CDC updates tularemia treatment, prophylaxis recommendations
Fluoroquinolones (ciprofloxacin or levofloxacin) and doxycycline are now recommended as first-line treatments for tularemia outbreaks of any size, the CDC said, while other drugs have been downgraded to third-tier options due to their side effects.
The CDC updated recommendations for treating or postexposure prophylaxis of tularemia, an uncommon but potentially serious disease caused by the gram-negative coccobacillus Francisella tularensis.
Tularemia occurs naturally in the U.S., but because it has a low infectious inoculum, it is also classified as a potential bioterrorism agent. The recommendations were published Oct. 2 in MMWR.
Notable changes from previous recommendations, published in 2001, include the use of two overarching categories: treatment, and pre- and postexposure prophylaxis. If intentional release of F. tularensis is confirmed or strongly suspected, clinicians are encouraged to treat symptomatic patients with two distinct classes of antimicrobial drugs, at least one of which is considered first-line, until antimicrobial susceptibility patterns are known, the CDC said. This treatment regimen increases the likelihood that at least one effective drug would be given.
Ciprofloxacin and doxycycline have been shifted from alternative choices to first-line treatment options. Levofloxacin has been added as a first-line drug for treatment and prophylaxis. Streptomycin is now a third-tier treatment option. Although highly effective, it has greater risk for certain adverse events compared with gentamicin and has limited availability in the U.S. Azithromycin has been added as an alternative option for prophylaxis and as a third-tier option for treatment. Chloramphenicol was downgraded to a third-tier option for treatment because of the risk for serious adverse events.
Rifampin was added as a third-tier option for prophylaxis. While it has in vitro activity against F. tularensis, concerns for induced resistance limit its use to combination therapy in certain clinical situations. During a response to a large-scale event, rifampin is a viable option for prophylaxis when supplies of first-line agents are unavailable, according to the CDC.
“These guidelines use newer evidence generated in the past 2 decades to provide recommendations for management of tularemia resulting from naturally occurring or bioterrorism-related transmission,” said the CDC. “These recommendations can aid health care providers during clinical care of patients with tularemia and can be used to develop and strengthen emergency response plans and preparedness at the local, state, and Federal levels.”