Microbiologic profile of endodontic infections from HIV- and HIV+ patients using multiple-displacement amplification and checkerboard DNA-DNA hybridization

Abstract

Objective: To compare the microbiota of endodontic infections in necrotic pulp from HIV-negative and HIV-positive subjects.

Materials and methods: Root canal samples from necrotic pulp were collected from 40 HIV- and 20 HIV+ subjects. Pulps were amplified using multiple displacement amplification (MDA). Then, checkerboard DNA-DNA hybridization was employed to assess the levels of 107 microbial taxa. The percentage of DNA probe count and the percentage of teeth colonized by each test species were investigated. Significant differences between groups regarding proportions of taxa and prevalence of the test species were sought using the Mann-Whitney test and the Chi-square analysis, respectively.

Results: The most prevalent taxa detected were Dialister pneumosintes, Stenotrophomonas maltophilia, Streptococcus sobrinus, Corynebacterium diphteriae, and Helicobacter pylori among HIV- subjects and D. pneumosintes, Prevotella tannerae, Porphyromonas gingivalis, Parvimonas micra, Prevotella nigrescens, and Corynebacterium diphtheriae among HIV+ individuals. D. pneumosintes, C. diphtheria, and C. albicans were the most abundant species in the HIV- group, whereas the predominant taxa in HIV+ samples were P. tannerae, D. pneumosintes and Olsenella uli. P. tannerae, O. uli, Veilonella dispar, Bacteroides fragilis, and Actinomyces meyeri were significantly more abundant in HIV+ samples.

Conclusions: There were significant differences in the prevalence and proportions of specific microbial taxa between HIV- and HIV+ individuals. The root canal microbiota may represent a reservoir of important oral and medical pathogens, mainly in HIV+ individuals.

Figure 1

Bilateral bar chart of the frequency of detection (prevalence ± SEM) of 107 microbial taxa in root canal samples taken from 40 HIV negative patients (white bars) and 20 HIV+ patients (black bars). A detection level threshold of 10⁵ cells was employed. The significance of differences between groups was determined using the Chi-square analysis. The data are ordered in descending order of prevalence in HIV negative samples. ss, subsp. ◆ p< 0.001; ∎ p< 0.01; ★ p< 0.05.

Figure 2

Bilateral bar chart of the mean percentages of the DNA probe counts (± SEM) for 107 microbial species in MDA-amplified root canal samples taken from 40 HIV negative patients (white bars) and 20 HIV+ patients (black bars). The proportion of each species was averaged across subjects in the two clinical groups separately. The significance of differences between groups was determined using the Mann-Whitney test. The data are ordered in descending order of mean percentages of DNA probe counts detected in HIV negative samples. ss, subsp. ◆ p< 0.001; ∎ p< 0.01; ★ p< 0.05. Note: only taxa that comprised at least 1% of the total microbiota were eligible to be considered statistically significantly different.