We have been using Trimethoprim-sulfamethoxazole (TMP-SMX ) for years as prophylaxis for immunosuppressed HIV/AIDS patients. I have always been concerned that TMP-SMX prophylaxis may lead to antimicrobial resistance not only to TMP-SMX, but also to other antibiotics.
Clinical Infectious Diseases recently published an article and review of literature of TMP-SMX prophylaxis in HIV-infected and/or exposed individuals and the impact on bacterial resistance.
From a total of 501studies, only 8 studies were of high quality, of which only 2 had been specifically designed to answer this question. One good-quality study reported no change, and another good-quality study reported mixed findings; among HIV-exposed infants, TMP-SMX prophylaxis increased pneumococcal resistance to clindamycin but had no effect on pneumococcal resistance to penicillin, tetracycline, erythromycin, and chloramphenicol.
Of cohort studies assessing the impact on MRSA, the meta-analysis showed a protective effect of TMP-SMX prophylaxis on MRSA (relative risk, .29; 95% confidence interval, .12 - 0.7).
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| Clin Infect Dis 2011 May; 52(9):1184-94. |
One study reported an increase in colonization with vancomycin-resistant enterococcus.
This is a mixed bag of results, from few quality studies. The use of TMP-SMX prophylaxis protects against MRSA infection/colonization yet may increase resistance in pneumococci and enterococci.
From my perspective, the benefits of TMP-SMX use, as prophylaxis in HIV/AIDS patients, appears to outweigh the risks of bacterial resistance.
