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Grgic I, Gorenec L. Human Cytomegalovirus (HCMV) Genetic Diversity, Drug Resistance Testing and Prevalence of the Resistance Mutations: A Literature Review. Trop Med Infect Dis 2024; 9:49. [PMID: 38393138 PMCID: PMC10892457 DOI: 10.3390/tropicalmed9020049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/07/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024] Open
Abstract
Human cytomegalovirus (HCMV) is a pathogen with high prevalence in the general population that is responsible for high morbidity and mortality in immunocompromised individuals and newborns, while remaining mainly asymptomatic in healthy individuals. The HCMV genome is 236,000 nucleotides long and encodes approximately 200 genes in more than 170 open reading frames, with the highest rate of genetic polymorphisms occurring in the envelope glycoproteins. HCMV infection is treated with antiviral drugs such as ganciclovir, valganciclovir, cidofovir, foscarnet, letermovir and maribavir targeting viral enzymes, DNA polymerase, kinase and the terminase complex. One of the obstacles to successful therapy is the emergence of drug resistance, which can be tested phenotypically or by genotyping using Sanger sequencing, which is a widely available but less sensitive method, or next-generation sequencing performed in samples with a lower viral load to detect minority variants, those representing approximately 1% of the population. The prevalence of drug resistance depends on the population tested, as well as the drug, and ranges from no mutations detected to up to almost 50%. A high prevalence of resistance emphasizes the importance of testing the patient whenever resistance is suspected, which requires the development of more sensitive and rapid tests while also highlighting the need for alternative therapeutic targets, strategies and the development of an effective vaccine.
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Affiliation(s)
- Ivana Grgic
- Department of Molecular and Immunological Diagnostic, University Hospital for Infectious Diseases “Dr. Fran Mihaljevic”, 10000 Zagreb, Croatia
| | - Lana Gorenec
- Department of Molecular and Immunological Diagnostic, University Hospital for Infectious Diseases “Dr. Fran Mihaljevic”, 10000 Zagreb, Croatia
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2
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Veleanu A, Kelch MA, Ye C, Flohr M, Wilhelm A, Widera M, Martinez-Sobrido L, Ciesek S, Toptan T. Molecular Analyses of Clinical Isolates and Recombinant SARS-CoV-2 Carrying B.1 and B.1.617.2 Spike Mutations Suggest a Potential Role of Non-Spike Mutations in Infection Kinetics. Viruses 2022; 14:v14092017. [PMID: 36146823 PMCID: PMC9506066 DOI: 10.3390/v14092017] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/09/2022] [Accepted: 09/09/2022] [Indexed: 11/16/2022] Open
Abstract
Some of the emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants are less susceptible to neutralization with post-vaccine sera and monoclonal antibodies targeting the viral spike glycoprotein. This raises concerns of disease control, transmissibility, and severity. Numerous substitutions have been identified to increase viral fitness within the nucleocapsid and nonstructural proteins, in addition to spike mutations. Therefore, we sought to generate infectious viruses carrying only the variant-specific spike mutations in an identical backbone to evaluate the impact of spike and non-spike mutations in the virus life cycle. We used en passant mutagenesis to generate recombinant viruses carrying spike mutations of B.1 and B.1.617.2 variants using SARS-CoV-2- bacterial artificial chromosome (BAC). Neutralization assays using clinical sera yielded comparable results between recombinant viruses and corresponding clinical isolates. Non-spike mutations for both variants neither seemed to effect neutralization efficiencies with monoclonal antibodies nor the response to treatment with inhibitors. However, live-cell imaging and microscopy revealed differences, such as persisting syncytia and pronounced cytopathic effect formation, as well as their progression between BAC-derived viruses and clinical isolates in human lung epithelial cell lines and primary bronchial epithelial cells. Complementary RNA analyses further suggested a potential role of non-spike mutations in infection kinetics.
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Affiliation(s)
- Andrei Veleanu
- Institute for Medical Virology, University Hospital, Goethe University Frankfurt, D-60596 Frankfurt am Main, Germany
| | - Maximilian A. Kelch
- Institute for Medical Virology, University Hospital, Goethe University Frankfurt, D-60596 Frankfurt am Main, Germany
| | - Chengjin Ye
- Texas Biomedical Research Institute, San Antonio, TX 78227-5302, USA
| | - Melanie Flohr
- Institute for Medical Virology, University Hospital, Goethe University Frankfurt, D-60596 Frankfurt am Main, Germany
| | - Alexander Wilhelm
- Institute for Medical Virology, University Hospital, Goethe University Frankfurt, D-60596 Frankfurt am Main, Germany
| | - Marek Widera
- Institute for Medical Virology, University Hospital, Goethe University Frankfurt, D-60596 Frankfurt am Main, Germany
| | | | - Sandra Ciesek
- Institute for Medical Virology, University Hospital, Goethe University Frankfurt, D-60596 Frankfurt am Main, Germany
- German Centre for Infection Research (DZIF), Partner Site Frankfurt am Main, D-60596 Frankfurt am Main, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Theodor Stern Kai 7, D-60595 Frankfurt am Main, Germany
| | - Tuna Toptan
- Institute for Medical Virology, University Hospital, Goethe University Frankfurt, D-60596 Frankfurt am Main, Germany
- Correspondence: ; Tel.: +49-69-6301-4536
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3
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Torii Y, Horiba K, Kawada JI, Haruta K, Yamaguchi M, Suzuki T, Uryu H, Kashiwa N, Goishi K, Ogi T, Ito Y. Detection of antiviral drug resistance in patients with congenital cytomegalovirus infection using long-read sequencing: a retrospective observational study. BMC Infect Dis 2022; 22:568. [PMID: 35733089 PMCID: PMC9219161 DOI: 10.1186/s12879-022-07537-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 06/08/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Congenital human cytomegalovirus (cCMV) infection can cause sensorineural hearing loss and neurodevelopmental disabilities in children. Ganciclovir and valganciclovir (GCV/VGCV) improve long-term audiologic and neurodevelopmental outcomes for patients with cCMV infection; however, antiviral drug resistance has been documented in some cases. Long-read sequencing can be used for the detection of drug resistance mutations. The objective of this study was to develop full-length analysis of UL97 and UL54, target genes with mutations that confer GCV/VGCV resistance using long-read sequencing, and investigate drug resistance mutation in patients with cCMV infection. METHODS Drug resistance mutation analysis was retrospectively performed in 11 patients with cCMV infection treated with GCV/VGCV. UL97 and UL54 genes were amplified using blood DNA. The amplicons were sequenced using a long-read sequencer and aligned with the reference gene. Single nucleotide variants were detected and replaced with the reference sequence. The replaced sequence was submitted to a mutation resistance analyzer, which is an open platform for drug resistance mutations. RESULTS Two drug resistance mutations (UL54 V823A and UL97 A594V) were found in one patient. Both mutations emerged after 6 months of therapy, where viral load increased. Mutation rates subsided after cessation of GCV/VGCV treatment. CONCLUSIONS Antiviral drug resistance can emerge in patients with cCMV receiving long-term therapy. Full-length analysis of UL97 and UL54 via long-read sequencing enabled the rapid and comprehensive detection of drug resistance mutations.
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Affiliation(s)
- Yuka Torii
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya, Japan
| | - Kazuhiro Horiba
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya, Japan.,Department of Genetics, Research Institute of Environmental Medicine Nagoya University, Furo-cho, Chikusa-ku, 464-8601, Nagoya, Japan.,Department of Human Genetics and Molecular Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya, Japan
| | - Jun-Ichi Kawada
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya, Japan
| | - Kazunori Haruta
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya, Japan
| | - Makoto Yamaguchi
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya, Japan
| | - Takako Suzuki
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya, Japan
| | - Hideko Uryu
- Department of Pediatrics, National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku-ku, Tokyo, Japan
| | - Naoyuki Kashiwa
- Department of Pediatrics, National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku-ku, Tokyo, Japan
| | - Keiji Goishi
- Department of Pediatrics, National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku-ku, Tokyo, Japan
| | - Tomoo Ogi
- Department of Genetics, Research Institute of Environmental Medicine Nagoya University, Furo-cho, Chikusa-ku, 464-8601, Nagoya, Japan.,Department of Human Genetics and Molecular Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya, Japan
| | - Yoshinori Ito
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya, Japan. .,Department of Pediatrics and Child Health, Nihon University School of Medicine, 30-1 Oyaguchi, Kami-cho, Itabashi-ku, 173-8610, Tokyo, Japan.
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4
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Assessment of UL56 Mutations before Letermovir Therapy in Refractory Cytomegalovirus Transplant Recipients. Microbiol Spectr 2022; 10:e0019122. [PMID: 35343771 PMCID: PMC9045154 DOI: 10.1128/spectrum.00191-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
De novo mutations in the UL56 terminase subunit and its associated phenotypes were studied in the context of cytomegalovirus (CMV) transplant recipients clinically resistant to DNA-polymerase inhibitors, naive to letermovir. R246C was the only UL56 variant detected by standard and deep sequencing, located within the letermovir-resistance-associated region (residues 230–370). R246C emerged in 2/80 transplant recipients (1 hematopoietic and 1 heart) since first cytomegalovirus replication and responded transiently to various alternative antiviral treatments in vivo. Recombinant phenotyping showed R246C conferred an advanced viral fitness and was sensitive to ganciclovir, cidofovir, foscarnet, maribavir, and letermovir. These results demonstrate a low rate (2.5%) of natural occurring polymorphisms within the letermovir-resistant-associated region before its administration. Identification of high replicative capacity variants in patients not responding to treatment or experiencing relapses could be helpful to guide further therapy and dosing of antiviral molecules. IMPORTANCE We provide comprehensive data on the clinical correlates of both CMV genotypic follow-up by standard and deep sequencing and the clinical outcomes, as well as recombinant phenotypic results of this novel mutation. Our study emphasizes that the clinical follow-up in combination with genotypic and phenotypic studies is essential for the assessment and optimization of patients experiencing HCMV relapses or not responding to antiviral therapy. This information may be important for other researchers and clinicians working in the field to improve the care of transplant patients since drug-resistant CMV infections are an important emerging problem even with the new antiviral development.
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Tamura S, Osawa S, Ishida N, Miyazu T, Tani S, Yamade M, Iwaizumi M, Hamaya Y, Kosugi I, Furuta T, Sugimoto K. Prevalence of UL97 gene mutations and polymorphisms in cytomegalovirus infection in the colon associated with or without ulcerative colitis. Sci Rep 2021; 11:13676. [PMID: 34211066 PMCID: PMC8249415 DOI: 10.1038/s41598-021-93168-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 06/22/2021] [Indexed: 12/13/2022] Open
Abstract
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.
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Affiliation(s)
- Satoshi Tamura
- Department of Endoscopic and Photodynamic Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
- First Department of Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
| | - Satoshi Osawa
- Department of Endoscopic and Photodynamic Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan.
| | - Natsuki Ishida
- First Department of Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
| | - Takahiro Miyazu
- First Department of Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
| | - Shinya Tani
- First Department of Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
| | - Mihoko Yamade
- First Department of Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
| | - Moriya Iwaizumi
- Department of Laboratory Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
| | - Yasushi Hamaya
- First Department of Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
| | - Isao Kosugi
- Department of Regenerative and Infectious Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
| | - Takahisa Furuta
- Center for Clinical Research, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
| | - Ken Sugimoto
- First Department of Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan
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Yang SL, Lin TW, Lin HC, Wang HY, Chang PY, Wang PN, Yang S, Lu JJ. Molecular Epidemiology of Cytomegalovirus UL97 and UL54 variants in Taiwan. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2021; 54:971-978. [PMID: 33632621 DOI: 10.1016/j.jmii.2021.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 01/16/2021] [Accepted: 01/25/2021] [Indexed: 12/20/2022]
Abstract
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.
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Affiliation(s)
- Shu-Li Yang
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
| | - Ting-Wei Lin
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Hsin-Chieh Lin
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Hsin-Yao Wang
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan; Ph.D. Program in Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan
| | - Pi-Yueh Chang
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Po-Nan Wang
- Department of Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Internal Medicine, Division of Hematology and Oncology, Chang Gung Memorial Hospital, Taoyun, Taiwan
| | - Shuan Yang
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Jang-Jih Lu
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan; Department of Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
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7
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Douglas CM, Barnard R, Holder D, Leavitt R, Levitan D, Maguire M, Nickle D, Teal V, Wan H, van Alewijk DCJG, van Doorn LJ, Chou S, Strizki J. Letermovir Resistance Analysis in a Clinical Trial of Cytomegalovirus Prophylaxis for Hematopoietic Stem Cell Transplant Recipients. J Infect Dis 2021; 221:1117-1126. [PMID: 31781762 DOI: 10.1093/infdis/jiz577] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/14/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Letermovir (LET), a cytomegalovirus (CMV) deoxyribonucleic acid (DNA) terminase inhibitor, was recently approved for prophylaxis of CMV infection in adult CMV-seropositive recipients of allogeneic hematopoietic stem cell transplantation. Cytomegalovirus genotyping was performed to identify LET-resistance-associated variants (RAVs) among subjects in a Phase 3 trial. METHODS The CMV UL56 and UL89 genes, encoding subunits of CMV DNA terminase, were sequenced from plasma collected from subjects with clinically significant CMV infection (CS-CMVi). Novel variants were evaluated by recombinant phenotyping to assess their potential to confer resistance to LET. RESULTS Genotyping was successful for 50 of 79 LET subjects with CS-CMVi. Resistance-associated variants (encoding pUL56 V236M and C325W) were detected independently in subjects 1 and 3 who experienced CS-CMVi while receiving LET prophylaxis, and 2 other variants (encoding pUL56 E237G and R369T) were detected >3 weeks after subjects 2 and 3, respectively, had discontinued LET prophylaxis and received preemptive therapy with ganciclovir. CONCLUSIONS The detected incidence of CMV resistance among subjects who received LET as prophylaxis in this Phase 3 trial was low. The LET RAVs that were detected mapped to the CMV UL56 gene at positions associated with reduced susceptibility to LET based on resistance selections in cell culture.
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Affiliation(s)
- Cameron M Douglas
- Infectious Disease Research, Merck & Co., Inc., Kenilworth, New Jersey, USA
| | - Richard Barnard
- Infectious Disease Research, Merck & Co., Inc., Kenilworth, New Jersey, USA
| | - Daniel Holder
- Biostatistics and Research Decision Sciences, Merck & Co., Inc., Kenilworth, New Jersey, USA
| | - Randi Leavitt
- Clinical Research, Merck & Co., Inc., Kenilworth, New Jersey, USA
| | - Diane Levitan
- Translational Molecular Biomarkers, Merck & Co., Inc., Kenilworth, New Jersey, USA
| | - Maureen Maguire
- Translational Molecular Biomarkers, Merck & Co., Inc., Kenilworth, New Jersey, USA
| | - David Nickle
- Pharmacogenomics and Genetics, Merck & Co., Inc., Kenilworth, New Jersey, USA
| | - Valerie Teal
- Biostatistics and Research Decision Sciences, Merck & Co., Inc., Kenilworth, New Jersey, USA
| | - Hong Wan
- Biostatistics and Research Decision Sciences, Merck & Co., Inc., Kenilworth, New Jersey, USA
| | | | | | - Sunwen Chou
- Department of Veterans Affairs Medical Center, Oregon Health and Science University, Portland, Oregon, USA
| | - Julie Strizki
- Infectious Disease Research, Merck & Co., Inc., Kenilworth, New Jersey, USA
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8
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Hofmann E, Sidler D, Dahdal S, Bittel P, Suter-Riniker F, Manuel O, Walti LN, Hirzel C. Emergence of letermovir resistance in solid organ transplant recipients with ganciclovir resistant cytomegalovirus infection: A case series and review of the literature. Transpl Infect Dis 2020; 23:e13515. [PMID: 33210830 DOI: 10.1111/tid.13515] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/27/2020] [Accepted: 11/08/2020] [Indexed: 10/23/2022]
Abstract
Ganciclovir (GCV)-resistant cytomegalovirus (CMV) infection is a common problem among solid organ transplant (SOT) recipients without prior CMV immunity (CMV D+/R-). GCV-resistant CMV represents a particular challenge for CMV management. Letermovir is a recently licensed antiviral agent for primary CMV prophylaxis in allogenic hematopoietic stem cell transplant (HSCT) recipients. Given the favorable safety profile and its oral bioavailability letermovir may be considered a valuable off-label option for secondary prophylaxis of GCV-resistant CMV in SOT recipients. Here, we describe our experience with letermovir as secondary prophylaxis for GCV-resistant CMV in two renal transplant recipients and review the literature in regard of previously published cases. Letermovir resistance emerged after a few months of secondary prophylaxis in the two renal transplant recipients. In both cases, the previously described UL56 C325Y letermovir resistance mutation was detected. In vitro studies of letermovir suggest a relatively low genetic barrier to resistance. Therefore, caution is warranted when using letermovir as secondary prophylaxis for GCV-resistant CMV infection.
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Affiliation(s)
- Eveline Hofmann
- Department of Infectious Diseases, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Daniel Sidler
- Department of Nephrology, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Suzan Dahdal
- Department of Nephrology, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Pascal Bittel
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | | | - Oriol Manuel
- Infectious Diseases Service, Department of Medicine, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Laura N Walti
- Department of Infectious Diseases, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Cédric Hirzel
- Department of Infectious Diseases, Bern University Hospital, University of Bern, Bern, Switzerland
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9
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Van Leer Buter CC, de Voogd DWK, Blokzijl H, de Joode AAE, Berger SP, Verschuuren EAM, Niesters HGM. Antiviral-resistant cytomegalovirus infections in solid organ transplantation in the Netherlands. J Antimicrob Chemother 2020; 74:2370-2376. [PMID: 31093660 PMCID: PMC7183806 DOI: 10.1093/jac/dkz196] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 04/01/2019] [Accepted: 04/03/2019] [Indexed: 02/07/2023] Open
Abstract
Objectives Antiviral resistance in cytomegalovirus (CMV) may result from mutations in the molecular targets of antiviral agents. The aim of this study was to investigate both the prevalence of resistance-associated mutations and the factors associated with antiviral resistance in solid organ transplant (SOT) patients with repeated high CMV loads during antiviral treatment. Methods SOT patients were selected retrospectively, based on CMV loads of >30000 IU/mL at least twice in a period during which treatment was given. Patient samples were tested for antiviral resistance by Sanger sequencing the UL97 and UL54 genes of CMV, which code for the viral kinase and polymerase. Factors predisposing to and resulting from the development of antiviral resistance mutations were analysed. Results Multiple samples from 113 SOT patients were tested, showing resistance-associated mutations in 25 patients (22%). A further 20 (18%) patients showed mutations that were not known to be associated with antiviral resistance. Several factors were associated with development of resistance-associated mutations in UL97 as well as UL54, including human leucocyte antigen (HLA) mismatch, which occurred more frequently in the group of patients with resistance mutations. High-level resistance mutations were most frequently seen in UL97. Conclusions This study shows that by selecting patients solely on the basis of virological response to treatment, more patients with antiviral resistance mutations are identified. In this study we confirm findings by other groups that primary infections are associated with resistance development. Moreover, we show that HLA mismatch is associated with the development of antiviral resistance, which suggests a role for host immunity in the development of resistance.
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Affiliation(s)
- Coretta C Van Leer Buter
- Department of Medical Microbiology, University Medical Centre Groningen, Groningen, The Netherlands
| | - Danielle W K de Voogd
- Department of Medical Microbiology, University Medical Centre Groningen, Groningen, The Netherlands
| | - Hans Blokzijl
- Department of Gastroenterology and Hepatology, University Medical Centre Groningen, Groningen, The Netherlands
| | - Anoek A E de Joode
- Division of Nephrology, Department of Internal Medicine, University Medical Centre Groningen, Groningen, The Netherlands
| | - Stefan P Berger
- Division of Nephrology, Department of Internal Medicine, University Medical Centre Groningen, Groningen, The Netherlands
| | - Erik A M Verschuuren
- Department of Pulmonary Diseases, University Medical Centre Groningen, Groningen, The Netherlands
| | - Hubert G M Niesters
- Department of Medical Microbiology, University Medical Centre Groningen, Groningen, The Netherlands
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10
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Advances in the genotypic diagnosis of cytomegalovirus antiviral drug resistance. Antiviral Res 2020; 176:104711. [PMID: 31940472 DOI: 10.1016/j.antiviral.2020.104711] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/22/2019] [Accepted: 01/09/2020] [Indexed: 12/20/2022]
Abstract
Cytomegalovirus (CMV) drug resistance mutation maps are updated with recent information for polymerase inhibitors, the terminase inhibitor letermovir and the UL97 kinase inhibitor maribavir. Newly mapped mutations and their phenotypes provide more detail on cross-resistance properties and suggest the need to expand the CMV gene regions covered in diagnostic testing. Next-generation deep sequencing technology offers a more sensitive, higher resolution view of emerging antiviral resistance and is recommended for use in clinical trials. Issues of standardization and diagnostic utility in comparison with traditional Sanger sequencing remain unresolved. Quality control is important for the accurate and reproducible detection of mutant viral populations in clinical specimens.
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11
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Boonsathorn S, Pasomsub E, Techasaensiri C, Apiwattanakul N. Analysis of Ganciclovir-Resistant Cytomegalovirus Infection Caused by the UL97 Gene Mutation in Codons 460 and 520 in Pediatric Patients: A Case Series. Open Forum Infect Dis 2019; 6:ofz480. [PMID: 32528998 PMCID: PMC7275293 DOI: 10.1093/ofid/ofz480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 10/31/2019] [Indexed: 11/14/2022] Open
Abstract
Background Drug-resistant cytomegalovirus (CMV) infection has been increasingly recognized. However, there are limited data in pediatric patients. In this study, the prevalence and factors associated with CMV infection with UL97 mutations in pediatric patients treated with ganciclovir but not responding to treatment were evaluated. Methods This retrospective study was conducted from January 2013 to December 2017. All patients who were suspected of having ganciclovir-resistant CMV infection and had never had ganciclovir prophylaxis were included. Genotypic assay for UL97 mutations in codons 460 and 520 conferring ganciclovir resistance was performed. Factors associated with the presence of UL97 mutations were analyzed. Results Of 34 patients included, 10 patients (29.4%) had a genotypically confirmed UL97 mutation. The median age (interquartile range [IQR]) was 3 (0.85–8.68) years. Ganciclovir resistance was tested at a median time (IQR) of 22.5 (14.3–31) days after initiation of ganciclovir. All resistant isolates harbored a UL97 mutation in codon 460. Compared with patients infected with CMV without UL97 mutation, those infected with UL97 mutation strains were younger (median age [IQR], 3.02 [0.85–8.68] vs 10.45 [2.7–16.4] years) and had a higher maximum viral load (median [IQR], 5.06 [4.74–6.05] vs 4.42 [4.03–4.87] copies/mL). Six of 10 (60%) patients were successfully treated with high-dose ganciclovir (7.5 mg/kg twice daily). Conclusions UL97 mutation ganciclovir-resistant CMV infection was not uncommon in the pediatric population. Screening for this mutation should be considered in patients experiencing virological worsening while ganciclovir is given, even if patients have not previously received ganciclovir prophylaxis.
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Affiliation(s)
- Sophida Boonsathorn
- Department of Pediatrics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Ekawat Pasomsub
- Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Chonnamet Techasaensiri
- Department of Pediatrics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Nopporn Apiwattanakul
- Department of Pediatrics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
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12
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Piret J, Boivin G. Clinical development of letermovir and maribavir: Overview of human cytomegalovirus drug resistance. Antiviral Res 2019; 163:91-105. [PMID: 30690043 DOI: 10.1016/j.antiviral.2019.01.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 01/28/2023]
Abstract
The prevention and treatment of human cytomegalovirus (HCMV) infections is based on the use of antiviral agents that currently target the viral DNA polymerase and that may cause serious side effects. The search for novel inhibitors against HCMV infection led to the discovery of new molecular targets, the viral terminase complex and the viral pUL97 kinase. The most advanced compounds consist of letermovir (LMV) and maribavir (MBV). LMV inhibits the cleavage of viral DNA and its packaging into capsids by targeting the HCMV terminase complex. LMV is safe and well tolerated and exhibits pharmacokinetic properties that allow once daily dosing. LMV showed efficacy in a phase III prophylaxis study in hematopoietic stem cell transplant (HSCT) recipients seropositive for HCMV. LMV was recently approved under the trade name Prevymis™ for prophylaxis of HCMV infection in adult seropositive recipients of an allogeneic HSCT. Amino acid substitutions conferring resistance to LMV selected in vitro map primarily to the pUL56 and rarely to the pUL89 and pUL51 subunits of the HCMV terminase complex. MBV is an inhibitor of the viral pUL97 kinase activity and interferes with the morphogenesis and nuclear egress of nascent viral particles. MBV is safe and well tolerated and has an excellent oral bioavailability. MBV was effective for the treatment of HCMV infections (including those that are refractory or drug-resistant) in transplant recipients in two phase II studies and is further evaluated in two phase III trials. Mutations conferring resistance to MBV map to the UL97 gene and can cause cross-resistance to ganciclovir. MBV-resistant mutations also emerged in the UL27 gene in vitro and could compensate for the inhibition of pUL97 kinase activity by MBV. Thus, LMV and probably MBV will broaden the armamentarium of antiviral drugs available for the prevention and treatment of HCMV infections.
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Affiliation(s)
- Jocelyne Piret
- Research Center in Infectious Diseases, CHU of Quebec and Laval University, Quebec City, QC, Canada
| | - Guy Boivin
- Research Center in Infectious Diseases, CHU of Quebec and Laval University, Quebec City, QC, Canada.
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13
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Cherrier L, Nasar A, Goodlet KJ, Nailor MD, Tokman S, Chou S. Emergence of letermovir resistance in a lung transplant recipient with ganciclovir-resistant cytomegalovirus infection. Am J Transplant 2018; 18:3060-3064. [PMID: 30286286 PMCID: PMC6263820 DOI: 10.1111/ajt.15135] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/25/2018] [Accepted: 09/27/2018] [Indexed: 01/25/2023]
Abstract
Following a year of valganciclovir prophylaxis, a lung transplant recipient developed cytomegalovirus (CMV) infection that became resistant to ganciclovir, as confirmed by detection of UL97 kinase mutation M460V and a previously uncharacterized UL54 DNA polymerase mutation L516P. The latter mutation is now shown to confer ganciclovir and cidofovir resistance. As predicted from the viral genotype, foscarnet therapy was effective, but resumption of valganciclovir as secondary prophylaxis resulted in a plasma viral load rebound to 3.6 log10 copies/mL several weeks later. Valganciclovir was then replaced by letermovir, resulting in gradual viral load reduction in the first 5 weeks to below the quantitation limit (2.7 log10 copies/mL) for 1 week, followed by 10 weeks of rising viral loads reaching 4.3 log10 copies/mL while on letermovir. At this point, CMV genotypic testing revealed UL56 mutation C325Y, which confers absolute resistance to letermovir. Retreatment with foscarnet was successful. This case adds to the considerable list of proven ganciclovir resistance mutations, and provides an early experience with letermovir resistance after off-label therapeutic use. This experience is consistent with in vitro observations of rapid emergence of letermovir-resistant CMV after drug exposure.
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Affiliation(s)
- Lauren Cherrier
- Department of Pharmacy Services, Dignity Health, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, USA
| | - Aasya Nasar
- Department of Pharmacy Services, Dignity Health, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, USA
| | - Kellie J. Goodlet
- Department of Pharmacy Practice, College of Pharmacy, Midwestern University, Glendale, Arizona, USA
| | - Michael D. Nailor
- Department of Pharmacy Services, Dignity Health, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, USA
| | - Sofya Tokman
- Division of Transplant Pulmonology, Norton Thoracic Institute, Dignity Health, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, USA
| | - Sunwen Chou
- Oregon Health & Science University and Portland VA Health Care System, Oregon, USA
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14
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Hartline CB, Keith KA, Eagar J, Harden EA, Bowlin TL, Prichard MN. A standardized approach to the evaluation of antivirals against DNA viruses: Orthopox-, adeno-, and herpesviruses. Antiviral Res 2018; 159:104-112. [PMID: 30287226 DOI: 10.1016/j.antiviral.2018.09.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/25/2018] [Accepted: 09/28/2018] [Indexed: 01/07/2023]
Abstract
The search for new compounds with a broad spectrum of antiviral activity is important and requires the evaluation of many compounds against several distinct viruses. Researchers attempting to develop new antiviral therapies for DNA virus infections currently use a variety of cell lines, assay conditions and measurement methods to determine in vitro drug efficacy, making it difficult to compare results from within the same laboratory as well as between laboratories. In this paper we describe a common assay platform designed to facilitate the parallel evaluation of antiviral activity against herpes simplex virus type 1, herpes simplex virus type 2, varicella-zoster virus, cytomegalovirus, vaccinia virus, cowpox virus, and adenovirus. The automated assays utilize monolayers of primary human foreskin fibroblast cells in 384-well plates as a common cell substrate and cytopathic effects and cytotoxicity are quantified with CellTiter-Glo. Data presented demonstrate that each of the assays is highly robust and yields data that are comparable to those from other traditional assays, such as plaque reduction assays. The assays proved to be both accurate and robust and afford an in depth assessment of antiviral activity against the diverse class of viruses with very small quantities of test compounds. In an accompanying paper, we present a standardized approach to evaluating antivirals against lymphotropic herpesviruses and polyomaviruses and together these studies revealed new activities for reference compounds. This approach has the potential to accelerate the development of broad spectrum therapies for the DNA viruses.
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Affiliation(s)
- Caroll B Hartline
- Department of Pediatrics, University of Alabama School of Medicine, Birmingham, AL, 35233, United States
| | - Kathy A Keith
- Department of Pediatrics, University of Alabama School of Medicine, Birmingham, AL, 35233, United States
| | - Jessica Eagar
- Department of Pediatrics, University of Alabama School of Medicine, Birmingham, AL, 35233, United States
| | - Emma A Harden
- Department of Pediatrics, University of Alabama School of Medicine, Birmingham, AL, 35233, United States
| | | | - Mark N Prichard
- Department of Pediatrics, University of Alabama School of Medicine, Birmingham, AL, 35233, United States.
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15
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Galitska G, Biolatti M, De Andrea M, Leone A, Coscia A, Bertolotti L, Ala U, Bertino E, Dell'Oste V, Landolfo S. Biological relevance of Cytomegalovirus genetic variability in congenitally and postnatally infected children. J Clin Virol 2018; 108:132-140. [PMID: 30312910 DOI: 10.1016/j.jcv.2018.09.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/24/2018] [Accepted: 09/28/2018] [Indexed: 12/30/2022]
Abstract
BACKGROUND Human cytomegalovirus (HCMV) is the leading cause of congenital infections resulting in severe morbidity and mortality among infected children. Although the virus is highly polymorphic, particularly in genes contributing to immune evasion, the mechanisms underlying its genetic variability and pathogenicity are only partially understood. OBJECTIVES We aimed to characterize different HCMV clinical strains isolated from 21 congenitally- or postnatally-infected children for in vitro growth properties and genetic polymorphisms. STUDY DESIGN The growth of various HCMV isolates was analyzed in different cell culture models. Genetic polymorphism was assessed by genetic and phylogenetic analysis of viral genes involved in virulence (UL144, US28, and UL18), latency (UL133-138), or drug resistance (UL54 and UL97). RESULTS Here, we report a high degree of genetic and phenotypic diversity in distinct HCMV clinical isolates, as shown by their in vitro growth properties. In particular, HCMV isolates displayed the highest degree of genetic variability in the UL144 gene, where we were able to define four distinct genotypes within the cohort based on UL144 heterogeneity. Lastly, among all isolates we were able to identify 36 mutations in UL54 and 2 in UL97. CONCLUSIONS Our findings indicate that surprisingly high levels of genetic HCMV variability correlate with a high degree of phenotypic polymorphism, which in turn might differentially influence the growth, fitness, and drug susceptibility of HCMV.
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Affiliation(s)
- Ganna Galitska
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | - Matteo Biolatti
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | - Marco De Andrea
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy; Department of Translational Medicine, Novara Medical School, Novara, Italy
| | - Agata Leone
- Neonatal Unit, Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | - Alessandra Coscia
- Neonatal Unit, Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | - Luigi Bertolotti
- Department of Veterinary Science, University of Turin, Grugliasco, Italy
| | - Ugo Ala
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy
| | - Enrico Bertino
- Neonatal Unit, Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | - Valentina Dell'Oste
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy.
| | - Santo Landolfo
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy.
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16
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Chou S, Ercolani RJ, Derakhchan K. Antiviral activity of maribavir in combination with other drugs active against human cytomegalovirus. Antiviral Res 2018; 157:128-133. [PMID: 30040968 PMCID: PMC6097806 DOI: 10.1016/j.antiviral.2018.07.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 07/15/2018] [Accepted: 07/19/2018] [Indexed: 12/11/2022]
Abstract
The human cytomegalovirus (CMV) UL97 kinase inhibitor maribavir is in Phase III clinical trials as antiviral therapy, including use for infections refractory or resistant to standard therapy. To assess its activity in combination with approved and experimental CMV antivirals, and with the mTor inhibitor rapamycin (sirolimus), drug effects were tested by in vitro checkerboard assays and the data were analyzed using a three dimensional model based on an independent effects definition of additive interactions. Baseline virus and representative drug-resistant mutants were tested. According to the volume of synergy at 95% confidence, maribavir showed additive interactions with foscarnet, cidofovir, letermovir and GW275175X when tested against wild type and mutant viruses, strong antagonism with ganciclovir, and strong synergy with rapamycin, the latter suggesting a potentially useful therapeutic combination.
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Affiliation(s)
- Sunwen Chou
- Division of Infectious Diseases, Oregon Health & Science University, USA; Portland Veterans Affairs Health Care System, OR USA.
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17
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New Locus of Drug Resistance in the Human Cytomegalovirus UL56 Gene Revealed by In Vitro Exposure to Letermovir and Ganciclovir. Antimicrob Agents Chemother 2018; 62:AAC.00922-18. [PMID: 29914965 DOI: 10.1128/aac.00922-18] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 06/14/2018] [Indexed: 11/20/2022] Open
Abstract
Letermovir is a human cytomegalovirus (CMV) terminase inhibitor recently approved as prophylaxis in stem cell transplant recipients. In further studies of emerging drug resistance, a baseline laboratory CMV strain was serially propagated in cell culture under a combination of letermovir and ganciclovir. In eight experiments, UL56 terminase gene mutations were detected beginning at 10 passages and included novel amino acid substitutions V236A, L328V, and A365S in a region previously associated with letermovir resistance. Outside this region, the UL56 substitution C25F was detected at moderate drug concentrations in two experiments as either the first detected mutation or an addition to a preexisting V231L substitution. In all cases, mutation at UL56 codon 325 conferring absolute letermovir resistance eventually developed at a median of 20 passages. No UL97 kinase or UL54 DNA polymerase mutations relevant to ganciclovir resistance were detected until many passages after the first detection of the UL56 mutations. UL56 substitutions V236A, L328V, and A365S were shown to confer borderline or low-grade letermovir resistance, while C25F conferred a 5.4-fold increase in letermovir resistance (50% effective concentration [EC50]) by itself and a 46-fold increase in combination with V231L. The evolution of resistance mutations sooner in UL56 than in UL54 or UL97 is consistent with prior in vitro observations, and UL56 codon 25 is a genetic locus for letermovir resistance distinct from loci previously described.
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18
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Brunnemann AK, Hoffmann A, Deinhardt-Emmer S, Nagel CH, Rose R, Fickenscher H, Sauerbrei A, Krumbholz A. Relevance of non-synonymous thymidine kinase mutations for antiviral resistance of recombinant herpes simplex virus type 2 strains. Antiviral Res 2018; 152:53-57. [PMID: 29427675 DOI: 10.1016/j.antiviral.2018.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 02/02/2018] [Accepted: 02/05/2018] [Indexed: 11/27/2022]
Abstract
Therapy or prophylaxis of herpes simplex virus type 2 (HSV-2) infections with the nucleoside analog aciclovir (ACV) can lead to the emergence of drug-resistant HSV-2 strains, particularly in immunocompromised patients. In this context, multiple amino acid (aa) changes can accumulate in the ACV-converting viral thymidine kinase (TK) which hampers sequence-based diagnostics significantly. In this study, the so far unknown or still doubted relevance of several individual aa changes for drug resistance in HSV-2 was clarified. For this purpose, ten recombinant fluorescent HSV-2 strains differing in the respective aa within their TK were constructed using the bacterial artificial chromosome (BAC) pHSV2(MS)Lox. Similar TK expression levels and similar replication behavior patterns were demonstrated for the mutants as compared to the unmodified BAC-derived HSV-2 strain. Subsequently, the resulting strains were tested for their susceptibility to ACV as well as penciclovir (PCV) in parallel to a modified cytopathic effect (CPE) inhibition assay and by determining the relative fluorescence intensity (quantified using units, RFU) as a measure for the viral replication capacity. While aa changes Y53N and R221H conferred ACV resistance with cross-resistance to PCV, the aa changes G25A, G39E, T131M, Y133F, G150D, A157T, R248W, and L342W maintained a susceptible phenotype against both antivirals. The CPE inhibition assay and the measurement of relative fluorescence intensity yielded comparable results for the phenotypic testing of recombinant viruses. The latter test showed some technical advantages. In conclusion, the significance of single aa changes in HSV-2 TK on ACV/PCV resistance was clarified by the construction and phenotypic testing of recombinant viral strains. This was facilitated by the fluorescence based method.
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Affiliation(s)
- Anne-Kathrin Brunnemann
- Institute for Infection Medicine, Christian-Albrecht University of Kiel and University Medical Center Schleswig-Holstein, Brunswiker Straße 4, 24105 Kiel, Germany
| | - Anja Hoffmann
- Section of Experimental Virology, Institute for Medical Microbiology, Jena University Hospital, Hans-Knöll-Straße 2, 07745 Jena, Germany
| | - Stefanie Deinhardt-Emmer
- Section of Experimental Virology, Institute for Medical Microbiology, Jena University Hospital, Hans-Knöll-Straße 2, 07745 Jena, Germany
| | - Claus-Henning Nagel
- Heinrich Pette Institute, Leibniz-Institute for Experimental Virology, Martinistraße 52, 20251 Hamburg, Germany
| | - Ruben Rose
- Institute for Infection Medicine, Christian-Albrecht University of Kiel and University Medical Center Schleswig-Holstein, Brunswiker Straße 4, 24105 Kiel, Germany
| | - Helmut Fickenscher
- Institute for Infection Medicine, Christian-Albrecht University of Kiel and University Medical Center Schleswig-Holstein, Brunswiker Straße 4, 24105 Kiel, Germany
| | - Andreas Sauerbrei
- Section of Experimental Virology, Institute for Medical Microbiology, Jena University Hospital, Hans-Knöll-Straße 2, 07745 Jena, Germany
| | - Andi Krumbholz
- Institute for Infection Medicine, Christian-Albrecht University of Kiel and University Medical Center Schleswig-Holstein, Brunswiker Straße 4, 24105 Kiel, Germany.
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19
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Differentiated Levels of Ganciclovir Resistance Conferred by Mutations at Codons 591 to 603 of the Cytomegalovirus UL97 Kinase Gene. J Clin Microbiol 2017; 55:2098-2104. [PMID: 28446569 DOI: 10.1128/jcm.00391-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 04/17/2017] [Indexed: 12/28/2022] Open
Abstract
Diagnostic mutations in the cytomegalovirus UL97 kinase gene are used to assess the level of associated ganciclovir resistance and therapeutic options. The best-known mutations at codons 460, 520, or 591 to 607 individually confer 5- to 10-fold-decreased ganciclovir susceptibility, except that a 3-fold decrease occurs in the case of the amino acid substitution C592G. Less common point and in-frame deletion mutations at codons 591 to 603 remain incompletely characterized. The ganciclovir susceptibilities of 17 mutants in this codon range were evaluated by use of the same recombinant phenotyping system and extensive assay replicates in two types of cell cultures. Amino acid substitutions K599E and T601M conferred no ganciclovir resistance, while A591V conferred 3.8-fold-decreased susceptibility. In-frame deletions of three or more codons conferred at least 8-fold-increased ganciclovir resistance, while the level of resistance conferred by one- or two-codon deletions varied from 4- to 10-fold, depending on their location. Measured levels of ganciclovir resistance were closely comparable when assays were performed in either fibroblasts or modified retinal epithelial cells. The significant revision of a few previously published resistance phenotypes and the new data strengthen the interpretation of genotypic testing for cytomegalovirus drug resistance.
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20
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Chou S. Foscarnet resistance mutations mapping to atypical domains of the cytomegalovirus DNA polymerase gene. Antiviral Res 2017; 138:57-60. [PMID: 27940027 PMCID: PMC5209250 DOI: 10.1016/j.antiviral.2016.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 11/29/2016] [Accepted: 12/05/2016] [Indexed: 12/26/2022]
Abstract
Human cytomegalovirus UL54 DNA polymerase gene mutations that confer foscarnet resistance in clinical practice typically cluster in the amino terminal 2, palm and finger domains. Exposure to foscarnet in cell culture selected for mutations elsewhere in UL54, including amino acid substitutions S290R in the amino terminal 1 domain and E951D in the palm 2 domain. These are newly confirmed to confer foscarnet resistance and slightly decreased ganciclovir susceptibility. Other emergent substitutions N495K, T552N and T838A are known to confer foscarnet resistance, while additional ones Q783R and V798A only slightly affected susceptibility. An expanded set of domains is involved in foscarnet resistance and its genotypic diagnosis.
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Affiliation(s)
- Sunwen Chou
- Division of Infectious Diseases, Oregon Health and Science University, Portland, OR, USA; Department of Veterans Affairs Medical Center, Portland, OR, USA.
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21
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How I treat resistant cytomegalovirus infection in hematopoietic cell transplantation recipients. Blood 2016; 128:2624-2636. [PMID: 27760756 DOI: 10.1182/blood-2016-06-688432] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 10/17/2016] [Indexed: 12/20/2022] Open
Abstract
Cytomegalovirus (CMV) infection is a significant complication in hematopoietic cell transplantation (HCT) recipients. Four antiviral drugs are used for preventing or treating CMV: ganciclovir, valganciclovir, foscarnet, and cidofovir. With prolonged and repeated use of these drugs, CMV can become resistant to standard therapy, resulting in increased morbidity and mortality, especially in HCT recipients. Antiviral drug resistance should be suspected when CMV viremia (DNAemia or antigenemia) fails to improve or continue to increase after 2 weeks of appropriately dosed and delivered antiviral therapy. CMV resistance is diagnosed by detecting specific genetic mutations. UL97 mutations confer resistance to ganciclovir and valganciclovir, and a UL54 mutation confers multidrug resistance. Risk factors for resistance include prolonged or previous anti-CMV drug exposure or inadequate dosing, absorption, or bioavailability. Host risk factors include type of HCT and degree of immunosuppression. Depending on the genotyping results, multiple strategies can be adopted to treat resistant CMV infections, albeit no randomized clinical trials exist so far, after reducing immunosuppression (if possible): ganciclovir dose escalation, ganciclovir and foscarnet combination, and adjunct therapy such as CMV-specific cytotoxic T-lymphocyte infusions. Novel therapies such as maribavir, brincidofovir, and letermovir should be further studied for treatment of resistant CMV.
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22
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The D-form of a novel heparan binding peptide decreases cytomegalovirus infection in vivo and in vitro. Antiviral Res 2016; 135:15-23. [PMID: 27678155 DOI: 10.1016/j.antiviral.2016.09.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/19/2016] [Accepted: 09/22/2016] [Indexed: 12/14/2022]
Abstract
Human cytomegalovirus (HCMV) infection in utero can lead to congenital sensory neural hearing loss and mental retardation. Reactivation or primary infection can increase the morbidity and mortality in immune suppressed transplant recipients and AIDS patients. The current standard of care for HCMV disease is nucleoside analogs, which can be nephrotoxic. In addition resistance to current treatments is becoming increasingly common. In an effort to develop novel CMV treatments, we tested the effectiveness of the D-form of a novel heparan sulfate binding peptide, p5RD, at reducing infection of ganciclovir (GCV) resistant HCMVs in vitro and MCMV in vivo. HCMV infection was reduced by greater than 90% when cells were pretreated with p5RD. Because p5RD acts by a mechanism unrelated to those used by current antivirals, it was effective at reducing GCV resistant HCMVs by 85%. We show that p5RD is resistant to common proteases and serum inactivation, which likely contributed to its ability to significantly reduced infection of peritoneal exudate cells and viral loads in the spleen and the lungs in vivo. The ability of p5RD to reduce HCMV infectivity in vitro including GCV resistant HCMVs and MCMV infection in vivo suggests that this peptide could be a novel anti-CMV therapeutic.
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23
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Hutterer C, Hamilton S, Steingruber M, Zeitträger I, Bahsi H, Thuma N, Naing Z, Örfi Z, Örfi L, Socher E, Sticht H, Rawlinson W, Chou S, Haupt VJ, Marschall M. The chemical class of quinazoline compounds provides a core structure for the design of anticytomegaloviral kinase inhibitors. Antiviral Res 2016; 134:130-143. [PMID: 27515131 DOI: 10.1016/j.antiviral.2016.08.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 07/28/2016] [Accepted: 08/05/2016] [Indexed: 12/26/2022]
Abstract
HCMV is a member of the family Herpesviridae and represents a worldwide distributed pathogen with seropositivity rates in the adult population ranging between 40% and 90%. Notably, HCMV infection is a serious, sometimes life-threatening medical problem for newborns and immunosuppressed individuals, including transplant recipients and patients under antitumoral chemotherapy. Current standard therapy with valganciclovir has the disadvantage of inducing drug-resistant virus mutants and toxicity-related side effects. Our analysis stresses the earlier finding that kinase inhibitors of the quinazoline class exert an antiviral response by targeting the viral protein kinase pUL97 without inducing resistance. Therefore, quinazolines have been used as a core structure to gain insight in the mode of inhibitor-kinase interaction. Here, we demonstrate that (i) the novel quinazolines Vi7392 and Vi7453 are highly active against HCMV laboratory and clinically relevant strains including maribavir- and ganciclovir-resistant variants, (ii) antiviral activity is not cell-type specific and was also detected in a placental explant tissue model using a genetically intact HCMV strain (iii) the viral kinase pUL97 represents a target of the anticytomegaloviral activity of these compounds, (iv) induction of pUL97-conferring drug resistance was not detectable under single-step selection, thus differed from the induction of ganciclovir resistance, and (v) pUL97 drug docking simulations enabled detailed insights into specific drug-target binding properties providing a promising basis for the design of optimized kinase inhibitors. These novel findings may open new prospects for the future medical use of quinazoline drug candidates and the use of drug-target dynamic simulations for rational design of antivirals.
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Affiliation(s)
- C Hutterer
- Institute of Clinical and Molecular Virology, Friedrich-Alexander University (FAU) of Erlangen-Nürnberg, Erlangen, Germany.
| | - S Hamilton
- Serology and Virology Division, SEALS Microbiology Prince of Wales Hospital Randwick NSW 2013 and SOMS and BABS, University of NSW, Sydney, Australia
| | - M Steingruber
- Institute of Clinical and Molecular Virology, Friedrich-Alexander University (FAU) of Erlangen-Nürnberg, Erlangen, Germany
| | - I Zeitträger
- Institute of Clinical and Molecular Virology, Friedrich-Alexander University (FAU) of Erlangen-Nürnberg, Erlangen, Germany
| | - H Bahsi
- Institute of Clinical and Molecular Virology, Friedrich-Alexander University (FAU) of Erlangen-Nürnberg, Erlangen, Germany
| | - N Thuma
- Institute of Clinical and Molecular Virology, Friedrich-Alexander University (FAU) of Erlangen-Nürnberg, Erlangen, Germany
| | - Z Naing
- Serology and Virology Division, SEALS Microbiology Prince of Wales Hospital Randwick NSW 2013 and SOMS and BABS, University of NSW, Sydney, Australia
| | - Z Örfi
- Department of Molecular Biology, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - L Örfi
- Semmelweis University, Department of Pharmaceutical Chemistry, Budapest, Hungary
| | - E Socher
- Division of Bioinformatics, Institute of Biochemistry, FAU of Erlangen-Nürnberg, Erlangen, Germany
| | - H Sticht
- Division of Bioinformatics, Institute of Biochemistry, FAU of Erlangen-Nürnberg, Erlangen, Germany
| | - W Rawlinson
- Serology and Virology Division, SEALS Microbiology Prince of Wales Hospital Randwick NSW 2013 and SOMS and BABS, University of NSW, Sydney, Australia
| | - S Chou
- Division of Infectious Diseases, Oregon Health and Science University and VA Medical Center, Portland, USA
| | - V J Haupt
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - M Marschall
- Institute of Clinical and Molecular Virology, Friedrich-Alexander University (FAU) of Erlangen-Nürnberg, Erlangen, Germany
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Campos AB, Ribeiro J, Boutolleau D, Sousa H. Human cytomegalovirus antiviral drug resistance in hematopoietic stem cell transplantation: current state of the art. Rev Med Virol 2016; 26:161-82. [DOI: 10.1002/rmv.1873] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 01/09/2016] [Accepted: 02/01/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Ana Bela Campos
- Molecular Oncology and Viral Pathology Group (CI-IPOP); Porto Portugal
- Faculty of Medicine; University of Porto; Porto Portugal
| | - Joana Ribeiro
- Molecular Oncology and Viral Pathology Group (CI-IPOP); Porto Portugal
- Virology Service; Portuguese Oncology Institute of Porto; Porto Portugal
- Faculty of Medicine; University of Porto; Porto Portugal
| | - David Boutolleau
- Sorbonne Universités; UPMC Université Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris); Paris France
- INSERM, U1135, CIMI-Paris; Paris France
- AP-HP, Hôpitaux Universitaires La Pitié-Salpêtrière - Charles Foix; Service de Virologie; Paris France
| | - Hugo Sousa
- Molecular Oncology and Viral Pathology Group (CI-IPOP); Porto Portugal
- Virology Service; Portuguese Oncology Institute of Porto; Porto Portugal
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25
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Javad Hosseini SM, Nemati E, Behzadian F, Einollahi B, Rahimi Petrudy A, Sohraby M, Taghipour M, Motalebi M. Evaluation of ganciclovir resistance in cytomegalovirus infection of renal transplant recipients in Tehran. Transplant Proc 2016; 47:1140-2. [PMID: 26036539 DOI: 10.1016/j.transproceed.2014.10.066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 10/28/2014] [Indexed: 10/23/2022]
Abstract
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.
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Affiliation(s)
- S M Javad Hosseini
- Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - E Nemati
- Nephrology Urology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
| | - F Behzadian
- Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - B Einollahi
- Nephrology Urology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - A Rahimi Petrudy
- Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - M Sohraby
- Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - M Taghipour
- Nephrology Urology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - M Motalebi
- Nephrology Urology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
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Rapid In Vitro Evolution of Human Cytomegalovirus UL56 Mutations That Confer Letermovir Resistance. Antimicrob Agents Chemother 2015; 59:6588-93. [PMID: 26259791 DOI: 10.1128/aac.01623-15] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 08/03/2015] [Indexed: 11/20/2022] Open
Abstract
Letermovir (LMV) is an experimental cytomegalovirus terminase inhibitor undergoing phase 3 clinical trials. Viral mutations have been described at UL56 codons 231 to 369 that confer widely variable levels of LMV resistance. In this study, 15 independent experiments propagating an exonuclease mutant viral strain in escalating LMV concentrations replicated 6 of the 7 published UL56 mutations and commonly elicited additional resistance-conferring mutations at UL56 codons 231, 236, 237, 244, 257, 261, 325, and 329. Mutations were first detected earlier in LMV (median, 3 passages) than in 8 parallel experiments with foscarnet (median, 15 passages). As LMV concentrations increased, the typical initial UL56 change F261L, which confers low-grade resistance, combined or was replaced with mutations conferring higher-grade resistance, eventually enabling normal viral growth in 30 μM LMV (>5,000-fold the 50% effective concentration [EC50] for the wild type). At high LMV concentrations, the UL56 changes C325F/R were commonly detected, as well as a combination of changes at codons 236, 257, 329, and/or 369. Recombinant viruses containing individual UL56 mutations and combinations were constructed to confirm their resistance phenotypes and normal growth in cell culture. Several double and triple mutants showed much higher LMV resistance than the respective single mutants, particularly those including changes at both codons 236 and 257. The multiplicity of pathways to high-grade LMV resistance with minimal viral growth impact suggests a low viral genetic barrier and the need for close monitoring during treatment of active infection.
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27
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Fischer L, Sampaio KL, Jahn G, Hamprecht K, Göhring K. Identification of newly detected, drug-related HCMV UL97- and UL54-mutations using a modified plaque reduction assay. J Clin Virol 2015. [DOI: 10.1016/j.jcv.2015.06.090] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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28
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Analysis of ganciclovir-resistant human herpesvirus 6B clinical isolates using quenching probe PCR methodology. Antimicrob Agents Chemother 2015; 59:2618-24. [PMID: 25691643 DOI: 10.1128/aac.04692-14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 02/11/2015] [Indexed: 11/20/2022] Open
Abstract
Quenching probe PCR (QP-PCR) analysis was used to determine the frequency of ganciclovir (GCV) resistance among clinical isolates of human herpesvirus 6B (HHV-6B) obtained from patients with primary viral infection and viral reactivation. Forty-two HHV-6B clinical isolates were repeatedly recovered from 15 hematopoietic stem cell transplant (HSCT) recipients, and 20 isolates were recovered from 20 exanthem subitum (ES) patients. Of the 15 HSCT recipients, 9 received GCV during the observation period; however, none of the ES patients were treated with GCV. Two established laboratory strains, Z29 and HST, were used as standards in this study. Regions 1 and 2 of the U69 gene of all of the clinical isolates demonstrated the same melting temperature as regions 1 and 2 of the Z29 strain. For region 3, the melting temperatures of all clinical isolates fell between the melting temperature of the plasmid containing the A462D single nucleotide polymorphism (SNP) and the melting temperature of the Z29 strain, and the melting temperatures profiles of all clinical isolates were similar to the melting temperature profile of the Japanese HST strain. As expected, none of the 20 clinical isolates recovered from the ES patients and the 14 isolates recovered from the HSCT recipients who did not receive GCV treatment carried the six known SNPs associated with GCV resistance. Interestingly, these six SNPs were not detected in the 28 clinical isolates recovered from the 9 HSCT recipients who received GCV. Additional sequence analysis of the U69 gene from the 15 representative isolates from the 15 HSCT recipients identified other SNPs. These SNPs were identical to those identified in the HST strain. Therefore, the rate of emergence of GCV-resistant HHV-6B strains appears to be relatively low, even in HSCT recipients treated with GCV.
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Göhring K, Hamprecht K, Jahn G. Antiviral Drug- and Multidrug Resistance in Cytomegalovirus Infected SCT Patients. Comput Struct Biotechnol J 2015; 13:153-9. [PMID: 25750703 PMCID: PMC4348572 DOI: 10.1016/j.csbj.2015.01.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 01/27/2015] [Accepted: 01/29/2015] [Indexed: 01/23/2023] Open
Abstract
In pediatric and adult patients after stem cell transplantation (SCT) disseminated infections caused by human cytomegalovirus (HCMV) can cause life threatening diseases. For treatment, the three antivirals ganciclovir (GCV), foscarnet (PFA) and cidofovir (CDV) are approved and most frequently used. Resistance to all of these antiviral drugs may induce a severe problem in this patient cohort. Responsible for resistance phenomena are mutations in the HCMV phosphotransferase-gene (UL97) and the polymerase-gene (UL54). Most frequently mutations in the UL97-gene are associated with resistance to GCV. Resistance against all three drugs is associated to mutations in the UL54-gene. Monitoring of drug resistance by genotyping is mostly done by PCR-based Sanger sequencing. For phenotyping with cell culture the isolation of HCMV is a prerequisite. The development of multidrug resistance with mutation in both genes is rare, but it is often associated with a fatal outcome. The manifestation of multidrug resistance is mostly associated with combined UL97/UL54-mutations. Normally, mutations in the UL97 gene occur initially followed by UL54 mutation after therapy switch. The appearance of UL54-mutation alone without any detection of UL97-mutation is rare. Interestingly, in a number of patients the UL97 mutation could be detected in specific compartments exclusively and not in blood.
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Affiliation(s)
- Katharina Göhring
- Institute of Medical Virology and Epidemiology of Viral Diseases, University Hospital of Tübingen, 72076 Tübingen, Germany
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30
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Characterization of multiple cytomegalovirus drug resistance mutations detected in a hematopoietic stem cell transplant recipient by recombinant phenotyping. J Clin Microbiol 2014; 52:4043-6. [PMID: 25143583 DOI: 10.1128/jcm.02205-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytomegalovirus resistance to antivirals is a major problem in transplant recipients. We evaluated the impact of five mutations (A594V, L595F, and E655K in the UL97 gene and V526L and E756K in the UL54 gene), detected in a blood sample from a stem cell transplant recipient, on drug susceptibilities and replicative capacities of recombinant viruses.
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31
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Improved detection of emerging drug-resistant mutant cytomegalovirus subpopulations by deep sequencing. Antimicrob Agents Chemother 2014; 58:4697-702. [PMID: 24890586 DOI: 10.1128/aac.03214-14] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In immunosuppressed hosts, the development of multidrug resistance complicates the treatment of cytomegalovirus (CMV) infection. Improved genotypic detection of impending drug resistance may follow from recent technical advances. A severely T-cell-depleted patient with chronic lymphocytic leukemia developed CMV pneumonia and high plasma viral loads that were poorly responsive to antiviral therapy. Serial plasma specimens were analyzed for mutant viral populations by conventional and high-throughput deep-sequencing methods. Uncharacterized mutations were phenotyped for drug resistance using recombinant viruses. Conventional genotyping detected viruses with the UL97 kinase substitution C607Y after ganciclovir treatment, a transient subpopulation of UL54 polymerase L773V mutants first detected 8 weeks after foscarnet was started, and a subpopulation of a mutant with deletion of UL54 codons 981 and 982 2 months after the addition of cidofovir. Deep sequencing of the same serial specimens revealed the same UL54 mutants sooner, along with a more complex evolution of known and newly recognized mutant subpopulations missed by conventional sequencing. The UL54 exonuclease substitutions D413N, K513R, and C539G were newly shown to confer ganciclovir-cidofovir resistance, while L773V was shown to confer foscarnet resistance and add to the ganciclovir resistance conferred by UL97 C607Y. Increased sequencing depth provided a more timely and detailed diagnosis of mutant viral subpopulations that evolved with changing anti-CMV therapy.
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Differential properties of cytomegalovirus pUL97 kinase isoforms affect viral replication and maribavir susceptibility. J Virol 2014; 88:4776-85. [PMID: 24522923 DOI: 10.1128/jvi.00192-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The human cytomegalovirus (HCMV)-encoded kinase pUL97 is required for efficient viral replication. Previous studies described two isoforms of pUL97, the full-length isoform (M1) and a smaller isoform likely resulting from translation initiation at codon 74 (M74). Here, we report the detection of a third pUL97 isoform during viral infection resulting from translation initiation at codon 157 (isoform M157). The consistent expression of isoform M157 as a minor component of pUL97 during infection with clinical and laboratory-adapted HCMV strains was suppressed when codon 157 was mutagenized. Viral mutants expressing specific isoforms were generated to compare their growth and drug susceptibility phenotypes, as well as pUL97 intracellular localization patterns and kinase activities. The exclusive expression of isoform M157 resulted in substantially reduced viral growth and resistance to the pUL97 inhibitor maribavir while retaining susceptibility to ganciclovir. Confocal imaging demonstrated reduced nuclear import of amino-terminal deletion isoforms compared to isoform M1. Isoform M157 showed reduced efficiency of various substrate protein interactions and autophosphorylation, whereas Rb phosphorylation was preserved. These results reveal differential properties of pUL97 isoforms that affect viral replication, with implications for the antiviral efficacy of maribavir. IMPORTANCE The HCMV UL97 kinase performs important functions in viral replication that are targeted by the antiviral drug maribavir. Here, we describe a naturally occurring short isoform of the kinase that when expressed by itself in a recombinant virus results in altered intracellular localization, impaired growth, and high-level resistance to maribavir compared to those of the predominant full-length counterpart. This is another factor to consider in explaining why maribavir appears to have variable antiviral activity in cell culture and in vivo.
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Komatsu TE, Pikis A, Naeger LK, Harrington PR. Resistance of human cytomegalovirus to ganciclovir/valganciclovir: A comprehensive review of putative resistance pathways. Antiviral Res 2014; 101:12-25. [DOI: 10.1016/j.antiviral.2013.10.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 10/20/2013] [Accepted: 10/21/2013] [Indexed: 11/26/2022]
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Cytomegalovirus mutants resistant to ganciclovir and cidofovir differ in susceptibilities to synguanol and its 6-ether and 6-thioether derivatives. Antimicrob Agents Chemother 2013; 58:1809-12. [PMID: 24379208 DOI: 10.1128/aac.02544-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The methylenecyclopropane nucleoside (MCPN) analogs synguanol and its 6-alkoxy (MBX2168) and 6-alkylthio (MBX1616) derivatives retained good in vitro activities against several common ganciclovir-resistant UL97 kinase variants of human cytomegalovirus. Foscarnet-MCPN cross-resistance was observed among UL54 polymerase variants. UL54 exonuclease domain ganciclovir-cidofovir dual-resistant variants were remarkably more hypersensitive to these MCPNs than to cyclopropavir, with some 50% effective concentration ratios that were <0.1× the wild type. Different categories of MCPNs may have therapeutically exploitable mechanistic differences in viral DNA polymerase inhibition.
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35
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Chou S, Boivin G, Ives J, Elston R. Phenotypic evaluation of previously uncharacterized cytomegalovirus DNA polymerase sequence variants detected in a valganciclovir treatment trial. J Infect Dis 2013; 209:1219-26. [PMID: 24273181 DOI: 10.1093/infdis/jit654] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND In a large randomized trial comparing oral valganciclovir and intravenous ganciclovir for treatment of cytomegalovirus disease in solid organ transplantation, confirmed genotypic drug resistance was uncommon (<5%), but definitive interpretation was limited by the detection of 110 uncharacterized UL54 viral DNA polymerase sequence variants. METHODS Based on treatment history and genetic locus of the sequence changes, 39 of the sequence variants were prioritized for recombinant phenotyping by construction of cloned viral mutants and drug susceptibility testing in cell culture. RESULTS Four amino acid substitutions were newly confirmed to alter ganciclovir susceptibility: A505V and I726T conferred a borderline decrease in ganciclovir and cidofovir susceptibility, while Q578L and G841S conferred slightly decreased ganciclovir and foscarnet susceptibility. A nonviable phenotype was found for 8 mutations distributed among amino terminal, exonuclease and catalytic domains. Retesting of stored study specimens could not confirm the original detection of >20 sequence variants, including the nonviable mutations and several resistance mutations. CONCLUSIONS Newly phenotyped UL54 sequence variants did not significantly change the reported incidence of drug resistance in the clinical trial. Unrecognized sequence variants in diagnostic genotyping reports should be confirmed by additional testing in order to improve clinical decision making.
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Affiliation(s)
- Sunwen Chou
- Division of Infectious Disease, Oregon Health and Science University and VA Medical Center, Portland
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Human cytomegalovirus UL97 kinase is involved in the mechanism of action of methylenecyclopropane analogs with 6-ether and -thioether substitutions. Antimicrob Agents Chemother 2013; 58:274-8. [PMID: 24145545 DOI: 10.1128/aac.01726-13] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methylenecyclopropane nucleoside (MCPN) analogs are being investigated for treatment of human cytomegalovirus (HCMV) infection because of favorable preclinical data and limited ganciclovir cross-resistance. Monohydroxymethyl MCPNs bearing ether and thioether functionalities at the purine 6 position have antiviral activity against herpes simplex virus (HSV) and varicella-zoster virus (VZV) in addition to HCMV. The role of the HCMV UL97 kinase in the mechanism of action of these derivatives was examined. When tested against a kinase-inactive UL97 K355M virus, a moderate 5- to 7-fold increase in 50% effective concentration (EC50) was observed, in comparison to a 13- to 25-fold increase for either cyclopropavir or ganciclovir. Serial propagation of HCMV under two of these compounds selected for three novel UL97 mutations encoding amino acid substitutions D456N, C480R,and Y617del. When transferred to baseline laboratory HCMV strains, these mutations individually conferred resistance to all of the tested MCPNs, ganciclovir, and maribavir. However, the engineered strains also demonstrated severe growth defects and abnormal cytopathic effects similar to the kinase-inactive mutant. Expressed and purified UL97 kinase showed in vitro phosphorylation of the newly tested MCPNs. Thus, HCMV UL97 kinase is involved in the antiviral action of these MCPNs, but the in vitro selection of UL97-defective viruses suggests that their activity against more typical ganciclovir-resistant growth-competent UL97 mutants may be relatively preserved.
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Novel method based on "en passant" mutagenesis coupled with a gaussia luciferase reporter assay for studying the combined effects of human cytomegalovirus mutations. J Clin Microbiol 2013; 51:3216-24. [PMID: 23863570 DOI: 10.1128/jcm.01275-13] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Human cytomegalovirus (HCMV) resistance to antivirals is a major problem in immunocompromised patients. Drug resistance is characterized by phenotypic testing or genotypic analysis of the phosphotransferase (UL97) and DNA polymerase (UL54) genes. However, genotypic assays require further characterization of unknown mutations in the drug resistance phenotype. Here, we describe a novel method for generating single or multiple mutations anywhere in the HCMV genome and for studying their effects on drug susceptibility. This method is based on cloning of the reference AD169 strain in a bacterial artificial chromosome and the use of "en passant" mutagenesis in bacteria to introduce mutations in recombinant HCMV without scar sequences. We also used this methodology to introduce the Gaussia luciferase reporter gene into the genome of the recombinant virus. To validate our system, the well-characterized single mutants with UL97 A594V and UL54 E756K mutations as well as the undescribed A594V/E756K double mutant were generated and their drug susceptibility profiles were determined by measuring the luciferase activity in cell culture supernatants. Drug susceptibility phenotypes for the A594V (8.2-fold increase in ganciclovir 50% effective concentration [EC50]) and E756K (1.9-, 3.9-, and 3.0-fold increases in ganciclovir, foscarnet, and cidofovir EC50s, respectively) mutants were similar to those previously reported, while the double mutant exhibited 10.8-, 4.1-, and 2.0-fold increases in ganciclovir, foscarnet, and cidofovir EC50s, respectively. The combination of the Gaussia luciferase reporter-based assay with the markerless "en passant" mutagenesis methodology constitutes an efficient system for studying phenotypes with single or multiple HCMV mutations.
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Use of high-dose ganciclovir for the treatment of cytomegalovirus replication in solid organ transplant patients with ganciclovir resistance-inducing mutations. Transplantation 2013; 95:1015-20. [PMID: 23407543 DOI: 10.1097/tp.0b013e31828555ac] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND Experience with high-dose ganciclovir for the management of resistant cytomegalovirus (CMV) replication in transplant patients is limited despite its adoption as an effective therapy by some consensus documents. METHODS We studied six cases of CMV replication in solid organ transplant patients whose genotypic testing showed mutations associated with different levels of resistance to ganciclovir. All were treated with high-dose intravenous ganciclovir (7.5-10 mg/kg/12 hr) or oral valganciclovir (1350-1800 mg/12 hr) corrected according to creatinine clearance. The virologic response was considered positive if the CMV plasma viral load was undetectable. Safety was evaluated by clinical assessment, including the review of vital signs and laboratory tests. RESULTS All patients had asymptomatic replication, except one who had digestive disease. Four patients received universal prophylaxis with valganciclovir. Two patients received preemptive therapy with valganciclovir for individual episodes of replication. Two of the six patients received steroid boluses before the episode of replication by resistant CMV. All patients responded to treatment, including those with mutations associated with a high level of ganciclovir resistance. Four patients had neutropenia (<1.5 × 10/L), but only one received treatment. CONCLUSIONS High-dose ganciclovir/valganciclovir can be an option in the treatment of resistant CMV replication and could be considered an alternative treatment in nonsevere patients for whom the use of foscarnet should be avoided. The toxicity of this regimen does not appear to limit its use.
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Rapid detection of human cytomegalovirus UL97 and UL54 mutations directly from patient samples. J Clin Microbiol 2013; 51:2354-9. [PMID: 23678068 DOI: 10.1128/jcm.00611-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus (CMV) is a significant contributor to morbidity and mortality in immunocompromised patients, particularly in the transplant setting. The availability of anti-CMV drugs has improved treatment, but drug resistance is an emerging problem. Here, we describe an improved, rapid, sequencing-based assay for the two genes in CMV where drug resistance occurs, the UL97 and UL54 genes. This assay is performed in 96-well format with a single master mix and provides clinical results within 2 days. It sequences codons 440 to 645 in the UL97 gene and codons 255 to 1028 in the UL54 gene with a limit of detection of 240 IU/ml. With this assay, we tested 43 specimens that had previously been tested for UL97 drug resistance and identified 3 with UL54 mutations. One of these patients had no concurrent UL97 mutation, pointing toward the need for an assay that facilitates dual UL97/UL54 gene testing for complete resistance profiling.
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Cytomegalovirus UL97 kinase catalytic domain mutations that confer multidrug resistance. Antimicrob Agents Chemother 2013; 57:3375-9. [PMID: 23650173 DOI: 10.1128/aac.00511-13] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus UL97 kinase mutations that commonly confer ganciclovir resistance cluster in different parts of the gene than those conferring resistance to maribavir, an experimental UL97 kinase inhibitor. The drug resistance, growth, and autophosphorylation phenotypes of several unusual UL97 mutations in the kinase catalytic domain were characterized. Mutations V466G and P521L, described in clinical specimens from ganciclovir-treated subjects, conferred a UL97 kinase knockout phenotype with no autophosphorylation, a severe growth defect, and high-level ganciclovir, cyclopropavir, and maribavir resistance, similar to mutations at the catalytic lysine residue K355. Mutations F342S and V356G, observed after propagation under cyclopropavir in vitro, showed much less growth attenuation and moderate- to high-level resistance to all three drugs while maintaining UL97 autophosphorylation competence and normal cytopathic effect in cell culture, a novel phenotype. F342S is located in the ATP-binding P-loop and is homologous to a c-Abl kinase mutation conferring resistance to imatinib. UL97 mutants with relatively preserved growth fitness and multidrug resistance are of greater concern in antiviral therapy than the severely growth-impaired UL97 knockout mutants. Current diagnostic genotyping assays are unlikely to detect F342S and V356G, and the frequency of their appearance in clinical specimens remains undefined.
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Successful ganciclovir treatment of primary cytomegalovirus infection containing the UL97 mutation N510S in an intestinal graft recipient. Infection 2013; 41:875-9. [PMID: 23546999 DOI: 10.1007/s15010-013-0458-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 03/27/2013] [Indexed: 10/27/2022]
Abstract
In solid organ transplantation, human cytomegalovirus (HCMV) is considered to be the most important viral pathogen. We report a case of a CMV R-/D+ small intestine transplant recipient with a primary CMV infection on valganciclovir prophylaxis. Sequencing of the HCMV DNA for drug resistance-associated mutations revealed the UL97 mutation N510S. This mutation has been initially reported to confer ganciclovir resistance. Based on in vitro recombinant phenotyping, this assumption has recently been questioned. Switching the antiviral treatment to an intravenous regimen of ganciclovir eliminated HCMV DNAemia, showing the in vivo efficacy of ganciclovir for the UL97 mutation N510S. Hence, knowledge of drug efficacy is crucial for an adequate choice of antiviral medication, carefully balancing antiviral potency versus the risk of harmful side effects.
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Cunha-Bang CD, Kirkby N, Sønderholm M, Sørensen SS, Sengeløv H, Iversen M, Rasmussen A, Gustafsson F, Frederiksen CM, Kjaer J, Lepri AC, Lundgren JD. The time course of development and impact from viral resistance against ganciclovir in cytomegalovirus infection. Am J Transplant 2013; 13:458-66. [PMID: 23282281 DOI: 10.1111/ajt.12042] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 10/12/2012] [Accepted: 10/24/2012] [Indexed: 01/25/2023]
Abstract
(Val)ganciclovir is used to treat cytomegalovirus (CMV) infection following solid organ (SOT) or hematopoietic stem cell (HSCT) transplantation. Treatment failures occur, but the contribution from 39 known ganciclovir-related mutations (GRMs) in the CMV-UL97 gene remains controversial. We propose a categorization of these GRMs potentially useful when interpreting sequence analyses in clinical settings. The UL97 gene was sequenced from first/recurrent CMV infections among consecutive SOT or HSCT recipients during 2004-2009. GRMs were categorized as: Signature GRM (sGRM) if in vitro ganciclovir IC(50) ratio for mutated versus wild-type virus >2 (n = 24); polymorphic GRM (pGRM) if ratio <2 (n = 15). (Val)ganciclovir treatment failure was defined as persistent viremia for 30 days or switch to foscarnet within this period. Of 99 (49 HSCT and 50 SOT) recipients with one CMV infection episode, 15 (13 HSCT and 2 SOT) experienced a total of 19 recurrent infection episodes. The prevalence of sGRM was 0% at start of first episode, whereas at start of recurrent episodes, prevalence was 37%. Only one sGRM was present at a time in individual patients. Patients with CMV containing an sGRM (vs. wild type)-but not with a pGRM-were at excess risk of treatment failure (odds ratio = 70.6 [95% CI:8.2-609.6]; p < 0.001). sGRMs emerged only following longer termed use of antiherpetic drugs and usually in recurrent CMV infection episodes. Risk of ganciclovir treatment failure was raised if an sGRM was detected.
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Affiliation(s)
- C da Cunha-Bang
- Center for Viral Diseases, Department of Infectious Diseases, Copenhagen University Hospital/Rigshospitalet, Copenhagen, Denmark.
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Le Page AK, Jager MM, Iwasenko JM, Scott GM, Alain S, Rawlinson WD. Clinical Aspects of Cytomegalovirus Antiviral Resistance in Solid Organ Transplant Recipients. Clin Infect Dis 2012; 56:1018-29. [DOI: 10.1093/cid/cis1035] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Kim YJ, Boeckh M, Cook L, Stempel H, Jerome K, Boucek R, Burroughs L, Englund J. Cytomegalovirus infection and ganciclovir resistance caused by UL97 mutations in pediatric transplant recipients. Transpl Infect Dis 2012. [DOI: 10.1111/j.1399-3062.2012.00760.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | | | | | - H. Stempel
- Seattle Children's Hospital; Seattle; Washington; USA
| | | | - R. Boucek
- Seattle Children's Hospital; Seattle; Washington; USA
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Human Cytomegalovirus (CMV) UL97 D605E Mutation Has a Higher Prevalence in Infants With Primary CMV Infection Compared With Transplant Recipients With CMV Recurrence. Transplant Proc 2012. [DOI: 10.1016/j.transproceed.2012.06.069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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46
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Zhang Y, Zhao Z, Sun J, Cao G, Zhao F, Hu J, Liu L, Ji Y. A new mutation in the human cytomegalovirus UL97 gene may confer ganciclovir resistance in Chinese kidney transplant recipients. Arch Virol 2012; 158:247-50. [DOI: 10.1007/s00705-012-1479-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Accepted: 08/07/2012] [Indexed: 11/30/2022]
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Boivin G, Goyette N, Farhan M, Ives J, Elston R. Incidence of cytomegalovirus UL97 and UL54 amino acid substitutions detected after 100 or 200 days of valganciclovir prophylaxis. J Clin Virol 2012; 53:208-13. [DOI: 10.1016/j.jcv.2011.12.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 11/29/2011] [Accepted: 12/15/2011] [Indexed: 10/14/2022]
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48
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Cyclopropavir susceptibility of cytomegalovirus DNA polymerase mutants selected after antiviral drug exposure. Antimicrob Agents Chemother 2011; 56:197-201. [PMID: 21968367 DOI: 10.1128/aac.05559-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus (CMV) UL54 DNA polymerase (pol) mutants with known patterns of resistance to current antivirals ganciclovir (GCV), foscarnet (FOS), and cidofovir (CDV) were tested for cyclopropavir (CPV) susceptibility by a standardized reporter-based yield reduction assay. Exonuclease and A987G (region V) mutations at codons commonly associated with dual GCV-CDV resistance in clinical isolates paradoxically conferred increased CPV susceptibility. Various polymerase catalytic region mutations conferring FOS resistance with variable low-grade GCV and CDV cross-resistance also conferred CPV resistance, with 50% effective concentration (EC(50)) increases of 3- to 13-fold. CPV EC(50) values against several pol mutants were increased about 2-fold by adding UL97 mutation C592G. Propagation of a CMV exonuclease mutant under CPV selected for pol mutations less often than UL97 mutations. In 21 experiments, one instance each of mutations E756D and M844V, which were shown individually to confer 3- to 4-fold increases in CPV EC(50), was detected. Unlike GCV and CDV, exonuclease mutations are not a preferred mechanism of CPV resistance, but mutations in and near pol region III may confer CPV resistance by affecting its recognition as an incoming base for DNA polymerization.
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Hakki M, Drummond C, Houser B, Marousek G, Chou S. Resistance to maribavir is associated with the exclusion of pUL27 from nucleoli during human cytomegalovirus infection. Antiviral Res 2011; 92:313-8. [PMID: 21906628 DOI: 10.1016/j.antiviral.2011.08.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 08/18/2011] [Accepted: 08/22/2011] [Indexed: 01/13/2023]
Abstract
Select mutations in the human cytomegalovirus (HCMV) gene UL27 confer low-grade resistance to the HCMV UL97 kinase inhibitor maribavir (MBV). It has been reported that the 608-amino acid UL27 gene product (pUL27) normally localizes to cell nuclei and nucleoli, whereas its truncation at codon 415, as found in a MBV-resistant mutant, results in cytoplasmic localization. We now show that in the context of full-length pUL27, diverse single amino acid substitutions associated with MBV resistance result in loss of its nucleolar localization when visualized after transient transfection, whereas substitutions representing normal interstrain polymorphism had no such effect. The same differences in localization were observed during a complete infection cycle with recombinant HCMV strains over-expressing full-length fluorescent pUL27 variants. Nested UL27 C-terminal truncation expression plasmids showed that amino acids 596-599 were required for the nucleolar localization of pUL27. These results indicate that the loss of a nucleolar function of pUL27 may contribute to MBV resistance, and that the nucleolar localization of pUL27 during HCMV infection depends not only on a carboxy-terminal domain but also on a property of pUL27 that is affected by MBV-resistant mutations, such as an interaction with component(s) of the nucleolus.
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Affiliation(s)
- Morgan Hakki
- Division of Infectious Diseases, Oregon Health & Science University, Portland, OR 97239, USA.
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Tanaka K, Hori T, Yoto Y, Hatakeyama N, Yamamoto M, Suzuki N, Tsutsumi H. Human cytomegalovirus UL97 D605E polymorphism has a high prevalence in immunocompetent Japanese infants and children. Microbiol Immunol 2011; 55:328-30. [PMID: 21362026 DOI: 10.1111/j.1348-0421.2011.00327.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
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.
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Affiliation(s)
- Kaori Tanaka
- Department of Pediatrics, Sapporo Medical University School of Medicine, Chuo-ku, Sapporo, Japan.
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