Nongyao Sawangjaroen

MicroRNAs (miRNAs), derived from extracellular vesicles (EVs) are circulating intercellular communicators which influence pathogenesis and could be used as potential diagnostic markers. In this study, plasma-derived EVs from Plasmodium knowlesi-infected patients (n = 13) and healthy individuals (n = 10) were isolated using size exclusion chromatography and ultracentrifugation. The presence of EVs was confirmed by transmission electron microscopy and Western immunoblotting, and quantified by nanoparticle tracking analysis. The EVs isolated from patients exhibited a larger size, accompanied by an elevated concentration of EVs. The relative expression levels of 8 human miRNAs were quantified using reverse transcriptase quantitative polymerase chain reaction. Compared to uninfected groups, hsa-miR-223-5p (P-value = 0.0002) and hsa-miR-486-5p (P-value = 0.025) were upregulated in P. knowlesi-infected patients. Bioinformatic analysis revealed that these miRNAs are predicted to target both human host and parasite genes, and they were found to be enriched in various malaria-related pathways. The areas under the receiver operating characteristic curve of hsa-miR-223-5p and hsa-miR-486-5p were 0.9154 and 0.8231, respectively, suggesting the potential of EV-miRNAs as diagnostic markers. Results revealed that EV-miRNAs may play a significant role in the progression of P. knowlesi infection. Further investigations should explore their potential impact on gene expression regulation as diagnostic biomarkers or targets for therapeutic interventions.

Highly sensitive diagnostic tools are crucial for individual screening during an epidemic of leptospirosis. To aid in developing a diagnostic tool for the sensitive detection of pathogenic strains,... Method summary In the present study, a quantitative polymerase chain displacement reaction for pathogenic Leptospira spp. was evaluated. The technique combines quantitative PCR (qPCR) and strand di...

To monitor drug resistance in Plasmodium vivax, a multidrug resistance 1 (Pvmdr1) gene and a putative transporter protein (Pvcrt-o) gene were used as molecular markers for chloroquine resistance. The biomarkers, the dihydrofolate reductase (Pvdhfr) gene and the dihydropteroate synthetase (Pvdhps) gene, were also used for the detection of resistance to sulphadoxine-pyrimethamine (SP); this drug is often accidentally used to treat P. vivax infections. Clinical blood samples (n = 120) were collected from patients who had been to one of eight malaria-endemic countries and diagnosed with P. vivax infection. The chloroquine resistance marker, the Pvmdr1 gene, showed F976:L1076 mutations and L1076 mutation. A K10 insertion in the Pvcrt-o gene was also found among the samples successfully sequenced. A combination of L/I57:R58:M61:T117 mutations in the Pvdhfr gene and G383:G553 mutations in the Pvdhps gene were also observed. Mutations found in these genes indicate that drug resistance is present in these eight countries. Whether or not countries are using chloroquine to treat P. vivax, there appears to be an increase in mutation numbers in resistance gene markers. The detected changes in mutation rates of these genes do suggest that there is still a trend towards increasing P. vivax resistance to chloroquine. The presence of the mutations associated with SP resistance indicates that P. vivax has had exposure to SP and this may be a consequence of either misdiagnosis or coinfections with P. falciparum in the past.

Toxoplasmosis is one of the most common opportunistic parasitic diseases in patients living with HIV/AIDS. This study aimed to determine the seroprevalence of Toxoplasma infection in HIV-infected patients and to identify associated risk factors in Toxoplasma seropositive patients. This study was conducted at a regional public hospital in Hat Yai, southern Thailand during October 2009 to June 2010. Blood samples were collected from 300 HIV-infected patients. Each subject also answered a socio-demographic and risk factors associated with Toxoplasma infection. The prevalence of anti-Toxoplasma IgG antibodies in HIV-infected patients was 109 (36.3%), of which 83 (76.2%) had past infection and 26 (23.9%) had recently acquired Toxoplasma infection as indicated by their IgG avidity. Multivariate analysis using logistic regression showed that gender difference (adjusted OR=1.69, 95% CI=1.05-2.72) was the only factor associated with Toxoplasma infection. From the results obtained, these HIV-infected patients could be at high risk of developing clinical evidence of severe toxoplasmosis. Therefore, it is necessary to introduce primary behavioral practices to prevent Toxoplasma infection among HIV-infected patients.

During 2009 to 2010, a total of 408 blood samples collected from malaria patients in Ranong (149) and Yala (259) Provinces, Thailand were investigated for Plasmodium spp using microscopic examination. There are no statistical differences in the prevalence of P. falciparum and P. vivax in samples collected from Ranong and Yala (46% vs 52%, and 54% vs 45%, respectively). Single nucleotide polymorphism of codon 86 in pfmdr1 (encoding P. falciparum multidrug resistance protein 1) was investigated among 75 samples of P. falciparum and 2 samples of P. knowlesi. A pfmdr1 N86Y mutation was detected in 1 out of 29 samples and 45 out of 46 samples obtained from Ranong and Yala Provinces, respectively. It is interesting that pfmdr1 was detected in two P. knowlesi DNA samples obtained previously from Ranong Province which was 99% homologous to pfmdr1 obtained from falciparum parasites in the same area but the mutation was not observed. The difference in multidrug resistance protein in Plasmodium obtained from those two border areas of Thailand will be of use in monitoring drug resistance in these border regions of the country.