Antibiotic resistance in lactic acid bacteria isolated from human dental plaque

Dental caries is a significant public health problem which results in destruction of the calcified tissues of tooth. Lactobacillus has been reported to occur in high numbers in dental caries. The aim of this study was to screen for the incidence of Lactobacillus from cases of dental caries and to determine the antibiotic resistance profile of them. Specimens from dental plaque were collected from 30 patients. Phenotypic and molecular methods were used for identification of Lactobacillus. The antimicrobial sensitivity test was performed to determine their resistance to 7 antibiotics. Then molecular detection of antibiotic resistance genes was carried out using Multiplex PCR method. Out of 30 dental plaque samples, Lactobacillus was isolated from 14 (46/6%) of them. mecA gene was the most important determinant responsible for penicillin resistance. Also bla TEM gene had greater role in Cefazolin and Cefixime resistance than bla SHV. bla SHV and bla OXA-1 genes had the same part in Amoxicillin-Clavulanic acid resistance. Also tetracycline resistance caused by both tetK and tetM genes identically. In conclusion Lactobacillus have important role in the formation of dental plaque which usually shows multidrug resistant patterns to commonly used antibiotics.

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