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Introduction: Methicillin-resistant Staphylococcus aureus is globally a major public health threat. Resistance to methicillin originates from a modified protein (PBP2a) encoded by the mecA gene. The PVL gene as an important virulence factor increases the pathogenicity of MRSA. Epidemiology and characteristics of MRSA differ in different geographical regions. This study was conducted to characterize and determine the antibiotic susceptibility profile of MRSA strains isolated from patients in Hospital Tengku Ampuan Afzan, Pahang, Malaysia and to detect the presence of the mecA and PVL genes in the isolates. Materials and methods: In this study a total of 36 isolates of MRSA have been collected during a period of three months (1st February - 30th April 2018). The susceptibility pattern of the isolates to ten different commonly used antibiotics were determined and the target genes were addressed by real-time PCR experiment. Results: Based on the identifying criteria, 44.4% of the isolates were CA-MRSA, and 55.5% were HA-MRSA. Resistance to oxacillin, cefoxitin and penicillin was 100%, gentamicin 88.8%, erythromycin 33.3%, tetracycline 77.7%, trimethoprim-sulfamethoxazole 61.1%, clindamycin 13.8%, chloramphenicol 11.1%, but no resistant strain of vancomycin was detected. Most of the isolates were resistant to more than three groups of antibiotics. Realtime PCR revealed that all the isolates were mecA positive and 4 isolates were PVL-positive. PVL-positive strains were CA-MRSA and susceptible to clindamycin. Conclusion: The study confirms multi-drug resistant MRSA in the study area, and shows that resistance to methicillin is mecA mediated. PVL carrier strains were present and related to CA-MRSA strains of the isolates. [ABSTRACT FROM AUTHOR]

Background: In occult hepatitis C virus infection (OCI), hepatitis C virus ribonucleic acid (HCV RNA) is detectable in peripheral blood mononuclear cells (PBMCs) but is not evident in serum or plasma. Understanding of OCI in patients with seronegative anti-HCV antibodies is limited. Methods: In this study, six HCV isolates from haemodialysis (HD) patients with seronegative OCI were identified by molecular assays and phylogenetic analysis. The virus infectivity was assessed ex vivo using a primary naïve PBMC culture system. HCV isolates obtained from the PBMCs of 10 patients with chronic HCV infection (CCI) were characterised concurrently and used as positive controls in the cell culture. Results: Sequence analysis of the 5' untranslated region (UTR) and non-structural 5B (NS5B) region revealed that HCV genotype 3 was the most prevalent virus type in both the OCI and CCI groups. One of the occult HCV isolates was identified as a mixed type. The mean viral load (log10 RNA copies/106 cells) in the PBMC samples of the OCI group (M = 3.4, SD = 0.7) was lower than that of the CCI group (M = 4.6, SD = 1.7). Upon culture, de novo OCI-HCV replicates were detected in five out of six naïve PBMC cultures. Analysis of the replicates showed a single guanine addition in the domain III of 5'-UTR but the overall molecular structure was retained. Conclusion: Seronegative OCI is an active form of infection that replicates at a low level in PBMCs. Seronegative OCI may share the same route of transmission as CCI. The retained viral competency may have an implication for its persistence. [ABSTRACT FROM AUTHOR]