Isolement et identification des bactéries du microbiote buccal résident et leur caractérisation pour la formation des biofilms dans la cavité orale

Abstract

The oral microbiota constitutes a diverse microbial community composed of bacteria, viruses and fungi. Thanks to advances in identification techniques, more than 700 species have been recognized, although some remain uncharacterized. This study aims to isolate, identify and characterize the resident microbes most involved in biofilm formation in clinical samples. During the study, samples were taken from healthy and unhealthy subjects. The samples were collected in the dental clinics of the city of Mostaganem, with sterile swabs and transferred and tubes containing 1 ml of nutrient broth to the laboratory, where they were incubated for 24 hours at 37°C. Then, the microorganisms were isolated on different culture media after identification macroscopically, microscopically and by biochemical tests. In addition, the isolates were tested for sensitivity/resistance to antibiotics. Finally, the formation of biofilm was qualitatively detected using methods on Red Congo agar and that in glass test tubes. A total of 15 microbial strains were isolated during the study, 24 of which were Gram-positive and 3 were Gram-negative. The most dominant species of Gram-positive strains was Staphylococcus sp (n = 9). On the other hand, overall, the dominated families were Staphylococcaceae followed by Streptococcaceae and Enterococcaceae. One of the most cariogenic strains of Klebsiella pneumoniae was also isolated. Biofilm formation tests revealed a strong adhesion capacity in the isolated strains. Current research has revealed that biofilm formation in Streptococcus sp, Escherichia coli and Klebsiella pneumoniae species was predominant against Candida albicans strains. Ultimately, the complexity of the host-oral microbiota interaction and the importance of biofilms highlight the need to continue research efforts in this field. A better understanding of these phenomena is the key to maintaining a favorable microbial balance and significantly improving the overall oral health of the population.