Detection and Quantification of Differentially Culturable Tubercle Bacteria in Sputum from Patients with Tuberculosis.
Am J Respir Crit Care Med
; 194(12): 1532-1540, 2016 12 15.
Article
in En
| MEDLINE
| ID: mdl-27387272
ABSTRACT
RATIONALE Recent studies suggest that baseline tuberculous sputum comprises a mixture of routinely culturable and differentially culturable tubercle bacteria (DCTB). The latter seems to be drug tolerant and dependent on resuscitation-promoting factors (Rpfs). OBJECTIVES:
To further explore this, we assessed sputum from patients with tuberculosis for DCTB and studied the impact of exogenous culture filtrate (CF) supplementation ex vivo.METHODS:
Sputum samples from adults with tuberculosis and HIV-1 and adults with no HIV-1 were used for most probable number (MPN) assays supplemented with CF and Rpf-deficient CF, to detect CF-dependent and Rpf-independent DCTB, respectively. MEASUREMENTS AND MAINRESULTS:
In 110 individuals, 19.1% harbored CF-dependent DCTB and no Rpf-independent DCTB. Furthermore, 11.8% yielded Rpf-independent DCTB with no CF-dependent DCTB. In addition, 53.6% displayed both CF-dependent and Rpf-independent DCTB, 1.8% carried CF-independent DCTB, and 13.6% had no DCTB. Sputum from individuals without HIV-1 yielded higher CF-supplemented MPN counts compared with counterparts with HIV-1. Furthermore, individuals with HIV-1 with CD4 counts greater than 200 cells/mm3 displayed higher CF-supplemented MPN counts compared with participants with HIV-1 with CD4 counts less than 200 cells/mm3. CF supplementation allowed for detection of mycobacteria in 34 patients with no culturable bacteria on solid media. Additionally, the use of CF enhanced detection of sputum smear-negative individuals.CONCLUSIONS:
These observations demonstrate a novel Rpf-independent DCTB population in sputum and reveal that reduced host immunity is associated with lower prevalence of CF-responsive bacteria. Quantification of DCTB in standard TB diagnosis would be beneficial because these organisms provide a putative biomarker to monitor treatment response and risk of disease recurrence.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Sputum
/
Tuberculosis, Pulmonary
/
HIV Infections
/
Mycobacterium tuberculosis
Type of study:
Diagnostic_studies
/
Prevalence_studies
/
Risk_factors_studies
Limits:
Adult
/
Female
/
Humans
/
Male
Country/Region as subject:
Africa
Language:
En
Journal:
Am J Respir Crit Care Med
Journal subject:
TERAPIA INTENSIVA
Year:
2016
Type:
Article
Affiliation country:
South Africa