Anti-tuberculosis drug resistance in strains of Mycobacterium tuberculosis isolated from patients in a tertiary hospital in Bahia

Abstract

Anti-tuberculosis drug resistance, particularly multiresistance, is a crucial issue in the control of tuberculosis (TB). This study estimated the prevalence of primary and acquired anti-tuberculosis drug resistance in strains of Mycobacterium tuberculosis isolated from hospitalized patients, to identify the risk factors for resistance, and to evaluate the its impact on hospital mortality for tuberculosis. Strains of Mycobacterium tuberculosis from 217 patients hospitalized for TB were analyzed. Subjects were recruited sequentially at a TB reference hospital in Salvador, Bahia, Brazil from July 2001 to July 2003. Multiresistant (MR) strains were defined as strains resistant to rifampicin and isoniazid. Of a total of 217 strains isolated, 41 (19.0%, 95%CI: 14.1-24.5%) were resistant to at least one drug. Prevalence of primary resistance was 7.0% (10/145), while a prevalence of 43.1% (31/72) was found for acquired resistance. Primary resistance to one drug alone was found in 2.1% (3/145) and acquired monoresistance in 5.6% (4/72). Prevalence of MR strains in general was 14.3% (31/217), of which 4.2% (6/145) consisted of primary MR and 34.7% (25/72) of acquired MR. Three strains showed resistance to more than one drug, but were not classified as MR. In the multivariate analysis, abandoning treatment remained strongly associated with resistance (adjusted OR: 7.21; 95%CI: 3.27-15.90; p<0.001) following adjustment for 3 potential confounders (gender, alcohol dependence and HIV-infection). An association was found between resistance and mortality from tuberculosis, even after adjustment for HIV status, age, sex and alcohol dependence (adjusted OR: 7.13; 95%CI: 2.25-22.57; p<0.001). High prevalences of resistance, principally acquired resistance including MR, were found in patients hospitalized for TB in Bahia. This finding was strongly associated with having abandoned treatment, and confirmed the need to standardize the procedure for requesting sensitivity tests in this population at the time of hospital admission.

Prevalence and clinical predictors of drug‐resistant tuberculosis in three clinical settings in Calabar, Nigeria

“…Abandonment of TB treatment, presence of cavitary lesions on chest radiograph, younger age (<40 years) and male sex, were confirmed to be significant predictors of anti TB drug resistance in the present study. Similar findings have also been reported by other researchers in Brazil (8,16). Erratic or selective compliance to treatment and default causes M. tuberculosis to be exposed to sub-lethal doses for insufficient durations.…”

“…Numerous risk factors have been identified for DR‐TB. They include defaulting on TB treatment, advanced disease on chest radiography (pulmonary cavities) and history of imprisonment . Others include young adult age, male sex and alcohol dependence .…”

Primary bacillary resistance in multidrug-resistant tuberculosis and predictive factors associated with cure at a referral center in São Paulo, Brazil

“…It was amazing to find the proportion of 36% of primary MDR-TB in this sample, once, in Brazil, the rate of this descriptor is very low, around 4% 3 11 , 23 , 25 - 27 It is worth to remember that many patients who showed resistance came from other services and were, afterwards, assisted at the reference center mentioned here, which characterizes that the percentage of the general population is lower than what is shown in the sample.…”

Prevalence of multidrug‐resistant tuberculosis in Latin America and the Caribbean: a systematic review and meta‐analysis

“…1604 citations were later deleted, resulting in 200 selected references for full‐text screening. After reading the full texts of the 200 articles, 143 were excluded, and 57 articles were included in our review [8‐64]. Thirty‐four of 57 publications included data from more than one population type, yielding an equivalent of 91 studies ( n = 32 962 participants).…”