ABSTRACT
AIMS: To accelerate the identification and differentiation of clinically relevant nontuberculous mycobacteria (NTM) with two sets of multiplex PCR (mPCR) targeting the 16S-23S rRNA internal transcribed spacer (ITS) region for timely patient management. METHODS AND RESULTS: Two mPCR assays were developed: Slow-Growers (SG) mPCR was used for the detection of slow-growing mycobacteria, which included Mycobacterium avium complex, Mycobacterium kansasii, Mycobacterium gordonae and Mycobacterium xenopi whilst the other mPCR assay labelled as Fast-Growers (FG) mPCR was used for the detection of Mycobacterium fortuitum complex, Mycobacterium abscessus and Mycobacterium chelonae. In these assays, a common forward primer based on a conserved section of the 16S rRNA region was used in conjunction with species-specific reverse primers. The mPCRs were tested against 247 clinical mycobacterial isolates and demonstrated 100% specificity and sensitivity. Identification of the mycobacterial species was also validated by DNA sequencing of the 16S-23S ITS region and when further confirmation was needed, hsp65 sequencing was performed. CONCLUSIONS: The mPCR assays could be a potentially useful diagnostic tool for the rapid and accurate identification of clinically relevant NTM. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, we looked at the frequency of hospital isolated NTM over the last 5 years (2005-2010), and an mPCR targeting the ITS region was developed for NTM species that appeared to be more prevalent in the context of Singapore.
Subject(s)
Bacteriological Techniques/methods , DNA, Ribosomal Spacer/genetics , Mycobacterium Infections/diagnosis , Mycobacterium/genetics , Polymerase Chain Reaction , RNA, Ribosomal, 16S/genetics , Humans , Mycobacterium/classification , Mycobacterium/isolation & purification , Mycobacterium Infections/microbiology , RNA, Ribosomal, 23S/genetics , Reproducibility of Results , Sensitivity and Specificity , SingaporeABSTRACT
The extent of heavy metal cation contamination in the Shing Mun River has been assessed. Sediment samples were taken at eight strategic locations along the river system. The highest concentrations of copper (Cu, 1.66 mg/g), lead (Pb, 0.354 mg/g), zinc (Zn, 2.2 mg/g) and chromium (Cr, 0.047 mg/g) were found in the Fo Tan Nullah, a major tributary of the Shing Mun River. The highest concentrations of aluminum (114 mg/g) and cadmium (Cd, 0.047 mg/g) were found in the Shing Mun Main River Channel. These contaminated sediments, accumulated over the years on the river bed, could act as secondary sources of pollution to the overlying water column in the river.
