Non-tuberculous mycobacteria in extra-pulmonary specimens: Role of nosocomial transmission

Background: Non-tuberculous mycobacteria (NTM) are ubiquitous in nature and cause infections in both immuno-compromised patients and immuno-competent individuals. Healthcare associated NTM infections have been reported wordwide. Treatment of NTM infections requires determination of clinical significance, identification and susceptibility profile. From Pakistan there is lack of data on healthcare associated NTM infections. This study was performed to determine NTM isolates and their clinical significance from extra-pulmonary clinical specimens submitted at a tertiary care hospital laboratory. Methods: NTM isolated from 25955 clinical specimens over a period of 24 months (January 2010 to December 2011) were included. All NTM were identified using conventional tests. Clinical details were extracted from laboratory data. Drug susceptibility testing (DST) was performed by broth microdilution and interpreted according to Clinical and Laboratory Standards Institute's document M24-A2. Results: A total of 12 NTM were isolated from extra-pulmonary specimens over the study period. Of these 8 were rapidly growing mycobacteria (RGM) and 4 were slow growing mycobacteria (SGM). Clinical significance could be determined in 9/12 specimens. Seven NTM isolates from 3 patients were post-surgical and likely to be healthcare associated infections. Conclusion: This is the first study reporting healthcare associated NTM infections from extra-pulmonary clinical specimens from Pakistan. Isolation of NTM from clinical specimens should prompt to evaluate their clinical significance. Healthcare associated NTM infections should be suspected in non-healing post-surgical wounds.