The interaction of human immunodeficiency virus and multidrug-resistant Mycobacterium tuberculosis

Abstract

The association of human immunodeficiency virus infection (HIV) with increased rates of multidrug-resistant (MDR) tuberculosis (TB) in the United States (US) has been well-documented [1–4]. Furthermore, a number of studies conducted in the US have identified HIV infection as a risk factor for acquired drug resistance [5–6]. During the late 1980s and early 1990s, large outbreaks of MDRTB primarily involving HIV-infected patients occurred in hospitals, correctional facilities and other institutional settings in the US [7– 12]. Similar outbreaks also occurred in other established market economies during the 1990s [13–17]. In these outbreaks, active TB developed within a few weeks or months following exposure to an infectious MDRTB patient, leading to multiple transmissions in a short period of time. Furthermore, the outbreaks were characterized by delayed diagnosis, extended infectious periods, and delays in initiation of appropriate treatment, which contributed to high mortality and morbidity. More recent data have documented a decline in new MDRTB cases and improvement in clinical outcomes for HIV-infected patients [2,18–20]. This chapter describes trends in MDRTB and HIV co-infection and key characteristics of MDRTB patients with HIV infection in the US based on national surveillance data from 1993–1997, and summarizes the key findings in published outbreaks of MDRTB involving HIV-infected persons in US and other established market economies. This chapter will demonstrate that the association of HIV infection with drugresistant TB is largely attributable to nosocomial outbreaks of MDRTB in various congregate settings. However, HIV-infected patients may be at some increased risk of acquired drug resistance, particularly rifampicin monoresistance, and various plausible but unproven explanations for this association are presented.