[Comparison of the results of M. tuberculosis cultures on liquid media in MB/BacT system and solid Löwenstein Jensen media in selected patients].
OBJECTIVE
The study was performed to evaluate the performances of the MB/BacT System in comparison to solid media Löwenstein Jensen for the recovery and the time for the detection of mycobacteria from specimens of selected patients from a dust and chemical polluted area, where the incidence of tuberculosis is higher than the mean county incidence- as control- and silicotuberculosis patients.


METHODS
We processed 193 selected specimens (156 as control and 37 from silicotuberculosis patients). All specimens have been processed for microscopic examination, culture on Löwenstein Jensen media and in Middlebrook7H9 liquid media in automatic system MB/BacT Sputum, bronchial aspirate and tongue swab had been previously decontaminated, but aseptically obtained specimens not, before inoculation onto the culture media.


RESULTS
The culture positivity mean time for control was 14,56 days in MB/BacT system and 28.66 days on Löwenstein Jensen, and 17.7 days, and 77 days respectively for silicotuberculosis patients specimens, without significant difference between the two groups (chi2 = 0,33; p = 0,565; IC95).


CONCLUSIONS
Simultaneously culture of selected specimens by using two different culture media for Mycobacterium strains isolation can contribute (it the improvement of the results by the shortage of diagnostic time. The precocity of the culture positive results in MB/BacTsystem (but also on LJ media), are directly related with the number of colonies forming units (CFU) in the processed specimen. The positive results on MB/BacT system in the first 14 days of incubation are related to rich cultures on LJ media, in the great majority of cases. Positive results on LJ media have been obtained after 21 days of incubation. All isolated strains have been M tuberculosis.
Spitalul Clinic de Pneumoftiziologie Leon Daniello, Cluj-Napoca. daniela@xnet.ro
Daniela
D
Homorodean
D001431:Bacteriological Techniques / Q000379:methods; D001992:Bronchoalveolar Lavage Fluid; D003470:Culture Media; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000254:growth & development / Q000302:isolation & purification*; D012189:Retrospective Studies; D013048:Specimen Handling; D013183:Sputum; D013997:Time Factors; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis
D003470:Culture Media