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Rapid recovery and identification of Mycobacterium tuberculosis within 48 hours of receipt of a clinical specimen — efficient use of rapid methods
Rapid Recovery and Identification of Mycobacterium tuberculosis within 48 Hours of Receipt of a Clinical Specimen — Efficient Use of Rapid Methods David R. Miller, B.S., Sharon M. Deml, B.S., Arthur P. Guruswamy, B.S., Lynette K. Ostgaard, B.S., Peggy S. Schneider, B.S., Donna J. Hata, Ph.D., and Glenn D. Roberts, Ph.D., Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN
Abstract We report the rapid recovery and identification of Mycobacterium tuberculosis within 48 h of receipt of the clinical specimen. This was accomplished using a combination of the BACTEC MGIT 960 (BD Diagnostic Systems, Sparks, MD), cytocentrifugation, and the M. tuberculosis Accuprobe (Gen-Probe, Inc., San Diego, CA).
Introduction During the past 2 decades, the emphasis in clinical mycobacteriology has been directed toward the rapid detection and identification of mycobacteria, particularly Mycobacterium tuberculosis. We have seen the introduction of specific nucleic acid probes used for identification of mycobacterial cultures (1-4); several systems designed for the rapid recovery of organisms from clinical specimens (5-23), and molecular assays designed for the detection of mycobacterial nucleic acid in clinical specimens or identification of mycobacterial species (24,25). As experience is gained with these newer methods, it is important to share observations that may benefit other laboratories in ways that will improve patient care and shorten the time to reporting of results. This report describes observations that led to the rapid recovery and identification of M. tuberculosis from a Mycobacterial Growth Indicator Tube (MGIT; BD Diagnostic Systems, Sparks, MD) that was contaminated with a heavy growth of Staphylococcus aureus.
Specimen Processing and Identification of Mycobacteria A sputum sample from a 53-year-old female suspected of having mycobacterial disease was submitted to the Clinical Mycobacteriology Laboratory at the Mayo Clinic for culture and acidfast smear at 10:56 a.m. on 26 March,
Mailing Address: Glenn D. Roberts, Ph.D., Division of Clinical Microbiology, Hilton 460C, Mayo Clinic, 200 First Street, SW, Rochester, MN 55905. Tel.: 507-284-3704. Fax: 507-284-4272. E-mail: roberts.glenn@ mayo.edu
176
0196-4399/00 (see frontmatter)
2001. The specimen was treated with an equal volume of BBL MycoPrep Reagent (BD Diagnostic Systems, Sparks, MD), mixed, and incubated at 25°C for 15 min. MycoPrep buffer was added up to a total volume of 50 ml, and the suspension was mixed and centrifuged for 15 min at 3,000 × g at 10°C. After centrifugation, the supernatant was removed and the sediment was suspended in 3 ml of MycoPrep buffer, followed by vigorous mixing. A 50-µl aliquot of sediment was placed on a glass microscope slide and allowed to air dry, followed by heat fixation. The auramine-rhodamine stain was performed as described previously (26). Cultures were performed by inoculating 0.5 ml of sediment into an MGIT tube and onto each half of a biplate that contained Middlebrook 7H10 agar and Middlebrook Mitchison Selective 7H11 selective agar with antimicrobials (REMEL, Lenexa, KS). All MGIT tubes were supplemented with the antimicrobial solution provided by the manufacturer. After inoculation, tubes were placed into the BACTEC MGIT 960 system and were incubated at 35 to 37°C for 6 weeks. Biplates were sealed in polyethylene bags, incubated at 37°C in the presence of 5 to 7% CO2, and observed weekly for the presence of growth during the 8-week incubation period. A 50-µl aliquot was removed from cultures that signaled positive in the MGIT system and inoculated onto the surface of a sheep blood agar plate to determine if the culture exhibited bacterial contamination. In addition, 0.15 ml of the medium in the MGIT tube was gently injected into a cytospin funnel containing 0.15 ml of sodium hypochlorite. This mixture was allowed © 2004 Elsevier
to stand for 5 min to inactivate any viable mycobacteria. The cytospin funnel assembly was placed into a carrier, and slides were centrifuged in a Shandon Cytospin 3 (ThermoShandon; Pittsburgh, PA) at 451.6 × g for 15 min. All slides were stained with a carbol-fuchsin acidfast stain and observed microscopically for the presence of mycobacteria. A 1.5-ml aliquot was removed from each positive MGIT tube and centrifuged for 15 min at 20,800 × g in a 5417C centrifuge (Eppendorf AG; Hamburg, Germany), and the supernatant was discarded. The pellet was used for extraction of nucleic acid, and Accuprobes for Mycobacterium tuberculosis and M. avium-M. intracellulare were applied. Testing and interpretation of results were in accordance with the manufacturer’s instructions. Identification of cultures recovered from solid media was made by selecting the most appropriate Accuprobes based on phenotypic characters or by nucleic acid sequencing if probe results were negative, as described previously (10). The auramine-rhodamine stain for acid-fast bacilli was positive and was reported on 26 March, 2001. The MGIT tube became positive on 28 March (28 h after inoculation). Microscopic examination of the cytospin preparation showed cording and acid-fast bacteria. By the next day, the subculture that was placed on a sheep blood agar plate showed complete overgrowth with S. aureus. Despite the presence of bacterial overgrowth, an aliquot from the MGIT tube was subjected to Accuprobe testing and the identification was reported as M. tuberculosis complex on the same day. Growth of M. tuberculosis complex was detected on both segments of the biplate after 11 days of incubation. Clinical Microbiology Newsletter 26:22,2004
Figure 1. Flow chart of rapid detection of M. tuberculosis from a patient.
Two additional sputa were submitted for culture on 27 March; both were initially acid-fast smear positive, and growth appeared in the MGIT tube after 5.5 and 6.3 days, respectively. Neither was contaminated with S. aureus; biplates showed many colonies of M. tuberculosis complex after 8 days of incubation.
Observations and Conclusions We describe the very rapid recovery and identification of M. tuberculosis complex from the sputum of a patient with tuberculosis (Fig. 1). Results were reported within 48 h of receipt of the clinical specimen using a combination of the MGIT and the Accuprobe for M. tuberculosis complex. This occurred despite the presence of large numbers of S. aureus bacteria in the broth culture. Rapid growth in an MGIT tube is commonly regarded as bacterial contamination, and this can result in additional time and cost for reprocessing the specimen and a subsequent delay in reporting of patient results. Clinical microbiology laboratories have a number of rapid methods available to them but often fail to use them in a timely manner by batching specimens and performing testing only when the laboratory decides to do it. The use of rapid tests provides information that may affect (i) the timely administration of appropriate therapy, (ii) a decrease in the length of the hospital stay, (iii) placement in respiratory isolation, and (iv) tuberculosis control. Furthermore, when the laboratory provides a rapid diagnosis, cost savings result by decreasClinical Microbiology Newsletter 26:22,2004
ing additional testing, personnel time, and supplies. The Mayo Clinic mycobacteriology laboratory performs all rapid methods as they are needed; nucleic acid probe testing and sequencing are performed daily. The simple use of cytocentrifugation prior to examining the acid-fast smear made from MGIT tubes is done to increase the sensitivity of the detection of mycobacteria.
Conclusion This short note is meant to remind clinical microbiologists that the laboratory can play an even more important role in the timely diagnosis and control of tuberculosis and subsequent cost savings to the patient and laboratory, if rapid testing is used in an optimal manner. References 1. Alcaide, F. et al. 2000. Evaluation of the BACTEC MGIT 960 and the MB/BacT systems for recovery of mycobacteria from clinical specimens and for species identification by DNA AccuProbe. J. Clin. Microbiol. 38:398-401. 2. Goto, M. et al. 1991. Evaluation of acridinium-ester-labeled DNA probes for identification of Mycobacterium tuberculosis and Mycobacterium aviumMycobacterium intracellulare complex in culture. J. Clin. Microbiol. 29:24732476. 3. Hanna, B.A. et al. 1999. Multicenter evaluation of the BACTEC MGIT 960 system for recovery of mycobacteria. J. Clin. Microbiol. 37:748-752. 4. Peterson, E.M. et al. 1989. Direct identification of Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium intracellulare from amplified
© 2004 Elsevier
primary cultures in BACTEC media using DNA probes. J. Clin. Microbiol. 27:1543-1547. 5. Abe, C. 1996. Evaluation of a new rapid detection system for mycobacteria using an oxygen sensitive fluorescent sensor. J. Jpn. Assoc. Infect. Dis. 70:360-365. (In Japanese.) 6. Abe, C. et al. 1999. Comparison of the newly developed MB redox system with mycobacteria growth indicator tube (MGIT) and 2% Ogawa egg media for recovery of mycobacteria in clinical specimens. Kekkaku 74:707-713. (In Japanese.) 7. Casal, M., J. Gutierrez, and M. Vaquero. 1997. Clinical interest of a new simple system for isolating Mycobacterium tuberculosis. Rev. Clin. Espanola 197:148-151. (In Spanish.) 8. Chew, W.K. et al. 1998. Clinical evaluation of the Mycobacteria Growth Indicator Tube (MGIT) compared with radiometric (Bactec) and solid media for isolation of Mycobacterium species. J. Med. Microbiol. 47:821-827. 9. Chien, H.P. et al. 2000. Comparison of the BACTEC MGIT 960 with Lowenstein-Jensen medium for recovery of mycobacteria from clinical specimens. Int. J. Tuberc. Lung Dis. 4:866-870. 10. Hall, L. et al. 2003. Evaluation of the MicroSeq system for identification of mycobacteria by its ribosomal DNA sequencing and its integration into a routine clinical mycobacteriology laboratory. J. Clin. Microbiol. 41:14471453. 11. Ichiyama, S. et al. 1997. Mycobacterium growth indicator tube testing in conjunction with the AccuProbe or the AMPLICOR-PCR assay for detecting
0196-4399/00 (see frontmatter)
177
12.
13.
14.
15.
16.
178
and identifying mycobacteria from sputum samples. J. Clin. Microbiol. 35:2022-2025. Idigoras, P. et al. 2000. Comparison of the automated nonradiometric Bactec MGIT 960 system with LowensteinJensen, Coletsos, and Middlebrook 7H11 solid media for recovery of mycobacteria. Eur. J. Clin. Microbiol. Infect. Dis. 19:350-354. Kobayashi, I. et al. 1999. Evaluation of mycobacteria growth indicator tube (MGIT), an automated culture system for detection of mycobacteria from clinical specimens. J. Jpn. Assoc. Infect. Dis. 73:172-178. (In Japanese.) Levidiotou, S. et al. 1999. Detection of mycobacteria in clinical specimens using the mycobacteria growth indicator tube (MGIT) and the Lowenstein Jensen medium. Microbiol. Res. 154:151-155. Pfyffer, G.E. et al. 1997. Comparison of the Mycobacteria Growth Indicator Tube (MGIT) with radiometric and solid culture for recovery of acid-fast bacilli. J. Clin. Microbiol. 35:364-368. Rohner, P. et al. 2000. Evaluation of the Bactec 960 automated nonradiometric
0196-4399/00 (see frontmatter)
17.
18.
19.
20.
system for isolation of mycobacteria from clinical specimens. Eur. J. Clin. Microbiol. Infect. Dis. 19:715-717. Saito, H. et al. 1996. Rapid detection of acid-fast bacilli with Mycobacteria Growth Indicator Tube (MGIT). Kekkaku 71:399-405. (In Japanese.) Saitoh, H. and N. Yamane. 2000. Comparative evaluation of BACTEC MGIT 960 system with MB/BacT and egg-based media for recovery of mycobacteria. Rinsho Biseibutsu Jinsoku Shindan Kenkyukai Shi 11:1926. (In Japanese.) Somoskovi, A. et al. 2000. Comparison of recoveries of Mycobacterium tuberculosis using the automated BACTEC MGIT 960 system, the BACTEC 460 TB system, and Lowenstein-Jensen medium. J. Clin. Microbiol. 38:23952397. Somoskovi, A. and P. Magyar. 1999. Comparison of the mycobacteria growth indicator tube with MB redox, Lowenstein-Jensen, and Middlebrook 7H11 media for recovery of mycobacteria in clinical specimens. J. Clin. Microbiol. 37:1366-1369.
© 2004 Elsevier
21. Tazawa, Y. et al. 1998. Experience and clinical usefulness of BACTEC MGIT 960. Rinsho Biseibutsu Jinsoku Shindan Kenkyukai Shi 9:59-65. (In Japanese.) 22. Williams-Bouyer, N. et al. 2000. Comparison of the BACTEC MGIT 960 and ESP culture system II for growth and detection of mycobacteria. J. Clin. Microbiol. 38:4167-4170. 23. Yan, J.J. et al. 2000. Comparison of the MB/BacT and BACTEC MGIT 960 system for recovery of mycobacteria from clinical specimens. Diagn. Microbiol. Infect. Dis. 37:25-30. 24. Bergmann, J.S., W.E. Keating, and G.L.Woods. 2000. Clinical evaluation of the BDProbeTec ET system for rapid detection of Mycobacterium tuberculosis. J. Clin. Microbiol. 38:863-865. 25. Hasegawa, M. et al. 2001. Direct identification of mycobacteria from the positive cultures in mycobacteria growth indicator tube (MGIT). J. Jpn. Assoc. Infect. Dis. 75:300-306. (In Japanese.) 26. Mork-Lewis, K.L., L. Stockman, and G.D. Roberets. 1998. Abstr. 98th Annu. Meet. Am. Soc. Microbiol., abstr. 180.
Clinical Microbiology Newsletter 26:22,2004
Abstract We report the rapid recovery and identification of Mycobacterium tuberculosis within 48 h of receipt of the clinical specimen. This was accomplished using a combination of the BACTEC MGIT 960 (BD Diagnostic Systems, Sparks, MD), cytocentrifugation, and the M. tuberculosis Accuprobe (Gen-Probe, Inc., San Diego, CA).
Introduction During the past 2 decades, the emphasis in clinical mycobacteriology has been directed toward the rapid detection and identification of mycobacteria, particularly Mycobacterium tuberculosis. We have seen the introduction of specific nucleic acid probes used for identification of mycobacterial cultures (1-4); several systems designed for the rapid recovery of organisms from clinical specimens (5-23), and molecular assays designed for the detection of mycobacterial nucleic acid in clinical specimens or identification of mycobacterial species (24,25). As experience is gained with these newer methods, it is important to share observations that may benefit other laboratories in ways that will improve patient care and shorten the time to reporting of results. This report describes observations that led to the rapid recovery and identification of M. tuberculosis from a Mycobacterial Growth Indicator Tube (MGIT; BD Diagnostic Systems, Sparks, MD) that was contaminated with a heavy growth of Staphylococcus aureus.
Specimen Processing and Identification of Mycobacteria A sputum sample from a 53-year-old female suspected of having mycobacterial disease was submitted to the Clinical Mycobacteriology Laboratory at the Mayo Clinic for culture and acidfast smear at 10:56 a.m. on 26 March,
Mailing Address: Glenn D. Roberts, Ph.D., Division of Clinical Microbiology, Hilton 460C, Mayo Clinic, 200 First Street, SW, Rochester, MN 55905. Tel.: 507-284-3704. Fax: 507-284-4272. E-mail: roberts.glenn@ mayo.edu
176
0196-4399/00 (see frontmatter)
2001. The specimen was treated with an equal volume of BBL MycoPrep Reagent (BD Diagnostic Systems, Sparks, MD), mixed, and incubated at 25°C for 15 min. MycoPrep buffer was added up to a total volume of 50 ml, and the suspension was mixed and centrifuged for 15 min at 3,000 × g at 10°C. After centrifugation, the supernatant was removed and the sediment was suspended in 3 ml of MycoPrep buffer, followed by vigorous mixing. A 50-µl aliquot of sediment was placed on a glass microscope slide and allowed to air dry, followed by heat fixation. The auramine-rhodamine stain was performed as described previously (26). Cultures were performed by inoculating 0.5 ml of sediment into an MGIT tube and onto each half of a biplate that contained Middlebrook 7H10 agar and Middlebrook Mitchison Selective 7H11 selective agar with antimicrobials (REMEL, Lenexa, KS). All MGIT tubes were supplemented with the antimicrobial solution provided by the manufacturer. After inoculation, tubes were placed into the BACTEC MGIT 960 system and were incubated at 35 to 37°C for 6 weeks. Biplates were sealed in polyethylene bags, incubated at 37°C in the presence of 5 to 7% CO2, and observed weekly for the presence of growth during the 8-week incubation period. A 50-µl aliquot was removed from cultures that signaled positive in the MGIT system and inoculated onto the surface of a sheep blood agar plate to determine if the culture exhibited bacterial contamination. In addition, 0.15 ml of the medium in the MGIT tube was gently injected into a cytospin funnel containing 0.15 ml of sodium hypochlorite. This mixture was allowed © 2004 Elsevier
to stand for 5 min to inactivate any viable mycobacteria. The cytospin funnel assembly was placed into a carrier, and slides were centrifuged in a Shandon Cytospin 3 (ThermoShandon; Pittsburgh, PA) at 451.6 × g for 15 min. All slides were stained with a carbol-fuchsin acidfast stain and observed microscopically for the presence of mycobacteria. A 1.5-ml aliquot was removed from each positive MGIT tube and centrifuged for 15 min at 20,800 × g in a 5417C centrifuge (Eppendorf AG; Hamburg, Germany), and the supernatant was discarded. The pellet was used for extraction of nucleic acid, and Accuprobes for Mycobacterium tuberculosis and M. avium-M. intracellulare were applied. Testing and interpretation of results were in accordance with the manufacturer’s instructions. Identification of cultures recovered from solid media was made by selecting the most appropriate Accuprobes based on phenotypic characters or by nucleic acid sequencing if probe results were negative, as described previously (10). The auramine-rhodamine stain for acid-fast bacilli was positive and was reported on 26 March, 2001. The MGIT tube became positive on 28 March (28 h after inoculation). Microscopic examination of the cytospin preparation showed cording and acid-fast bacteria. By the next day, the subculture that was placed on a sheep blood agar plate showed complete overgrowth with S. aureus. Despite the presence of bacterial overgrowth, an aliquot from the MGIT tube was subjected to Accuprobe testing and the identification was reported as M. tuberculosis complex on the same day. Growth of M. tuberculosis complex was detected on both segments of the biplate after 11 days of incubation. Clinical Microbiology Newsletter 26:22,2004
Figure 1. Flow chart of rapid detection of M. tuberculosis from a patient.
Two additional sputa were submitted for culture on 27 March; both were initially acid-fast smear positive, and growth appeared in the MGIT tube after 5.5 and 6.3 days, respectively. Neither was contaminated with S. aureus; biplates showed many colonies of M. tuberculosis complex after 8 days of incubation.
Observations and Conclusions We describe the very rapid recovery and identification of M. tuberculosis complex from the sputum of a patient with tuberculosis (Fig. 1). Results were reported within 48 h of receipt of the clinical specimen using a combination of the MGIT and the Accuprobe for M. tuberculosis complex. This occurred despite the presence of large numbers of S. aureus bacteria in the broth culture. Rapid growth in an MGIT tube is commonly regarded as bacterial contamination, and this can result in additional time and cost for reprocessing the specimen and a subsequent delay in reporting of patient results. Clinical microbiology laboratories have a number of rapid methods available to them but often fail to use them in a timely manner by batching specimens and performing testing only when the laboratory decides to do it. The use of rapid tests provides information that may affect (i) the timely administration of appropriate therapy, (ii) a decrease in the length of the hospital stay, (iii) placement in respiratory isolation, and (iv) tuberculosis control. Furthermore, when the laboratory provides a rapid diagnosis, cost savings result by decreasClinical Microbiology Newsletter 26:22,2004
ing additional testing, personnel time, and supplies. The Mayo Clinic mycobacteriology laboratory performs all rapid methods as they are needed; nucleic acid probe testing and sequencing are performed daily. The simple use of cytocentrifugation prior to examining the acid-fast smear made from MGIT tubes is done to increase the sensitivity of the detection of mycobacteria.
Conclusion This short note is meant to remind clinical microbiologists that the laboratory can play an even more important role in the timely diagnosis and control of tuberculosis and subsequent cost savings to the patient and laboratory, if rapid testing is used in an optimal manner. References 1. Alcaide, F. et al. 2000. Evaluation of the BACTEC MGIT 960 and the MB/BacT systems for recovery of mycobacteria from clinical specimens and for species identification by DNA AccuProbe. J. Clin. Microbiol. 38:398-401. 2. Goto, M. et al. 1991. Evaluation of acridinium-ester-labeled DNA probes for identification of Mycobacterium tuberculosis and Mycobacterium aviumMycobacterium intracellulare complex in culture. J. Clin. Microbiol. 29:24732476. 3. Hanna, B.A. et al. 1999. Multicenter evaluation of the BACTEC MGIT 960 system for recovery of mycobacteria. J. Clin. Microbiol. 37:748-752. 4. Peterson, E.M. et al. 1989. Direct identification of Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium intracellulare from amplified
© 2004 Elsevier
primary cultures in BACTEC media using DNA probes. J. Clin. Microbiol. 27:1543-1547. 5. Abe, C. 1996. Evaluation of a new rapid detection system for mycobacteria using an oxygen sensitive fluorescent sensor. J. Jpn. Assoc. Infect. Dis. 70:360-365. (In Japanese.) 6. Abe, C. et al. 1999. Comparison of the newly developed MB redox system with mycobacteria growth indicator tube (MGIT) and 2% Ogawa egg media for recovery of mycobacteria in clinical specimens. Kekkaku 74:707-713. (In Japanese.) 7. Casal, M., J. Gutierrez, and M. Vaquero. 1997. Clinical interest of a new simple system for isolating Mycobacterium tuberculosis. Rev. Clin. Espanola 197:148-151. (In Spanish.) 8. Chew, W.K. et al. 1998. Clinical evaluation of the Mycobacteria Growth Indicator Tube (MGIT) compared with radiometric (Bactec) and solid media for isolation of Mycobacterium species. J. Med. Microbiol. 47:821-827. 9. Chien, H.P. et al. 2000. Comparison of the BACTEC MGIT 960 with Lowenstein-Jensen medium for recovery of mycobacteria from clinical specimens. Int. J. Tuberc. Lung Dis. 4:866-870. 10. Hall, L. et al. 2003. Evaluation of the MicroSeq system for identification of mycobacteria by its ribosomal DNA sequencing and its integration into a routine clinical mycobacteriology laboratory. J. Clin. Microbiol. 41:14471453. 11. Ichiyama, S. et al. 1997. Mycobacterium growth indicator tube testing in conjunction with the AccuProbe or the AMPLICOR-PCR assay for detecting
0196-4399/00 (see frontmatter)
177
12.
13.
14.
15.
16.
178
and identifying mycobacteria from sputum samples. J. Clin. Microbiol. 35:2022-2025. Idigoras, P. et al. 2000. Comparison of the automated nonradiometric Bactec MGIT 960 system with LowensteinJensen, Coletsos, and Middlebrook 7H11 solid media for recovery of mycobacteria. Eur. J. Clin. Microbiol. Infect. Dis. 19:350-354. Kobayashi, I. et al. 1999. Evaluation of mycobacteria growth indicator tube (MGIT), an automated culture system for detection of mycobacteria from clinical specimens. J. Jpn. Assoc. Infect. Dis. 73:172-178. (In Japanese.) Levidiotou, S. et al. 1999. Detection of mycobacteria in clinical specimens using the mycobacteria growth indicator tube (MGIT) and the Lowenstein Jensen medium. Microbiol. Res. 154:151-155. Pfyffer, G.E. et al. 1997. Comparison of the Mycobacteria Growth Indicator Tube (MGIT) with radiometric and solid culture for recovery of acid-fast bacilli. J. Clin. Microbiol. 35:364-368. Rohner, P. et al. 2000. Evaluation of the Bactec 960 automated nonradiometric
0196-4399/00 (see frontmatter)
17.
18.
19.
20.
system for isolation of mycobacteria from clinical specimens. Eur. J. Clin. Microbiol. Infect. Dis. 19:715-717. Saito, H. et al. 1996. Rapid detection of acid-fast bacilli with Mycobacteria Growth Indicator Tube (MGIT). Kekkaku 71:399-405. (In Japanese.) Saitoh, H. and N. Yamane. 2000. Comparative evaluation of BACTEC MGIT 960 system with MB/BacT and egg-based media for recovery of mycobacteria. Rinsho Biseibutsu Jinsoku Shindan Kenkyukai Shi 11:1926. (In Japanese.) Somoskovi, A. et al. 2000. Comparison of recoveries of Mycobacterium tuberculosis using the automated BACTEC MGIT 960 system, the BACTEC 460 TB system, and Lowenstein-Jensen medium. J. Clin. Microbiol. 38:23952397. Somoskovi, A. and P. Magyar. 1999. Comparison of the mycobacteria growth indicator tube with MB redox, Lowenstein-Jensen, and Middlebrook 7H11 media for recovery of mycobacteria in clinical specimens. J. Clin. Microbiol. 37:1366-1369.
© 2004 Elsevier
21. Tazawa, Y. et al. 1998. Experience and clinical usefulness of BACTEC MGIT 960. Rinsho Biseibutsu Jinsoku Shindan Kenkyukai Shi 9:59-65. (In Japanese.) 22. Williams-Bouyer, N. et al. 2000. Comparison of the BACTEC MGIT 960 and ESP culture system II for growth and detection of mycobacteria. J. Clin. Microbiol. 38:4167-4170. 23. Yan, J.J. et al. 2000. Comparison of the MB/BacT and BACTEC MGIT 960 system for recovery of mycobacteria from clinical specimens. Diagn. Microbiol. Infect. Dis. 37:25-30. 24. Bergmann, J.S., W.E. Keating, and G.L.Woods. 2000. Clinical evaluation of the BDProbeTec ET system for rapid detection of Mycobacterium tuberculosis. J. Clin. Microbiol. 38:863-865. 25. Hasegawa, M. et al. 2001. Direct identification of mycobacteria from the positive cultures in mycobacteria growth indicator tube (MGIT). J. Jpn. Assoc. Infect. Dis. 75:300-306. (In Japanese.) 26. Mork-Lewis, K.L., L. Stockman, and G.D. Roberets. 1998. Abstr. 98th Annu. Meet. Am. Soc. Microbiol., abstr. 180.
Clinical Microbiology Newsletter 26:22,2004