Characterization of Human Cytomegalovirus Strains by Analysis of Short Tandem Repeat Polymorphisms

Human cytomegalovirus (HCMV) strains display genetic polymorphisms, and these polymorphisms can be analyzed to study viral transmission and pathogenesis. Recently, short tandem repeat (STR) length polymorphisms have been identified in the HCMV genome. We assessed the utility of STRs in characterizing HCMV strains and found that a multiplexed PCR assay using primers based upon these STRs accurately maps HCMV strains. Using primers for 10 microsatellite regions, the STR profiles of 44 wild-type and 2 laboratory strains of HCMV were characterized. The results of STR analysis were compared with those for strain characterization using nucleotide sequencing and restriction fragment length polymorphism analysis. In each instance, STR analysis accurately and specifically identified strains that were indistinguishable or distinct by conventional molecular analysis. Analysis of short tandem repeats also detected polymorphisms that supported simultaneous excretion of two HCMV strains. These results indicate that STR analysis allows rapid, precise molecular characterization of HCMV strains

Evaluation of glycoprotein B genotypes and load of CMV infecting blood leukocytes on prognosis of AIDS patients

BACKGROUND: Cytomegalovirus (CMV) remains an important pathogen to immunocompromised patients even in the era of HAART. The present study aimed at evaluating the influence of CMV viral load and its gB genotypes on AIDS patients' outcome. METHODS: Blood samples of 101 AIDS patients were collected and tested for HIV load, CD4 - cell count and opportunistic pathogens, including CMV. Semi-nested PCRs were run to detect CMV genome and in the positive samples, gB genotyping and CMV load were established using enzymatic restriction and real time PCR, respectively. All patients were clinically followed for four years. RESULTS: In thirty patients (31%) CMV was detected and all fatal cases (n = 5) occurred in this group of patients (p = 0.007), but only two patients had CMV disease (1.9%). However, viral load was not statistically associated with any analyzed parameter. The most frequently observed CMV genotype was gB2 (45.16%) followed by gB3 (35.48%). gB2 genotype was more frequently found in patients with CD4-cell counts under 200 cells/mm³ (p = 0.0017), and almost all fatal cases (80%) had gB2 genotype. CONCLUSIONS: Our study suggests that CMV and its polymorphisms in biologically relevant genes, such as the gB encoding ORF, may still influence the prognosis and outcome of AIDS patients. The gB2 genotype was associated to patient's bad outcome