The authors provide an "invited article" on rapidly growing mycobacteria.
Definition: The simple definition is that these mycobacteria "form mature colonies on solid agar in 7 days (from subculture)." The main clinically important members are Mycobacterium fortuitum, M chelonae, and M abscessus.
Source: These organisms are ubiquitous in nature and found in a wide range of sources including water, soil, rocks, and bioaerosols. They survive harsh environments, and biofilm formation is one of the strategies to do it.
Infection vs Pseudoinfection: Pseudoinfections are common due to contaminated instruments, contaminated solutions, and laboratory cross-contamination. A pseudo-outbreak should be suspected when there is a cluster from laboratory reporting without true evidence of infection or an atypical host.
Infections: Table 1 summarizes 5 categories of infection: (1) catheter infections, (2) keratomileusis, (3) soft tissue, (4) pulmonary, and (5) disseminated disease.
Treatment: Table 2 summarizes the drugs used for the major 3 pathogens in this group. Skin and soft tissue infections are usually treated for 3-6 months with excellent probability of cure, sometimes with assistance of surgical debridement. Pulmonary disease involving M abscessus is generally treated with intermittent intravenous imipenem or cefoxitin plus a macrolide; this infection is rarely "cured." Pulmonary infection due to M fortuitum, by contrast, is often successfully treated with 2-3 antibiotics given for 12-24 months. A common regimen is sulfamethoxazole, moxifloxacin, and minocycline. Drugs selected for skin and soft tissue infections are usually intravenous imipenem or cefoxitin combined with amikacin.
Medscape Infectious Diseases. 2006;8(2) © 2006 Medscape
Cite this: Mycobacteria: September 2006 - Medscape - Sep 12, 2006.