title: HIV-1 genotypic zidovudine drug resistance and the risk of maternal--infant transmission in the women and infants transmission study. The Women and Infants Transmission Study Group.
abstract: OBJECTIVE
  Although the treatment of pregnant women and their infants with zidovudine (ZDV) has been remarkably effective in preventing the perinatal transmission of human HIV-1, many potentially preventable infections still occur. To examine whether the risk of perinatal infection is increased among women who carry ZDV-resistant HIV-1, the role of genotypic ZDV resistance in perinatal transmission was evaluated.
  
  
  METHODS
  The reverse transcriptase (RT) region of clinical isolates from culture supernatants of 142 HIV-1-infected women enrolled in the Women and Infants Transmission Study (WITS), who had been treated with ZDV during pregnancy was sequenced. Results from genotypic sequencing were linked to demographic, laboratory, and obstetrical databases, and the magnitude of association of having consensus drug-resistant HIV-1 RT mutations with transmission was estimated.
  
  
  RESULTS
  Twenty-five per cent (34/142) of maternal isolates had at least one ZDV-associated resistance mutation. A lower CD4 cell percentage and count (P= 0.0001) and higher plasma HIV-1 RNA (P=0.006) were associated with having any ZDV resistance mutation at delivery. Having any RT resistance mutation [odds ratio (OR): 5.16; 95% confidence interval (CI): 1.40, 18.97; P=0 0.01], duration of ruptured membranes [OR: 1.13 (1.02, 1.26) per 4 h duration; P= 0.02], and total lymphocyte count [OR: 1.06 (1.01, 1.10) per 50 cells higher level; P=0.009] were independently associated with transmission in multivariate analysis.
  
  
  CONCLUSIONS
  Maternal ZDV resistant virus was predictive of transmission, independent of viral load, in these mothers with moderately advanced HIV-1 disease, many of whom had been treated with ZDV before pregnancy.
authors.affiliation: Division of Epidemiology, University of Minnesota, School of Public Health, Minneapolis 55454, USA. welles@epi.umn.edu
authors.forename: S L
authors.initials: SL
authors.lastname: Welles
authors.forename: J
authors.initials: J
authors.lastname: Pitt
authors.forename: R
authors.initials: R
authors.lastname: Colgrove
authors.forename: K
authors.initials: K
authors.lastname: McIntosh
authors.forename: P H
authors.initials: PH
authors.lastname: Chung
authors.forename: A
authors.initials: A
authors.lastname: Colson
authors.forename: S
authors.initials: S
authors.lastname: Lockman
authors.forename: M G
authors.initials: MG
authors.lastname: Fowler
authors.forename: C
authors.initials: C
authors.lastname: Hanson
authors.forename: S
authors.initials: S
authors.lastname: Landesman
authors.forename: J
authors.initials: J
authors.lastname: Moye
authors.forename: K C
authors.initials: KC
authors.lastname: Rich
authors.forename: C
authors.initials: C
authors.lastname: Zorrilla
authors.forename: A J
authors.initials: AJ
authors.lastname: Japour
mesh_terms: D019380:Anti-HIV Agents / Q000627:therapeutic use; D004352:Drug Resistance, Microbial / Q000235:genetics; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy / Q000635:transmission* / Q000821:virology; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy / Q000821:virology; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use; D019562:Viral Load; D015215:Zidovudine / Q000627:therapeutic use*
chemical_list: D019380:Anti-HIV Agents; D018894:Reverse Transcriptase Inhibitors; D015215:Zidovudine; D054303:HIV Reverse Transcriptase