eMedicine Specialties > Infectious Diseases > Mycobacterial Infections
Mycobacterium Fortuitum
Updated: Dec 3, 2007
Introduction
Background
Mycobacterium fortuitum is a nontuberculous mycobacterium (NTM), a grouping that encompasses all mycobacteria outside of the Mycobacterium tuberculosis complex. M fortuitum is classified in the Runyon group IV, rapidly growing mycobacteria. It has been found in natural and processed water sources, as well as in sewage and dirt. Distribution is probably worldwide.
Pathophysiology
M fortuitum infection can cause various clinical syndromes. It is an uncommon cause of NTM lung disease. Local cutaneous disease, osteomyelitis, joint infections, and ocular disease (eg, keratitis, corneal ulcers) may occur after trauma. M fortuitum infection is a rare cause of isolated lymphadenitis. Disseminated disease, usually with disseminated skin lesions and soft tissue lesions, occurs almost exclusively in the setting of severe immunosuppression, especially AIDS. Endocarditis has been documented.
Surgical-site infections due to M fortuitum infection are well-documented, especially in association with cardiothoracic surgery. The source is frequently contamination of the wound, directly or indirectly, with colonized tap water. Other nosocomial infections with this organism include infections of implanted devices (eg, catheters) and injection-site abscesses. Pseudo-outbreaks have been associated with contaminated endoscopes. Recent outbreaks have also been described in immunocompetent hosts after use of contaminated whirlpool footbaths in nail salons.1
Frequency
United States
NTM infections are not required to be reported; therefore, exact estimates of disease prevalence and incidence are impossible to determine. The most recent estimates come from voluntary reports tracked by the Centers for Disease Control and Prevention (CDC). From 1993-1996, 4.65-5.99 cases per million persons were reported to the CDC.2 Sputum was the most frequently reported site, but this may represent a bias in the sites most likely to be cultured for mycobacteria.
Most cases are reported from the southeast United States, including Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee, Virginia, and West Virginia, and the south-central United States, including Arkansas, Kansas, Louisiana, Missouri, Oklahoma, and Texas. Because all cases were likely not reported and some positive culture results may not represent disease, which is perhaps especially true of positive sputum culture results, these numbers may significantly overestimate or underestimate true disease incidence. However, they suggest the general order of magnitude of the situation. An increased appreciation of these organisms as true pathogens may be the reason NTM infection rates are perceived to be increasing, even excluding Mycobacterium avium complex (MAC) infections in persons with AIDS.
International
The World Health Organization does not track NTM infections. Incidence and prevalence undoubtedly vary greatly by locale.
Mortality/Morbidity
- Mortality due to localized M fortuitum infection is rare. Death may result from extensive pulmonary or disseminated disease in patients who are immunocompromised.
- Morbidity depends largely on the site of the infection. Localized skin lesions may eventually heal without therapy or surgical intervention. At other sites, chronic infection is the rule.
Race
No clear racial predilection exists.
Sex
No sexual predominance is known; however, from 1993-1996, more cases reported to the CDC were involved men than did women.2 Whether this represents a true sex-based preference or reflects a bias in testing and reporting is unclear.
Age
In general, no known age predominance exists. Lung disease in a younger patient (<50 y) strongly suggests a primary underlying lung disorder. Isolated lymphadenitis primarily occurs in children.
Clinical
History
- Patients with skin disease may develop a nonhealing but nonspreading wound or skin ulcer.
- Patients with lung disease may develop a chronic cough.
- Pulmonary and disseminated disease cause easy fatigability, occasional fever, night sweats, and weight loss. These symptoms are less common with M fortuitum infection than with tuberculosis.
Physical
No findings are pathognomonic of M fortuitum infection. Physical findings depend on the infection site.
- Eye: Keratitis or corneal ulcers may be present.
- Lungs: Rales or rhonchi may be present.
- Heart: Valvular murmur with endocarditis may be present.
- Abdomen: Diffuse tenderness with peritonitis may be present (eg, a patient undergoing peritoneal dialysis).
- Skin: Ulcerative skin lesions and/or subcutaneous nodules may be present. Deeper infections may lead to draining fistulas.
Causes
- Trauma or injection - Skin lesions, subcutaneous lesions, ocular lesions, and osteomyelitis
- Immunosuppression - Disseminated disease, especially in patients with AIDS or in those who use corticosteroids
- Lung disease – Bronchiectasis
More on Mycobacterium Fortuitum |
 Overview: Mycobacterium Fortuitum |
| Differential Diagnoses & Workup: Mycobacterium Fortuitum |
| Treatment & Medication: Mycobacterium Fortuitum |
| Follow-up: Mycobacterium Fortuitum |
| References |
| Next Page » |
References
Winthrop KL, Abrams M, Yakrus M, Schwartz I, Ely J, Gillies D, et al. An outbreak of mycobacterial furunculosis associated with footbaths at a nail salon. N Engl J Med. May 2 2002;346(18):1366-71. [Medline].
CDC. Nontuberculous mycobacteria reported to the Public Health Laboratory Information System by State Public Health Laboratories United States, 1993-1996. [Full Text].
ATS. Diagnosis and treatment of disease caused by nontuberculous mycobacteria. This official statement of the American Thoracic Society was approved by the Board of Directors, March 1997. Medical Section of the American Lung Association. Am J Respir Crit Care Med. Aug 1997;156(2 Pt 2):S1-25. [Medline].
Wallace RJ, Swenson JM, Silcox VA, Bullen MG. Treatment of nonpulmonary infections due to Mycobacterium fortuitum and Mycobacterium chelonei on the basis of in vitro susceptibilities. J Infect Dis. Sep 1985;152(3):500-14. [Medline].
Heifets LB. Antimycobacterial drugs. Semin Respir Infect. Jun 1994;9(2):84-103. [Medline].
Brown-Elliott BA, Wallace RJ, Crist CJ. Comparison of in vitro activities of gatifloxacin and ciprofloxacin against four taxa of rapidly growing mycobacteria. Antimicrob Agents Chemother. Oct 2002;46(10):3283-5. [Medline].
Wallace RJ, Brown-Elliott BA, Crist CJ. Comparison of the in vitro activity of the glycylcycline tigecycline (formerly GAR-936) with those of tetracycline, minocycline, and doxycycline against isolates of nontuberculous mycobacteria. Antimicrob Agents Chemother. Oct 2002;46(10):3164-7. [Medline].
ATS/IDSA: Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, et al. An Official ATS/IDSA Statement: Diagnosis, Treatment, and Prevention of Nontuberculous Mycobacterial Diseases. Am J Respir Crit Care Med. February 2007;175:367-416. [Medline].
Griffith DE, Wallace RJ. New developments in the treatment of nontuberculous mycobacterial (NTM) disease. Semin Respir Infect. Dec 1996;11(4):301-10. [Medline].
Kyle SD, Porter WM. Mycobacterium chelonae infection successfully treated with oral clarithromycin and linezolid. Br J Dermatol. Nov 2004;151(5):1101. [Medline].
Wagner D, Young LS. Nontuberculous mycobacterial infections: a clinical review. Infection. Oct 2004;32(5):257-70. [Medline].
Wallace RJ, Brown-Elliott BA, Ward SC. Activities of linezolid against rapidly growing mycobacteria. Antimicrob Agents Chemother. Mar 2001;45(3):764-7. [Medline].
Further Reading
Keywords
Mycobacterium fortuitum infection, M fortuitum, M fortuitum infection, nontuberculous mycobacterium, NTM, mycobacteria other than tuberculosis, MOTT, Mycobacterium tuberculosis, M tuberculosis, M fortuitum complex, abscess, injection-site abscess, Runyon classification, Runyon's classification, Runyon classification group IV, Runyon group IV, rapid grower, NTM lung disease, cardiothoracic surgery, mycobacteremia, osteomyelitis, bronchiectasis
