B (n=4), and S. Stanley (n=1). Antimicrobial susceptibility testing revealed 2 antibiogram patternS. Eleven Salmonella isolates were susceptible to all antimicrobial agents tested, except sulfamethoxazole, and the other 2 isolates were susceptible to all antimicrobials. Genetic characterization of 13 Salmonella isolates by PFGE revealed 9 PFGE patterns that were grouped into 4 major clusters, A, B, C and D, with an 80% similarity value. This study revealed a low prevalence of Salmonella in meat goats in the Northeastern region of Thailand. Salmonella isolates were susceptible to most antimicrobials tested, with a very high proportion of resistance to sulfamethoxazole being observed

Epidemiology and Antimicrobial Resistance of Salmonella Isolated from Racehorses and Horsemen in Northeastern Thailand

Salmonella is one of the major causes of foodborne diseases in humans. These bacteria can colonize within the gastrointestinal tracts of both humans and animals, and there have been reports of incidences of Salmonella in horses. This study aimed to investigate the prevalence, serotypes, and antimicrobial resistance of Salmonella isolates from racehorses and horsemen, as well as to explore the possible transmission between horses and humans. Fecal samples from racehorses (247 samples) and horsemen (33 samples) were collected from horse farms located in 3 provinces of upper Northeastern Thailand between March and August 2019. Salmonella was isolated and identified. Broth microdilution was used to determine the minimal inhibitory concentrations (MICs) of the antimicrobial agents for antimicrobial. Salmonella isolates were detected in 4.86% (12/247) of racehorses and 3.03% (1/33) of horsemen. The most commonly found serotypes in the isolates obtained from the racehorses were Abony (25%) and Iganda (16.67%). Only the Tumodi II serotype was found in one horseman. Salmonella isolates collected from the racehorses had been the most resistant to streptomycin (66.67%), while the isolate from a horsemen had been resistant to ampicillin, streptomycin, oxytetracycline, and to tetracycline. Although Salmonella transmission between racehorses and horsemen was not found to be obviously present in this study, the appropriate use of antimicrobials and hygienic procedures are still necessary in order to prevent antimicrobial resistance and the transmission of drug-resistant Salmonella between horses and humans

IDENTIFICATION OF MAJOR STREPTOCOCCUS SUIS SEROTYPES 2, 7, 8 AND 9 ISOLATED FROM PIGS AND HUMANS IN UPPER NORTHEASTERN THAILAND

Abstract. Streptococcus suis serotype 2 infections occur in many provinces of northeastern Thailand. However, knowledge concerning the prevalence of the common S. suis serotypes (1, 1/2, 2, 5, 7, 8, 9, 14 and 16) among healthy and diseased pigs in upper northeastern Thailand remains limited. This study investigated S. suis isolates from pigs (healthy and diseased) and also from humans using 11 conventional biochemical tests, 16S rDNA PCR and sequence analysis and multiplex PCR genotyping of porcine cps and gdh. Thirty-three isolates were obtained between 2009 and 2012 from blood or cerebrospinal fluid of patients from northeastern Thailand previously diagnosed with S. suis infection, based on clinical symptoms and laboratory diagnosis using 11 biochemical tests and PCR detection of 16S rDNA and cps. Eleven S. suis isolates were obtained between 2006 and 2009 from diseased pigs with clinical signs and laboratory diagnoses. In addition, 43 isolates obtained from 741 nasal swab cultures of slaughtered pigs between 2011 and 2012 were included. All three methods showed similar sensitivity in detection of S. suis from clinical and diseased pig specimens, although in healthy pigs, the 11 conventional biochemical methods yielded 2.3% false positives, and the gdh PCR detection method exhibited 31% false negatives. S. suis was present among healthy pigs in 8 of 10 provinces in upper northeastern Thailand, giving an average prevalence of 5.7% (range 1%-17%) using conventional methods together with 16S rDNA PCR assay. False positives by conventional methods were due to species with similar phenotypes, such as viridian streptococci, and are not statistically different from those obtained with the 16S rDNA PCR method, and the false negatives using gdh PCR assay will require further investigation. As S. suis was recovered from both diseased and healthy pigs, raw or undercooked pork products should be considered unsafe for handling or consumption in these regions of Thailand