Detection of hydrogen peroxide-producing Lactobacillus species in the vagina: a comparison of culture and quantitative PCR among HIV-1 seropositive women.
BACKGROUND
The presence of hydrogen peroxide (H(2)O(2)) producing Lactobacillus in the vagina may play a role in controlling genital HIV-1 shedding. Sensitive molecular methods improve our ability to characterize the vaginal microbiota; however, they cannot characterize phenotype. We assessed the concordance of H(2)O(2)-producing Lactobacillus detected by culture with quantitative PCR (qPCR) detection of Lactobacillus species commonly assumed to be H(2)O(2)-producers.


METHODS
Samples were collected as part of a prospective cohort study of HIV-1 seropositive US women. Cervicovaginal lavage specimens were tested for L. crispatus and L. jensenii using 16S rRNA gene qPCR assays. Vaginal swabs were cultured for Lactobacillus and tested for H(2)O(2)-production. We calculated a kappa statistic to assess concordance between culture and qPCR.


RESULTS
Culture and qPCR results were available for 376 visits from 57 women. Lactobacilli were detected by culture at 308 (82%) visits, of which 233 of 308 (76%) produced H(2)O(2). L. crispatus and/or L. jensenii were detected at 215 (57%) visits. Concordance between detection of L. crispatus and/or L. jensenii by qPCR and H(2)O(2)-producing Lactobacillus by culture was 75% (kappa = 0.45).


CONCLUSIONS
Among HIV-1 seropositive women, there was a moderate level of concordance between H(2)O(2)-producing Lactobacillus detected by culture and the presence of L. crispatus and/or L. jensenii by qPCR. However, one-quarter of samples with growth of H(2)O(2)-producing lactobacilli did not have L. crispatus or L. jensenii detected by qPCR. This discordance may be due to the presence of other H(2)O(2)-producing Lactobacillus species.
Department of Epidemiology, University of Washington, Box 359909, 325 9th Avenue, Seattle, WA 98104, USA. jbalkus@u.washington.edu
Jennifer E
JE
Balkus
Caroline
C
Mitchell
Kathy
K
Agnew
Congzhou
C
Liu
Tina
T
Fiedler
Susan E
SE
Cohn
Amneris
A
Luque
Robert
R
Coombs
David N
DN
Fredricks
Jane
J
Hitti
D000293:Adolescent; D000328:Adult; D001431:Bacteriological Techniques / Q000379:methods; D015331:Cohort Studies; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D005260:Female; D015658:HIV Infections / Q000382:microbiology* / Q000821:virology; D015497:HIV-1 / Q000302:isolation & purification; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007778:Lactobacillus / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism*; D008875:Middle Aged; D011446:Prospective Studies; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D014481:United States; D014621:Vagina / Q000382:microbiology*; D044364:Vaginal Douching; D055815:Young Adult
D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D006861:Hydrogen Peroxide