October 30, 2013

Preserving antibiotic arsenal for TB

Clinicians should be cautious about prescribing newer fluoroquinolone antibiotics to patients with TB risk factors; doing so may jeopardize the use of these agents against TB.

Fluoroquinolone antibiotics are an important part of regimens for multidrug-resistant tuberculosis (TB). Exposure to these agents prior to a TB diagnosis (for a different bacterial infection), however, may provoke drug resistance in Mycobacterium tuberculosis.

To assess whether the specific type of fluoroquinolone used before a TB diagnosis impacts the development of drug-resistant TB, Yuri van der Heijden, M.D., and colleagues performed a case-control study of TB patients reported to the Tennessee Department of Health from 2002-2009. Cases had fluoroquinolone-resistant M. tuberculosis isolates; controls had drug-susceptible isolates. The investigators found that the duration of exposure to newer fluoroquinolones (levofloxacin, moxifloxacin, gatifloxacin) – but not to older drugs (ciprofloxacin, ofloxacin) – was associated with the drug-sensitivity of M. tuberculosis and the frequency of drug-resistant mutations.

The findings, reported in the September International Journal of Antimicrobial Agents, support caution in prescribing newer fluoroquinolones to patients with TB risk factors – to avoid jeopardizing the use of these agents against TB.

This research was supported by National Institutes of Health grants AI063200, AI065298 and AI007474.

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