Rapid Grower Broth Suscep.
M abscessus Susceptibility Testing
M chelonae Susceptibility Testing
M fortuitum Complex Susceptibility Testing
AFB Susceptibility Testing
Rapid-grower Susceptibility Testing
Determine the susceptibility of rapidly-growing mycobacterial isolates to a profile of antimycobacterial agents. Interpretive categories include the following.
Susceptible: This category implies that an infection due to the strain may be appropriately treated with the dosage of the recommended agent unless otherwise contraindicated.
Intermediate: Susceptibility is not certain since the available data does not permit categorization as either susceptible or resistant.
Resistant: Strains falling in this category are not inhibited by the usually achievable systemic concentration of the agent with normal dosage schedules and/or fall in the range where specific microbial resistance mechanisms are likely, and/or clinical efficacy has not been reliable in treatment studies.
Failure to take all drugs in a multidrug regimen can lead to a shift toward resistant organisms and treatment failure. M fortuitum isolates are susceptible in vitro to multiple antimicrobial drugs and the clinical response to therapeutic agents appears to closely parallel the in vitro susceptibility patterns; however, this observation has not been evaluated by randomized controlled trials. M abscessus has limited in vitro susceptibility to any agent and clinical response in the treatment of pulmonary disease. There does appear, however, a correlation for M abscessus between in vitro susceptibility and clinical response for skin and soft tissue infections, although this has not been evaluated by randomized controlled trials. Few data are available to validate susceptibility testing as a guide for choosing antibiotics. Until the relationship between in vitro susceptibility testing and the clinical response to antimicrobial drugs is better understood and clarified, the clinician should use in vitro susceptibility data with an awareness of the limitations and that the disease may not be eradicated in a particular patient with therapy based on those results. Test results are not intended to be used as the sole means for patient management. Extended incubation for up to 14 days will occur to evaluate the organism for inducible macrolide resistance.
Rapidly-growing mycobacteria isolated from a primary clinical specimen, on a submitted AFB conventional solid medium, or an AFB broth medium
Pure culture isolate on an AFB conventional solid medium or a minimum of 1 mL of AFB broth medium
Conventional or broth medium, tightly sealed, in etiologic agent packaging
Maintain media at room temperature.
Specimen received in leaking or in broken transport tube or vial; specimen received in expired transport medium; mixed culture; unlabeled culture or name discrepancy between specimen and request label