Failure to detect the IS6110 repetitive DNA element of Mycobacterium tuberculosis in exhaled breath condensate of patients with active pulmonary tuberculosis
Abstract number: 902_p1484
To detect the presence of IS6110 repetitive DNA element of Mycobacterium tuberculosis (MTB) in exhaled breath condensate (EBC), a simple, non-invasive method to sample pulmonary lining fluid of patients with active pulmonary tuberculosis.
Ten hospitalised patients with positive sputum smears for MTB were identified by routine microscopy. Sputum samples were sent for routine culture and susceptibilities. EBC was collected from these patients within 6 days of initiating anti-tuberculous therapy (median, 36 h). EBC samples were concentrated by high-speed centrifugation and then analysed by RT-PCR using primers designed to amplify a 245 base-pair IS6110 DNA fragment of MTB. Amplified DNA was detected by ethidium bromide staining, agarose gel electrophoresis and confirmed by SaI digestion. Exogenous MTB DNA was added to EBC samples to detect PCR inhibitors. EBC samples were also cultured on Lowenstein/Jensen agar plates for 6 weeks.
MTB was identified in nine out of 10 routine sputum cultures. One isolate was identified as M. kansasii. The IS6110 repetitive DNA element of MTB was not detected in any of the 10 EBC samples. By contrast, exogenous MTB DNA added to EBC samples evoked the characteristic band pattern of MTB on agarose gel electrophoresis. Cultures of EBC showed no growth of MTB.
The IS6110 repetitive DNA element of MTB was not detected in EBC in patients with active pulmonary tuberculosis. This could be related, in part, to anti-tuberculous therapy initiated before collection of EBC. We suggest that EBC should be collected from these patients before initiating anti-tuberculous therapy."
|Session name:||XXIst ISTH Congress|
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