Occurrence, diversity and molecular characterization of oral bacterial biofilms from Pupils in Southwestern Nigeria

Bacterial pathogenesis within a host arises from the presence and infection of harmful bacteria. One of the modes of bacterial existence in humans is the formation of biofilms. Biofilms are composed of aggregates of bacterial cells which can be found in the oral cavity and other parts of the human body. These bacteria can disseminate from the oral cavity to the internal organs of the body. The aim of this study was to identify and classify the oral bacterial diversity of pupils in parts of the southwest of Nigeriausing phenotypic methods and Next Generation Sequencing (NGS) and to determine the presence of genes responsible for bacterial biofilm production. Participants were recruited from Lagos, Osun and Oyo States in Nigeria. Phenotypic and biochemical identification revealed 27 gram negative and gram-positive bacteria. Eight(8) bacteria occurred in all four locations (A, B, C and D). Biofilm-producing bacteria identified by NGS include C_110A, C_105, D_1, A_37 and B_87 which are Pseudomonas (99%), Bacillus (95%), Proteus mirabilis (93%), Serratia (88%) and Alcaligenes faecalis (82%) respectively. This study also uncovered the presence of unclassified Providencia sp. WCHPHu000369, and Unclassified Serratia sp. SCBI. rpoS and algC genes mapped successfully to Pseudomonas aeruginosa, icaC, rpoS, icaA and comE mapped to Proteus mirabilis, scaA, icaB, icaD, icaA and rpoS mapped to Serratia marcescens. No biofilm-producing gene mapped to Alcaligenes faecalis suggesting a possibly novel biofilm-production mechanism. The location ranked lowest in the oral health and related quality of life spectrum showed the greatest bacterial diversity, suggesting that the occurrence and diversity of pathogenic oral biofilm-producing bacteria in a geographical location is directly related to its living conditions. Results presented will advise research in geographical oral bacterial diversity and in systematic design of prophylactic measures.