Levofloxacin - Antibiotic Abuse and Bacterial Resistance

Antibiotic Abuse and Bacterial Resistance

See also: Antibiotic abuse and Antibiotic resistance

Resistance to levofloxacin and other fluoroquinolones may evolve rapidly, even during a course of treatment. Numerous pathogens, including Staphylococcus aureus, enterococci, and Streptococcus pyogenes now exhibit resistance worldwide. There are three known mechanisms of resistance. Some types of efflux pumps can act to decrease intracellular quinolone concentration. In gram-negative bacteria, plasmid-mediated resistance genes produce proteins that can bind to DNA gyrase, protecting it from the action of quinolones. Finally, mutations at key sites in DNA gyrase or Topoisomerase IV can decrease their binding affinity to quinolones, decreasing the drug's effectiveness.

Years ago, the FDA had added warnings regarding the proper use of Levaquin within the package inserts to combat such prescription abuse. Advising physicians that levofloxacin: "...should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria...."

Though considered to be a very important and necessary drug required to treat severe and life-threatening bacterial infections, the associated prescription abuse of levofloxacin remains unchecked, which has contributed to the problem of bacterial resistance. The overuse of antibiotics, such as happens with children suffering from otitis media, has given rise to a breed of super-bacteria that are resistant to antibiotics entirely.

Fluoroquinolones, including levofloxacin, had become the most commonly prescribed class of antibiotics to adults in 2002. Nearly half (42%) of these prescriptions were for conditions not approved by the FDA, such as acute bronchitis, otitis media, and acute upper respiratory tract infection, according to a study that was supported in part by the Agency for Healthcare Research and Quality. In addition, they are commonly prescribed for medical conditions that are not even bacterial to begin, with such as viral infections, or those to which no proven benefit exists.