Microbial function and genital inflammation in young South African women at high risk of HIV infection.

BACKGROUND: Female genital tract (FGT) inflammation is an important risk factor for HIV acquisition. The FGT microbiome is closely associated with inflammatory profile; however, the relative importance of microbial activities has not been established. Since proteins are key elements representing actual microbial functions, this study utilized metaproteomics to evaluate the relationship between FGT microbial function and inflammation in 113 young and adolescent South African women at high risk of HIV infection. Women were grouped as having low, medium, or high FGT inflammation by K-means clustering according to pro-inflammatory cytokine concentrations. RESULTS: A total of 3186 microbial and human proteins were identified in lateral vaginal wall swabs using liquid chromatography-tandem mass spectrometry, while 94 microbial taxa were included in the taxonomic analysis. Both metaproteomics and 16S rRNA gene sequencing analyses showed increased non-optimal bacteria and decreased lactobacilli in women with FGT inflammatory profiles. However, differences in the predicted relative abundance of most bacteria were observed between 16S rRNA gene sequencing and metaproteomics analyses. Bacterial protein functional annotations (gene ontology) predicted inflammatory cytokine profiles more accurately than bacterial relative abundance determined by 16S rRNA gene sequence analysis, as well as functional predictions based on 16S rRNA gene sequence data (p < 0.0001). The majority of microbial biological processes were underrepresented in women with high inflammation compared to those with low inflammation, including a Lactobacillus-associated signature of reduced cell wall organization and peptidoglycan biosynthesis. This signature remained associated with high FGT inflammation in a subset of 74 women 9 weeks later, was upheld after adjusting for Lactobacillus relative abundance, and was associated with in vitro inflammatory cytokine responses to Lactobacillus isolates from the same women. Reduced cell wall organization and peptidoglycan biosynthesis were also associated with high FGT inflammation in an independent sample of ten women. CONCLUSIONS: Both the presence of specific microbial taxa in the FGT and their properties and activities are critical determinants of FGT inflammation. Our findings support those of previous studies suggesting that peptidoglycan is directly immunosuppressive, and identify a possible avenue for biotherapeutic development to reduce inflammation in the FGT. To facilitate further investigations of microbial activities, we have developed the FGT-DB application that is available at http://fgtdb.org/ . Video Abstract.

Inflammatory and antimicrobial properties differ between vaginal Lactobacillus isolates from South African women with non-optimal versus optimal microbiota.

Female genital tract (FGT) inflammation increases HIV infection susceptibility. Non-optimal cervicovaginal microbiota, characterized by depletion of Lactobacillus species and increased bacterial diversity, is associated with increased FGT cytokine production. Lactobacillus species may protect against HIV partly by reducing FGT inflammation. We isolated 80 lactobacilli from South African women with non-optimal (Nugent 4-10; n = 18) and optimal microbiota (Nugent 0-3; n = 14). Cytokine production by vaginal epithelial cells in response to lactobacilli in the presence and absence of Gardnerella vaginalis was measured using Luminex. Adhesion to vaginal epithelial cells, pH, D/L-lactate production and lactate dehydrogenase relative abundance were assessed. Lactobacilli from women with non-optimal produced less lactic acid and induced greater inflammatory cytokine production than those from women with optimal microbiota, with IL-6, IL-8, IL-1α, IL-1ß and MIP-1α/ß production significantly elevated. Overall, lactobacilli suppressed IL-6 (adjusted p < 0.001) and IL-8 (adjusted p = 0.0170) responses to G. vaginalis. Cytokine responses to the lactobacilli were inversely associated with lactobacilli adhesion to epithelial cells and D-lactate dehydrogenase relative abundance. Thus, while cervicovaginal lactobacilli reduced the production of the majority of inflammatory cytokines in response to G. vaginalis, isolates from women with non-optimal microbiota were more inflammatory and produced less lactic acid than isolates from women with optimal microbiota.

Antimicrobial and inflammatory properties of South African clinical Lactobacillus isolates and vaginal probiotics.

Bacterial vaginosis (BV) causes genital inflammation and increased HIV acquisition risk. The standard-of-care for BV, antibiotic therapy, is associated with high recurrence rates. Probiotics may improve treatment outcomes, although substantial heterogeneity in efficacy has been observed during clinical trials. To evaluate the potential to improve existing probiotics, we compared the inflammatory and antimicrobial (adhesion, H2O2, D-lactate and L-lactate production) characteristics of 23 vaginal Lactobacillus isolates from South African women, commercial vaginal probiotics (L. casei rhamnosus, L. acidophilus) and 4 reference strains. All lactobacilli induced inflammatory cytokine production by genital epithelial cells and produced D-lactate. Of six isolates assessed, five suppressed inflammatory responses to Gardnerella vaginalis. Although the L. acidophilus probiotic was the most adherent, many clinical isolates produced greater amounts of H2O2, D-lactate and L-lactate than the probiotics. The most L-lactate and H2O2 were produced by L. jensenii (adjusted p = 0.0091) and L. mucosae (adjusted p = 0.0308) species, respectively. According to the characteristics evaluated, the top 10 isolates included 4 L. jensenii, 2 L. crispatus, 1 L. mucosae, 1 L. vaginalis and the L. acidophilus probiotic. There is potential to develop an improved vaginal probiotic using clinical Lactobacillus isolates. Inflammatory profiles are critical to evaluate as some isolates induced substantial cytokine production.

Frequency of Betapapillomavirus infections among HIV infected and uninfected Black Zimbabweans with cutaneous lesions.

Human papillomavirus (HPV) types from the Betapapillomavirus (ß-HPV) genus are plentiful in non-melanoma skin cancers and warts among Caucasians, but there is paucity of information among black Africans. To determine the frequency of ß-HPV genotypes in cutaneous infections among Black Zimbabweans, a cross-sectional study was carried out in which blood samples and skin biopsies were collected from patients infected and uninfected with HIV attending a referral hospital. We included 144 participants (72 infected and 72 uninfected with HIV) with clinically apparent cutaneous warts (n = 34), suspected non-melanoma skin cancers (n = 98) and Kaposi sarcoma (KS) (n = 18). The skin biopsies were analyzed for HPV DNA presence and type. ß-HPV DNA was identified among 70% (101/144) and was significantly higher among patients infected with HIV, 79% (57/72) compared to the HIV uninfected 61% (44/72) [OR = 2.42, 95% CI (1.09-5.47), P = 0.018]. All patients with warts, 89% of those with KS and 58% of those with non-melanoma skin cancers were HPV DNA positive and ß-HPV type 14 was identified in nearly half of the study participants 49.3% (71/144). Single HPV infections were observed in 33.7% (34/101) of the participants that were HPV DNA positive, 66.3% (67/101) had multiple HPV types. There was no significant difference between patients infected and uninfected with HIV in terms of multiple HPV infections. The distribution of different HPV types did not reveal any association with age and gender but there was an association between HPV 14 and HIV immune status. ß-HPVs are not uncommon among the Black Zimbabweans with skin lesions.

Presence of Betapapillomavirus in Kaposi sarcoma lesions.

Human herpes virus 8 (HHV 8) is recognized as the necessary cause of Kaposi sarcoma (KS) and in the recent past the human papillomavirus (HPV) has been linked to the development of cutaneous basal cell and squamous cell carcinomas. In a cross sectional study investigating Beta-HPV infections in skin lesions, an unexpected occurrence of HPV DNA was found in KS lesions of HIV infected individuals. Of the 18 KS cases included in the study 16 (89%) had HPV DNA detected. The most common Betapapillomavirus types were HPV14 [15 cases (83.3%)], HPV12 [8 cases (44.4%)], and HPV24 [7 cases (39%)]. Multiple Beta-HPV types were detected in 10 (62.5%) of the participants with HPV DNA positive lesions; of these 7 had a CD4+ count below 350 cells/µl and 3 had CD4+ counts above 350 cells/µl. The presence of Beta-HPV DNA in KS lesions is a newly described phenomenon. Further studies to elucidate the role of Beta-HPV in KS need to be conducted as it is possible that HHV 8 may not be the solitary viral carcinogen in KS tumorigenesis.