Comparison of C18-Carboxypropylbetaine and Standard N-Acetyl-l-Cysteine-NaOH Processing of Respiratory Specimens for Increasing Tuberculosis Smear Sensitivity in Brazil

摘要: Techniques to improve the sensitivity of smear microscopy would facilitate early tuberculosis (TB) diagnosis and disease control, especially in low-income countries where positive predictive value is high. C18-carboxypropylbetaine (CB-18) a zwitterionic detergent that helps compensate for innate buoyancy mycobacteria, potentially enhancing recovery by centrifugation. Previous data suggest CB-18 may increase smear, culture, molecular amplification diagnostic testing. The goal present study was evaluate if technique using light could be improved treating respiratory samples with CB-18. In first phase, specimens were collected consecutively from patients suspected pulmonary tertiary-care hospital Rio de Janeiro, Brazil (236 analyzed). After protocol modifications, another 120 evaluated. standard N-acetyl-l-cysteine sodium hydroxide (NALC-NaOH) treatment, concentration centrifugation, Ziehl-Neelsen staining. Culture on Lowenstein-Jensen slants performed all use as “gold standard.” No undergoing active TB treatment included. initial processing resulted 59.6% specificity 96.8% compared 66.0% 96.8%. Using modified protocol, increased 71.4% 97.0% versus 61.9% 99.0%. yield acid-fast bacillus absence fluorescence PCR NALC-NaOH not significantly different, although power detect difference assay low.