Overuse of antibiotics makes bacteria more drug resistant

Between 2002 and 2006, academic medical centers in the United States increased their use of antibacterial drugs. According to new research published in the November 10 issue of Archives of Internal Medicine, a greater use of broad-spectrum agents and the antibiotic vancomycin accounted for much of this increase.

The researchers used claims data from university teaching hospitals and measured antibiotic use between 2002 and 2006. In addition, pharmacists or physicians who were specialists in infectious diseases in 19 hospitals filled out a 12-question survey in 2006 and 2007. The questions gathered data on factors thought to influence antimicrobial drug use, such as the existence of a hospital stewardship program to help control antibiotic use.

In 35 hospitals studied in 2006, about 63.5% of discharged patients (492 721 of 775 731) received an antibacterial drug. Data from five years in 22 hospitals revealed that between 2002 and 2006, the average total antibacterial use increased from 798 days of therapy per every 1,000 patient-days to 855 per 1000 patient-days.

An analysis of antibiotic use by drug class found that fluoroquinolones were most frequently used, and over the five years their use stayed constant. However, there were five broad-spectrum antibiotic classes, acting against several different kinds of bacteria, which had significant increases in usage. "The other change contributing to the increase in total use was the marked increase in the use of vancomycin," note the authors. "During five years, the mean vancomycin use increased by 43 percent." Between 2004 and 2006, vancomycin became the most commonly used antibacterial in the hospitals.