Prevalence of human cytomegalovirus UL97 D605E mutation in transplant recipients in China

Prevalence of UL97 gene mutations and polymorphisms in cytomegalovirus infection in the colon associated with or without ulcerative colitis

Cytomegalovirus (CMV) reactivation in the colon is common in patients with severe ulcerative colitis (UC). Ganciclovir (GCV) resistance conferring CMV UL97 gene mutations have been reported in recent years. However, the prevalence of UL97 gene mutations in GCV-naive CMV infection in the colon remains unknown. We investigated the prevalence of CMV UL97 gene mutations in patients with colonic CMV infection associated with or without UC. Twenty-two GCV-naive patients with colonic CMV infection, 15 with UC and 7 with other diseases, were enrolled. Frozen biopsy samples or formalin-fixed paraffin-embedded samples were used for nested polymerase chain reaction (PCR) amplification of the UL97 gene. Sanger DNA sequencing was performed. In comparison with AD169 reference strain, natural polymorphisms were frequently detected in codons N68D (100%), I244V (100%), and D605E (86.4%). Seven polymorphisms were detected infrequently (< 10%) outside the kinase domain. However, no known GCV resistance mutations were found. There seemed to be no difference between the ratio of polymorphisms in patients with and without UC. In conclusions, we did not detect UL97 gene mutations associated with GCV resistance in GCV-naive patients with or without UC. Consistent with previous reports, D605E polymorphism may be used as a genetic marker for CMV in East Asian countries.

Molecular Epidemiology of Cytomegalovirus UL97 and UL54 variants in Taiwan

BACKGROUND

The antiviral resistance of cytomegalovirus (CMV) infections is associated with mutations in the CMV UL54 and UL97 gene regions and is a serious problem in immunocompromised patients. However, the molecular epidemiology of UL54 and UL97 in Taiwan is unclear.

METHODS

We conducted a retrospective study of patients with CMV infections between January and December 2016 in two tertiary hospitals, one regional hospital in Taiwan. CMV DNAemia was confirmed by elevated CMV DNA titers. Then the regions of the UL54 and UL97 mutations were amplified by PCR and sequenced.

RESULTS

Of 729 patients with CMV syndrome, 112 CMV DNAemia patients were enrolled. Twelve novel variants in UL54 (P342S, S384F, K434R, S673F, T754M, R778H, C814S, M827I, G878E, S880L, E888K, and S976N) and one novel variant in UL97 (M615T) were discovered. UL97 antiviral resistance mutations (L595S, M460I, and M460V) were found in four patients (3.6%). In the drug resistance strains, the mutation events occurred after 83-150 days of therapy, and drug resistance was also observed in these patients. The following high frequency variants were observed: D605E in UL97 and A885T, N898D, V355A, N685S, and A688V in UL54.

CONCLUSION

The results demonstrate that the positive rate of CMV DNAemia was 15.3% (112/729) among the patients with clinical CMV infection symptoms. The proportion of antiviral resistance CMV strains within CMV DNAemia patients was 3.6%. With the information of polymorphism incidence in the UL54 and UL97 patients from our study, determination of the genetic profile of UL54 and UL97 among immunocompromised populations with refractory CMV infection is recommended.

Human cytomegalovirus UL54 and UL97 mutations for detection of ganciclovir resistance in congenital infection

Aim: Ganciclovir (GCV) is used as an antiviral drug for the treatment of human cytomegalovirus infection. The aim of this study was to demonstrate GCV-resistant human cytomegalovirus in congenitally infected neonates. Patients & methods: DNA of CMV positive newborn samples was extracted and UL97 and UL54 genes were amplified by PCR and real-time PCR. Sequencing of UL97 and UL54 genes were performed and analyzed. Results: UL97 GCV resistance mutation C603W was detected in one newborn. D605E was the most common polymorphism in UL97 observed in 7/13 (53.8%) of samples. N685S, A688V, A885T and N898D were four known common UL54 polymorphisms. Conclusion: The rate of GCV resistance in congenital CMV is low. Common polymorphisms in UL97 and UL54 genes are also reported as new mutations.

Human cytomegalovirus pUL97 drug-resistance mutations in congenitally neonates and HIV-infected, no-drug-treated patients

Aim: Human cytomegalovirus (HCMV) treatment is hard to achieve because of viral protein target sequence variations. Objectives: We aimed to find HCMV pUL97 kinase variations in HIV- and congenitally infected patients. Methods: Twenty HCMV-positive DNA samples from nonganciclovir treated congenitally infected neonates and HIV positive patients were used for PCR restriction fragment length polymorphism. Variations were assessed computationally for pUL97 functionality. Results: P521L, D605E and N597Y substitutions were prevalent significantly in congenital infection. Furthermore, we found those mutations have neutral or low impact on pUL97 functionality. In addition, we found a new K599Q substitution in an HIV-infected individual. Conclusion: More prevalent substitutions related to low-grade ganciclovir resistance were found in congenitally infected neonates in comparison with HIV-infected patients.

Evaluation of ganciclovir resistance in cytomegalovirus infection of renal transplant recipients in Tehran

BACKGROUND

Human cytomegalovirus (CMV) infection is a major issue in solid organ transplant recipients. Although development of prophylaxis and preemptive procedures have presented significantly improved consequences in CMV infection, increasing incidence of antiviral resistance has raised virologists' concern.

METHODS

The present study focused on kidney transplant recipients with high quantities of CMV load after antiviral therapy. We collected 5 mL blood from each of 58 patients. DNA extraction was performed with the use of the QIAamp DNA Mini kit (Qiagen), in accordance with the manufacturer's instructions.

RESULTS

Our population study was 38% female and 62% male. CMV DNA was observed in 50 specimens (86%) with the range of 1.9 × 10(3) to 11 × 10(7) copies/mL serum. All of these patients had received ganciclovir for >3 months. Sequencing showed 18 mutations in 10 patients. Among these, 16 mutations were associated with Ul97 and the rest with Ul54 gene. Forty CMV-positive patients did not show any mutations.

CONCLUSIONS

The consequences of long-term ganciclovir resistance could not be determined.

Human cytomegalovirus UL97 D605E polymorphism has a high prevalence in immunocompetent Japanese infants and children

There is no existing data on UL97 mutation in human cytomegalovirus (HCMV) isolates obtained from individuals who have never been exposed to ganciclovir (GCV). UL97 codons 439 to 645 from 61 CMV isolates from 61 immunocompetent Japanese infants and children were sequenced directly. No known GCV resistance mutations were found, meaning that the UL97 mutation had resulted from the use of GCV. On the other hand, a mutation at codon 605 (D to E) was frequently identified (56/61: 91.8%). This could be a genetic marker for HCMV in East Asian counties, because of its low prevalence in the strains of HCMV circulating in Western countries.

Valganciclovir as pre-emptive therapy for cytomegalovirus infection post-allogenic stem cell transplantation: implications for the emergence of drug-resistant cytomegalovirus

OBJECTIVES

Valganciclovir is a well established drug for the management of cytomegalovirus (CMV) infection in haematopoietic stem cell transplantation (HSCT). Data concerning its safety regarding the development of drug resistance are required. The aim of the present study was to retrospectively investigate CMV drug resistance in a group of HSCT patients experiencing relapses of CMV infection after a first-line pre-emptive antiviral therapy.

METHODS

Thirteen adult HSCT patients out of 26 with asymptomatic CMV infection, experiencing relapsing infections 45-155 days after either intravenous (iv) ganciclovir (2 patients) or valganciclovir (11 patients), were studied. Genotypic assays for mutations in the viral phosphotransferase (UL97) and DNA-polymerase (UL54) genes were directly applied on patient specimens. Baseline CMV sequences were compared with those at the time of relapses to identify drug-resistant strains.

RESULTS

UL97 mutations A594V and M460V known to confer drug resistance developed in one relapsing patient who received iv ganciclovir as first-line therapy, corresponding to a rate of 7.7% of relapses due to drug-resistant strains and an overall 3.8% rate of infections due to CMV drug-resistant strains. UL54 drug resistance mutations were absent. No evidence of drug resistance was found in patients on valganciclovir either as first-line therapy or as treatment for relapses.

CONCLUSIONS

The safety profile of valganciclovir as anti-CMV pre-emptive therapy was confirmed, as well as that monitoring CMV drug resistance with genotypic tests on sequential isolates over the time-course of therapy offers guidance to tailor antiviral treatment in a clinically relevant time frame.