Elucidation of cytomegalovirus disease recurrence in an HIV-1-positive patient

Cytomegalovirus (CMV) is responsible for the most common opportunistic viral infection in patients with acquired immunodeficiency syndrome (AIDS). The colon is a common site for CMV infection in patients positive for the human immunodeficiency virus (HIV). The clinical diagnosis of CMV infection is based on the characteristic endoscopic appearance of extensive ulceration of the gastric mucosa. A 54-year-old HIV-positive man visited our hospital because of high fever. The patient presented with diarrhea, and colonoscopy was performed. Ganciclovir was administered, with a good clinical response. However, the patient complained of the same symptoms again 6 months later. Nested polymerase chain reaction (PCR) was performed on all the patient's samples to detect CMV, followed by sequencing of the UL97 gene for CMV resistance detection. The PCR tests for Legionella, Chlamydia pneumoniae, Pneumocystis carinii, and Aspergillus were negative. DNA preparations from biopsy specimens of areas of colon ulceration were positive for CMV. Six months after treating the colon ulcerations, the PCR for CMV was positive, and the possible emergence of CMV mutants conferring ganciclovir resistance was examined. Direct sequencing of the PCR products revealed the known V594 mutation in the UL97 gene predisposing for ganciclovir resistance as well as the polymorphisms (579, GGC-->GGT) and (598, GGT-->GGC) in all samples tested. In summary, molecular biology methods can be used for early detection of CMV in characteristic colonic lesions in HIV-1-positive patients. Furthermore, detection of mutant strains resistant to antiviral drugs as well as polymorphisms elucidate the natural history of the infection.