Household contacts of patients with TB likely to have same drug resistance
Household contacts of patients with drug-resistant TB should be treated for the infection under the assumption that they are also infected with drug-resistant TB, according to a systematic review and meta-analysis in Clinical Infectious Diseases.
“We wanted to help make evidence-based recommendations for the clinical management of household members of patients with drug-resistant tuberculosis (TB). There is some disagreement on how to manage these household members, particularly in countries where there is a high prevalence of TB,” Courtney M. Yuen, PhD, instructor at Harvard Medical School and associate epidemiologist in the division of global health equity at Brigham and Women’s Hospital, told Healio.
Yuen explained that TB disease or infection caused by drug-resistant bacteria must be treated with different drugs than disease or infection caused by drug-susceptible bacteria. As a result, when a household member of a patient with drug-resistant TB is diagnosed with TB disease or infection, the clinician must decide which drugs to use.
“Some clinicians say that household members are likely to be infected with the same drug-resistant bacteria as the initial patient,” Yuen said. “Others say that household members are just as likely to have been infected outside the home with TB that is not drug resistant.”
Yuen and colleagues performed a systematic review and meta-analysis of studies published through July 24, 2018 that reported drug-resistant TB and secondary cases within patient households. The researchers then estimated resistance profile concordance defined as the percentage of secondary cases whose Mycobacterium tuberculosis strains were resistant to the same drugs as the strains from their index cases as well as isoniazid and rifampin concordance, which was defined as whether or not the index and secondary cases had identical susceptibilities for isoniazid and rifampin only.
The researchers identified 33 eligible studies that evaluated resistance profile concordance between 484 secondary cases and their household index cases. According to Yuen, the results demonstrated that, in households of patients with TB that was resistant to at least one of the two main first-line therapies for TB (isoniazid or rifampin), 83% of household members with TB also had resistance to these drugs. However, only 54% of household members with TB had a full drug resistance profile that matched that of the initial patient, she continued.
According to the study results, the pooled resistance profile concordance was 54.3% (95% CI, 40.7-67.6). Pooled isoniazid/rifampin concordance was 82.6% (95% CI, 72.3-90.9). A sub-analysis of 16 studies conducted in countries with a high TB burden demonstrated similar concordance estimates. Insufficient data prevented the researchers from conducting a sub-analysis among secondary pediatric cases.
“If a household member of a patient with drug-resistant TB is diagnosed with TB disease or infection, clinical management should assume drug resistance,” Yuen said. “However, it is still important to perform drug resistance testing for any household member with TB disease because he or she may need to be treated with a different regimen than the initial patient.”