Multidrug-resistant tuberculosis in the Amazonas State, Brazil, 2000-2011

SETTINGS

Amazonas is facing increasing challenges in tuberculosis (TB) control, with nearly 3000 cases per year, and multidrug-resistant TB (MDR-TB) may jeopardise the TB control programme.

OBJECTIVE

To assess the number of MDR-TB cases in the Amazonas and to improve estimates of the burden of TB.

DESIGNS

The Brazilian National Mandatory Disease Reporting System (SINAN) and the Brazilian Epidemiological Surveillance System of Multidrug Resistance (TBMR) were searched for MDR-TB cases in the State of Amazonas from 2000 to 2011.

RESULTS

Eighty-one MDR-TB cases were notified. The rates of primary MDR-TB, initial MDR-TB during the first treatment regimen and acquired MDR-TB were respectively 3.8%, 13.7% and 82.7%; 26.9% of previously treated patients had ⩾ 4 treatment cycles. The MDR-TB cases reported 263 contacts, only 35.0% of whom were examined. The cure and death rates among the 81 patients with MDR-TB were respectively 45.7% and 25.9%.

CONCLUSIONS

The number of MDR-TB cases seems incompatible with the high TB prevalence in the Amazonas. Most patients were unaware of contact with TB patients. TB is endemic in the Amazonas. This highlights the need for improving resistance investigation among all TB cases.

Primary drug resistance among pulmonary treatment-naïve tuberculosis patients in Amazonas State, Brazil

BACKGROUND

Multidrug-resistant tuberculosis (MDR-TB) is the main indicator of previous treatment in tuberculosis (TB) patients. MDR-TB among treatment-naïve patients indicates infection with drug-resistant Mycobacterium tuberculosis strains, and such cases are considered primary drug-resistant cases.

OBJECTIVE

To estimate the prevalence of drug resistance in pulmonary TB (PTB) treatment-naïve patients and to identify the socio-demographic and clinical characteristics of the resistant population.

METHODS

A total of 205 treatment-naïve PTB patients from Manaus, Amazonas State, Brazil, were enrolled. Drug susceptibility testing (DST) was performed on all positive mycobacterial cultures using the 1% proportion method.

RESULTS

Positive M. tuberculosis cultures were obtained from only 175 patients for DST. The prevalence of primary MDR-TB was 1.7% (3/175); 14.3% (25/175) of the cultures presented resistance to at least one of the drugs. Resistance to streptomycin, isoniazid, rifampicin and ethambutol was respectively 8.6%, 6.9%, 3.4% and 2.3%. An association between TB patients with resistance to more than one drug and known previous household contact with a TB patient was observed (P= 0.008, OR 6.7, 95%CI 1.2-67.3).

CONCLUSIONS

Although the prevalence of primary MDR-TB currently is relatively low, it may become a major public health problem if tailored treatment is not provided, as resistance to more than one drug is significantly associated with household contact.