Clinical Significance of Nontuberculous Mycobacteria Isolates in a Canadian Tertiary Care Center

Choudhri, S. H.; Manfreda, Jure; Wolfe, Jonathan; Parker, S.; Long, Richard

doi:10.1093/clinids/21.1.128

Cited by 38 publications

(26 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alternatively, the addition of PCR inhibitor scavengers or the use of a chemiluminescence approach to improve the detection of the restriction-digested DNA fragments might also have to be considered. Recently, the global trend has been toward the isolation from sputum samples of more and more NTM organisms in addition to M. tuberculosis (4,10,15). Based on the statistical results from the Chang Gung Memorial Hospital, which is the largest tertiary medical center in Taiwan, the isolation of NTM increased significantly from 248 (19%) in 2003 to 407 (30%) in 2006 (P Ͻ 0.0005).…”

Section: Resultsmentioning

confidence: 99%

Rapid Identification of Mycobacteria from Smear-Positive Sputum Samples by Nested PCR-Restriction Fragment Length Polymorphism Analysis

Chia

Kuo

et al. 2008

J Clin Microbiol

View full text Add to dashboard Cite

The rapid identification of mycobacteria from smear-positive sputum samples is an important clinical issue. Furthermore, the availability of a cheap, technically simple, and accurate method also would benefit mycobacterial laboratories in developing countries. In the present study, we aimed to develop an assay allowing the identification of the Mycobacterium tuberculosis complex (MTBC) and other frequently isolated nontuberculous mycobacteria (NTM) directly from smear-positive sputum samples. A nested PCR-restriction fragment length polymorphism analysis (nested-PRA) assay that focuses on the analysis of the hsp65 gene was developed and The rapid identification of Mycobacterium spp. from smearpositive sputum samples is very important from clinical viewpoints. This is because, in addition to increased clinical infections due to Mycobacterium tuberculosis complex (MTBC) organisms, the percentage of infections with nontuberculous mycobacteria (NTM) also has been increasing recently (1, 6-8, 11, 16, 20, 21, 31), especially among immunocompromised patients (11). Strategies used for the clinical management of patients with MTBC or NTM infections are different. Patients who are suspected to have MTBC infections have to receive proper medication or even be placed in an isolation room immediately. Therefore, the correct and rapid identification of MTBC and NTM organisms represents a clinical emergency that should not be underestimated.The traditional diagnosis of mycobacterial infections from sputum samples in the mycobacterial laboratory is based primarily on demonstrating the presence of the acid-fast bacilli (AFB) in the smear, followed by a positive culture and the testing of the physiological/biochemical identification of the isolate (19). This approach has a number of defects, including that it is time-consuming, has low sensitivity, and has poor discrimination between closely related NTM species (29). High-performance liquid chromatography is an alternative approach for the identification of mycobacteria, and this approach can identify more than 50 different species (9); however, a concentration of more than 10 6 bacteria per ml is required. Recently, a paranitrobenzoic acid assay has been applied directly to clinical samples as a rapid screening assay for the detection of and differentiation between MTBC and NTM (32). Nevertheless, this approach does not allow further NTM species differentiation and has a long incubation time (3 weeks) before the results can be read.Recently, the development of PCR-based methods for the rapid identification and differentiation of mycobacterial organisms has significantly improved the diagnosis efficiency in terms of both sensitivity and specificity (3,5,12,14,17,22,24,26,27,30). We previously developed a multiplex nested PCR combined with lateral-flow technology for the rapid diagnosis of M. tuberculosis and MTBC isolates and the differentiation of these organisms from NTM organisms (28). In addition, a multiplex PCR system for the rapid detection and differentiation of MTBC mem...

show abstract

Section: Resultsmentioning

confidence: 99%

Rapid Identification of Mycobacteria from Smear-Positive Sputum Samples by Nested PCR-Restriction Fragment Length Polymorphism Analysis

Chia

Kuo

et al. 2008

J Clin Microbiol

View full text Add to dashboard Cite

show abstract

“…Because of this, guidelines for determining the clinical significance of a positive NTM isolates were published (American Thoracic Society 1997, British Thoracic Society 2000. These guidelines suggest that isolation of NTM on multiple occasions or on a single occasion from a sterile site should be supported by evidence of an actual disease process (Choudhri et al 1995, American Thoracic Society 1997. Although this was not the scope of this study, we note that the number of NTM cultures received by the reference laboratory exceeds the number of the patients with disease.…”

Section: Discussionmentioning

confidence: 99%

Molecular characterization of Mycobacterium kansasii isolates in the State of São Paulo between 1995-1998

Chimara

Giampaglia

Martins

et al. 2004

Mem. Inst. Oswaldo Cruz

View full text Add to dashboard Cite

show abstract

“…Either exposure scenario is plausible; M. avium strains are reported to persist at drinking-water POU taps for up to 26 months (4). Diagnosis of M. avium complex infections is frequently missed or delayed, particularly among patients with no commonly recognized risk factors for infection (1). Limitations of the study include the lack of patient-specific information, including exposure history and disease status.…”

mentioning

confidence: 99%

Molecular Comparison of Mycobacterium avium Isolates from Clinical and Environmental Sources

Hilborn

Yakrus

Covert

et al. 2008

Appl Environ Microbiol

View full text Add to dashboard Cite

We collected Mycobacterium avium isolates from clinical and drinking-water sources and compared isolates among themselves and to each other using molecular methods. Four clinical isolates were related to water isolates. Groups of indistinguishable clinical isolates were identified. The groups of identical clinical isolates suggest a common source of exposure.Mycobacterium avium has been associated with infections among individuals of all ages and has been found in drinking water (2,3,6,9). We isolated M. avium from point-of-use (POU) water taps delivering municipal drinking water within a single county (2, 4). We used molecular methods to compare the genetic relatedness of M. avium isolates from water and isolates from residents receiving the water to determine if we could identify drinking water as a source of exposure.We collaborated with personnel from laboratories that isolate and identify mycobacteria from human specimens collected during patient care activities. We obtained clinical isolates of M. avium complex that were collected from county residents during the study period. We recorded each anatomic site of collection and each patient's residential zip code. The study was approved by and conducted in adherence with the human subjects' requirements of the Institutional Review Board of the University of North Carolina at Chapel Hill.A subset of viable M. avium complex clinical isolates was selected for molecular analysis using specific selection criteria. Isolates were more likely to be analyzed when they were isolated from a sterile site and the patient's zip code was included in the municipal water distribution area. M. avium complex isolates were identified as either M. avium or Mycobacterium intracellulare using multilocus enzyme electrophoresis (MEE) (11,12). Isolates identified as M. avium which shared an electrophoretic type (ET) were further subtyped by pulsed-field gel electrophoresis (PFGE) using 40 U of XbaI for each restriction reaction (7). The Tenover criteria were used to evaluate relatedness of PFGE fragment patterns (10).Groups of related isolates were evaluated to confirm that isolates were collected from unique individuals. If isolates were collected from the same individual or if we could not confirm that the isolates were collected from unique individuals, we retained only the isolate with the earliest collection date from the group. Twenty-seven M. avium isolates from four drinking-water POU sites were typed using MEE. Among 23 isolates and 4 identical ETs, PFGE was used for greater genetic discrimination, yielding 4 identical or closely related PFGE groups.We received 253 M. avium complex clinical isolates: 200 (79%) from respiratory sites, 37 (15%) from normally sterile sites, and 16 (6%) from other sites, such as wounds and stool. We analyzed 126 of these using MEE; of these, 88 (70%) were identified as M. avium. Fifty-six of the 88 (64%) M. avium isolates were from respiratory sites, 25 (28%) from normally sterile sites, and 7 (8%) from other sites, such as wounds and stool.Seven...

show abstract

Clinical Significance of Nontuberculous Mycobacteria Isolates in a Canadian Tertiary Care Center

Cited by 38 publications

References 13 publications

Rapid Identification of Mycobacteria from Smear-Positive Sputum Samples by Nested PCR-Restriction Fragment Length Polymorphism Analysis

Rapid Identification of Mycobacteria from Smear-Positive Sputum Samples by Nested PCR-Restriction Fragment Length Polymorphism Analysis

Molecular characterization of Mycobacterium kansasii isolates in the State of São Paulo between 1995-1998

Molecular Comparison of Mycobacterium avium Isolates from Clinical and Environmental Sources

Contact Info

Product

Resources

About