An Analysis of Resistance Patterns of Oral Streptococci Obtained from Orofacial Infections Against Beta-lactams, Clindamycin and Vancomycin over 2014-2018

Purpose: Comparison of viridans group Streptococcus (VGS) susceptibility to benzylpenicillin, ampicillin, clindamycin and vancomycin in order to determine resistance rates to assess whether guidelines for prophylactic or therapeutic antibiotic treatment include the present resistance patterns. Materials and Methods: A retrospective analysis of antimicrobial susceptibility testing (AST) over 4 consecutive years (2014-2017) and 4 months in 2018 for 779 VGS isolates (cumulative data). Isolates originated from pus from orofacial infections cases and tissue fragments from patients undergoing maxillofacial surgeries Results: The highest resistance rate was observed to clindamycin. The highest overall resistance rate was for Streptococcus parasanguinis 43% and S. constellatus 49%; the lowest was for S. anginosus 12%. All S. anginosus isolates were susceptible to ampicillin during tested period. All isolates of analysed species were susceptible to vancomycin through studied period. Conclusion: Due to high resistance levels, individual antibiotic susceptibility testing for strains should become mandatory. Schlagwörter: Streptococcus viridians (VGS), susceptibility, clindamycin, resistance rate