Sputum conversion among patients with pulmonary tuberculosis: are there implications for removal of respiratory isolation?

Abstract

High initial sputum bacillary counts and drug resistance result in delayed culture conversion. This should be taken into account when decisions regarding the potential discontinuation of isolation are made. The early identification of drug resistance is important for effective infection control in hospitals.

Prevention of nosocomial transmission of extensively drug-resistant tuberculosis in rural South African district hospitals: an epidemiological modelling study

“…Falsenegatives (one minus sensitivity, multiplied by the population tested) were subjected to the standard therapy efficacy value. Furthermore, MDR-TB patients receiving second-line treatment reverted to non-infectious status over the course of 5.5 weeks, which is simulated by inserting this rate of conversion into Equations 10 through 18 [70].…”

Role of 2-month sputum smears in predicting culture conversion in pulmonary tuberculosis

“…Documentation of sputum culture conversion is also recommended as a necessary criterion before completion of anti-TB treatment in current treatment guidelines [5]. Based on the high predictive value of sputum culture conversion in treatment response [4,6,7], identification of the clinical factors that are associated with a lower sputum culture conversion rate is of crucial importance in PTB management [8][9][10].In spite of the high accuracy of sputum culture conversion in the assessment of treatment response, the long yield time limits its usefulness in clinical practice. As a simple and rapid test, sputum smears are frequently adopted as a substitute for sputum cultures to evaluate infectivity and treatment effectiveness.…”

“…Documentation of sputum culture conversion is also recommended as a necessary criterion before completion of anti-TB treatment in current treatment guidelines [5]. Based on the high predictive value of sputum culture conversion in treatment response [4,6,7], identification of the clinical factors that are associated with a lower sputum culture conversion rate is of crucial importance in PTB management [8][9][10].…”

Can treatment delay be utilized as a key variable for monitoring the pool of infectious tuberculosis in a population?

“…Three recent studies estimated the median time to sputum culture conversion after first-line treatment to 28 days [37], 33 days [38] and 34 days [39], but the viability of the organisms rapidly deteriorate after treatment onset [40]. From several studies conducted in the 1960s, the praxis of releasing the hospitalized ss+ patient from isolation after two weeks on a regime including rifampicin was established, and is still the part of authoritative recommendations [41].…”