Background: Overuse of antibiotics for viral respiratory illness contributes to antibiotic resistance. Understanding patterns of prescription could help inform policies to curtail overuse.
Methods: We studied influenza like infection (ILI) among subjects 0-65y at five military hospitals 2010-2014. Nasopharyngeal swabs collected within 72 hours of illness onset were tested by a multiplex PCR detecting bacteria and viruses. Demographics, antibiotic use and symptoms on days 0 and 7 were collected. We categorized subjects as no use, early use <72 hours from illness onset (EU) or late use (LU) of antibiotics. Antibiotics were prescribed at provider discretion, and providers did not know PCR results.
Results: Antibiotics were prescribed to 200/785 (25.5%) subjects, with 124(62%) EU. Children were more likely to receive antibiotics than adults (32.3% vs. 22.8%, p<0.01); however, the timing of receiving antibiotics among users did not differ between age groups (p=0.19). Sex, race, tobacco exposure, obesity, daycare attendance, receipt of flu vaccine and neuraminidase inhibitor use were not related to antibiotic use patterns. There was no difference in antibiotic use pattern across the four viral respiratory seasons, but more antibiotics were used in the first season (33.3% versus 20.8- 22.5%, p=0.008).<span" roman"="Roman"" new="New">Both adults and children with more severe lower respiratory symptoms on presentation were more likely to receive antibiotics (p=.001 and .03, respectively). In addition, adults with detection of bacterial pathogens only were more likely to receive antibiotics (p=.001), in particular, those having GABS detection (p=.03). Adults with Flu A less often received any antibiotics (p=.02) and those with HMPV were more often LU (p=.001), when compared to other viruses. No pattern of specific etiology among children was related to antibiotic use.
Conclusion: In our population with ready access to free healthcare, antibiotic use in ILI was more common in pediatrics and had no correlation to bacterial detection. Potentially rapid PCRs would be most useful in pediatric primary care portals to reduce antibiotic overuse in ILI. LU in adults with HMPV suggests that HMPV may lead to a higher rate of secondary bacterial infection in adults than do other viral etiologies of ILI.