Antibiotic Resistance of Campylobacter jejuni and C. coli Isolated from Children with Diarrhea in Thailand and Japan.

A total of 29 Campylobacter jejuni and C. coli strains were isolated from Thai and Japanese children with diarrhea using the Loop-mediated Isothermal Amplification method. The samples were evaluated for mutations in gyrA and 23S rRNA in order to assess resistance against fluoroquinolones and macrolides, respectively. Among the isolated strains, 9 (8 C. jejuni and 1 C. coli) were from Thai children, and the other 20 (C. jejuni) were isolated from Japanese children. High fluoroquinolone resistance rates were observed in Thai (66.7%) and Japanese (90%) children. Macrolide resistance was not observed in Japanese children but was observed at a considerable rate of 12.5% of C. jejuni isolated in the Thai cohort. The results indicate that continuous monitoring of resistance of Campylobacter strains to fluoroquinolones and macrolides is definitely necessary.

Loop-Mediated Isothermal Amplification (LAMP) for Detection of Campylobacter jejuni and C. coli in Thai Children with Diarrhea.

Campylobacter species are common causes of bacterial diarrhea, and Campylobacter jejuni and C. coli are known as the predominant causative agents in humans. Recent studies suggested that loop-mediated isothermal amplification (LAMP) is an efficient and practical tool for rapid detection of C. jejuni and C. coli in clinical samples. We used LAMP to screen 151 stool samples for Campylobacter; these samples were collected in 2012 from Thai children with diarrhea. The PCR method discriminated C. jejuni and C. coli among the detected Campylobacter strains; these species were subjected to sequencing of the hipO gene (in C. jejuni) or the ask gene (in C. coli). The results suggest that the prevalence of Campylobacter infection among Thai children with diarrhea is 8.6%, and C. jejuni is the most prevalent species.

Detection and characterization of a novel human parechovirus genotype in Thailand.

Human parechoviruses (HPeV), member in the family Picornaviridae, cause respiratory symptoms primarily in infants and young children. Currently, 16 genotypes have been described based on phylogenetic analysis of VP1 sequences, all of which have a global distribution. The purpose of this study was to investigate the prevalence and genotype distribution of HPeV in Thailand. A total of 171 fecal specimens collected during October 2012 to May 2013 from children with diarrhea in Chiang Mai, Thailand were investigated for HPeV by RT-PCR and sequence analysis. HPeVs were found in 3 out of 171 (1.8%) fecal specimens tested. Of these, one was HPeV1 which is commonly detected in children with gastroenteritis and another one was uncommon HPeV14 genotype. Most interestingly, the sequence of the third HPeV positive sample (CMH-N185-12) did not cluster with any of the known 16 genotypes and therefore is proposed as a candidate HPeV genotype 17.

SAffold viruses in pediatric patients with diarrhea in Thailand.

Saffold virus (SAFV) is a newly discovered human virus which is classified into the genus Cardiovirus of the family Picornaviridae. A total of 608 fecal specimens collected during January 2012 to December 2013 from children with diarrhea in Chiang Mai, Thailand were investigated for SAFV by RT-nested PCR and sequence analysis. Of these, nine out of 608 (1.5%) were positive for SAFVs and four genotypes were identified, SAFV1, SAFV2, SAFV3, and SAFV4. SAFV mono-infection was found in five cases (CMH-S038-12, CMH-S071-12, CMH-S102-12, CMH-N029-12, and CMH-S048-13), while co-infection with other viruses causing diarrhea was observed in four cases (CMH-S021-12, CMH-S115-12, CMH-N048-13 and CMH-N103-13). This study provides more information about the genetic background of SAFV circulating in pediatric patients with diarrhea in Thailand.

Molecular characterization of norovirus variants and genetic diversity of noroviruses and sapoviruses in Thailand.

Norovirus (NoV) and Sapovirus (SaV) have been reported as a common cause of acute gastroenteritis worldwide. For a decade, surveillances of NoV and SaV have been conducted continually in Thailand. To monitor the epidemiological situation and to determine the genetic variation of NoV and SaV in Chiang Mai, Thailand, 567 samples collected from pediatric patients hospitalized with acute gastroenteritis were examined during 2007, and 2010-2011 by semi-nested RT-PCR and nucleotide sequencing methods. NoV was detected at 15.9%. Phylogenetic analysis revealed multiple NoV genotypes, GI/14 (1.1%), GII/1 (1.1%), GII/2 (1.1%), GII/3 (4.4%), GII/4 (65.6%), GII/6 (10.0%), GII/7 (2.2%), GII/12 (4.4%), GII/13 (3.3%), GII/16 (5.7%), and unclassified genotype (1.1%), circulating in this area. Among these, NoV GII/4 was the most prevalent genotype with a predominance of GII/4 2009 over other variants, 1996, 2006a, and 2006b. For SaV, the prevalence was 1.2% which was much lower than those of NoV and only SaV GI/1 was detected. This study highlights the epidemiology of NoV and SaV and genetic diversity of viruses circulating in pediatric patients hospitalized with acute gastroenteritis in Chiang Mai, Thailand.

A wide variety of diarrhea viruses circulating in pediatric patients in Thailand.

BACKGROUND: Viral gastroenteritis has been recognized as one of the most common illnesses that affects infants and young children all over the world. A wide variety of viruses associated with the disease are continually being reported. To investigate the epidemiological situation of diarrhea virus infection in Chiang Mai, Thailand, surveillance was conducted during January to December 2007. METHODS: A total of 160 fecal specimens collected from pediatric patients admitted to the hospital with acute gastroenteritis were tested for the presence of group A, B, and C rotaviruses, norovirus, sapovirus, astrovirus, adenovirus, Aichi virus, enterovirus, bocavirus, and human parechovirus by RT-multiplex PCR. RESULTS: Of 160 fecal specimens tested, 85 (53.1%) were positive for diarrhea viruses. Of these, group A rotavirus was the predominant with a prevalence of 27.5%, followed by norovirus GII (11.9%), sapovirus (3.1%), enterovirus (2.5%), human parechovirus (1.9%), and norovirus GI, astrovirus, adenovirus (each 0.6%). Mixed-infections of 2 or 3 viruses were observed in 7 (4.4%) patients. However, none of groups B and C rotaviruses and Aichi virus were detected in this study. Monthly distribution analysis revealed that all those diarrhea viruses were detected continually throughout the year at a low level of infection except for group A rotavirus and norovirus infections which appeared to peak in a cool season in January-March and December, respectively. CONCLUSIONS: This surveillance revealed a wide variety of diarrhea viruses currently circulating in pediatric patients with acute gastroenteritis in Chiang Mai, Thailand.

Circulating of human bocavirus 1, 2, 3, and 4 in pediatric patients with acute gastroenteritis in Thailand.

Human bocavirus (HBoV) is a newly identified human parvovirus that associated with respiratory and gastrointestinal diseases. Epidemiological surveillance of HBoV was conducted on fecal specimens collected from hospitalized children with diarrhea in Chiang Mai, Thailand in 2011. Among a total of 222 fecal specimens tested, 17 (7.7%) were positive for HBoV by PCR. Of the 17 HBoV positive samples, double- or triple-infections together with other enteric viruses were found in 10 (58.8%) pediatric patients, while monoinfection with HBoV alone was detected in seven (41.2%) cases. Mixed infection among HBoV with norovirus GII was frequently observed in this population. The partial VP1 nucleotide sequences of all 17 HBoV strains demonstrated that all four species of HBoV were found in the specimens tested. Eleven strains were HBoV1. Other three strains showed the sequence identity with HBoV2, which were most closely related to the HBoV2A. In addition, other two HBoV strains showed the highest level of nucleotide sequence identity with the HBoV3. It was surprisingly to observe that one Thai HBoV strain showed a unique characteristic similar to the HBoV4, a rare species of HBoV found in acute gastroenteritis patients. In summary, this study presents the genetic background information of HBoV circulated in acute gastroenteritis children in Chiang Mai, Thailand and it was clearly demonstrated that HBoVs circulated in this area were genetically diverse as all four species of HBoVs (HBoV1-4) were detected in the fecal specimens collected from pediatric patients admitted to the hospitals in this area.

Detection and molecular characterization of cosavirus in adults with diarrhea, Thailand.

Human cosavirus (HCoSV) is a newly discovered virus in Picornaviridae family. At present it is not clear whether HCoSV is associated with diseases, including gastroenteritis in humans, as epidemiological data is limited. Epidemiological surveillance of HCoSV was conducted on 150 fecal specimens collected from children and 150 samples from adults with diarrhea in Thailand by RT-PCR screening. HCoSV was found in a single adult specimen and not in any of the fecal specimens from children. This represents the first report of HCoSV infection in patients with diarrhea in Thailand. Extensive epidemiological surveillance of novel viruses associated with diarrhea in other populations may provide a better understanding of the distribution, genetic diversity, and association of the viral agents associated with acute gastroenteritis in humans.