EFFECT OF TRANSPORTATION AND ACID NEUTRALIZATION ON RECOVERY OF MYCOBACTERIA FROM PROCESSED SPECIMENS

Because of the increasing incidence of tuberculosis, more rapid detect ion of mycobacteria has become an important issue, Realizing that not every clinical laboratory has a rapid detection system for growing myc obacteria, this study was conducted to examine the feasibility of subm itting sediments of processed specimens to a reference laboratory for further testing in a radiometric system. Using N-acetyl-L-cysteine-NaO H solution, 247 respiratory specimens were processed at a diagnostic l aboratory, Half of each sediment was cultured on conventional media. T he remainder was kept at 4 degrees C for a period of up to 1 week befo re transportation to a reference laboratory for culture by BACTEC syst em. Both laboratories recovered 25 organisms: 15 as Mycobacterium tube rculosis (MT) and 10 as M avium complex (MAC). Additionally, mycobacte ria (MT [3], MAC [6], M gordonae [4], and M fortuitum [1]) were recove red from 14 specimens by the diagnostic laboratory that were not grown by the reference laboratory. These results indicate a significant dec rease in viability of mycobacteria after processing of the specimens. Acid neutralization of the digested respiratory sediments significantl y improved the recovery rate of mycobacteria even after 2 days of dela y in culture. This preliminary work suggests that more extensive studi es will provide useful information to delineate approaches to submitti ng neutralized sediments for mycobacterial cultures.