Comparison of the Yield of Tuberculosis among Contacts of Multidrug-resistant and Drug-sensitive Tuberculosis Patients in Ethiopia Using GeneXpert as a Primary Diagnostic Test
This study compared the yield of TB among contacts of multidrug-resistant tuberculosis (MDR-TB) index cases with that of drug-sensitive TB (DS-TB) index cases in a program setting.
A comparative cross-sectional study was conducted among contacts of sputum-smear-positive new index DS-TB cases and MDR-TB index cases. After contacts were screened, we used GeneXpert for the diagnosis of TB.
The study included 111 MDR-TB and 119 DS-TB index cases. A total of 340 and 393 contacts of MDR-TB and DS-TB index cases, respectively, were traced, of whom 331 among MDR-TB contacts and 353 for DS-TB contacts were screened. The presumptive TB cases were 20 (6%) and 41 (11%) for MDR-TB and DS-TB contacts, respectively. The prevalence of TB among MDR-TB and DS-TB contactswas 2.7% and 4.0%, respectively. The majority of the MDR-TB contacts diagnosed with TB had MDR-TB; the reverse was true for drug-sensitive TB.
The yield of TB among contacts of MDR-TB and DS-TB using GeneXpert was high as compared to population-level prevalence. The likelihood of diagnosing RR (Rifampicin Resistant)-TB among contacts of MDR-TB index cases is higher in comparison with contacts of DS-TB index cases. The use of GeneXpert in DS TB contact investigation has an added advantage of diagnosing RR cases in contrast to using the nationally recommended AFB microscopy for DS TB contact investigation.