No abstract

Hepatitis C virus (HCV) can be classified into six major genotypes. The HCV genotypes variability accounts for its geographical distribution, its responses to treatments and the clinical outcomes. The aim of this study was to determine the distribution of HCV genotypes among volunteer blood donors in Thailand. Samples from 135 anti-HCV positive blood donors were analyzed. HCV RNA and genotyping was carried out using nested polymerase chain reaction (PCR) and genotype-specific primer PCR for a portion of the core region. HCV RNA was detected in 109 samples (80.7%). Genotype analysis demonstrated four different genotypes. The most common was genotype 3a (36.7%), followed by genotype 6 (29.4%), 1a (19.3%), 1b (6.4%) and mixed infection (1.8%). Seven samples were untyped (6.4%) in the present study. In several previous reports, the prevalence found in Thailand was HCV genotypes 3, 1 and 6. The present results show an increasing importance of the genotype 6 in HCV infections. This study has also described for the first time in Thailand mixed infections of HCV genotypes.

Pseudomonas aeruginosa is a leading cause of nosocomial and serious life-threatening infections and infections caused by this bacterium continue to pose a major medical challenge worldwide. The ability of P . aeruginosa to produce multiple virulence factors and in particular to form biofilms makes this bacterium resistant to all known antibiotics. As a consequence, standard antibiotic therapy are increasingly become ineffective to clear such infections associated with biofilms. In search for novel effective agents to combat P . aeruginosa biofilm infections, a series of the BmKn‒2 scorpion venom peptide and its truncated derivatives were synthesized and their antibiofilm activities assessed. Among the peptides tested, BmKn‒22 peptide, which was a modified peptide of the parental BmKn‒2 scorpion venom peptide, clearly demonstrated the most potential inhibitory activity against P . aeruginosa biofilms without affecting the bacterial growth. This peptide was not only capable of inhibiting the formation of P . aeruginosa biofilms, but also disrupting the established biofilms of P . aeruginosa . Additionally, BmKn‒22 peptide was able to inhibit the production of key virulence factor pyocyanin of P . aeruginosa . Our results also showed that BmKn‒22 peptide significantly reduced lasI and rhlR expression, and suggested that BmKn‒22 peptide-mediated inhibition of P . aeruginosa biofilms and virulence factors was achieved through the components of quorum-sensing systems. Combination of BmKn‒22 peptide with azithromycin resulted in a remarkable reduction P . aeruginosa biofilms. Since this peptide exhibited low toxicity to mammalian cells, all our results therefore indicate that the BmKn‒22 peptide is a promising antibiofilm agent against P . aeruginosa and warrant further development of this peptide as a novel therapeutic for treatment of P . aeruginosa ‒associated biofilm infections.

For HCV-6, the subtype 6f was commonly found in Thai blood donors. Comparison of core protein from various HCV-6 subtypes showed substantial polymorphisms, which may form the basis of future studies using samples from patients with clear HCV histories. This feature can be applied to therapies tailored to particular genotype variants.

ABSTRACT:The hepatitis C virus (HCV) contains seven genotypes heterogeneously distributed around the world. HCV displays a high genetic diversity relevant to epidemiology, transmission, and clinical management. To explore the genetic variation of HCV in a local Thai population, we investigated the restriction fragment length polymorphism (RFLP) pattern of the core gene in 31 samples of HCV genotype 3a found in blood donors. The polymorphisms of these HCVs were clustered into five RFLP patterns (IV). Fifteen samples (48%) clustered as the RFLP pattern I and ten samples (32%) as pattern III profiles which have been previously reported. In addition, there were four samples (13%) manifest as pattern II, one sample (3%) as pattern IV, and one sample (3%) as pattern V. This study provides pointers to the molecular epidemiology of HCV genotype 3a distributed in Thailand.