Sociodemographic factors associated with the success or failure of anti-tuberculosis treatment in the Chiapas Highlands, Mexico, 2019-2022.

OBJECTIVE: To estimate the incidence rate of tuberculosis (TB) in the Highlands (Tsotsil-Tseltal) region of Chiapas and to analyze sociodemographic factors that might influence the success of anti-TB treatment from the period of January 2019 to June 2022. METHODS: Retrospective study in which the TB databases of the National Epidemiological Surveillance System (SINAVE) were analyzed. TB incidence rates were calculated based on the number of registered TB cases and estimated annual populations. The success-failure of anti-TB treatment was analyzed according to sociodemographic indicators, degree of concentration of indigenous population of the municipality of residence and admission to SINAVE. RESULTS: Two hundred thirty-three cases were analyzed. The variables associated to a lower success rate of treatment against TB were: living in a municipality with high-very high concentration of indigenous population, being indigenous, having a primary school education or lower, and agricultural occupation. The number of TB diagnosed from 2020-2022 and the incidence rates from 2020-2021 decreased significantly compared to 2019. CONCLUSIONS: It is necessary to strengthen the follow-up of TB cases in the region, mainly in areas with high-very high indigenous concentration, in people with low levels of education and engaged in agricultural work.

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.

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.