First characterization of methanogens in oral cavity in Malian patients with oral cavity pathologies

Abstract

BackgroundThe oral cavity of humans is inhabited by several hundreds of bacterial species and other microorganisms such as fungi and archaeal methanogens. Regarding methanogens, data have been obtained from oral cavity samples collected in Europe, America and Asia. There is no study published on the presence of methanogens in the oral cavity in persons living in Africa. The objective of our study was to bring new knowledge on the distribution of oral methanogens in persons living in Mali, Africa.MethodsA total of 31 patients were included in the study during a 15-day collection period in September. Bacterial investigations consisted in culturing the bacteria in 5% sheep blood–enriched Columbia agar and PolyViteX agar plates. For archaeal research, we used various methods including culture, molecular biology and fluorescent in situ hybridization (FISH).ResultsEight of 31 (26%) oral samples collected in eight patients consulting for stomatology diseases tested positive in polymerase chain-reaction (PCR)-based assays for methanogens including five cases of Methanobrevibacter oralis and one case each of Methanobrevibacter smithii, Methanobrevibacter massiliense and co-infection Methanobrevibacter oralis and Methanobrevibacter massiliense.ConclusionsIn this pilot study, we are reporting here the first characterization of methanogens in the oral cavity in eight patients in Mali. These methanogen species have already been documented in oral specimens collected from individuals in Europe, Asia, North America and Brazil.

Diversity of Methanogens in Animals’ Gut

“…These results could be explained by the fact that the pig is an omnivore, which means that its diet is close to that of humans compared to other animals. In addition, 50% of M. smithii in our study was found in pigs, indicating that M. smithii was the most prevalent methanogen in the digestive tract of pigs, consistent with work carried out in humans where the high prevalence of M. smithii in the digestive tract has been demonstrated [45,49].…”

The oralome and its dysbiosis: New insights into oral microbiome-host interactions

“…Five different methanogenic archaea genera have been identified in the oral cavity of healthy patients - Methanobrevibacter, Methanosphaera, Methanosarcina, Thermoplasmata and Methanobacterium [73] . Among these, Methanobrevibacter oralis, Methanobacterium congelense/curvum and Methanosarcina mazeii are the main archaea species found in healthy patients [73] , [74] , [75] , [76] , [77] , with M. oralis dominating over other species at a prevalence of 40% [72] , [76] , [78] . Archaea are members of the oral microbiome, however, they are considered less abundant and diverse than oral bacteria [79] .…”

“…Archaea species have also been implicated in oral diseases, as they are known to form biofilms, and can interact with the human immune system [80] . Several studies identified increased numbers of M. oralis in periodontitis, peri -implantitis and root canal necrosis cases [73] , [75] , [76] , [78] , [81] , possibly implicating the species in those diseases. Further, studies have demonstrated that archaea coexist with periodontal pathogens, such as Treponema denticola , Tannarella forsythia and Porphyromonas gingivalis [72] , [75] , [78] .…”

Methanobrevibacter smithii tonsillar phlegmon: a case report

“…Although previously unreported, here, detection of M. smithii in tonsillar pus was not surprising as M. smithii is known to colonize the oral fluid microbiota [ 22 ], being further implicated in oral cavity dysbiosis such as periodontitis and peri implantitis [ 23 , 24 ]. The presence of methanogens in saliva reinforces the hypothesis of a possible inflammation of the salivary glands that would cause tonsillar phlegmon [ 2 , 25 ].…”