Study On Species Identification Of Clinical Mycobacterium Isolates From Fujian Province, China

Objective To study the value of the morphological characteristic and colloidal Goldmethod in rapid identification of mycobacterial species of clinical isolaates. Toanalyze the species of clinical Nontuberculous Mycobacteria (NTM) isolates to knowthe distribution of NTM in Fujian province.Methods A total of3681clinical isolates of Mycobacteria were identified by meansof the morphological characteristic and colloidal Gold method, and the results werecompared with conventional PNB/TCH differential medium methods. Then, speciesof NTM were identified by hsp65and rpoB PCR-RFLP methods.Results Of3681clinical isolates,405strains (11.0%) were identified as NTM.Using the results of species identification with PNB/TCH differential mediummethods as a goldern standard, the sensitivity, specificity, positive predictive value(PPV) and negative predictive value (NPV) of mycobacterial species identification bymorphological characteristic were98.4%(3225/3276) and95.8%(388/405),99.97%and91.2%, and the sensitivity, specificity, PPV and NPV of identification bycolloidal Gold method were98.8%（3237/3276）and99.7%(404/405),99.5%and88.4%, respectively. When the smears of culture positive samples showed serpentinecord morphology and the colloidal Gold test were positive, the culture would bereported to contain Mycobacterium tuberculosis complex(MTBC), and it’s PPV was100.0%. When the cord morphology and the colloidal Gold test were all negative, theculture would be reported to contain NTM, and it’s NPV was100.0%.A total of405NTM strains were identified to species by hsp65and rpoBPCR-RFLP methods, in which24species or complex of NTM were identified,including173(42.72%) M. intracellular,88(21.73%) M. avium,55(13.58%) M.abscessus,28(6.91%),M. gordonae,19(4.69%) M. massiliense,9(2.22%) M.fortuitum,6(1.48%) M. lentiflavum,5(1.23%) M. marseillens,3(7.41%) M. szulgai, 2(0.49%) M. saskatchewanens, M. seoulense, M. shimoidei, M. triplex,1(0.25%) M.Gordonia bronchialis, M. chelonae, M. colombiense, M. genavense, M. holsaticum, M.kansasii, M. kumamotonense, M. mantenii, M. monacense, M. septicum, M.stomatepiae, respectively.Conclusions The prevalence rate of NTM was11.0%in Fujian province during2009-2010. The morphological characteristic and colloidal Gold method were fast,easy, accurate method for the dentification of MTBC and NTM. Combining these twomethods could improve detectiong accuracy. Most of NTM isolates in Fujian provinceare Group Ⅲ M. avium complex accounting for64.5%, the following was Group Ⅳrapidly growing NTM accounting for24.0%.