Family Cluster of Rifampicin-Resistant Tuberculosis in a Municipality in Southern Brazil

In 2021, a 21-year-old female patient was diagnosed with bilateral cavitary pulmonary tuberculosis with rifampicin resistance confirmed by GeneXpert molecular testing. She initiated standard treatment for RR-TB (6Bdq+Lfx+Lzd+Trd/12Lfx+Lzd+Trd), evolving favorably after an adverse reaction to terizidone. She was transferred to southern Brazil in 2022, when contact investigation was conducted. Her cousin, a 22-year-old male living in the same household, was diagnosed with unilateral cavitary pulmonary tuberculosis, also with positive molecular testing and culture positive for rifampicin-resistant Mycobacterium tuberculosis. He initiated the same therapeutic regimen with good response. Subsequently, the partner of the initial patient, a 26-year-old male, developed persistent cough and was diagnosed with RR-TB. Diagnosis was confirmed by GeneXpert molecular testing and positive culture, and treatment was initiated with the BPaL regimen (Bedaquiline 3 × /week, Pretomanid, and Linezolid), with favorable clinical evolution. The couple’s son, a 5-month-old male infant, was investigated as a contact and diagnosed with pulmonary tuberculosis with positive molecular testing for Mycobacterium tuberculosis, with indeterminate traces for rifampicin resistance. He initiated the 6Bdq+Lfx+Lzd+Trd/12Lfx+Lzd+Trd regimen, with satisfactory therapeutic response to date. None of the patients had positive HIV serology, alcohol use, or immunosuppressive conditions. All presented pulmonary disease, with cavitary patterns in adults and compatible imaging findings in the infant.