Misidentification of Mycobacterium peregrinum , the Causal Organism of a Case of Bacteremia and Automatic Implantable Cardioverter Defibrillator-Associated Infection, Due to Its Unusual Acid-Fast Staining Characteristics

Abstract

We report an unusual case of Mycobacterium peregrinum bacteremia and infection of an automatic implantable cardioverter defibrillator that was originally misidentified as a Nocardia sp. due, in part, to its partially acid-fast staining characteristic, morphology, and odor. The misdiagnosis had a direct effect on patient care, though the patient was subsequently successfully treated. CASE REPORTA 74-year-old white male was admitted with a past history of ischemic cardiomyopathy, coronary artery disease, hypertension, and a recent diagnosis of nonsustained ventricular tachycardia requiring placement of an automatic implantable cardioverter defibrillator (AICD) 6 weeks earlier. He presented to our institution with persistent erythema and a history of a pustule around the AICD insertion site on his left chest wall. The patient stated he immediately noted erythema around the insertion site after AICD placement and was prescribed a 10-day course of cephalexin at a 3-week follow-up with his cardiologist. Subsequently, he noted a pustule along the suture line and was admitted for further evaluation and management. On physical examination he was nontoxic in appearance and afebrile, his vital signs were stable, and his physical examination was within normal limits except for the left chest area. The left chest wall was erythematous in an area of 4 to 5 cm where the AICD site had been inserted subcutaneously; there was a deep purple discoloration along the incision line, and the area was warm to touch and minimally tender to palpation. There was no obvious pustule or purulent discharge along the incision, and the surrounding area was not fluctuant. Laboratory data were unremarkable except for a creatinine level of 1.7 mg/dl, which was his baseline. Blood cultures were drawn on admission, and empirical vancomycin was begun. On the day of admission he underwent extraction of the AICD and the leads in the electrophysiology laboratory. Deep-pocket tissue and superficial wound specimens were sent for routine bacterial, fungal, and acid-fast bacillus cultures.The described wound specimens and two sets of blood cultures were submitted to the microbiology laboratory for bacterial culture. Direct Gram-stained smears of the wound cultures demonstrated rare to few polymorphonuclear leukocytes with no organisms seen. After 4 days of incubation, growth was detected in both blood cultures and in the thioglycolate broth media of both wound cultures.On the fifth hospital day, Gram-stained smears of the wound broth cultures were reported as having gram-positive rods. One day later, growth was detected on the sheep blood and chocolate agar plates, and no growth was detected on the MacConkey agar plate. Colonies were tan, flat, and dry and upon further incubation became wrinkled in appearance and exhibited a musty odor. The Vitek Identification System (bioMérieux, Hazelwood, MO) was unable to identify the isolate. The isolate was subcultured to Columbia agar for identification using the API CORYNE system (bioMérieux, Hazelwood, MO), but it t...

Rapid Identification of Mycobacterial Whole Cells in Solid and Liquid Culture Media by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

“…In these cases, MALDI-TOF MS can be performed immediately after acid-fast staining with the same equipment used for routine bacteria or fungi, thus avoiding misidentifications (27,35).…”

Occurrence and antimicrobial susceptibility of Mycobacterium peregrinum in ornamental fish

“…Recently, the number of reported cases of infection caused by non-tuberculous mycobacterium has increased, and the clinical importance of these organisms is growing (8,19,31). The identification of M. peregrinum in fish is significant because it can be a human pathogen that is responsible for infections commonly associated with human skin and soft tissues (19), bacteriaemia (14,27), pneumonia (16), and tonsillar abscessus (26). This study illustrates that the infection can cause mycobacteriosis in humans.…”

Micobacteriosis diseminada con compromiso de válvula aórtica protésica: primer caso de Mycobacterium peregrinum de tipo III reportada en Colombia

“…Although M. peregrinum was first proposed in 1962, only in the last years has been systematicly included (20)(21)(22). Like other rapidly growing mycobacteria, M. peregrinum has been reported as causing skin and soft tissue infections, peritonitis (after cancer gastric surgery), primary bacteremia, pneumonia, tonsillar abscess, catheter-related bacteremia, and implantable cardioverter device infection (12,(23)(24)(25)(26)(27). Recently, Nagao informed 11 cases reported in the literature (12).…”