title: Molecular Analysis of Ganciclovir-Resistant Cytomegalovirus in Renal Transplant Recipients with High Viral Load.
abstract: BACKGROUND
  Gancyclovir-resistant (GanR) cytomegalovirus (CMV) remains an issue, especially in solid organ transplant (SOT) recipients. Some mutations in UL54 and UL97 confer this resistance. Long-lasting high-dose drug exposure, high viral load, together with lack of sufficient compliance with treatment may account for these mutations. The aim of this study was to detect UL97 and UL54 putative mutations conferring ganciclovir-resistance in renal organ transplant recipients with high CMV load.
  
  
  METHODS
  In this cross-sectional study, 58 serum samples were collected from renal transplant recipients who had referred to three hospitals in Tehran from January 2014 to June 2015. Specific criteria such as CMV syndrome, presence of CMV in blood and organ dysfunction were considered. Then, they were tested for viral load in their early fourth month of intravenous ganciclovir treatment. Fifty cases revealing more than 200 copies/mL were analyzed for mutations. Two fragments of UL54 and Ul97 genes were amplified and sequenced bidirectionally. Sequence alignment and statistical analysis were performed by Mutation Surveyor software and t-test respectively.
  
  
  RESULTS
  A significant difference was observed in viral load between seronegative and seropositive recipients (P = 0.036). The most frequent mutation was related to D605E in UL97 gene with the rate of 25%. Regardless of viral load, neither putative mutation nor simultaneous mutation was detected in either UL97 and UL54 regions.
  
  
  CONCLUSIONS
  In spite of high viral load and persistence of symptoms, our population study did not reveal putative mutations. Hence, the direct relationship between the presence of high quantity of CMV and the occurrence of putative mutation cannot be considered. Non-putative gancyclovir resistant mutations and prolonged drug exposure may have a role in these manifestations.
authors.affiliation: Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Majid
authors.initials: M
authors.lastname: Sohrabi
authors.affiliation: Department of Bioscience and Biotechnology, Malek Ashtar University of Technology, Tehran- Iran.
authors.forename: Farida
authors.initials: F
authors.lastname: Behzadian
authors.affiliation: Applied Virology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors.forename: Seied Mohammad Javad
authors.initials: SM
authors.lastname: Hosseini
authors.affiliation: Applied Virology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors.forename: Hadi
authors.initials: H
authors.lastname: Lashini
mesh_terms: D000998:Antiviral Agents / Q000627:therapeutic use*; D003430:Cross-Sectional Studies; D003587:Cytomegalovirus / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase / Q000235:genetics*; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D015774:Ganciclovir / Q000627:therapeutic use*; D006801:Humans; D007492:Iran; D016030:Kidney Transplantation / Q000009:adverse effects; D008297:Male; D009154:Mutation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics*; D066027:Transplant Recipients; D019562:Viral Load / Q000187:drug effects; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D000998:Antiviral Agents; C109367:UL54 protein, Human herpesvirus 5; D014764:Viral Proteins; D017853:Phosphotransferases (Alcohol Group Acceptor); C075365:ganciclovir kinase; D004259:DNA-Directed DNA Polymerase; D015774:Ganciclovir