Background: Three phenotypic identification systems (MicroScan, VITEK 2, and Crystal GP) were evaluated for their accuracy to identify coagulase-negative staphylococci (CNS). A total of 120 clinical isolates confirmed to be CNS via 16S rRNA sequencing and analysis with the MicroSeq 500 v2.0 database were assessed.

Background : For the detection of Mycobacterium tuberculosis complex (MTB), PCR is known to be sensitive, specific, and rapid compared to the conventional methods of acid-fast-bacilli (AFB) smear and culture. We evaluated a new approach for MTB detection using real-time PCR.Methods : The specificity of real-time PCR was evaluated using 20 MTB isolates and 37 nontuberculous mycobacteria (NTM) isolates identified by AccuProbe Mycobacterium tuberculosis complex colony identification test (Gen-Probe Inc., USA) and Myco-ID (M&D, Korea). One hundred sputum specimens (50 AFB smear-positive and 50 negative specimens) were analyzed using real-time PCR and Amplicor Mycobacterium tuberculosis test (Roche, Germany). The results of real-time PCR positives (55 samples) and negatives (598 samples) were analyzed by AFB smear and culture.Results : The real-time PCR assay accurately discriminated between MTB and NTM species. Realtime PCR and Amplicor test yielded the same results in 96.0% (96/100) of the sputum specimens tested. The sensitivity and specificity of real-time PCR based on AFB culture were 97.4% and 88.5%, respectively. Of the 55 real-time PCR positive specimens, 83.6% (46/55) were culture-positive, 30.9 % (17/55) were smear-positive, 52.7% (29/55) were smear-negative and culture-positive, and 14.5% (8/55) were both smear and culture-negative. Among the 598 real-time PCR negative specimens, 60 were not tested for AFB smear or culture and 10 were contaminated. Of the remaining 528 specimens, 478 (90.5%) were both smear and culture-negative and 39 (7.4%) were culture-positive.Conclusions : For the detection of MTB, real-time PCR was sensitive and specific and comparable to conventional methods. It can be used for rapid identification of M. tuberculosis in clinical laboratories. (Korean J Lab Med 2008;28:103-8)

Background : The isolation rate of nontuberculous mycobacteria (NTM) in clinical laboratories and the incidence of NTM infections are on the increase recently in Korea, but there have been only a few studies that reveal the general aspect of NTM isolation or species distribution. Therefore, this study was performed to examine the isolation rate of NTM, species identification, and the clinical significance of mycobacterial cultures.Methods : From August 2004 to May 2005, we examined mycobacterial isolates by AccuProbe test to differentiate NTM from Mycobacterium tuberculosis complex. NTM was then identified by polymerase chain reaction-restriction fragment length analysis (PCR-RFLP).Results : A total of 6,742 specimens from 2,784 patients were requested for mycobacterial culture. Mycobacteria were isolated from 776 specimens (11.5%). The isolation rates of NTMs among the total culture positive specimens and culture positive sputum specimens were 24.4% (189/776) and 25.3% (169/667), respectively. Fourteen species of NTM identified in 172 of the 175 specimens tested included M. avium (39.0%), M. intracellulare (22.7%), and M. abscessus (19.8%).Conclusions : Using AccuProbe tests and PCR-RFLP method for mycobacterial cultures processed in a clinical laboratory, we were able to identify NTMs to the species level. The isolation rate of NTM in this study was similar to that reported in past studies in Korea. In addition, we found that some of the NTMs isolated in this study could cause pulmonary diseases. (Korean J Lab Med 2006;26:161-7)

This real-time multiplex PCR technique can be carried out in a single tube and can differentiate between the three polymorphic sites of the two genes associated with Alzheimer's disease.

Our study revealed that the real-time nested PCR should be useful for diagnosis of enterovirus infections because of a high sensitivity and rapid detection.