To The Editor:
We read with great interest the article "In Vivo Efficacy of Antimicrobial-Coated Devices" (2007;89:792-7), by Darouiche et al., and acknowledge the excellent experimental work.
With active tuberculosis developing in approximately nine million people every year and 1.7 million deaths resulting from tuberculosis infection annually, tuberculosis is far from under control and is a major public health problem in Asia and Africa1. The increasing spread of multidrug-resistant tuberculosis and the recalcitrant nature of persistent infections pose additional challenges to treatment with currently available antituberculous drugs1. The majority of people in a developing country like India are routinely exposed to Mycobacterium tuberculosis, and the prevalence of Mycobacterium tuberculosis infection in all age groups in India is around 40%2.
The antibiotic levels on the implant used in the study are low; the coated implant, if made for humans, would increase rifampin levels proportionally. Our concern is that the suboptimal use of antituberculous medications creates a selective milieu in the host's tissues where the initially low numbers of drug-resistant mutants are able to replicate, eventually replacing the initially drug-susceptible Mycobacterium tuberculosis population3. Although this study used a companion drug to prevent the development of resistance in Staphylococcus aureus, there is no companion drug against Mycobacterium tuberculosis, thus increasing the chance of selecting resistant mutants. A study4 has also shown emergence of rifampin resistance in methicillin-resistant Staphylococcus aureus in tuberculosis wards, and, hence, it is possible that rifampin resistance in Mycobacterium tuberculosis could occur when rifampin is used to treat methicillin-resistant Staphylococcus aureus.
Rifampin-minocycline is a useful drug in the management of implant-related infection, but a word of caution must be expressed regarding its use, especially in developing countries. The possibilities of adding to the burden of multidrug-resistant tuberculosis in such a scenario would seriously set back the public health program of tuberculosis control, which is a greater public health concern and one in which rifampin is a very important drug.