Antibiotic Use Associated with Confirmed Influenza, Pertussis, and Nontyphoidal Salmonella Infections

Purpose: Antibiotics are not the recommended treatment for uncomplicated influenza or nontyphoidal salmonella infections, whereas they are for current pertussis infection. We investigated adherence to these recommendations in a population of older community-dwelling adults. Methods: Population-based prospective cohort study of Australian adults 45 years of age and older followed by record-linkage to laboratory-confirmed influenza, pertussis, and nontyphoidal salmonella notifications, hospitalization records, and antibiotic dispensing data from January 1, 2009 to December 31, 2015. Proportions of those with infections who were prescribed antibiotics were estimated, and characteristics associated with antibiotic prescribing were examined. Results: There were 1,056 influenza, 151 pertussis, and 334 nontyphoidal salmonella cases in the cohort eligible for analysis. Antibiotics were dispensed in 56.2% (594/1,056) of influenza, 78.8% (119/151) of pertussis, and 39.5% (132/334) of nontyphoidal salmonella cases within the +/- 10-day window around the infection onset date. The likelihood of antibiotic dispensing did not differ according to most participant characteristics examined, including whether cases had an associated hospitalization, their age, and recorded comorbidities. Macrolides were the predominant class of antibiotics dispensed for pertussis (79%), whereas both beta-lactams (36.3%) and macrolides (35.4%) were used for cases of influenza. There was no dominant antibiotic class dispensed among those with nontyphoidal salmonella. Conclusions: Given concerns regarding increasing antibiotic resistance, the high proportion of adults with influenza and nontyphoidal salmonella cases dispensed antibiotics indicate the need for further strengthening of antimicrobial stewardship by raising education and awareness of guidelines for managing these infections.