ABSTRACT
Background: Infancy is an important developmental period when the human microbiome is shaped. Given links between young age at antiretroviral treatment (ART) initiation and smaller persisting viral reservoirs, we hypothesized that earlier ART initiation may leave distinct microbial signatures in the oral cavity detectable in children living with HIV (CLWH). Method(s): Oral swab samples were collected from 477 CLWH and 123 children without HIV at two sites in Johannesburg, South Africa. CLWH had started ART < 2 years of age with 60% starting < 6 months of age. Most were wellcontrolled on ART at a median of 10 years of age when the swab was collected. Controls were age-matched and recruited from the same communities. Sequencing of the V4 amplicon of the 16S rRNA gene was done using established protocols. DADA2, decontam, and phyloseq were used for sequence inference, contaminant removal, and subsequent analyses. All p-values were adjusted for multiple testing using Benjamini-Hochberg false discovery rate method. Statistical analyses were performed with R. Result(s): CLWH had lower alpha diversity than uninfected children (Shannon index p< 0.0001). Genus-level abundances of Granulicatella, Streptococcus and Gemella were greater and Neisseria and Haemophilus were less abundant among CLWH compared to uninfected children. Associations were strongest among boys. There was no evidence of attenuation of associations with earlier ART initiation. In fact, decreased bacterial diversity and differences in taxa abundances in CLWH versus controls were consistent regardless of whether ART was started before or after 6 months of age. Shifts in genus-level taxa abundances relative to uninfected controls were most marked in children on regimens containing lopinavir/ritonavir;with few shifts seen if on regimens containing efavirenz. Conclusion(s): A distinct profile of less diverse oral bacterial taxa was observed in school-age CLWH on ART versus uninfected age-matched children suggesting persisting interference of HIV and its treatments on microbiota in the mouth. Any effects of earlier ART initiation were not detectable at this age. Studies of treated adults with HIV have observed similar shifts in taxa abundances. Oral microbiota have been linked to salivary cytokine levels with associations between Granulicatella and IL-8 and Neisseria and IL-6. Declines in Neisseria abundances in oral samples have been associated with more severe outcomes in influenza and COVID-19.
ABSTRACT
Introduction: Postmenopausal women with recurrent urinary tract infections (RUTI) are repeatedly exposed to antibiotics and therefore at risk for colonization by multi-drug resistant organisms. Methenamine hippurate (MH) is FDAapproved for the prevention of RUTI;however, the mechanism of action of MH or, more specifically, the role of MH in the alteration of the urobiome is not known. Since preliminary data has shown that MH may be effective against some bacteria (e.g., Escherichia coli), but not others (e.g., Enterococcus faecalis), we hypothesize that resident bladder microbiota will be altered by administration of MH. Objective: Our objective is to determine the longitudinal effect of MH on the urobiome of postmenopausal women with RUTI. Methods: A longitudinal study with a convenient sample of 10 postmenopausal women with a clinical history of RUTI was conducted (Figure 1). UDI6 questionnaires, voided urine, catheterized urine, and peri-urethral swabs were obtained at baseline and three months after daily MH use. Expanded quantitative urine culture (EQUC) was performed on these specimens. In addition, during the 3-month timeframe, four self-collection windows were completed (windows A-D): (A) prior to initiating MH (baseline urobiome), (B) one week after starting MH, (C) two weeks before the 3-month follow-up, and (D) one week before the 3-month follow-up. Voided urine and peri-urethral swabs were collected daily for one week during windows A-D to determine how the urobiome changed. Sequencing of samples from these collection windows is pending. Results: Ten participants enrolled;however, three participants were not able to complete the study due to allergic reaction, improper handling of samples, and COVID infection. Six participants have completed the study;microbiological studies for one participant are still in process. There were no episodes of acute cystitis for any participant during the length of the study. UDI6 results suggested a trend towards a decrease in frequency, leakage with urgency, and abdominal pain;however, none of these were statistically significant (Table 1). Of the six remaining participants, the average baseline urine pH was 5.8 ± 0.8. For the completed participants, an initial microbiological comparison of EQUC results at baseline and 3-month visits show differences in sample diversity. Specifically, the number of species detected (richness) in catheterized urine increased for all but one participant (Figures 2A and 2B) though there was little or no changes in overall diversity (Shannon Index, Figure 2B) or evenness (Pielou's Index, Figure 2C) for any sample type. Exposure to MH did not result in the loss of uropathogenic species present in catheterized urine at baseline;instead, additional uropathogenic and commensal microbiota were detected at the 3-month visit. Conclusions: UDI6 trended towards symptom improvement in frequency, urge incontinence, and pain, consistent with RUTI prevention and symptoms control. Microbiological results suggest that MH increases the richness of the bladder urobiome. This consistent trend suggests MH may reduce RUTI events by altering the urobiome community richness instead of eliminating uropathogenic microbiota from the bladder. Further studies are needed to understand the interaction between MH and a host that is susceptible to uropathogen overgrowth (Table Presented).