Canada's First Case of a Multidrug-Resistant Corynebacterium diphtheriae Strain, Isolated from a Skin Abscess

Abstract

A toxigenic Corynebacterium diphtheriae biovar mitis sequence type 136 (ST136) strain was recovered from a toe infection of an unvaccinated patient recently returned from India. The isolate was resistant to clindamycin, erythromycin (ermX positive), tetracycline, and trimethoprim-sulfamethoxazole, intermediate to ceftriaxone and cefotaxime, and had high MICs for telithromycin and chloramphenicol but was sensitive to other drugs. CASE REPORTA 38-year-old male was seen by a family physician in a city located in a western Canadian province for an evaluation of an abscess on his left second toe which started 3 days prior while the patient was visiting family and friends in India. The patient had no history of traumatic injury, denied contact with sick persons, and had an unknown vaccination history. A swab of the left second toe was sent within hours to a private laboratory for bacterial culture and drug sensitivity testing. The patient was prescribed 500 mg of cephalexin three times a day for 10 days, and he recovered uneventfully. Patient consent to describe this case was obtained for the purpose of this study.The direct Gram stain of the specimen revealed Gram-positive cocci and Gram-positive bacilli. After ϳ48 h of incubation under facultatively anaerobic conditions at 35°C on 5% sheep blood agar, the culture grew colonies which were identified as group A streptococci and Staphylococcus aureus. In addition, the culture also grew creamy, opaque, slightly raised nonhemolytic colonies; Gram smear of the isolate revealed Grampositive bacilli with club-shaped ends and occasional V forms. This strain was urease negative and facultatively anaerobic. Colonies were black with dark halos on Tinsdale medium (17). The isolate was referred to the BC Center for Disease Control Laboratory for confirmation and identification as Corynebacterium diphtheriae. This strain fermented glucose and maltose but not lactose, mannitol, glycogen, or xylose. When studied by conventional methods, this strain reduced nitrate to nitrite and was catalase positive. Black colonies typical for C. diphtheriae grew on freshly prepared cystine-tellurite blood agar (17). Albert's staining (18a) was performed after 24 h of growth on Loeffler's medium (PML Microbiologicals, bioMérieux), where typical blue-black metachromatic granules against a green cytoplasm were observed, consistent with C. diphtheriae (6). The strain was forwarded to the Canadian National Microbiology Laboratory (NML) for further characterization and toxigenicity testing (NML identifier 090066).Growth in brain heart infusion broth was not enhanced by the addition of ϳ1% (vol/vol) sterile Tween 80, a feature that, if present, is suggestive of C. diphtheriae biovar intermedius (9). Using conventional carbohydrate broth sugars (2), the strain was corroborated as being positive for catalase, reduction of nitrate, and fermentation of glucose, fructose, galactose, maltose, mannose, and ribose but not glycerol, glycogen, lactose, mannitol, raffinose, sucrose, trehalose, or xylose. Oxidase wa...

Antibiotic Susceptibility Pattern of Corynebacterium diphtheriae Isolated from Outbreaks in Indonesia 2010-2015

“…It also reported from a study in Polish, whereas there was a multidrug resistance C. diphtheriae case in Canada which was resistant to clindamycin, erythromycin, tetracycline and trimethoprim-sulfamethoxazole. (7,(17)(18)(19)(20) In our study, there were 6 isolates (10.5%) that resistance to two antibiotics, such as tetracycline and clindamycin, vancomycin and clindamycin, vancomycin and tetracycline, also penicillin and vancomycin. Then 4 isolates (7%) resistance to 3-5 antibiotics.…”

Detection Methods for Laboratory Diagnosis of Diphtheria

“…Moreover, there are only a few studies comparing different antibiotic susceptibility testing methods for corynebacteria (Martinez-Martinez et al 1995;Weiss et al 1996;Zapardiel et al 1994). Therefore, in the absence of standardized criteria and guidelines for agar diffusion tests many authors use CLSI guidelines for other Gram-positive bacteria (Mina et al 2011;Pereira et al 2008;Sing et al 2003). Usually, blood supplemented Mueller-Hinton agar is used for antimicrobial resistance testing by agar diffusion assays 9.10 Typing Methods for C. diphtheriae Typing techniques are needed not only to identify a common source during an local outbreak situation by exploring the strain identity of different isolates, but also for monitoring clonal relatedness and population structure of endemically or epidemically spreading strains.…”

“…Antimicrobial resistance against either penicillin or erythromycin, the two antibiotics of choice in eliminating diphtheria-causing corynebacteria, has been described both in C. diphtheriae-albeit very rarely (Coyle et al 1979;Dixon 1984;Engler et al 2001b;Kneen et al 1998;Mina et al 2011;Pereira et al 2008;von Hunolstein et al 2002) and C. ulcerans (Schuhegger et al 2009;Tiwari et al 2008). Therefore, antibiotic sensitivity testing is highly recommended.…”

The Family Corynebacteriaceae

“…This is remarkable as erythromycin had been considered the drug of choice for diphtheria patients in Seattle since the epidemic began in 1972 (Coyle et al 1979). Multidrug resistance of Corynebacterium diphtheriae has been reported recently in a biovar mitis strain isolated from a skin abscess of an unvaccinated patient (Mina et al 2011). Corynebacterium amycolatum, Corynebacterium jeikeium, and Corynebacterium urealyticum are generally regarded as multidrug resistant (Philippon and Bimet 1990;de Miguel-Martinez et al 1996;Funke et al 1997b;Soriano and Tauch 2008;Fernandez-Roblas et al 2009).…”