Is the antibiotic that was administered as a protective measure in the U.S. during the anthrax scare in 2001 becoming less effective against other bacteria because of overuse?
In 1994, ciprofloxacin (Cipro canadian, Bayer) was found to be efficacious against 86% of bacterial samples analyzed; by the year 2000, the rate had declined to 76%.
In a multicenter study, researchers examined data on infections in hospitalized patients in 43 states, including Washington, DC, from 1994 to 2000. Ailments included respiratory and urinary infections caused by various bacteria.
Many organisms had grown resistant to fluoroquinolones, a class of antibiotics that includes ciprofloxacin. The anthrax bacterium was not studied, and the researchers noted that their findings did not mean that the drug was becoming less effective against anthrax, which often affects animals but rarely humans.
Bacteria that became increasingly resistant during the study were all common causes of infections and included Escherichia coli.
When a drug is used repeatedly against the same organism, it has the potential to mutate into drug-resistant forms. The greater resistance came at a time when physicians were increasingly prescribing generic ciprofloxacin and similar drugs for common ailments such as respiratory infections caused by viruses, which are unaffected by antibiotics, the researchers noted. They urged more judicious use of the floroquinolones to limit the downward trend.