A subfamily of transmembrane proteins from the superfamily of ATP-BINDING CASSETTE TRANSPORTERS that are closely related in sequence to ATP BINDING CASSETTE TRANSPORTER, SUBFAMILY B, MEMBER 1. When overexpressed, they function as ATP-dependent efflux pumps able to extrude lipophilic drugs, especially ANTINEOPLASTIC AGENTS, from cells causing multidrug resistance (DRUG RESISTANCE, MULTIPLE). Although ATP BINDING CASSETTE TRANSPORTER, SUBFAMILY B share functional similarities to MULTIDRUG RESISTANCE-ASSOCIATED PROTEINS they are two distinct subclasses of ATP-BINDING CASSETTE TRANSPORTERS, and have little sequence homology
Tuberculosis resistant to chemotherapy with two or more ANTITUBERCULAR AGENTS, including at least ISONIAZID and RIFAMPICIN. The problem of resistance is particularly troublesome in tuberculous OPPORTUNISTIC INFECTIONS associated with HIV INFECTIONS. It requires the use of second line drugs which are more toxic than the first line regimens. TB with isolates that have developed further resistance to at least three of the six classes of second line drugs is defined as EXTENSIVELY DRUG-RESISTANT TUBERCULOSIS
Drug Resistance, Multiple, Bacterial -- prevention & control : Addressing the threat of drug-resistant tuberculosis : a realistic assessment of the challenge : workshop summary / Robert Giffin and Sally Robinson, rapporteurs ; Institute of Medicine of the National Academies
