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At least 19 recordsLinked to original sources
PubMed2005

Species identification of mycobacteria in paraffin-embedded tissues: frequent detection of nontuberculous mycobacteria.

Diagnosis of infections caused by mycobacteria, especially nontuberculous mycobacteria still represents a difficult task both in microbiology and pathology. The aim of this study was to determine the frequency of mycobacterial DNA detectable by PCR in formalin-fixed paraffin-embedded tissues showing suspicious granulomatous lesions. A total of 190 archival specimens were analyzed, using a nested PCR protocol, which amplifies a fragment of the mycobacterial 65-kDa heat-shock protein gene. Restriction fragment-length polymorphisms and sequencing were utilized to further analyze the obtained PCR products. Corresponding microbiological culture results were available for 41 cases. We detected mycobacterial DNA in 119 cases (63%), of which 71 (60%) were positive for Mycobacterium tuberculosis complex DNA and 41 (34%) for DNA of nontuberculous mycobacteria. Seven cases (6%) could not be subtyped for technical reasons. The largest group of nontuberculous mycobacteria comprised 29 cases (25% of the 119 positive cases), which were assigned to Mycobacterium fortuitum complex. Mycobacterium avium-intracellulare complex was detected in eight (7%) cases, Mycobacterium gordonae in three (2.5%) and Mycobacterium rhodesiae in a single case (0.8%). All cases of Mycobacterium tuberculosis were unequivocally identified by restriction fragment-length polymorphism analysis. In contrast, sequencing provided a gain of information over restriction fragment-length polymorphism analysis in 37% of the nontuberculous mycobacteria cases (15 of 41). Alignment studies on DNA of nontuberculous mycobacteria showed frequent sequence variations, supporting the existence of sequevars. Comparison of molecular data to available results of microbiological culture assays showed a good concordance of 83%. In conclusion, amplification and sequencing of the mycobacterial 65-kDa heat-shock protein gene is an excellent tool for species identification of mycobacteria, especially nontuberculous mycobacteria, in formalin-fixed paraffin-embedded tissues.

Base Sequence↗
PubMed2000

[Application of DNA-DNA hybridization, DDH MYCOBACTERIA 'Kyokuto' to species-identification of mycobacteria grown in Middlebrook 7H9 broth].

A colorimetric DNA-DNA hybridization for the genetic identification of mycobacteria, DDH MYCOBACTERIA 'KYOKUTO' (Kyokuto Pharmaceuticals, Tokyo) was evaluated for the clinical isolates of mycobacteria grown in Middlebrook 7H9 broth of MB/BacT (Organon Teknika, Durham, NC, U.S.A.). When the MB/BacT gave the positive interpretation, 10 ml of Middlebrook 7H9 broth was collected from the bottle. After centrifugation at 3,000 rpm for 10 min, two drops of acetone were added to the pellet, then let it stand for one hour at the room temperature. The air-dried pellet was resuspended in a small volume of distilled water, and proceeded to the identification described. Of 136 clinical isolates of mycobacteria, comprising of 76 M. tuberculosis complex and 60 nontuberculous mycobacteria (NTM), ninety-five (70%) were correctly identified when compared to the reference identification. Thirty (22%) isolates resulted in the unidentified due to negative reaction throughout the test wells, and the remaining 11 (8%) were also unidentified due to low likelihoods. According to the package insert, the DDH MYCOBACTERIA may not be applicable to the isolates grown in Middlebrook broth. However, our test procedure using acetone prior to the extraction of bacterial DNA enables us to directly identify the isolates of mycobacteria grown in Middlebrook 7H9 broth of MB/BacT.

Acetone↗
PubMed2005

[Evaluation of INNO-LiPA mycobacteria, INNO-LiPA Mycobacteria v2 and hsp65 sequencing for identification of the clinical nontuberculous mycobacterial isolates].

In this study, polymerase chain reaction (PCR) reverse hybridization based line probe assays, INNO-LiPA Mycobacteria and INNO-LiPA Mycobacteria v2 (Innogenetics, Ghent, Belgium) and partial sequencing of hsp65 gene were evaluated for the identification of 29 clinical mycobacterial isolates. Unique hsp65 sequences identified during the study were deposited in EMBL (European Molecular Biology Laboratory) under accession numbers AY379074, AY379077, AY379075 and AY553874. All mycobacterial isolates were identified at the genus level on both LiPA assays, whereas 8 of 9 different known mycobacteria species (M. kansasii, M. gordonae, M. avium, M. intracellulare, M. chelonae, M. abscessus, M. fortuitum and M. peregrinum) were identified at species level with LiPA Mycobacteria v2. A clear correlation was found between the results of identifications obtained by the both LiPA assays, which targeted the 16S-23S rRNA ITS region, and DNA sequencing, which targeted the hsp65 gene. In conclusion, although LiPA Mycobacteria v2 could not identify all mycobacteria species, it may be especially useful for routine work in clinical laboratories, which are not capable of carrying out DNA sequencing.

Amino Acid Sequence↗
PubMedDate not supplied

[Comparison of BBL mycobacteria growth indicator tube (MGIT) method, BACTEC radiometric system and Lowenstein-Jensen culture media for the detection of mycobacteria in clinical specimens].

The need for more rapid diagnostic tests for early detection of mycobacteria in clinical specimens has become more apparent for the control of tuberculosis. Several commercial systems, as well as conventional media, are available for the culture of acid-fast bacteria (AFB). The aim of this study was to evaluate the Mycobacteria Growth Incubator Tube (MGIT), BACTEC 460 and Lowenstein-Jensen (LJ) media for the recovery of mycobacteria from processed clinical specimens. A total of 75 clinical specimens which were found positive for AFB in smear microscopy were included to the study, and of them 73 were grown in MGIT system, 70 in BACTEC 460 system and 74 on the LJ slants. Average periods for the detection of mycobacteria for BACTEC 460, MGIT systems and LJ medium were 7.3 days, 10.9 days and 19.4 days, respectively. As a result, it was found that the recovery of mycobacteria in MGIT system is comparable to BACTEC 460 system. It appears to be a safer system than BACTEC 460 system, and may be used for detection of mycobacteria in laboratories desiring a non-radioactive method.

Bacteriological Techniques↗
PubMed1997

Comparative evaluation of the mycobacteria growth indicator tube with the BACTEC 460 TB system and Löwenstein-Jensen medium for isolation of mycobacteria from clinical specimens.

SETTING: The utilization of new simples and rapid methods of diagnosis is currently of great interest for tuberculosis control. OBJECTIVE: The Mycobacteria Growth Indicator Tube (MGIT) was evaluated and compared with the BACTEC 460 TB system and Löwenstein-Jensen (LJ) medium for isolation capacity and detection time of mycobacteria. DESIGN: In total 337 specimens from various body sites of 276 patients were tested for the presence of mycobacteria. Specimens were decontaminated using the standard Na OH-NALC method, then processed in MGIT broth, in BACTEC vial, and on LJ medium for comparative study. Ziehl Neelsen staining was used as a reference. RESULTS: MGIT had 95.4% sensitivity, 100% specificity, 100% positive predictive value, and 89.3% negative predictive value. The clinical concordance between MGIT and LJ medium was 0.87 and between MGIT and BACTEC, 0.96. The mean time to detection for Mycobacterium tuberculosis was 11 days (range 7-31 days) with MGIT. For M. avium and other atypical mycobacteria, the mean time to detection were 3 and 8 days, respectively. CONCLUSION: The Mycobacteria Growth Indicator Tube appears to be a rapid, easy-to-use system with a high accuracy for detecting mycobacteria directly from clinical specimens.

Bacteriological Techniques↗
PubMed1999

Detection of mycobacteria in clinical specimen using the mycobacteria growth indicator tube (MGIT) and the Lowenstein Jensen medium.

The recovery rates of mycobacteria strains isolated from 1200 clinical specimens using the mycobacteria growth indicator tube (MGIT) system and the conventional Lowenstein Jensen medium (LJ) were assessed. Of the 87 mycobacterial isolates recovered, 54 belonged to the M. tuberculosis complex (MTB) and 33 to the non-tuberculosis complex (NTM). MGIT recovered 78 (89.65%) mycobacteria isolates (51 MTB (94.44%) and 27 NTM (81.81%) and LJ recovered 70 (80.46%) mycobacteria isolates (49 MTB (90.74%) and 21 NTM (63.63%). Sixty one (70.1%) of the total mycobacteria isolates were recovered with both systems (46 (85.2%) MTB and 15 (45.5%) NTM). No significant difference was found between MGIT and LJ (p > 0.05) in both MTB and NTM recoveries. The average detection time for MTB was significantly shorter with MGIT than with LJ, in both the smear-positive specimens (8 vs 30 days: p < 0.0001) and smear-negative specimens (15 vs 30 days: p < 0.001). The average detection time of NTM was also shorter for MGIT (15 vs 30 days: p < 0.0001). However, the contamination rate was higher in MGIT (8.5%) than in LJ (3%). The results suggest that the use of MGIT contributes to a more rapid and effective diagnosis of mycobacterial infections particularly when combined with the classical LJ.

Culture Media↗
PubMed2006

Use of the BACTEC Mycobacteria Growth Indicator Tube 960 automated system for recovery of Mycobacteria from 9,558 extrapulmonary specimens, including urine samples.

The BACTEC Mycobacteria Growth Indicator Tube 960 (MGIT 960) system was applied for recovery of mycobacteria from extrapulmonary specimens and compared with solid media (Löwenstein-Jensen and Stonebrink). A total of 9,558 specimens were investigated, comprising 3,074 body fluids, 1,878 tissues, and 2,069 urine samples, from which the recovery of mycobacteria was not yet established for MGIT 960. In total, the MGIT 960 was able to detect 446 (90.3%) of the 494 isolates of Mycobacterium tuberculosis complex (MTBC) and 223 (86.0%) out of the 259 isolates of nontuberculous mycobacteria (NTM). In comparison to this, culture on solid medium revealed 358 (72.6%) MTBC isolates and 164 (66.8%) NTM isolates. While 136 (27.6%) of the MTBC isolates and 95 (19.2%) of the NTM isolates were recovered from the MGIT 960 only, 48 (9.7%) of the MTBC isolates and 36 (13.9%) NTM isolates grew only on solid media. Thus, the overall sensitivities for the recovery of mycobacteria from extrapulmonary specimens with MGIT 960 and solid media were 88.8% and 69.3%, respectively. However, the efficiency of the MGIT 960 system can be maximized with additional culture on solid media.

Bacteriuria↗
PubMed1988

Investigation of mycobacteria in Crohn's disease tissue by Southern blotting and DNA hybridisation with cloned mycobacterial genomic DNA probes from a Crohn's disease isolated mycobacteria.

A mycobacterial aetiology for Crohn's disease (CD) has been suggested. Slow growing mycobacteria indistinguishable from M paratuberculosis, the causative agent of enteritis in ruminants (Johne's disease) have been isolated from CD tissues. We have used cloned genomic DNA probes derived from a CD isolated mycobacteria strain Ben, to investigate the presence of mycobacterial DNA sequences in CD tissues. DNA was extracted from total tissue from 17 CD and four control gut specimens. DNA was digested with restriction endonucleases, electrophoresed and transferred to nylon membranes by Southern blotting and hybridised to radiolabelled DNA probes. No mycobacterial DNA was detected in any tissue sample studied. Reconstitution experiments with known numbers of in vitro cultured mycobacteria showed sensitive detection of mycobacterial DNA. DNA extracted from mouse liver, infected with M lepraemurium revealed a strong hybridisation signal and showed the applicability of the experimental approach to the detection of mycobacterial DNA in naturally infected tissues. The results do not provide evidence for the involvement of mycobacteria in the pathogenesis of CD but do not exclude the possibility of low levels of infection in subsets of intestinal cells with spheroplast or cell wall deficient forms of mycobacteria.

Blotting, Southern↗
PubMed1980

Usefulness of picric acid-sauton agar medium for differentiating slowly growing mycobacteria from rapidly growing mycobacteria.

A modified Sauton agar medium containing 0.2% picric acid was useful for differentiating slowly growing mycobacteria from rapidly growing mycobacteria. Slowly growing mycobacteria, with the exception of Mycobacterium simiae, failed to grow on this medium. Rapidly growing mycobacteria, with the exception of Mycobacterium chelonei subsp. chelonei, grew on the medium. These 2 species may therefore be differentiated by the use of the picric acid medium.

Agar↗
PubMed1988

DNA probes for mycobacteria. I. Isolation of DNA probes for the identification of Mycobacterium tuberculosis complex and for mycobacteria other than tuberculosis (MOTT).

Traditional methods used in identifying mycobacteria such as acid-fast bacillus stains and culture are often time-consuming, insensitive and non-specific. The isolation of DNA probes, coupled to a non-radioactive, e.g. biotin-based detection system, have the potential to foster the development of clinical assays for Mycobacterium tuberculosis and mycobacteria other than tuberculosis (MOTT) that are rapid, sensitive and specific. To this end, we have isolated two different probes: one which is specific for the Mtb complex and one which recognizes all other potentially pathogenic mycobacteria. The use of these probes in combination should allow the detection and differentiation of M. tuberculosis from MOTT. To isolate the first probe, we prepared a library of M. tuberculosis DNA fragments in a lambda EMBL phage vector. Recombinant phage were screened by plaque-lift hybridization procedures using nick-translated mycobacterial genomic DNA to identify sequences specific to the Mtb complex. Inserts from candidate recombinant phage were purified, nick-translated and hybridized against a wide variety of filter-bound mycobacterial and non-mycobacterial DNAs. Two clones were identified which hybridized to the closely related M. tuberculosis, M. bovis and M. microti but not to other species of mycobacteria. The second probe was isolated by preparing a library of M. malmoense DNA fragments in lambda EMBL and screening by plaque-lift hybridization. One clone was identified which, in addition to recognizing members of the Mtb complex, also hybridized to M. intracellulare, M. malmoense, M. scrofulaceum, M. simiae, M. xenopi, M. avium, M. szulgai, M. kansasii and M. haemophilum. None of the three clones hybridized to DNA from non-mycobacterial species.

Animals↗
PubMed2005

Examination of specimens for mycobacteria in clinical laboratories in 21 countries: a 10-year review of the UK National Quality Assessment Scheme for Mycobacteria Culture.

Results from clinical diagnostic microbiology laboratories taking part in the UK National Quality Assessment Service (UK NEQAS) scheme for Mycobacteria Culture between 1993 and 2003 were evaluated and assessed to determine whether the perceived increase in the use of rapid methods is improving time-to-positive reporting of results. Four simulated sputum specimens containing mycobacteria in mixed cultures with normal commensal organisms were distributed three times a year. Participating laboratories were required to report on the presence of 'mycobacteria' and on the time required to obtain a positive result. The overall level of performance with the mycobacteria culture external quality assessment specimens remained consistently high, with an average success rate of 94% over 10 years. The mean time-to-positive decreased from 24 to 17 days during the previous 8 years. A survey questionnaire, circulated in 2002, addressed the use of continuous automated mycobacterial liquid culture (CAMLiC) and molecular methods. The increase in the use of rapid culture methods for the detection of Mycobacterium tuberculosis has resulted in an overall reduction in time-to-positive data reported by participants, and has provided an indication of participants' ability to meet the 21-day target recommended by the CDC for the detection and identification of M. tuberculosis.

Bacteriological Techniques↗
PubMed1999

[Evaluation of mycobacteria growth indicator tube (MGIT), an automated culture system for detection of mycobacteria from clinical specimens].

We compared the Mycobacteria Growth Indicator Tube 960 (MGIT 960) and Ogawa medium (OM) for the detection of mycobacteria (acid fast bacteria: AFB) using 882 sputum specimens. Overall, 120 strains of AFB were isolated by the MGIT 960 system and 99 strains of AFB were isolated by using OM. As far as Mycobacterium tuberculosis is concerned, 88 and 71 isolates were achieved by the MGIT 960 and OM respectively. A total of 28 isolates (18 isolates of M. tuberculosis and 10 isolates of nontuberculous mycobacteria: NTM) were detected by the MGIT 960 only whereas only 2 isolates (1 M. tuberculosis and 1 NTM) were detected by OM only. Of these sputum specimens, 72 were smear positive for AFB. The rates of smear negative but culture positive specimens were 8.0% (65 out of 809) for the MGIT 960 system and 6.2% (50 out of 809) for OM. The contamination rate for MGIT 960 was only 1.2%. The average time required for detection of M. tuberculosis was 14.1 days by the MGIT 960 system and 24.6 days by OM. For the NTM, the average detection time were 8.3 days for the MGIT 960 system and 22.8 days for OM. These results indicate that the MGIT 960 system allows detection of mycobacteria significantly faster than OM.

Automation↗
PubMed1989

DNA polymorphism in Mycobacterium paratuberculosis, "wood pigeon mycobacteria," and related mycobacteria analyzed by field inversion gel electrophoresis.

Mycobacterium paratuberculosis strains, mycobacteria from patients suffering from Crohn's disease, "wood pigeon mycobacteria," and representatives of Mycobacterium avium-Mycobacterium intracellulare were compared by restriction endonuclease DraI digestion and field inversion gel electrophoresis. Characteristic profiles were seen for M. paratuberculosis, including isolates from patients suffering from Crohn's disease, for wood pigeon mycobacteria, and for M. avium-M. intracellulare serotypes 2, 16, 18, and 19. Two M. paratuberculosis strains used for vaccine production (St 18 and 316 F) presented patterns different from those of the other M. paratuberculosis strains. Strains St 18 yielded a pattern identical to that of the M. avium type strain serotype 2, whereas 316 F gave a unique pattern. The method developed in this study represents a useful taxonomic tool for the identification and classification of mycobacteria.

Animals↗
PubMed2000

Comparison of the mycobacteria growth indicator tube with radiometric and solid culture for isolation of mycobacteria from clinical specimens and susceptibility testing of Mycobacterium tuberculosis.

We compared the mycobacteria growth indicator tube (MGIT) system with the BACTEC 460 TB and Loewenstein-Jensen (LJ) systems for the recovery of mycobacteria (acid-fast bacilli [AFB]) from 600 clinical specimens. A total of 50 AFB (32 Mycobacterium tuberculosis complex, 10 M. avium complex, 3 M. gordonae, 3 M. xenopi, 1 M. terrae and 1 M. fortuitum) were detected. MGIT recovered 50 isolates of AFB (100% sensitivity), and BACTEC 460 TB and LJ recovered 49 (98% sensitivity) and 19 (38% sensitivity) AFB isolates, respectively. The mean times to detect mycobacteria were 10, 10 and 25 days for MGIT, BACTEC 460, and LJ slants. All isolates of M. tuberculosis complex were tested for susceptibility to streptomycin, isoniazid, rifampin, and ethambutol with the MGIT and BACTEC 460 TB. Both systems yielded identical susceptibility data with different mean times to report (5.38 days for MGIT versus 7.33 days for BACTEC 460 TB, P<0.05). The results suggest that MGIT is equivalent to BACTEC 460 TB in its ability to support the growth of mycobacteria, but significantly more efficient than LJ. MGIT may also be used for susceptibility testing of primary antituberculosis drugs.

Anti-Bacterial Agents↗
PubMed2001

[Comparison of the newly developed MYCOACID system with mycobacteria growth indicator tube (MGIT) and newly developed 2% Ogawa medium (S) for recovery of mycobacteria in clinical specimens].

The detection rate of mycobacteria from patients' specimens and the time required to get positive culture were compared among newly developed MYCOACID SYSTEM, MGIT, Ogawa K medium and 2% Ogawa medium (S). A total of 249 sputum samples taken from patients were used as the study subjects and 124 kinds of mycobacteria were isolated. For 135 cases clinically diagnosed as pulmonary tuberculosis, the detection rate was 44.4% for MYCOACID, 47.4% for MGIT and 38.5% for Ogawa K medium, showing that there are no significant differences in the detection rate between MYCOACID and MGIT, and MYCOACID and Ogawa K medium but the differences was significant between MGIT and Ogawa K medium (p = 0.02). The mean days needed for detection of Mycobacterium tuberculosis complex was 12.3 days for MYCOACID, 13.4 days for MGIT, and 26.8 days for Ogawa K medium, indicating significant differences in the time to get positive culture between Ogawa K medium and either of both liquid media (p < 0.001). Furthermore, 2% Ogawa medium (S) was used only for the detection of mycobacteria among previously untreated tuberculosis and there were no significant differences in the detection rate between 2% Ogawa medium (S) and either of both liquid media. The time to get positive culture for 2% Ogawa medium (S) was 18.2 days, which was longer than that for either of liquid media, MYCOACID and MGIT, but it was significantly shorter (7.9 days) than that for Ogawa K medium (p = 0.003). These results demonstrate that the liquid culture systems both MYCOACID and MGIT were very useful for the detection of mycobacteria compared with Ogawa K medium.

Bacteriological Techniques↗
PubMedDate not supplied

Metabolic studies on mycobacteria. V. A preliminary report on the ATP synthesis by mycobacteria including M. leprae by using different substrates.

By deletion and addition of various substrates in Sauton's and Dubos media, an experimental system has been standardised in which the role of various nutrients in the energy synthesis of mycobacteria can be determined. By using this system with cultivable mycobacteria it was observed that glycerol and asparagine are the important ingredients for ATP synthesis by mycobacteria. Glucose further enhanced the ATP synthesis and growth of these mycobacteria. In the media containing asparagine or glycerol, there was marginal increase in the ATP in the M. leprae suspensions initially but this was not sustained and there was no progressive increase in biomass or multiplication. When M. leprae was incubated in the media from which both these substrates were deleted, there was progressive decline in ATP levels right from the beginning. From these preliminary results, it appears that asparagine and glycerol may be useful as substrates for ATP synthesis by M. leprae and need to be investigated further. In depth studies are necessary to find out the factors which results in the inability of M. leprae to utilise these and other substrates in a substrained manner for its multiplication and growth in artificial media.

Adenosine Triphosphate↗
PubMed1993

Inability to detect mycobactin in mycobacteria-infected tissues suggests an alternative iron acquisition mechanism by mycobacteria in vivo.

Although most species of mycobacterium are capable of producing mycobactin, it is not known if conditions within the host allow for mycobactin synthesis or whether it even plays a role in iron acquisition in vivo. We employed the mycobactin-auxotroph, Mycobacterium paratuberculosis, in a bioassay to examine tissues from animals infected with either Mycobacterium tuberculosis, Mycobacterium avium or M. paratuberculosis for the presence of mycobactin or compounds which demonstrate mycobactin-like activity. Other iron-binding compounds, including purified siderophores from unrelated organisms and host iron-binding proteins were also evaluated in the bioassay for growth induction of M. paratuberculosis in the absence of mycobactin. Although mycobactin could be easily demonstrated in tissues artificially seeded with mycobacteria, no mycobactin could be detected in heavily infected tissues. None of the purified siderophores from unrelated microorganisms were found to support growth of M. paratuberculosis in the absence of mycobactin. Host iron-binding proteins (transferrin, lactoferrin, ferritin, hemin) also failed to induce growth in the bioassay at pH 6.8, however, when the pH was adjusted between 5-6.2, transferrin and lactoferrin promoted growth of M. paratuberculosis without mycobactin, probably as a result of the dissociation of iron rather than a specific interaction. We confirm that mycobacteria are incapable of iron uptake when iron is chelated to siderophores from unrelated organisms and conclude that mycobactin-mediated mechanisms of iron-acquisition by mycobacteria do not appear to have as significant a role in vivo as in vitro. In addition, evidence is presented that suggests iron-containing transferrin and lactoferrin at low pH may circumvent the need for mycobactin by M. paratuberculosis.

Animals↗