Antimicrobial susceptibility of clinical isolates of Actinomyces and related genera reveals an unusual clindamycin resistance among Actinomyces urogenitalis strains

作者：Barberis Claudia^*; Budia Mabel; Palombarani Susana; Hernan Rodriguez Carlos; Soledad Ramirez Maria; Arias Barbara; Bonofiglio Laura; Famiglietti Angela; Mollerach Marta; Almuzara Marisa; Vay Carlos

来源：Journal of Global Antimicrobial Resistance, 2017, 8: 115-120.

DOI：10.1016/j.jgar.2016.11.007

• Actinomyces spp.
• Clindamycin
• Antimicrobial susceptibility

Objectives: Patterns of antimicrobial susceptibility in Actinomyces and related genera are very limited in the literature. Data of predominant susceptibility profiles could contribute to the establishment of an accurate empirical treatment.
Methods: A total of 113 isolates from clinical samples were included in this study. Each isolate was identified using phenotypic methods and MALDI-TOF/MS. When discrepancies were observed, 16S rRNA gene sequencing was performed. The minimum inhibitory concentrations (MICs) of nine antimicrobial agents (penicillin, ceftriaxone, linezolid, tetracycline, clindamycin, erythromycin, ciprofloxacin, levofloxacin and vancomycin) were tested against the species Actinotignum schaalii (n = 23), Actinomyces turicensis (n = 18), Actinomyces europaeus (n = 13), Actinomyces naeslundii/Actinomyces viscosus group (n = 12), Actinomyces urogenitalis (n = 11), Actinomyces radingae (n = 11), Actinomyces neuii (n = 9), Actinomyces odontolyticus (n = 8), Bifidobacterium scardovii (n = 3), Actinomyces graevenitzii (n = 2), Alloscardovia omnicolens (n = 2) and Varibaculum cambriense (n = 1).
Results: All of the isolates were susceptible to penicillin, ceftriaxone, vancomycin and linezolid. Almost all of the A. urogenitalis isolates (8/11) were resistant to clindamycin and showed susceptibility to erythromycin, suggesting an L-phenotype, however no determinants of clindamycin resistance (lnu and lsa genes) were detected by PCR. High MIC values to quinolones were observed in 54/113 isolates (47.8%). All of the A. urogenitalis isolates were highly resistant to ciprofloxacin and levofloxacin.
Conclusions: These data highlight the importance of ongoing surveillance to provide relevant information for empirical management of infections caused by these organisms.

• 出版日期2017-3