Coordinating Opioid Use Treatment Through Medical Management With Infection Treatment (Project COMMIT)

Inclusion Criteria: * Adults able to provide written informed consent in English or Spanish; * Current hospitalization with a suspected or known bacterial or viral (HIV/HCV/HBV) infection including but not limited to bacteremia, Candidal fungemia, osteomyelitis, endophthalmitis, septic thrombophlebitis, infected pseudoaneurysm, endocarditis, skin/soft tissue infection (SSTI), or septic arthritis; * Current moderate-to-severe OUD (DSM-5); * Willing to accept assignment to either ID/LAB or TAU, and to participate in research follow-up visits. Exclusion Criteria: * Severe medical or psychiatric disability making participation unsafe (e.g. imminent suicide risk); * Pregnancy, planning conception, or breast-feeding for female participants; * Allergy, hypersensitivity or medical contraindication to buprenorphine; * Moderate-severe liver impairment in the judgment of the study investigator; * Preexisting enrollment on methadone or buprenorphine (SL-B) maintenance AND intending to remain on methadone or buprenorphine maintenance upon discharge (patients already under effective treatment for OUD do not represent the target population of untreated OUD patients entering hospitals, nor would we want to disrupt established effective treatment). * Inability or unwillingness of subject to give informed consent.