Antibiotic Prescription During Flu Season Appears to Increase Resistance

Researchers note that increasing the influenza vaccination rate could help reduce overprescription of some antibiotics and combat antibiotic resistance.

Certain antibiotics that are prescribed at very high rates during influenza season are responsible for driving increases in antibiotic resistance, results of a study by researchers at Princeton University suggest. The study, which investigated the seasonal relationship between antibiotic prescriptions and antibiotic resistance in the United States between 1999 and 2007, was published online on July 1, 2012, in Clinical Infectious Diseases.

The researchers used data on antibiotic usage from IMS Health, which covers more than 70% of all prescriptions filled by retail pharmacies in the United States, and data on antibiotic resistance from The Surveillance Network, an electronic repository of susceptibility test results from more than 300 labs across the country. They looked at the effect of usage of aminopenicillin, fluoroquinolone, trimethoprim/sulfamethoxazole, and tetracycline on resistance of Escherichia coli to drugs in these classes.

Their results showed that the prevalence of resistant E. coli was significantly correlated with prescription rates of several antibiotics 1 month earlier. The cross-correlation coefficient was 0.22 for the aminopenicillins and 0.24 for the fluoroquinolones. Both of these antibiotic classes are prescribed at high rates; antibiotic classes prescribed at lower rates did not have a significant correlation with increased resistance. In addition, the researchers found that the prevalence of ciprofloxacin-resistant methicillin-resistant Staphylococcus aureus (MRSA) was significantly correlated with fluoroquinolone prescription rates 1 month earlier. This finding is particularly striking as it suggests that patterns of antibiotic use in the community have the ability to affect types of antibiotic resistance found primarily in hospital settings.

The researchers suggest that the likely driver of the increased antibiotic prescriptions is the rise of influenza and other respiratory infections in the cold months, for which antibiotics are frequently not appropriate. They note that increasing the influenza vaccination rate could help reduce the overprescription of some antibiotic classes and help stem the increase in antibiotic-resistant infections. In particular, they note that efforts to reduce MRSA and other forms of antibiotic resistance in the hospital setting are unlikely to be successful unless they are coordinated with campaigns to combat unnecessary antibiotic use on the community level as well.