The Oregon State University study, published in Infection Control and Hospital Epidemiology, suggests the incidence of diseases caused by these bacteria may be as much as 46 percent higher in summer than in winter.

The researchers said recognizing such seasonal trends may improve disease diagnosis, prompt treatments and lead to better interventions to prevent the infections in the first place.

"Gram-negative bacteria are a frequent cause of urinary tract, gastrointestinal and respiratory infections, as well as more serious things like pneumonia, wound or blood infections," study researcher Jessina McGregor of the OSU College of Pharmacy said in a statement. "Everyone knows there is a seasonality to some viral infections such as influenza or the common cold, but we're now finding that some of these bacterial infections peak in the heat of summer."

Working with scientists from OSU were researchers from the University of Maryland School of Medicine, the University of Florida and the Research Institute of the Hospital for Sick Children in Toronto. The findings were based on seven years of data from infections in a Baltimore hospital.