Search

Introduction: DEL is known to be one of the weakest D variants, which can be detected by the adsorption-elution technique or by molecular study. Currently, in Thailand, we do not routinely test for DEL variants serologically or genetically among serologic RhD-negative blood donors. Case Presentation: We reported 2 cases of alloimmunization after transfused with Rh DEL, RHD*DEL1 allele, in the Thai population. The first case was a 73-year-old male with anemia who presented with post-cardiac arrest and septic shock. The patient was group B, RhD-negative, and was transfused with RhD-negative red blood cells (RBCs). Antibody screening and identification found that the patient developed anti-D and anti-Mia during the admission course. The second case was a 38-year-old woman with pseudomyxoma peritonei who developed anti-D after receiving four units of RhD-negative RBCs during cytoreductive surgery with hyperthermic intraperitoneal chemotherapy. Both patients did not receive anti-D immunoglobulin and had no previous history of anti-D detection. We retrospectively investigated and found two units of RHD*DEL1 among the RBCs transfused to these patients. Discussion: Previous reports of several cases of anti-D alloimmunization in RhD-negative recipients transfused by RHD*DEL1, an Asian-type DEL, are limited only to East Asia. We first identified 2 patients with anti-D alloimmunization after receiving the RHD*DEL1 RBCs in the Thai population. This raises concern about Rh DEL screening among D-negative Thai blood donors and whether to remove DEL units from the D-negative inventory to improve patient safety. [ABSTRACT FROM AUTHOR]

Rotavirus A (RVA) is an important cause of acute gastroenteritis (AGE) in children. This study aims to investigate the molecular epidemiology of RVA in children hospitalized with AGE in Chiang Rai, Thailand in 2018–2020 by reverse transcription polymerase chain reaction. Of 302 samples, RVA was detected in 11.6% (35 samples): 11.3% (19/168) in 2018–2019 and 11.9% (16/134) in 2019–2020. G8P[8] was the predominant genotype at 68.4% in 2018–2019 and 81.2% in 2019–2020. G1P[8] (15.8%), G2P[4] (5.3%), G3P[8] (10.5%) in 2018–2019, and G9P[8] (18.8%) in 2019–2020 were also detected. Whole‐genome analysis of G8P[8] revealed a DS‐1‐like genetic backbone: G8‐P[8]‐I2‐R2‐C2‐M2‐A2‐N2‐T2‐E2‐H2. Phylogenetically, the VP7 genes of G8P[8] clustered in a major lineage with previously published 51 DS‐1‐like G8P[8] reference strains, closely related to 13 G8P[8] strains from Thailand and China. These G8P[8] strains contained two unique amino acid substitutions (A125S and N147D) in the VP7 antigenic epitopes. In addition, the VP1 and NSP2 genes of G8P[8] clustered in lineages separated from the DS‐1‐like G8P[8] reference strains with a high genetic divergence but were closely related to G1P[8], G2P[4], G3P[8], or G9P[8]. Several amino acid differences were observed in the VP7 and VP8* antigenic epitopes of G8P[8] compared with RVA vaccine strains. Homology modeling confirmed that these different amino acid residues were located on the surface‐exposed area of the structure. Taken together, the genetic analysis clearly defines the Chiang Rai DS‐1‐like G8P[8] strains as a novel reassortant strain that might have evolved genetically through reassortment events and consequently received their VP1 and NSP2 genes from locally cocirculating‐RVA genotypes. [ABSTRACT FROM AUTHOR]

Primary amebic meningoencephalitis (PAM) is a rare and fatal central nervous system infection caused by Naegleria fowleri, a free-living amoeba found in the environment. To date, eight pathogenic N. fowleri genotypes have been reported worldwide. We aimed to explore the genotypes of N. fowleri that cause primary amebic meningoencephalitis in Thailand. In 2021, the 17th PAM case was reported, and a retrospective literature search of PAM cases in Thailand from 1982 through April 2021 was performed. Phylogenetic and genotyping analyses of the two mitochondrial (12S rRNA and 16S rRNA) and nuclear (ITS1 and 5.8s rRNA) genes of N. fowleri were performed on four available clinical isolates. Based on the mitochondrial and nuclear genes, N. fowleri genotype T3 was found to cause PAM in three out of four cases. However, disagreement between the genotype based on the mitochondrial and nuclear genes was found in one of the PAM cases, in which the 12S rRNA locus suggested the causative genotype as T1, while the ITS1 implied genotype T4. The discrepancy between the mitochondrial and nuclear genome was previously observed, which suggests the possible horizontal gene transfer among N. fowleri species. Based on the ITS1 gene, two N. fowleri genotypes, T3 and T4, were found to be the genotypes causing PAM in this study. In addition, N. fowleri genotype T2 was previously reported in a traveler who was infected in Thailand. Thus, at least three genotypes (T2, T3, and T4) of N. fowleri are found to be associated with PAM in Thailand. [ABSTRACT FROM AUTHOR]

The basidiomycetes yeast Trichosporon is widespread in the natural environment, but can cause disease, mainly in immunocompromised patients. However, there have been only few studies about this infection in Thailand. In this study, we characterized 53 Trichosporon spp. isolated from urine samples from patients admitted to a single hospital in Bangkok, Thailand over a one-year period from 2019 to 2020. The strains were identified using colony morphology, microscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and nucleotide sequence analysis of intergenic spacer 1 (IGS1). Fifty-one isolates were Trichosporon asahii , and the remaining isolates were Trichosporon inkin and other Trichosporon species. Three genotypes of IGS1—1, 3, and 7 were observed among T. asahii. The sensitivity of the yeasts to the antifungal drugs amphotericin B, fluconazole, and voriconazole ranged from 0.25 to >16 μg ml−1, 0.5–8 μg ml−1, and 0.01–0.25 μg ml−1, respectively. We investigated biofilm formation by the isolates, and no biofilm production was found in one isolate, low biofilm production in forty-four isolates, and medium biofilm production in six isolates. T. inkin produced biofilms at low levels, and Trichosporon spp. produced biofilms at medium levels. This research increases our understanding of the molecular epidemiology of Trichosporon spp. isolated from one university hospital in Bangkok, Thailand, and reveals their genetic diversity, antifungal susceptibility profiles, and capacity for in vitro biofilm production. [ABSTRACT FROM AUTHOR]

Pneumocystis jirovecii is an important etiological agent of pneumonia that is underdiagnosed due to the inability to culture the organism. The 2019 PERCH study identified Pneumocystis as the top fungal cause of pneumonia in HIV-negative children using a PCR cutoff of 104 copies of Pneumocystis per mL of sample in nasopharyngeal/oropharyngeal (NP/OP) specimens. Given that Pneumocystis consists of an environmental ascus form and a trophic from (the latter is the form that attaches to the lung epithelium), it is possible that life-form-specific molecular assays may be useful for diagnosis. However, to accomplish this goal, these assays require genotypic information, as the current fungal genomic data are largely from the US and Europe. To genotype Pneumocystis across the globe, we developed an NGS-based genotyping assay focused on genes expressed in asci as well as trophs using PERCH throat swabs from Africa, Bangladesh, and Thailand, as well as North American samples. The NGS panel reliably detected 21 fungal targets in these samples and revealed unique genotypes in genes expressed in trophs, including Meu10, an ascospore assembly gene; two in mitochondrial gene ATP8, and the intergenic region between COX1 and ATP8. This assay can be used for enhanced Pneumocystis epidemiology to study outbreaks but also permits more accurate RT-CPR- or CRISPR-based assays to be performed to improve the non-bronchoscopic diagnosis of this under-reported fungal pathogen. [ABSTRACT FROM AUTHOR]

Primary amebic meningoencephalitis (PAM) is a rare and fatal central nervous system infection caused by Naegleria fowleri, a free-living amoeba found in the environment. To date, eight pathogenic N. fowleri genotypes have been reported worldwide. We aimed to explore the genotypes of N. fowleri that cause primary amebic meningoencephalitis in Thailand. In 2021, the 17th PAM case was reported, and a retrospective literature search of PAM cases in Thailand from 1982 through April 2021 was performed. Phylogenetic and genotyping analyses of the two mitochondrial (12S rRNA and 16S rRNA) and nuclear (ITS1 and 5.8s rRNA) genes of N. fowleri were performed on four available clinical isolates. Based on the mitochondrial and nuclear genes, N. fowleri genotype T3 was found to cause PAM in three out of four cases. However, disagreement between the genotype based on the mitochondrial and nuclear genes was found in one of the PAM cases, in which the 12S rRNA locus suggested the causative genotype as T1, while the ITS1 implied genotype T4. The discrepancy between the mitochondrial and nuclear genome was previously observed, which suggests the possible horizontal gene transfer among N. fowleri species. Based on the ITS1 gene, two N. fowleri genotypes, T3 and T4, were found to be the genotypes causing PAM in this study. In addition, N. fowleri genotype T2 was previously reported in a traveler who was infected in Thailand. Thus, at least three genotypes (T2, T3, and T4) of N. fowleri are found to be associated with PAM in Thailand. [ABSTRACT FROM AUTHOR]

Pterygium, a common ocular growth, has an unknown pathogenesis and aetiology. Environmental factors such as ultraviolet light, genetic factors and viral infections may be implicated in the development of pterygia. Human papillomavirus (HPV), an oncogenic virus, has previous been detected in individuals with pterygia. The aim of this study was to assess the prevalence of HPV genotypes in pterygia from Thai individuals. DNA was extracted from 389 pterygia. HPV was detected by nested PCR and HPV genotyping was conducted using reverse hybridization. The DNA sequences of HPV-L1 genes were analyzed. HPV was detected in only 6.8% (25/389) of pterygia from Thai individuals. The majority (16/25, 64%) of strains were genotyped as HPV-16 and the remainder (9/25, 36%) could not be typed. Four pterygia showed evidence of coinfection by HPV-16 and either HPV-18 (2/25, 8%) or HPV-58 (2/25, 8%). Nine of 11 samples showed the same HPV-16 L1 gene sequence that was identical to a HPV-16 reference sequence in GenBank. The remaining two samples each bore silent single nucleotide mutations (T1078G and T1081A) that did not result in amino acid changes. HPV, especially HPV-16, may be one of the pathogens causing pterygia in Thai individuals. Genotyping data suggested that HPV-16 from pterygia may be similar in sequence to HPV-16 causing cervical cancer. [ABSTRACT FROM AUTHOR]

Background. Infection with viruses especially rotavirus, norovirus, astrovirus, and adenovirus has been known to be a major cause of acute gastroenteritis in children under 5 years of age globally, particularly in developing countries. Also, some genotypes of enteroviruses (EVs) have been reported to be associated with gastroenteritis. This study is aimed to investigate the prevalence and genotype diversity of EV in children admitted to hospitals with acute gastroenteritis. Methods. A total of 1,736 fecal specimens were collected from children hospitalized with diarrhea in Chiang Mai, Thailand from 2015 to 2018. All specimens were tested for the presence of EV by RT-PCR of the 50 untranslated region. The genotypes of EV were further identified by nucleotide sequencing and phylogenetic analysis of the viral protein 1 (VP1) gene. Results. EV was detected in 154 out of 1,736 specimens (8.9%) throughout the study period. The prevalence of EV detected in 2015, 2016, 2017, and 2018 was 7.2%, 9.0%, 11.2%, and 8.6%, respectively. EV was detected all year round with a high prevalence during rainy season in Thailand. Overall, 37 genotypes of EV were identified in this study. Among these, coxsackievirus (CV)-A24 and CV-B5 (7.5% each), and EV-C96 (6.8%) were the common genotypes detected. Conclusion. This study demonstrates the prevalence, seasonal distribution, and genotype diversity of EV circulating in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand during the period 2015 to 2018. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to detect and characterize current genotypes of canine parvovirus (CPV) in Egypt during 2018. Materials and Methods: A total of 50 fecal swabs were collected from clinically infected domestic dogs of 2-5 months of age, suspected to suffer from CPV infection, from Cairo and Giza Governorates. The samples were subjected to qualitative antigen detection using the rapid test, followed by isolation on Madin-Darby Canine Kidney (MDCK) cells, molecular characterization with partial amplification of VP2 gene using polymerase chain reaction (PCR), followed by sequencing and phylogenetic analysis. Results: Out of 50 fecal samples, 20 samples were positive (40%) by Rapid CPV/canine coronavirus Ag Test Kit. These positive samples were cultured successfully on MDCK cells. Nine randomly chosen samples out of 30 apparently negative samples were amplified using PCR with primers Hfor and Hrev to yield a typical 630 bp fragment. Then, six randomly chosen samples out of nine were amplified using PCR with primers Pbs and Pbas to yield a typical 427 bp fragment. Sequencing, BLAST analysis and assembly of the two fragments (630 bp and 427 bp) to produce 912 bp fragments, in the six samples, revealed two serotypes CPV-2b and CPV-2c. The obtained strains were submitted to GenBank and given accession numbers MK642272, MK642273, MK642274, MK642275, MK642276, and MK642277. Phylogenetic analysis of the Egyptian strains serotype 2b illustrated that they were closely related to Thailand strains (accession numbers KP715709, KP715694, KP715701, and KP715700); while Egyptian strains serotype 2c was closely related to Thailand strains (accession numbers MH711894 and MH711902), Taiwanese strain (KU244254), Chinese strain (MF467242), and Vietnamese strain (accession number LC216910). Conclusion: The current research recommends further epidemiological studies to assess the extent of the occurrence of different serotypes of CPV in Egypt and the efficiency of imported and locally produced vaccines in protection against CPV infection. [ABSTRACT FROM AUTHOR]

Abstract Entamoeba nuttalli found in non-human primates is the phylogenetically closest species to Entamoeba histolytica and is potentially pathogenic. However, infection of wild long-tailed macaques (Macaca fascicularis) with E. nuttalli has not been found. In this study, the prevalence of Entamoeba infections in wild long-tailed macaques was examined in seven locations in six provinces of Thailand. The positive rate for E. nuttalli in 214 fecal samples was 43.9% using PCR, but no infection with E. histolytica or Entamoeba dispar was found, demonstrating that long-tailed macaque is one of the natural hosts for E. nuttalli. Twenty-four E. nuttalli isolates were successfully cultured and four of them were axenized. The sequences of the 18S ribosomal RNA genes of E. nuttalli from long-tailed macaques differed from those of E. nuttalli isolates from other species of wild macaques. Eleven types of sequences in serine-rich protein genes were identified in the 24 isolates and these were specific for each location in Thailand. By analysis of six tRNA-linked short tandem repeat loci, these isolates were divided into 14 types, and each type was also location-specific. Phylogenetic analysis revealed correlation between genotypes of the parasite and the geographic distribution of the host macaques. Genetic distance and geographic distance correlated significantly in a Mantel test, with r values of 0.888 based on the tRNA-linked short tandem repeat loci and 0.815 based on the serine-rich protein genes. These results suggest that genetic divergence and co-evolution of the parasite occurred during dispersion and colonization of the host macaque, and that genotypic analysis of the parasite may enable identification of the geographic localization of the host. Highlights • Entamoeba nuttalli was prevalent in wild long-tailed macaques in Central Thailand. • Twenty-four isolates of E. nuttalli were obtained from seven locations. • Sequences of 18S rDNA of the amebae differed from those of other species of wild macaques. • The 24 E. nuttalli isolates could be divided into 17 genotypes. • Genotypes of E. nuttalli isolates reflected the difference in geographic distribution. [ABSTRACT FROM AUTHOR]

Enterovirus (EV) infection is widespread and can lead to a broad range of clinical symptoms, from mild to severe forms of disease. EVs are not always classified as pathogen and the epidemiological surveillance of EV infection in acute gastroenteritis cases in Thailand remains unexplored. This study aims to investigate the frequency, seasonality and molecular characteristics of EV circulating in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand from 2010 to 2014. A total of 1266 fecal samples were included in this study. RT-PCR amplification of the 5′UTR was used for EV screening and phylogenetic analysis of the VP1 sequence was performed for EV genotyping. EV was detected in 5.8% of infections (73 out of 1266). Based on VP1 sequence analysis, over half (50.8%) of the identified EV cases were caused by species C, and the next two most frequent were species B and A (35.4% and 13.8%, respectively). This study identified 28 different EV genotypes, EV-C96 and coxsackievirus A24 were the most frequent genotype detected (12.3% each). EV was detected throughout the year with an increase of detection rate in December–January and May–June. In conclusion, this study reported the prevalence of EV infection with a wide variety of EV genotypes in children with acute diarrhea. [ABSTRACT FROM AUTHOR]

Background: Relapse infections resulting from the activation hypnozoites produced by Plasmodium vivax and Plasmodium ovale represent an important obstacle to the successful control of these species. A single licensed drug, primaquine is available to eliminate these liver dormant forms. To date, investigations of vivax relapse infections have been few in number. Results: Genotyping, based on polymorphic regions of two genes (Pvmsp1F3 and Pvcsp) and four microsatellite markers (MS3.27, MS3.502, MS6 and MS8), of 12 paired admission and relapse samples from P. vivax-infected patients were treated with primaquine, revealed that in eight of the parasite populations in the admission and relapse samples were homologous, and heterologous in the remaining four patients. The patients' CYP2D6 genotypes did not suggest that any were poor metabolisers of primaquine. Parasitaemia tended to be higher in the heterologous as compared to the homologous relapse episodes as was the IgG3 response. For the twelve pro- and anti-inflammatory cytokine levels measured for all samples, only those of IL-6 and IL-10 tended to be higher in patients with heterologous as compared to homologous relapses in both admission and relapse episodes. Conclusions: The data from this limited number of patients with confirmed relapse episodes mirror previous observations of a significant proportion of heterologous parasites in relapses of P. vivax infections in Thailand. Failure of the primaquine treatment that the patients received is unlikely to be due to poor drug metabolism, and could indicate the presence of P. vivax populations in Thailand with poor susceptibility to 8-aminoquinolines. [ABSTRACT FROM AUTHOR]

Bovine anaplasmosis is a serious tick-borne disease that is responsible for economic loss worldwide. The major surface proteins (MSPs), encoded by msp1 to msp5 genes of Anaplasma marginale, play an important role in host-pathogen and tick-pathogen interactions. These markers have been used for genetic characterization and phylogenetic studies. Despite domestic reports concerning suspected outbreaks of anaplasmosis in Thailand, genetic analysis of A. marginale in the country remains largely limited. Therefore, we aim to investigate the infection rate of the rickettsia organism in the Anaplasmataceae family throughout five regions of Thailand and to further characterize the key genetic markers: msp1a, msp2, and msp5 of A. marginale. From 2016 to 2021, we collected a total of 384 cattle blood samples across 18 provinces. Overall, the infection rate of the rickettsia organism in the Anaplasmataceae family was 46.1%. Over 65% of the positive samples were confirmed as A. marginale. We successfully obtained a total of 138 A. marginale msp1a (38), msp2 (79), and msp5 (21) sequences from all regions of the country. The msp1a and msp2 genes exhibit a high degree of genetic diversity, while the msp5 gene is highly conserved among the Thai isolates. Our findings regarding msp1a corroborated the genetic heterogeneity of A. marginale strains in endemic regions worldwide. Additionally, we found multiple novel variants for the first time in the current nationwide survey. We found 45 tandem repeat characters of the msp1a sequence. Among them, 24 characters were not shared with other countries. Collectively, we expanded the extent of genetic diversity in key markers; msp1a and msp2 genes, and further confirmed the previous finding that msp5 was highly conserved. The msp1a and msp2 genes could be useful for the surveillance of newly introduced strains. The current data may also be useful in designing a vaccine containing potential epitopes of different antigens in the future., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2022 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Merozoite surface proteins (MSPs) of malaria parasites play critical roles during the erythrocyte invasion and so are potential candidates for malaria vaccine development. However, because MSPs are often under strong immune selection, they can exhibit extensive genetic diversity. The gene encoding the merozoite surface protein-3 (MSP-3) of Plasmodium falciparum displays 2 allelic types, K1 and 3D7. In Thailand, the allelic frequency of the P. falciparum msp-3 gene was evaluated in a single P. falciparum population in Tak at the Thailand and Myanmar border. However, no study has yet looked at the extent of genetic diversity of the msp-3 gene in P. falciparum populations in other localities. Here, we genotyped the msp-3 alleles of 63 P. falciparum samples collected from 5 geographical populations along the borders of Thailand with 3 neighboring countries (Myanmar, Laos, and Cambodia). Our study indicated that the K1 and 3D7 alleles coexisted, but at different proportions in different Thai P. falciparum populations. K1 was more prevalent in populations at the Thailand-Myanmar and Thailand-Cambodia borders, whilst 3D7 was more prevalent at the Thailand-Laos border. Global analysis of the msp-3 allele frequencies revealed that proportions of K1 and 3D7 alleles of msp-3 also varied in different continents, suggesting the divergence of malaria parasite populations. In conclusion, the variation in the msp-3 allelic patterns of P. falciparum in Thailand provides fundamental knowledge for inferring the P. falciparum population structure and for the best design of msp-3 based malaria vaccines. [ABSTRACT FROM AUTHOR]

What is known and objective Abacavir ( ABC) is a commonly used nucleoside reverse-transcriptase inhibitor with potent antiviral activity against HIV-1. The US Food and Drug Administration and international HIV treatment guidelines recommend HLA-B*57:01 screening before initiating treatment with ABC. The current standard method for HLA-B*57:01 screening is limited by its high-cost, time-consuming and labour-intensive procedure with the requirement of a specialized laboratory. Our study aims to develop a more reliable screening test by selecting rs3093726 as an additional single nucleotide polymorphism ( SNP) to combine with rs2395029 for multiplex pyrosequencing development. It offers high-accuracy, cost-effective and rapid detection. Methods Multiplex pyrosequencing was developed for HLA-B*57:01 screening using rs2395029 and rs3093726 as a surrogate marker and tested in 130 Thai subjects in parallel with singleplex pyrosequencing of each SNP and the standard sequence-based method. Results and discussion Multiplex pyrosequencing showed 100% concordance when compared with both singleplex pyrosequencing and standard sequence-based method. This method showed 100% of negative predictive value ( NPV), positive predictive value ( PPV), specificity and sensitivity. What is new and conclusion Multiplex pyrosequencing is a powerful tool for HLA-B*57:01 screening using the rs2395029 and rs3093726 haplotype genotyping as surrogate marker for this HLA-B. The assay provides accurate, cost-effective and rapid detection of this haplotype. It can be applied for ABC hypersensitivity screening of the Thai population before initiating treatment with ABC. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To determine the distribution of human papillomavirus (HPV) genotypes in cervical adenocarcinoma in Thailand and to evaluate the clinicopathologic characteristics associated with common HPV genotypes. Methods: Formalin-fixed, paraffin-embedded tissues from 150 patients with adenocarcinoma were collected from 4 areas of Thailand. Infection with HPV was detected by nested polymerase chain reaction (PCR) with primers MY09/11 and GP5+/6+. Genotyping was performed using a linear array assay, followed by type-specific PCR targeting the E6/E7 regions of HPV-16, HPV-18, and HPV-52 if the linear array test was negative. Results: Human papillomavirus DNA was detected in 145 (97%) adenocarcinomas (132 single infections; 11 multiple infections; 2 tumors with undetermined HPV type). Genotype 18 was most common (66%), followed by HPV-16 (30%) and HPV-45 (3%). Infection with only HPV-16 and/or HPV-18 accounted for 88% of the HPV-positive tumors. Patients with HPV-18 infection had a younger age (P =0.009) and higher tumor grade (P <0.001) than patients with HPV-16 infection. Conclusion: The HPV detection rate in cervical adenocarcinomas in Thailand is high. The predominant genotype is HPV-18, being twice as common as HPV-16. Genotype variations are associated with patient age and tumor grade. Vaccination against HPV-16/HPV-18 might prevent almost 90% of adenocarcinomas. [Copyright &y& Elsevier]

Objective: To determine the distribution of HPV genotypes in cervical neuroendocrine carcinoma (NECA) in northern Thailand, and evaluate the correlation between HPV genotype and clinicopathologic features.Methods: Samples from 111 women treated for cervical NECA at Chiang Mai University Hospital between 1992 and 2009 were tested for HPV genotype. Samples were formaldehyde-fixed, paraffin-embedded, and tested via nested PCR and dot blot hybridization.Results: Ninety-seven of the 111 samples were adequate for DNA analysis. HPV DNA was detected in 93 samples, of which 76 (81.7%) were single, 14 (15.1%) were multiple, and 3 (3.2%) were untyped infections. HPV18 was the most common subtype (70 cases, 75.3%), followed by HPV16 (28 cases, 30.1%). Other genotypes included HPV58 (3.2%), HPV52 (2.1%), and HPV33 (1.1%). Collectively, HPV16 and/or HPV18 were found in 83 cases (89.3%). Women with HPV18 infection were significantly younger (42.0years) than those with non-HPV18 infections (54.1years) (P=0.003). Associated adenocarcinoma in situ was more frequently seen among women with HPV18 infection (P=0.034).Conclusions: HPV18 infection was predominant in cervical NECA. Variations in HPV genotype may be related to the clinicopathologic features and pathogenetic pathways of NECA. Vaccination against HPV16 and HPV18 might provide protection against cervical NECA in almost 90% of cases. [ABSTRACT FROM AUTHOR]

Abstract: In Thailand, gastric cancer incidence is considerably low despite the high prevalence of Helicobacter pylori infection. We investigated the prevalence of H. pylori infection and the genotypes of cagA by using 179 stool specimens obtained from asymptomatic Thai individuals. In this study, the prevalence of H. pylori infection was 43.6%, and the detection rate of cagA-positive strains was 43.5%. In addition, the proportion of the highly virulent East-Asian type of cagA was 7.2%. These results indicate that the low prevalence of cagA-positive H. pylori strain as well as the low prevalence of East-Asian genotype cagA-positive strains may contribute to the low gastric cancer incidence. [Copyright &y& Elsevier]

This study was undertaken to determine the genetic diversities of Giardia intestinalis isolated in Thailand. G. intestinalis cysts were collected from stool samples of 61 subjects residing in Bangkok or in rural communities of Thailand with and without gastrointestinal symptoms. All the cyst samples gave positive tpi amplicons (100% sensitivity), either of the 148- or the 81-bp tpi segments. Cyst assemblage identification of the 148- and 81-bp tpi gene segments by polymerase chain reaction showed that 8% of the cysts were assemblage A, 41% assemblage A and B combined, and 51% assemblage B. The prevalence of assemblage A was significantly lower than that of assemblage B and the mixed types. Restriction fragment length polymorphism (RFLP) of the 384-bp ß-giardin gene segment revealed that 12% and 88% of the assemblage A cysts were AI and AII respectively. RFLP, based on the 432-bp gdh gene segment, showed 45.5% of the assemblage B cysts to be BIII and 54.5% to be BIV. The AI sub-assemblage was less prevalent than the others. All subjects with AI and 50% of the subjects with BIII sub-assemblage cysts were symptomatic; 80% of symptomatic Bangkok residents were adults/elderly while 85% of the rural cases were children. [ABSTRACT FROM AUTHOR]

Summary: Spoligotyping and variable-number tandem repeats (VNTR) typing have been increasingly used for differentiating Mycobacterium tuberculosis strains with low copy numbers of IS6110. However, there are few studies comparing their potential to type the strains originating from South and Southeast Asia where many of the isolates have only a few copies, or even single copy, of IS6110. Here, we evaluated the genotyping of 187 M. tuberculosis isolates harboring 1–6 copies of IS6110, available from a population-based study in Chiangrai, northern Thailand during 1998–2000, using spoligotyping and VNTR typing. The low-copy-number isolates constituted about 34% of all M. tuberculosis isolated in the province. Discriminating capacities and cluster identification by the two methods were compared with each other and to those obtained by the standard IS6110-restriction fragment length polymorphism (RFLP) method. We found that VNTR typing based on the studied 10-loci set generated more distinct patterns (151 patterns) than spoligotyping (54 patterns) and IS6110-RFLP (65 patterns). Most of the RFLP- or spoligotyping-defined clusters were subdivided by VNTR typing. Combining IS6110-RFLP with VNTR typing produced 164 distinct patterns and 21.9% of clustered isolates whereas the combination of IS6110-RFLP and spoligotyping gave 103 different patterns and 59.4% of clustered isolates. Our results confirm the utility of VNTR typing as the secondary method of choice for investigating the epidemiology of M. tuberculosis with low copy numbers of IS6110. [Copyright &y& Elsevier]

Abstract: Streptococcus agalactiae (Group B streptococcus, GBS) is an important pathogen affecting humans and animals as well as aquatic species. Between April 2003 and March 2006, bacteria were isolated from infected red tilapia Oreochromis sp. and Nile tilapia O. niloticus cultured in Thailand. They were identified as GBS by API 20 STREP, polymerase chain reaction (PCR) and multiplex PCR-based reverse line blot hybridization (mPCR/RLB). Genotyping indicated that they belonged to two genotypes. One of these genotypes has not been identified in any of 1792 GBS isolates genotyped by mPCR/RLB; it belongs to serotype Ia and contains genes encoding proteins Cα (bca) and Cβ (bac), three insertions sequences (IS1381, IS861 and ISSag2) and the group II intron GBSi1. The other has recently been identified among invasive human isolates in Hong Kong; it belongs to an uncommon subtype of serotype III (III-4), contains bca, three insertion sequences (IS1381, ISSag1 and ISSag2) and a tetracycline resistance gene (tetM). Pathogenicity studies in red tilapia by experimental infection established that GBS is a pathogen of fish. Histopathological changes indicated that infection of tilapia with GBS produced disease with systemic involvement characterized by multiple necrotic foci in various tissues. The possible epidemiology and epizoology of these bacteria among human, mammal and aquatic species are discussed in this report. [Copyright &y& Elsevier]

Abstract Background: Hepatitis B virus (HBV) genotypes have distinct geographic distributions. The aim of the present study was to evaluate the distribution of HBV genotypes and their clinical relevance in Thailand. Methods: Hepatitis B virus genotypes among 107 hepatitis B carriers residing in Thailand were evaluated using serologic and genetic methods. They were clinically classified into asymptomatic carriers with normal serum alanine transaminase (ALT) levels and patients with chronic liver disease, such as those with chronic hepatitis (CH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). Results: Hepatitis B virus genotype distribution among the 107 patients was 25.2% for genotype B, 72.0% for genotype C and 2.8% for genotype D. The serum ALT levels, HBV-DNA and hepatitis B e antigen positivity were significantly higher in carriers infected with genotype C HBV than in those infected with genotype B (P < 0.05). The proportion of genotype B HBV was higher in asymptomatic carriers than in patients with CH and those who developed liver disease, such as LC and HCC (45.5, 16.9 and 25.0%, respectively; P < 0.05). In contrast, the proportion of genotype C HBV was higher in patients who developed liver disease and CH than in asymptomatic carriers (68.7, 83.0 and 50.0%, respectively; P < 0.05). Phylogenetic analysis based on entire genome sequences revealed three HBV isolates, which were classified into a subgroup of genotype C in isolates from South-East Asian countries. Conclusions: Genotypes B and C are the predominant types among hepatitis B carriers residing in Thailand and those genotypes influence the clinical manifestation in carriers with chronic hepatitis B infection. [ABSTRACT FROM AUTHOR]

The identification and characterization of viruses of the genus Enterovirus in healthy and infected livestock, including cattle and goats, have been increasing. Enterovirus E (EV-E) and Enterovirus F (EV-F) are commonly found in cattle, whereas Enterovirus G (EV-G) is found in goats. In this study, molecular and phylogenetic analyses were performed to determine the prevalence of EVs in cattle and goat feces from Kanchanaburi Province, Thailand. The presence of EVs in water samples and the feces of other animals collected from the areas surrounding cattle and goat farms was also investigated. By use of 5'-untranslated region (5' UTR) real-time reverse transcription-PCR (RT-PCR), EVs were detected in 39.5% of cattle samples, 47% of goat samples, 35.3% of water samples, and one pool of chicken feces. Phylogenetic analysis revealed the presence of EV-E and EV-F in cattle, EV-E and EV-G in goats, and EV-F in water samples and chicken feces. Analysis of enteroviral VP1 sequences from cattle revealed that the EV-E genotypes circulating in the study region were EV-E1, with a possible new genotype that is closely related to EV-E2. Analysis of enteroviral VP1 sequences from goats suggested the circulation of EV-G5 and a possible new genotype that is closely related to EV-G20. Sequence analyses also suggested that although the VP1 sequences from goats were closely related to those of EV-G, which were considered porcine enterovirus sequences, their 5' UTRs form a separated cluster with sequences of sheep and goat origin, suggesting a new classification of the ovine/caprine-specific enterovirus group. IMPORTANCE Possible new EV-E and EV-G genotypes were identified for EVs detected in this study. The EV-E viruses were also successfully isolated from MDBK cells. The goat EV sequence analysis suggested the presence of an ovine/caprine-specific EV group that is different from EV-G of porcine origin. The significance of our research is that it identifies and characterizes possible novel EVs, thereby indicating that enteroviruses in animals are continually evolving. The facts that enteroviruses can persist in the environment, contaminate it for long periods, and be transmitted between animals raise serious concerns regarding this group of viruses as emerging livestock pathogens., (Copyright © 2019 American Society for Microbiology.)

The genotype of Toxoplasma gondii has been extensively studied to determine whether its characteristics may influence the course of toxoplasmosis. Recent genotyping studies in South America have found Toxoplasma hybrid isolates or atypical strains which were more virulent and highly diverse than North American and European species. Although, the high seroprevalence of Toxoplasma infection among pregnant women and HIV-infected patients from Songklanagarind Hospital, Songkhla, Southern Thailand has been previously reported, there is no reported study of human genotyping data on T. gondii strains. This is the first genetic typing of T. gondii isolates obtained from naturally infected cats in Thailand. Five chromosomal loci were analyzed by a nested PCR-RFLP technique to determine the genotype of 13 T. gondii isolates from cat feces gathered in the South of Thailand. The PCR-RFLP patterns of SAG1, SAG2-new, SAG3, BTUB and GRA6 markers resulted in five diverse genotypes: the type I (one isolate), type III (two isolates), type II or type III (one isolate), recombinant genotypes (two isolates) and atypical genotypes (two isolates). The presence of unusual genotypes may lead to new virulent traits associated with more severe forms of human Toxoplasma infections. More evaluations are needed before conclusions could be made as to whether the oocysts from cat feces play an important role in the severity of Toxoplasma infections., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Two-thirds of the world's population is thought to be infected by Helicobacter pylori. Although most people infected with H. pylori are asymptomatic, this pathogen is associated with several gastric pathologies including cancer. The risk factors for colonization are still unclear and the genetic diversity within individual hosts has never been clearly investigated., Result: This study determined the prevalence of, and explored risk factors for, H. pylori infection directly from paired saliva (n = 110) and stool (n = 110) samples from asymptomatic persons in Northeast Thailand. Samples were subjected to indirect immunofluorescence assay (IFA), 16S rRNA-based real-time PCR and vacA-based semi-nested PCR. Partial vacA gene sequences of H. pylori were compared between saliva and stool samples. The overall prevalence of H. pylori infection in our asymptomatic study population was 64%. Age, gender, occupation and frequency of brushing teeth were not found to be associated with H. pylori colonization. The vacA gene was successfully sequenced from both saliva and stool samples of 12 individuals. For seven of these individuals, saliva and stool sequences fell into different clusters on a phylogenetic tree, indicating intra-host genetic variation of H. pylori., Conclusion: This study reports a high prevalence of H. pylori infection in asymptomatic persons in this region of Thailand and demonstrates that genotypes (vacA gene sequences) of H. pylori may differ between the oral cavity and intestinal tract.

Human papillomavirus (HPV) infection is an important cause of cervical cancer. Screening with cytology or combined cytology and HPV testing helps to detect early cervical cancers and precancerous lesions (high-grade squamous intraepithelial lesion or worse [HSIL+]). Minor cytological abnormalities (atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesion) account for the majority of abnormal cervical cytology results, but only 10-20% of women with minor cytological abnormalities have histologic HSIL+. Triage tests are useful to identify the high-risk patients and reduce the colposcopy burden. This study was aimed to evaluate the triage performance of combined HPV DNA testing and genotyping. Cervical samples from women with minor cytological abnormalities, who underwent colposcopy at Chiang Mai University Hospital in northern Thailand between October 2010 and February 2014, were tested for HPV DNA using Hybrid Capture 2 (HC2). Genotyping was performed using Linear Array assay. Of 223 women with cervical histology confirmation, histologic HSIL+ was detected in 25 women (11.2%). The sensitivity, specificity, positive predictive value, and negative predictive value of 3 triage methods for histologic HSIL+ were; 100%, 47.5%, 19.4%, and 100% by HC2 only; 40.0%, 88.4%, 30.3%, and 92.1% by combined HC2 and genotypes HPV16/18; and 96.0%, 75.8%, 33.3%, and 99.3% by combined HC2 and genotypes HPV16/18/52/58. Triage using combined HC2 and genotypes HPV16/18/52/58 showed significantly greater area under the receiver operating curve than the other 2 methods (P < 0.001). Combined HPV DNA testing and genotyping for HPV16/18/52/58 is useful for triaging women with minor cervical cytological abnormalities in northern Thailand., (© 2015 Wiley Periodicals, Inc.)

Background: Duffy (FY) blood group genotyping is important in transfusion medicine because Duffy alloantibodies are associated with delayed hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. In this study, FY allele frequencies in Thai blood donors were determined by in-house PCR with sequence-specific primers (PCR-SSP), and the probability of obtaining compatible blood for alloimmunized patients was assessed., Methods: Five hundred blood samples from Thai blood donors of the National Blood Centre, Thai Red Cross Society, were included. Only 200 samples were tested with anti-Fy(a) and anti-Fy(b) using the gel technique. All 500 samples and four samples from a Guinea family with the Fy(a-b-) phenotype were genotyped by using PCR-SSP. Additionally, the probability of obtaining antigen-negative red blood cells (RBCs) for alloimmunized patients was calculated according to the estimated FY allele frequencies., Results: The FY phenotyping and genotyping results were in 100% concordance. The allele frequencies of FY*A and FY*B in 500 central Thais were 0.962 (962/1,000) and 0.038 (38/1,000), respectively. Although the Fy(a-b-) phenotype was not observed in this study, FY*B(ES)/FY*B(ES) was identified by PCR-SSP in the Guinea family and was confirmed by DNA sequencing., Conclusions: Our results confirm the high frequency of the FY*A allele in the Thai population, similar to that of Asian populations. At least 500 Thai blood donors are needed to obtain two units of antigen-negative RBCs for the Fy(a-b+) phenotype.

Merozoite surface proteins (MSPs) of malaria parasites play critical roles during the erythrocyte invasion and so are potential candidates for malaria vaccine development. However, because MSPs are often under strong immune selection, they can exhibit extensive genetic diversity. The gene encoding the merozoite surface protein-3 (MSP-3) of Plasmodium falciparum displays 2 allelic types, K1 and 3D7. In Thailand, the allelic frequency of the P. falciparum msp-3 gene was evaluated in a single P. falciparum population in Tak at the Thailand and Myanmar border. However, no study has yet looked at the extent of genetic diversity of the msp-3 gene in P. falciparum populations in other localities. Here, we genotyped the msp-3 alleles of 63 P. falciparum samples collected from 5 geographical populations along the borders of Thailand with 3 neighboring countries (Myanmar, Laos, and Cambodia). Our study indicated that the K1 and 3D7 alleles coexisted, but at different proportions in different Thai P. falciparum populations. K1 was more prevalent in populations at the Thailand-Myanmar and Thailand-Cambodia borders, whilst 3D7 was more prevalent at the Thailand-Laos border. Global analysis of the msp-3 allele frequencies revealed that proportions of K1 and 3D7 alleles of msp-3 also varied in different continents, suggesting the divergence of malaria parasite populations. In conclusion, the variation in the msp-3 allelic patterns of P. falciparum in Thailand provides fundamental knowledge for inferring the P. falciparum population structure and for the best design of msp-3 based malaria vaccines.

Background: We aimed to compare HPA-1 to HPA-6 and HPA-15 genotyping results obtained by a simple-probe real-time polymerase chain reaction (PCR) technique with the multiplex PCR technique., Methods: Five hundred DNA samples from the Thai National Stem Cell Donor Registry (TSCDR) of the National Blood Centre, Thai Red Cross Society were included. Human platelet antigen (HPA) genotyping was performed by simple-probe real-time PCR and multiplex PCR techniques., Results: HPA-1, HPA-2, HPA-3, and HPA-4 genotyping results obtained by both techniques were in agreement. The misinterpretation of HPA-5, HPA-6, and HPA-15 genotypes was found in eight samples by simple-probe real-time PCR and HPA genotypes were confirmed by DNA sequencing. Two samples of HPA-5 were misinterpreted as HPA-5a5a instead of HPA-5a5b due to an NM&#95;002203.3:c.1594A>C mutation (rs199808499) near the HPA-5 polymorphism (5' side). Five samples of HPA-6a6b were misinterpreted as HPA-6b6b because of an NM&#95;000212.2:c.1545G>A mutation (rs4634) adjacent to the HPA-6 polymorphism (3' side). Interestingly, one sample of HPA-15a15b was misinterpreted as HPA-15b15b due to an NM&#95;133493.1:c.2118C>A mutation near the HPA-15 polymorphism (3' side)., Conclusions: HPA genotyping results by two PCR techniques were compared. Incorrect assignments were found due to genetic variations near each HPA single nucleotide polymorphism. Therefore, to avoid false assignation, the use of two genotyping techniques is recommended., (© 2014 Wiley Periodicals, Inc.)

We identified 10 patients in Thailand with culture-confirmed melioidosis who had Burkholderia pseudomallei isolated from their drinking water. The multilocus sequence type of B. pseudomallei from clinical specimens and water samples were identical for 2 patients. This finding suggests that drinking water is a preventable source of B. pseudomallei infection.