In VitroAntibiotic Susceptibility Pattern of Non-diphtheriae CorynebacteriumIsolates in Ontario, Canada, from 2011 to 2016

ABSTRACTNon-diphtheriae Corynebacterium-associated disease has been increasingly observed and often presents a conundrum to the treating physician. Analysis of antibiotic susceptibility testing data for 1,970 clinical Corynebacteriumisolates received between 2011 and 2016 revealed that empirical drug treatment options are limited to vancomycin and linezolid. Corynebacterium striatumwas the most frequently observed species during this study period, along with C. amycolatumand C. pseudodiphtheriticum/C. propinquum. Low levels of susceptibility to penicillin (14.5%), erythromycin (15.1%), and clindamycin (8.7%) were observed for non-diphtheriae Corynebacteriumspecies, while 3.0% of isolates were not susceptible to daptomycin. Similarly, 26.9% and 38.1% of Corynebacteriumisolates were susceptible to ciprofloxacin and trimethoprim-sulfamethoxazole, respectively. Our data show much lower susceptibility to penicillin than previously reported in the literature and an increasing number of isolates resistant to daptomycin, highlighting the need for continued antibiotic surveillance studies for appropriate patient management and treatment success.