Since the 1990s, a trend has been seen in which the number of hospital-acquired infections increase when the weather gets warmer, according to an article on the Popular Science website.
The first observations occurred when there seemed to be more troubles with bacterium Acinetobacter in the summer.
A closer inspection of the species showed there was no difference in the target; the lungs, gastrointestinal tract and bloodstream all had the same trend, the article said.
The only common factor was they were all Gram-negatives, the article said Finding the link between seasonality of infections and Gram-negative bacteria has been difficult. One possible option is the skin.