One of the ‘low tech’ life-saving advances for HIV patients has been the prophylactic use of the antibiotic cotrimoxazole. Cotrimoxazole, a combination of two antibiotics, trimethoprim and sulfamethoxazole, is effective against bacteria, including Pneumocystis jiroveci pneumonia (“PCP”) and toxoplasmosis, two of the leading killers of AIDS patients. The WHO’s support of universal prophylaxis of HIV patients with cotrimoxazole will greatly increase the adoption of this critical disease prevention strategy.
Many developing countries have been reluctant to adopt the use of this drug as a prophylactic because cotrimoxazole is used to treat many other diseases, such as bacillary dysentery which kills roughly 1 million children per year worldwide. In addition, it was commonly thought that, in developing countries, that PCP and toxoplasmosis were not the primary killers of AIDS patients. If cotrimoxazole were not that effective as a prophylactic, the widespread use of cotrimoxazole could lead to the evolution of resistance to cotrimoxazole in non-target organisms (such as diarrheal E. coli).
However, recent evidence suggests that cotrimoxazole is effective even when resistance is demonstrated in vitro*, lowering infant deaths from PCP by 43% in one study. In Uganda, where PCP is not a major cause of AIDS related deaths, mortality was lowered by 45%, primarily to due the prevention of diarrhea. It remains to be seen what the long-term effects of bathing much of the globe in a dilute solution of cotrimoxazole on resistance to this antibiotic and other antibiotic resistances (many resistances are associated with each other through a variety of genetic and biochemical mechanisms, so selection for resistance to cotrimoxazole could ‘drag along’ resistance to other antibiotics). Hopefully, the WHO support will encourage widespread use of this life-saving therapy.
*The more I delve into the nitty-gritty of antibiotic resistance, the more I realize