Characterization of the gram-positive bacterial profile in the oral fluid of HIV-infected patients diagnosed with oral candidiasis

Abstract

The health of the oral microbiome plays a crucial role in maintaining the overall health of HIV-infected patients. Alterations in the oral microbiota constitute a key factor contributing to the development of oral candidiasis. Contemporary studies have largely focused on describing microbial changes without providing an integrated understanding of their clinical implications, highlighting the need for comprehensive research to identify specific interaction patterns and assessing their impact on disease progression. The aim of this study is to determine the quantitative and qualitative composition of Gram-positive bacteria in the oral fluid of HIV-infected patients with diagnosed oral candidiasis.
Materials and methods.
The study enrolled 31 HIV-positive patients with confirmed oral candidiasis (study group) and 35 apparently healthy individuals (control group). The microbiome of unstimulated whole saliva was analyzed by gas chromatography—mass spectrometry (GC—MS) as described by G.A. Osipov.
Results.
In HIV-positive patients, the colonization density was markedly increased for Enterococcus spp. (157.8%), Streptococcus spp. (102%), Streptococcus mutans (85.4%), Staphylococcus epidermidis (100%), Staphylococcus aureus (303.5%), Peptostreptococcus anaerobius (21.6%), Propionibacterium acnes (127.2%), and Eubacterium spp. (122.8%). The expansion of these taxa, which correlated with the overgrowth of Candida spp., is explained by their capacity to form mixed biofilms and to secrete enzymes and organic acids that modify pH and substrate composition, thereby facilitating fungal colonization and increasing the risk of dental caries. Concomitantly, a sharp decline or complete elimination was recorded for Bacillus cereus (−100%), Clostridium spp. (−88.4%), Nocardia spp. (−86.4%), Lactobacillus spp. (−66.1%), Bifidobacterium spp. (−72.9%), and Actinomyces spp. (−100%). The reduction of these bacterial consortia likely reflects the loss of normally produced organic acids, metabolites, and bacteriocins that restrain Candida growth; their removal weakens the ecosystem, promoting fungal colonization and proliferation.
Conclusion.
HIV-infected patients with diagnosed oral candidiasis exhibit pronounced dysbiosis of the oral cavity. In the microbial landscape of Gram-positive bacteria in the oral fluid, there is a critical reduction of several taxa—including Bacillus cereus, Clostridium spp., Nocardia spp., Rhodococcus spp., Corynebacterium spp., Propionibacterium jensenii, Clostridium perfringens, and Clostridium ramosum—up to complete elimination. Additionally, HIV-infected patients with oral candidiasis show an increased proportion of opportunistic pathogens such as Staphylococcus spp., Streptococcus spp., Enterococcus spp., and Peptostreptococcus anaerobius, as well as Candida genus.