Study on the Growth Factors for Rapidly CultivatingMycobacteriumspp.

Abstract

Mycobacteria grow slowly. Therefore, a solid medium should be used for eight weeks and a liquid medium for six weeks. The purpose of this study was to find the growth factors that can grow Mycobacterium rapidly and to help develop a solid medium for rapid identification. Three types of Mycobacterium growth factors were evaluated with 10 Mycobacteria by adding activated charcoal, defibrinated sheep blood, and L-ascorbic acid to Difco TM Mycobacteria 7H11 agar (Becton, Dickinson and Company, Sparks, MD, USA). The time to detection and the distinguishability of a colony were compared with that of the current method. In the rapidly growing Mycobacterium, the difference in detection time between the new media and conventional media confirmed that the new media was faster. M. kansasii and M. intracelluare grew faster in 7H11 C than in 7H11 medium. MTB grew faster than the other media in 7H11 C. This study confirmed that the two growth factors affect fast-growing Mycobacteria and slow-growing Mycobacteria. 7H11 C showed better distinguishability than the conventional media in all 10 Mycobacterium due to the color contrast. In particular, when the MTB was grown, the size of the colonies was larger than with other media, so visualization was easy.