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Variability of infectious aerosols produced during coughing by patients with pulmonary tuberculosis.

ABSTRACT: Mycobacterium tuberculosis is transmitted by infectious aerosols, but assessing infectiousness currently relies on sputum microscopy that does not accurately predict the variability in transmission.To evaluate the feasibility of collecting cough aerosols and the risk factors for infectious aerosol production from patients with pulmonary tuberculosis (TB) in a resource-limited setting.We enrolled subjects with suspected TB in Kampala, Uganda and collected clinical, radiographic, and microbiological data in addition to cough aerosol cultures. A subset of 38 subjects was studied on 2 or 3 consecutive days to assess reproducibility.M. tuberculosis was cultured from cough aerosols of 28 of 101 (27.7%; 95% confidence interval [CI], 19.9-37.1%) subjects with culture-confirmed TB, with a median 16 aerosol cfu (range, 1-701) in 10 minutes of coughing. Nearly all (96.4%) cultivable particles were 0.65 to 4.7 ?m in size. Positive aerosol cultures were associated with higher Karnofsky performance scores (P = 0.016), higher sputum acid-fast bacilli smear microscopy grades (P = 0.007), lower days to positive in liquid culture (P = 0.004), stronger cough (P = 0.016), and fewer days on TB treatment (P = 0.047). In multivariable analyses, cough aerosol cultures were associated with a salivary/mucosalivary (compared with purulent/mucopurulent) appearance of sputum (odds ratio, 4.42; 95% CI, 1.23-21.43) and low days to positive (per 1-d decrease; odds ratio, 1.17; 95% CI, 1.07-1.33). The within-test (kappa, 0.81; 95% CI, 0.68-0.94) and interday test (kappa, 0.62; 95% CI, 0.43-0.82) reproducibility were high.A minority of patients with TB (28%) produced culturable cough aerosols. Collection of cough aerosol cultures is feasible and reproducible in a resource-limited setting.

SUBMITTER: Fennelly KP

PROVIDER: S-EPMC3443801 | biostudies-other | 2012 Sep

REPOSITORIES: biostudies-other

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Variability of infectious aerosols produced during coughing by patients with pulmonary tuberculosis.

Fennelly Kevin P KP Jones-López Edward C EC Ayakaka Irene I Kim Soyeon S Menyha Harriet H Kirenga Bruce B Muchwa Christopher C Joloba Moses M Dryden-Peterson Scott S Reilly Nancy N Okwera Alphonse A Elliott Alison M AM Smith Peter G PG Mugerwa Roy D RD Eisenach Kathleen D KD Ellner Jerrold J JJ

American journal of respiratory and critical care medicine 20120712 5

<h4>Rationale</h4>Mycobacterium tuberculosis is transmitted by infectious aerosols, but assessing infectiousness currently relies on sputum microscopy that does not accurately predict the variability in transmission.<h4>Objectives</h4>To evaluate the feasibility of collecting cough aerosols and the risk factors for infectious aerosol production from patients with pulmonary tuberculosis (TB) in a resource-limited setting.<h4>Methods</h4>We enrolled subjects with suspected TB in Kampala, Uganda an ...[more]

PMID: 22798319

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Project description:ObjectiveRecent guidelines recommend the use by healthcare personnel of a fit-tested N95 particulate respirator or higher-grade respiratory precaution in a patient undergoing bronchoscopy when pulmonary tuberculosis (PTB) is suspected. However, PTB may be unexpectedly diagnosed in this setting and therefore not evaluated, resulting in the unexpected exposure to Mycobacterium tuberculosis (MTB) of healthcare workers in the bronchoscopy suite. Here, we examined the incidence of unexpected exposure to MTB during flexible bronchoscopy and determined the exposure-related factors.MethodsBetween 2011 and 2013, a retrospective study was conducted to evaluate unexpected diagnoses of PTB in the bronchoscopy suite. During the study period, 1650 consecutive patients for whom previous CT scans were available and who underwent bronchoscopy for respiratory disease other than PTB were included. The results of bronchial washing, bronchoalveolar lavage, and post-bronchoscopic sputum were reviewed.ResultsPTB was unexpectedly diagnosed in 76 patients (4.6%). The presence of anthracofibrosis [odds ratio (OR), 3.878; 95% confidence interval (CI), 1.291-11.650; P = 0.016), bronchiectasis (OR, 1.974; 95% CI, 1.095-3.557; P = 0.024), or atelectasis (OR, 1.740; 95% CI, 1.010-2.903; P = 0.046) as seen on chest CT scan was independently associated with unexpected PTB. Patients with both anthracofibrosis and atelectasis were at much higher risk of unexpected PTB (OR, 4.606; 95% CI, 1.383-15.342; P = 0.013).ConclusionsThe risk of MTB exposure by healthcare personnel in the bronchoscopy suite due to patients with undiagnosed PTB has been underestimated. Therefore, in geographic regions with an intermediate PTB prevalence, such as South Korea (97/100,000 persons per year), higher-grade respiratory precaution, such as a fit-tested N95 particulate respirator, should be considered to prevent occupational exposure to MTB during routine bronchoscopy, especially in patients with CT-confirmed anthracofibrosis, bronchiectasis, or atelectasis.

Project description:Our earlier studies in tuberculosis (TB) patients indicate that in those where the process evolves to a larger pulmonary involvement, the immune endocrine response may promote an unfavorable environment. Chronic infectious diseases, and their persistent proinflammatory response, may affect mucosal barriers integrity favoring the translocation of gastrointestinal bacteria, leading to an increase of circulating lipopolysaccharides (LPS). Consequently, we quantified LPS levels in TB patients, with different degrees of pulmonary involvement, and controls (Co) and analyzed the possible relationship between LPS and inflammatory mediators i.e., C reactive protein (CRP), interleukin 6 (IL-6) and Interferon-gamma (IFN-γ), Erythrocyte Sedimentation Rate (ESR), steroid hormones (Cortisol and Dehydroepiandrosterone, DHEA), and inflammatory transcripts from peripheral blood mononuclear cells (IL-1β, IL-6, IFN-γ). LPS was assessed by the Limulus amoebocyte lysate assay and the ELISA technique was used to quantify hormones and cytokines in the plasma samples. Cytokine transcripts from PBMC were evaluated by qRT-PCR. Non-parametric tests were used. LPS levels were increased in TB patients, as did levels of CRP, IL-6, IFN-γ, cortisol and ESR. Severe patients had the highest amounts of circulating LPS; with moderate and severe cases showing much higher levels of CRP, ESR, IL-6, IFN-γ and cortisol/DHEA ratio, as an endocrine imbalance. Only in PBMC from severe cases was mRNA for IL-1β increased. Correlation analysis showed that levels of LPS from severe patients were positively associated with IL-6 and IFN-γ plasma concentrations and with IL-1β transcripts, while IL-6 had a positive correlation with the cortisol/DHEA ratio. The higher levels of circulating LPS during progressive TB may emerge as a contributing factor for the persistence of the greater immune endocrine imbalance distinctive of advanced disease, which might suggest a vicious cycle among LPS, inflammation and endocrine imbalance.

Dataset Information

Variability of infectious aerosols produced during coughing by patients with pulmonary tuberculosis.

Publications

Variability of infectious aerosols produced during coughing by patients with pulmonary tuberculosis.

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