Antibiotic Resistance of Streptococcus spp. Isolated from the Root Surface of Extracted Teeth to Penicillin V and Clindamycin Using E-Test

Antibiotics are used to treat and prevent oral infections. Clindamycin and penicillin are widely used drugs in this field. Poor use of antibacterial agents causes the emergence of antibiotic-resistant bacteria.

The present study examined and compared the frequency distribution of resistance of streptococci isolated from the root surface of extracted teeth to penicillin V and clindamycin. This study was conducted in 2021 in Yazd, Iran.

This was an analytical cross-sectional study performed in vitro. The samples were taken from the root surfaces of 50 teeth immediately after extraction and transferred to the laboratory in a transfer medium. After cultivation, isolation, and identification, the antibiotic resistance of isolates was measured by the E-test method. The data were analyzed using SPSS software (version 23).

Streptococci spp. were isolated from 46 samples (92%) without environmental contamination. The minimum inhibitory concentration (MIC) 50 and MIC 90 for penicillin V were 0.5 g/mL and 1 g/mL, respectively, and for clindamycin, 0.125 g/mL and 0.19 g/mL, respectively, which was significantly (P = 0.0001) lower for clindamycin. Intermediate sensitivity to penicillin V was 95.6%, and resistance to clindamycin was 21.8%.

It seems that except in limited cases where there is resistance to clindamycin, this antibiotic is amoreeffective drug to control the bacteria in the mouth. However, in some cases, aerobic isolates showed intermediate sensitivity to penicillin V; instead, resistance to clindamycin was observed.