COINFECTION OF THE IMMUNOCOMPROMISED BUT NOT THE IMMUNOCOMPETENT HOSTBY MULTIPLE HUMAN CYTOMEGALOVIRUS STRAINS

Coinfection by multiple human cytomegalovirus (HCMV) strains was inves tigated in immunocompetent individuals and AIDS patients. Thirty HCMV maternal and fetal or newborn isolate pairs from 9 cases of congenital HCMV infection as well as 36 HCMV isolates and 2 PCR-HCMV-positive CS F samples from 13 AIDS patients were tested by restriction fragment le ngth polymorphism analysis of multiple genome regions. Results from th e group of congenital infections showed that: i) all the 9 women with primary HCMV infection presumably harboured a single HCMV strain; ii) all strains were genetically unrelated; iii) isolates from infected fe tuses or newborns consisted of a single strain apparently indistinguis hable from the maternal strain; iv) no strain variations were observed in isolates from different body sites or in sequential isolates from newborns up to 8 months after birth. Results from the AIDS patient gro up demonstrated that; i) all patients were infected by unrelated strai ns; ii) 6/13 (46.1%) patients were coinfected by 2 or more HCMV strain s; iii) in a single patient two different HCMV strains were detected i n blood and urine, respectively, whereas a mixture of the two was foun d in the pharynx; iv) 4 patients showed the sequential appearance of a mixed virus population or different strains suggesting sequential rei nfections.