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Abstract Background There is growing evidence that perinatal HIV infection and exposure affect salivary pH and flow rate in children in most parts of the world, but not against the background of caries and the African demographic. This study aimed to evaluate the impact of HIV infection as well as exposure on salivary properties and their influence upon the dental caries experience among school-aged children in Nigeria. Method This cross-sectional study assessed the salivary flow rates and salivary pH of HIV infected and exposed school-aged (4–11) children receiving care at a Nigerian tertiary hospital. A total of 266 consenting participants which comprised of three groups as follows: (1) HIV Infected (HI) (n = 87), (2) HIV Exposed and Uninfected (HEU) (n = 82) and (3) HIV Unexposed and Uninfected (HUU) (n = 97) were recruited for the study. Questionnaires completed by parents/guardians were used for data collection. Three calibrated dentists performed oral examinations for dental caries. International Caries Detection and Assessment Scores (ICDAS) was used and presented as dmft/DMFT. Salivary pH was measured using MColourpHast™ pH indicator strips, while salivary flow rate was determined by collecting unstimulated whole saliva using the suction method. Data analysis relied on comparative statistics to determine the correlation between HIV exposure and infection on salivary pH and flow rates. Result Across the groups, (HI, HEU, and HUU) mean pH of the HI was significantly less than that of HEU and HUU. Similarly, there was a statistically significant difference in the SFR across the three groups (p = 0.004). Other variables such as gender, age and oral hygiene status expressed by the gingival inflammatory scores had no significant influence on the pH and SFR of study participants. There was a rather unexpected positive correlation of DMFT of HI and HEU groups with increasing salivary flow rate; though, the relationship was weak and not significant. Conclusion Perinatal HIV exposure and infection significantly impact salivary pH and flow rate among school-aged children in Nigeria. The findings of this study imply that HIV infection influenced the salivary pH, while HIV maternal exposure (without infection) impacted salivary flow rates when compared to the controls.

ABSTRACT Highly active antiretroviral treatment (HAART) has greatly reduced opportunistic infections in HIV-infected individuals. However, even with the use of HAART, HIV-infected individuals are still at an increased risk of oral diseases, including dental caries. Dental caries development is associated with microbial community shifts leading to community dysbiosis. HIV infection can significantly alter the bacteriome and mycobiome composition in the oral cavity; however, these impacts have not been assessed for caries initiation and progression. The aim of this study was to characterize the mycobiome for supragingival plaque samples from HIV-infected (HI), HIV-exposed-but-uninfected (HEU), and HIV-unexposed-and-uninfected (HUU) children with and without caries. To accomplish this, ITS1 amplicons of 127 samples were sequenced. We found that HIV infection and exposure resulted in changes to the supragingival plaque mycobiome for both health and caries. Overall, a reduction in community diversity as caries progressed was observed, with HI children having the lowest diversity and HEU children the highest. Candida albicans was the most abundant species identified, with 177 different amplicon sequence variants (ASVs). Two C. albicans ASVs dominated the data (53.0% and 38.5% of all taxonomic assignments). The more frequent ASV dominated HI and HUU communities, whereas the second dominated HEU communities. HEU children also had the lowest abundance of C. albicans and the highest number of health-associated taxa (taxa statistically associated with caries-free teeth). IMPORTANCE Globally, caries is among the most frequent chronic childhood disease, and the fungal component of the microbial community responsible is poorly studied despite evidence that fungi contribute to increased acid production exacerbating enamel demineralization. HIV infection is another global health crisis. Perinatal HIV exposure with infection are caries risk factors; however, the caries experience in the context of perinatal HIV exposure without infection is less clear. Using high-throughput amplicon sequencing, we find taxonomic differences that become pronounced during late-stage caries. Notably, we show a stronger correlation with health-associated taxa for HIV-exposed-but-uninfected children when compared to unexposed and uninfected children. This aligns with a lower incidence of caries in primary teeth at age 6 or less for exposed yet uninfected children. Ultimately, these findings could contribute to improved risk assessment, intervention, and prevention strategies such as biofilm disruption and the informed design of pro-, pre-, and synbiotic oral therapies.

ABSTRACT Children living with HIV have a higher prevalence of oral diseases, including caries, but the mechanisms underlying this higher prevalence are not well understood. Here, we test the hypothesis that HIV infection is associated with a more cariogenic oral microbiome, characterized by an increase in bacteria involved in the pathogenesis of caries. We present data generated from supragingival plaques collected from 484 children representing three exposure groups: (i) children living with HIV (HI), (ii) children who were perinatally exposed but uninfected (HEU), and (iii) unexposed and therefore uninfected children (HUU). We found that the microbiome of HI children is distinct from those of HEU and HUU children and that this distinction is more pronounced in diseased teeth than healthy teeth, suggesting that the impact of HIV is more severe as caries progresses. Moreover, we report both an increase in bacterial diversity and a decrease in community similarity in our older HI cohort compared to our younger HI cohort, which may in part be a prolonged effect of HIV and/or its treatment. Finally, while Streptococcus mutans is often a dominant species in late-stage caries, it tended to be found at lower frequency in our HI cohort than in other groups. Our results highlight the taxonomic diversity of the supragingival plaque microbiome and suggest that broad and increasingly individualistic ecological shifts are responsible for the pathogenesis of caries in children living with HIV, coupled with a diverse and possibly severe impact on known cariogenic taxa that potentially exacerbates caries. IMPORTANCE Since its recognition as a global epidemic in the early 1980s, approximately 84.2 million people have been diagnosed with HIV and 40.1 million people have died from AIDS-related illnesses. The development and increased global availability of antiretroviral treatment (ART) regimens have dramatically reduced the mortality rate of HIV and AIDS, yet approximately 1.5 million new infections were reported in 2021, 51% of which are in sub-Saharan Africa. People living with HIV have a higher prevalence of caries and other chronic oral diseases, the mechanisms of which are not well understood. Here, we used a novel genetic approach to characterize the supragingival plaque microbiome of children living with HIV and compared it to the microbiomes of uninfected and perinatally exposed children to better understand the role of oral bacteria in the etiology of tooth decay in the context of HIV exposure and infection.

Abstract Background HIV infection and its management confer a substantial health burden to affected individuals and have been associated with increased risk of oral and dental diseases. In this study, we sought to quantify HIV-associated differences in the prevalence and severity of dental caries in the primary and permanent dentition of 4–11-year-old Nigerian Children. Methods We used clinical, laboratory, demographic, and behavioral data obtained from an ongoing cohort study of age-matched HIV-infected (HI, n = 181), HIV-exposed-but-uninfected (HEU, n = 177), and HIV-unexposed-and-uninfected (HUU, n = 186) children. Measures of dental caries experience (i.e., prevalence and severity) were based on dmft/DMFT indices recorded by trained and calibrated clinical examiners. Differences in primary and permanent dentition caries experience between HI, HEU, and HUU were estimated using multivariable logistic and negative binomial regression modeling. Results HI children had significantly higher caries experience (33%) compared to HEU (15%) and HUU (22%) children. This difference persisted in fully adjusted analyses [odds ratio (OR) = 1.6; 95% confidence interval (CI) = 1.0–2.6], was most pronounced in the permanent dentition (OR = 3.4; 95% CI = 1.2–9.5), and mirrored differences in caries severity. While molars were predominantly affected in both primary and permanent dentitions, caries lesion patterns differed between dentitions. Caries severity was significantly associated with hypoplastic primary teeth, gingival inflammation, and lower CD4 counts. Conclusions We found that the higher prevalence and severity of dental caries among HI children was driven by increased burden of permanent dentition caries compared to their uninfected counterparts. The dentition-specific associations identified in this study highlight the need to design and implement age-specific caries prevention strategies. These may include intensified oral hygiene regimens aimed at mitigating the cariogenic impact of hyposalivation among HI children. Similarly, the long-lasting impacts of developmental defects of the enamel in the primary and permanent dentitions must not be ignored.

Abstract Background This study seeks to understand better the mechanisms underlying the increased risk of caries in HIV-infected school-aged Nigerian children by examining the relationship between the plaque microbiome and perinatal HIV infection and exposure. We also seek to investigate how perinatal HIV infection and exposure impact tooth-specific microbiomes' role on caries disease progression. Methods The participants in this study were children aged 4 to 11 years recruited from the University of Benin Teaching Hospital (UBTH), Nigeria, between May to November 2019. Overall, 568 children were enrolled in three groups: 189 HIV-infected (HI), 189 HIV-exposed but uninfected (HEU) and 190 HIV-unexposed and uninfected (HUU) as controls at visit 1 with a 2.99% and 4.9 0% attrition rate at visit 2 and visit 3 respectively. Data were obtained with standardized questionnaires. Blood samples were collected for HIV, HBV and HCV screening; CD4, CD8 and full blood count analysis; and plasma samples stored for future investigations; oral samples including saliva, buccal swabs, oropharyngeal swab, tongue swab, dental plaque were collected aseptically from participants at different study visits. Conclusions Results from the study will provide critical information on how HIV exposure, infection, and treatment, influence the oral microbiome and caries susceptibility in children. By determining the effect on community taxonomic structure and gene expression of dental microbiomes, we will elucidate mechanisms that potentially create a predisposition for developing dental caries. As future plans, the relationship between respiratory tract infections, immune and inflammatory markers with dental caries in perinatal HIV infection and exposure will be investigated.