Nouri Gharajalar, S., 2018. Molecular characterisation of multidrug resistant Lactobacillus isolated from dental plaque of dogs using a multiplex PCR assay. Bulg. J. Vet. Med., 21,
No 4, 436–444.

DOI: 10.15547/bjvm.2000

Dental caries is a significant public health problem in both humans and animals worldwide. Lactobacillus species have been reported to be highly prevalent in both superficial and deep caries. The aim of this study was to analyse the antibiotic resistance patterns of lactobacilli isolated from dog dental plaque samples. Thirty plaque samples were collected from dog teeth. All Lactobacillus isolates were identified using phenotypic and genotypic methods. Then, their antibiotic susceptibility patterns and genetic determinants responsible for antibiotic resistance were determined. Total of 17 isolates were identified as belonging to the genus Lactobacillus by both methods. The results of antibiotic susceptibility test showed that all isolates (100%) were resistant to cefazolin and cefixime; 94% and 88% – resistant to penicillin and tetracycline; 64%, 58%, 52% and 41% of Lactobacillus isolates were resistant to amoxicillin-clavulanic acid, nitrofurantoin, vancomycin and chloram­phenicol respectively. The results of resistance genes identification indicated that bla_TEM was the most important determinant responsible for cefazolin, cefixime and amoxicillin-clavulanic acid resistance. The mecA gene was responsible for penicillin resistance while both tetk and tetM genes were equally involved in tetracycline resistance. According to the widespread resistance patterns seen among Lactobacillus isolates in this study, we concluded that antibiotic therapy for oral microbial infections should be used only where extremely needed.

Key words: antibiotic resistance, dental plaque, dog, Lactobacillus