Tween 80 Improves the Acid-Fast Bacilli Quantification in the Magnetic Nanoparticle-Based Colorimetric Biosensing Assay (NCBA).

Despite its reduced sensitivity, sputum smear microscopy (SSM) remains the main diagnostic test for detecting tuberculosis in many parts of the world. A new diagnostic technique, the magnetic nanoparticle-based colorimetric biosensing assay (NCBA) was optimized by evaluating different concentrations of glycan-functionalized magnetic nanoparticles (GMNP) and Tween 80 to improve the acid-fast bacilli (AFB) count. Comparative analysis was performed on 225 sputum smears: 30 with SSM, 107 with NCBA at different GMNP concentrations, and 88 with NCBA-Tween 80 at various concentrations and incubation times. AFB quantification was performed by adding the total number of AFB in all fields per smear and classified according to standard guidelines (scanty, 1+, 2+ and 3+). Smears by NCBA with low GMNP concentrations (≤1.5 mg/mL) showed higher AFB quantification compared to SSM. Cell enrichment of sputum samples by combining NCBA-GMNP, incubated with Tween 80 (5%) for three minutes, improved capture efficiency and increased AFB detection up to 445% over SSM. NCBA with Tween 80 offers the opportunity to improve TB diagnostics, mainly in paucibacillary cases. As this method provides biosafety with a simple and inexpensive methodology that obtains results in a short time, it might be considered as a point-of-care TB diagnostic method in regions where resources are limited.

Health reform in Mexico: governance and potential outcomes.

Adopting key mechanisms to restructure public policy in developing countries is a crucial political task. The strengthening of infrastructure of health services, care quality, monitoring and population health; all might contribute to assuring the functionality of a national system for health monitoring and care. Over the last decades, the Mexican government has launched wide-ranging political reforms aiming to overcome socioeconomic and environmental problems, namely health, education, finances, energy and pension. The proposed (but yet not implemented) health reform in Mexico during E. Peña Nieto's administration (2012-2018) pretended an adjustment in Article 4 of the Mexican Constitution to compact medical care and reduce the State's responsibility to a provision of minimum health packages for the population. Here we use a simple analytical model to describe and interprete the concepts of context, process, actors and content and the outcome of three of the most important resulting components of this intended reform i.e. universality, basic packages, and 'outsourcing'. In light of the start of the Mexico's new federal administration, we argue that, if not properly defined by all actors, the implementation of such structural health reform in Mexico would precipitate a model of private/public association exacerbating a crisis of political representation, human rights, justice and governance.

Magnetic Nanoparticle-Based Biosensing Assay Quantitatively Enhances Acid-Fast Bacilli Count in Paucibacillary Pulmonary Tuberculosis.

A new method using a magnetic nanoparticle-based colorimetric biosensing assay (NCBA) was compared with sputum smear microscopy (SSM) for the detection of pulmonary tuberculosis (PTB) in sputum samples. Studies were made to compare the NCBA against SSM using sputum samples collected from PTB patients prior to receiving treatment. Experiments were also conducted to determine the appropriate concentration of glycan-functionalized magnetic nanoparticles (GMNP) used in the NCBA and to evaluate the optimal digestion/decontamination solution to increase the extraction, concentration and detection of acid-fast bacilli (AFB). The optimized NCBA consisted of a 1:1 mixture of 0.4% NaOH and 4% N-acetyl-L-cysteine (NALC) to homogenize the sputum sample. Additionally, 10 mg/mL of GMNP was added to isolate and concentrate the AFB. All TB positive sputum samples were identified with an increased AFB count of 47% compared to SSM, demonstrating GMNP's ability to extract and concentrate AFB. Results showed that NCBA increased AFB count compared to SSM, improving the grade from "1+" (in SSM) to "2+". Extending the finding to paucibacillary cases, there is the likelihood of a "scant" grade to become "1+". The assay uses a simple magnet and only costs $0.10/test. NCBA has great potential application in TB control programs.

Pulmonary tuberculosis infection among workers in the informal public transport sector in Lima, Peru.

BACKGROUND: Because a strong association was observed between pulmonary tuberculosis (TB) and the use of public transport, increasing with duration of journey, a study was carried out to assess infection by Mycobacterium tuberculosis and working conditions among workers in this sector. METHODS: A cross-sectional study was conducted between June and September 2008. A total of 104 workers from two public transport minibus ('combi') cooperatives covering marginal areas of the Ate-Vitarte district in Lima were interviewed. Demographic and occupational details were collected as well as prior family and personal history of TB and BCG vaccination. The tuberculin skin test (TST) was administered to each study subject and an induration of ≥ 10 mm was considered positive. Statistical analysis was based on logistic models, ORs and their 95% CIs. RESULTS: TST results were obtained for 70.2% (n=73), of whom 76.6% (n=56) were positive. Positivity was significantly associated with those who had worked for more than 2 years (crude OR 11.04; 95% CI 3.17 to 38.43) and more than 60 h/week (crude OR 9.8; 95% CI 2.85 to 33.72). These associations remained significant in a multivariate model as well. CONCLUSION: The association observed between years of working and weekly work burden among minibus workers suggests an occupational risk in service jobs in low-income countries with high TB prevalence. Consequently, other types of users are at increased risk for TB infection, with a causal relationship between effect and duration of exposure.

Public transportation and pulmonary tuberculosis, Lima, Peru.

The association between public transportation for commuting and pulmonary tuberculosis (TB) was analyzed in workers in Lima, Peru. Traveling in minibuses was a risk factor for pulmonary TB. Preventive measures need to be taken by health services to prevent spread of this disease.

Detection of pulmonary tuberculosis in Chiapas, Mexico.

PURPOSE: To estimate the prevalence of undiagnosed pulmonary tuberculosis (PTB) and the sensitivity of bacilloscopy in the border region of Chiapas, Mexico. METHODS: We actively sought individuals aged 15 years or more with chronic cough from the Border Region of Chiapas, Mexico in three settings: one regional hospital, seven Primary Care Centers (PCC), and 32 communities. Individuals (a total of 899) reporting chronic cough were asked to provide three samples of sputum for acid-fast smears and cultures. The quality of acid-fast smears was evaluated using culture as the gold standard. RESULTS: We obtained sputum specimens from 590 of 899 individuals with chronic cough. A diagnosis of PTB was confirmed in 78. A conservative estimate of the overall prevalence of PTB at the population level was 151 per 100,000 (95% CI: 88 to 241). In the regional hospital, the estimated case detection rate was 66% (29/44). The proportion of candidates for PTB therapy that were actually on treatment was 50% (14/28) at the PCC and 11% (2/19) in the communities. The sensitivity of the bacilloscopy was about 90% in the hospital, and slightly lower than 50% in the PCC and the communities. CONCLUSION: Improved procedures for PTB detection are required in the studied area to adequately control the disease and to provide therapy to affected patients.