ABSTRACT
The non-structural 5B (NS5B) gene is the target region to identify hepatitis C virus (HCV) subtypes. However, it is not always possible to amplify this region because of inherently high sequence variability. Nucleotide sequences of the non-structural 5A (NS5A) and NS5B genes and its concordance were determined from patients infected with HCV genotype 1 (HCV-1). Among the 30 HCV-1 samples, 7 (23%) were identified as subtype 1a and 23 (77%) were identified as 1b by NS5A sequencing. Sequence analysis of the NS5B showed that 13 (43%) were identified as 1a and 17 (57%) were identified as 1b. Out of the 13 samples identified as 1a by NS5B, 6 (46%) were correctly identified by NS5A. Of the 17 samples identified as 1b by NS5B, 16 (94%) were correctly identified by NS5A. The presence of glutamic acid (E) or aspartic acid (D) at position 2225 in the NS5A differentiates 1a from 1b subtypes, respectively. This study showed that the NS5A sequencing can identify HCV-1a and 1b subtypes with predictive values of 86% and 70% of cases, respectively. The overall concordance with NS5B was 73%. NS5B sequence analysis remains to be the reference method to identify HCV-1 subtypes. NS5A sequencing may be used to complement NS5B sequencing in case the NS5B gene cannot be successfully amplified.
Subject(s)
Humans , Male , Female , Aged , Middle Aged , Adult , Aspartic Acid , Genotype , Glutamic Acid , Hepacivirus , Hepatitis C , Nucleotides , Sequence Analysis , Viral Nonstructural ProteinsABSTRACT
We report a case of a 45-year old Filipino post-kidney transplant patient maintained on steroids, who presented with floaters in her left eye. Vitreous aspirate was analyzed using polymerase chain reaction (PCR) for human cytomegalovirus (HCMV) and herpes simplex virus (HSV). A distinct band (435 bp) was found that confirmed the presence of HCMV. Since a rapid and accurate diagnosis is crucial for prompt administration of antiviral therapy, PCR-based analysis of vitreous aspirate provides a valuable tool in the diagnosis of patients with retinitis caused by herpes viruses.