Populations with a high prevalence of AIDS-immunocompromised people are more likely to see the emergence of antibiotic-resistant bacterial infections, according to a study coauthored by researchers at the University of Tennessee, Knoxville, and published in PLOS One. “People with weakened immune systems are more vulnerable to opportunistic bacterial infections and are therefore frequently prescribed antibiotics to prevent or treat these infections;” said Nina Fefferman, a professor in UT’s Department of Ecology and Evolutionary Biology and coauthor of the study.

Immune systems

“This increases the exposure of those bacteria to antibiotics, giving them more chances to evolve to become resistant to the medication and contributing to the current serious public health threat of drug-resistant diseases.” The research was led by Ashley DeNegre, who at the time of the study was an ecology and evolutionary biology PhD student at Rutgers University-New Brunswick.

Kellen Myers, research assistant in UT’s Department of Ecology and Evolutionary Biology and the UT-based National Institute of Mathematical and Biological Synthesis; also participated in the research. For the study; scientists used mathematical models to integrate and extend results from many previous studies to consider the effect on the emergence of antibiotic resistance in two populations: the African nation of Swaziland, where there was a reported HIV/AIDS prevalence of 27.4% of the population, and Indonesia; in southeast Asia; where there was a much lower reported HIV/AIDS prevalence of 0.46 %.

Epidemiological patterns

The results provide a better understanding of epidemiological patterns in populations with a high number of immunocompromised people due to AIDS and HIV; with special attention to low-income communities in the developing world. “This work will hopefully help inform public health decision makers about how antibiotic stewardship should be tailored differently in high-prevalence AIDS-affected communities to help combat the rising global risk of drug-resistant infections;” said Fefferman.

People with weakened immune systems are especially vulnerable to infection. They may have problems with infections that recur, persist longer than usual, or are atypically severe. Minor infections like the common cold can be life-threatening. Recurrent infections can put patients who become “frequent fliers” at hospitals at greater risk of further contracting hospital-acquired infections.

As a result of this vulnerability, the immunocompromised bear a higher burden during disasters. Planning for public health measures and emergency preparedness requires consideration of the needs of immunocompromised people to reduce that disproportionate burden. Usually this kind of planning would start with a look at the incidence and prevalence of a public health issue; yet these measures don’t seem to exist for immunocompromised patients as a group.

Organ transplant

The diversity of causes of immunodeficiency may be the main reason that no one tracks the total number of affected patients. In a 2002 paper, researchers estimate that around 10 million people are immunocompromise; but they counted only “recipients of organ transplants; individuals with diagnosed and undiagnosed HIV infection or AIDS, and patients with cancer.”
Patients can either be born with an immune deficiency or they can acquire one. While it’s relatively rare to be born with an immune deficiency; over 200 different hereditary and genetic defects can cause a “primary” immunodeficiency. Acquired immune deficiency also has a variety of causes; therefore  including cancer and its treatments; the immunosuppressant drugs taken by transplant recipients and people with autoimmune disorders, malnutrition, aging; and HIV/AIDS. The estimate of 10 million mentioned above excludes a number of these groups.