Mycobacteria: September 2006
Mycobacteria: September 2006
De Groote MA, Huitt G. Infections due to rapidly growing mycobacteria. Clin Infect Dis. 2006;42:1756-1763.
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.
De Groote MA, Huitt G. Infections due to rapidly growing mycobacteria. Clin Infect Dis. 2006;42:1756-1763.
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.