Antimicrobial susceptibilities of Corynebacterium species and other non-spore-forming gram-positive bacilli to 18 antimicrobial agents

Abstract

The susceptibilities of 265 strains of Corynebacterium species and other non-spore-forming gram-positive bacilli to 18 antimicrobial agents were tested. Most strains were susceptible to vancomycin, doxycycline, and fusidic acid. Corynebacterium jeikeium and Corynebacterium urealyticum were the most resistant organisms tested. Resistance to ␤-lactams, clindamycin, erythromycin, azythromycin, ciprofloxacin and gentamicin was common among strains of Corynebacterium xerosis and Corynebacterium minutissimum. Ampicillin resistance among Listeria monocytogenes was more prevalent than previously reported. Optochin, fosfomycin, and nitrofurantoin showed very little activity against most organisms tested, but the use of nitrofurantoin as a selective agent in culture medium may prevent the recovery of some isolates. Except for the unvarying activity of vancomycin against Corynebacterium species, the antimicrobial susceptibilities of the latter to other antibiotics are usually unpredictable, such that susceptibility tests are necessary for selecting the best antimicrobial treatment.During the last two decades a renewed interest in Corynebacterium species and other non-spore-forming gram-positive bacilli has emerged among clinicians and microbiologists alike (2,8,9,32). Infections caused by these organisms are emerging, new species are being recognized (2, 9), and infections by toxigenic and nontoxigenic Corynebacterium diphtheriae strains are also being described with increasing frequency, indeed, in countries where diphtheria had been totally or almost eradicated (7, 26). However, this renewed interest has not been followed by an in-depth study to determine the antimicrobial susceptibilities of such organisms. Most available data come from scattered case reports, studies on a particular organism, or very old reports, sometimes published before 1960 (9).The aim of the study described here was to determine the antimicrobial susceptibilities of a variety of organisms, most of which were isolated from clinical specimens, against 18 antimicrobial agents. MATERIALS AND METHODSBacterial strains. We tested 265 strains of Corynebacterium species and other non-spore-forming gram-positive bacilli obtained from the following different sources: clinical samples (n ϭ 141), skin (n ϭ 25), bacterial collections (n ϭ 19), and referrals to our laboratory from other institutions (n ϭ 80). Strains from clinical samples were isolated during the period from 1985 to 1993. All strains were identified by conventional methods (2) and also by using the API Coryne system (25), were stored frozen in 10% skim milk, and were maintained at Ϫ70ЊC until use.Antimicrobial agents. The following antibiotics were kindly provided by the manufacturers as powders for in vitro study: ampicillin and oxacillin (SmithKline Beecham Laboratories, Worthing, United Kingdom), cephalothin and vancomycin (Lilly, S.A., Madrid, Spain), cefuroxime (Glaxo Laboratories, Madrid, Spain), imipenem (Merck Sharp & Dohme, Madrid, Spain), tetracycline, doxycycline, and azithromycin (Pf...

Antimicrobial Susceptibility Patterns of Coryneform Bacteria Isolated from Semen

“…Unlike earlier studies [6,8], in our study, C. jeikeium and C. seminale did not have low MICs of nitrofurantoin. Another discord with earlier reports was revealed in case of TMP/SMX that was highly active on the majority of the strains studied by us while weak or missing activity of it against C. striatum, C. jeikeium, D. hominis and T. otitidis has been described [18][19][20].…”

“…Our data corresponds to several studies that have shown high resistance of coryneforms to macrolides and lincosamines [6,7,15,17,18] and there is a distinct resistance pattern, MLSb (a co-occurring resistance to Macrolide, Lincosamine and Streptogramin B) [8]. In our study, 16 strains (13 C. seminale, 2 Cellulomonas/Microbacterium sp.…”

“…Therefore a renewed interest in Corynebacterium and similar species has emerged during the last decades among clinicians and microbiologists alike [5,6]. At the same time, there are few reports about their antimicrobial susceptibility.…”

“…At the same time, there are few reports about their antimicrobial susceptibility. These studies have frequently indicated high resistance of coryneform bacteria to antibiotics [6,7], and it is also proposed that corynebacteria can be the reservoir of drug resistance genes [8]. The susceptibility pattern of coryneform species has been researched mostly in association with emergence of multiresistant nosocomial pathogens, less data are available concerning the mucosal or physiological fluid strains.…”

Nondiphtherial Corynebacterium species isolated from clinical specimens of patients in a university hospital, Rio de Janeiro, Brazil

“…Because of the absence of accepted breakpoints for coryneform bacteria to interpretative categories, those established for Kirby-Bauer disk diffusion method by the NCCLS for organisms other than Haemophilus species and Neisseria gonorrhoeae were used by the authors. The breakpoints for Staphylococcus aureus were considered in the cases of penicillin, oxacillin and ampicillin (9,13,22,23).…”