Emerging Clarithromycin Resistant Mycobacterium fortuitum in Post Cardiac Surgery Sternal Wound Infection.

SESSION TITLE: Surgery Student/Resident Case Report PostersSESSION TYPE: Medical Student/Resident Case ReportPRESENTED ON: Tuesday, October 28, 2014 at 01:30 PM - 02:30 PMINTRODUCTION: Mycobacterium fortuitumsternal wound infection following cardiac surgery is a rare occurrence but has considerable morbidity because of emergence of resistant strains. We present a patient who was successfully treated for sternal wound infection caused by a Clarithromycin resistant M. fortuitum (CRMF).CASE PRESENTATION: A 62-year-old male with history of dyslipidemia, hypertension, asthma, and nicotine dependence underwent coronary artery bypass grafting and left ventricular aneurysmorrhaphy after having myocardial infarction. He developed a small wound at the cephalic end of the sternotomy scar draining thick, brown, odorless discharge three weeks postoperatively. He was immediately taken to the operating room for debridement of a track which was noticed extending from the cephalic end. No organisms were seen on direct staining but after two days, many acid fast bacilli were identified in the aerobic culture. Patient's empirical antibiotics were switched to clarithromycin, levofloxacin and linezolid. Two weeks after discharge, the organism was identified as Mycobacterium fortuitum by High Performance Liquid Chromatography (HPLC) with resistance to clarithromycin and sulfamethoxazole/trimethoprim (TMP/SMZ). With a six month course of levofloxacin and doxycycline, the patient had an excellent recovery including wound closure. No recurrence was noted during two years of follow-up.

DISCUSSION: Infection due to M. fortuitum is often resistant to all the standard anti-tuberculosis drugs, but clarithromycin, TMP/SMZ, doxycycline, and ciprofloxacin are usually recommended in combination according to in the vitro sensitivity data. Many M. fortuitum used to be susceptible to clarithromycin, but studies have shown that all isolates of M. fortuitum contain an erythromycin methylase gene, erm, which may induce macrolide resistance and contribute in an emergence of clarithromycin resistant strains. Consequently combination therapy is recommended for M. fortuitum with at least two susceptible medications in the era of emerging CRMF.CONCLUSIONS: A high index of suspicion based on clinical presentation is essential to diagnose Clarithromycin resistant M. fortuitum (CRMF) post cardiac surgery sternal infection for proper long term therapy. Beside surgical debridement appropriate blend of antibiotics based on sensitivity will ensure complete healing and prevent recurrence.Reference #1: Muthusami JC, Vyas FL, Mukundan U, Jesudason MR, Govil S, Jesudason SRB. Mycobacterium fortuitum: An iatrogenic cause of soft tissue infection in surgery. ANZ J Surg 2004;74:662-666.Reference #2: Unai S, Miessau J, Karbowski P, Bajwa G, Hirose H. Sternal wpund infection caused by Mycobacterium chelonae. J Card Surg 2013;28:687-692.Reference #3: Shah AK, Gambhir RPS, Hazra N, Katoch R. Non tuberculous mycobacteria in surgical wounds-a rising cause of concern? Indian J Surg 2010;72:206-210.

DISCLOSURE: The following authors have nothing to disclose: Hafiz Abdul Moiz Fakih, Shahbaz Ahmad, Emmanuel EluezeNo Product/Research Disclosure Information.