[New criteria for discharge from ward in patients with pulmonary tuberculosis using mycobacteria growth indicator tube].
OBJECTIVE
To find a new method to predict the result of the egg based Ogawa medium using the Mycobacterium Growth Indicator Tube (MGIT) system and to evaluate the usefulness of a new discharge criterion that uses the new prediction method for smear positive pulmonary tuberculosis patients.


METHODS
We compared mycobacterial growth of sputum specimens weekly between the Mycobacterium Growth Indicator Tube (MGIT) and the egg based Ogawa solid media, using a total of 3952 sputum specimens of patients with pulmonary tuberculosis (TB) who underwent chemotherapy in our hospital from September 2001 to March 2006 to find relationship between the results of the two culture methods and to utilize the findings to new discharge criteria of pulmonary TB patients. And we compared the duration of hospitalization between two patients' group: one group using the new discharge criterion, the other the old one.


RESULTS
We found that if a specimen shows negative culture on the MGIT system within the first two weeks, the same specimen shows negative or scant growth on the Ogawa media in the 8th week. Introducing this fact as a part of new criteria for hospital discharge of patients with pulmonary tuberculosis, the median duration of hospitalization in our hospital was shortened from 121 days to 71 days and no patient showed treatment failure.


CONCLUSIONS
We have used the result of sputum culture on Ogawa medium as a standard when we judge infectivity of patients with pulmonary tuberculosis in Japan, but it was one of the reasons why Japanese pulmonary tuberculosis patients stay long in TB hospital. Using our finding, we can predict the results of Ogawa system six weeks earlier, when a specimen shows negative culture on the MGIT system in the first 2 weeks. After we introduced this fact into new criteria for hospital discharge of patients with pulmonary tuberculosis, the median duration of hospitalization in our hospital was shortened and no patient shows treatment failure until now. We highly recommend the usefulness of the MGIT system (especially when a specimen shows negative growth in the first two weeks) as a reliable method of predicting infectivity of patients with pulmonary tuberculosis and propose that the new TB discharge criterion should be widely confirmed and used in other hospitals.
Fujino
Michihiro
M
Division of Pulmonary Medicine, Hokkaido Social Insurance Hospital, 1-8-3-18, Nakanoshima, Toyohira-ku, Sapporo-shi, Hokkaido 063-8618 Japan. fujino@hok-shaho-hsp.jp
Kishi
Fujiya
F
Akiyama
Yasushi
Y
Ogasawara
Hideki
H
Matsumoto
Hidenobu
H
D001431:Bacteriological Techniques / Q000295:instrumentation; D003470:Culture Media; D005260:Female; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000254:growth & development*; D010351:Patient Discharge; D013183:Sputum / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology*
D003470:Culture Media