PREVALENCE OF TRANSMISSION OF ZIDOVUDINE- RESISTANT VIRUSES IN SWITZERLAND

Zidovudine (ZDV) was the most widely used anti-HIV drug between 1987 a nd 1995, and, as already reported, transmission of ZDV-resistant virus es occurs. Several mutations of the reverse transcriptase gene have be en identified; one of them affects the 215 codon and is associated wit h a high degree of resistance. We have determined, using selective PCR , the prevalence of transmission of 215 mutant isolates in 134 patient s with primary HIV infection (PHI) and have identified 8 patients with 215 mutant virus between 1989 and 1995 in Switzerland. Mutant resista nt viruses have been isolated from patients treated with most antivira l drugs. A systematic search for mutant viruses may provide useful inf ormation for the adaptation of treatment strategies.