Seasonal and monthly variation of Streptococcus pneumoniae and other pathogens in bacteremia (1961-1981).

Laboratory data, on positive blood cultures, were reviewed for the period 1961-1981. A total of 1809 episodes of bacteremia and fungemia were evaluated as to monthly occurrence. Of these, 42% were due to Gram positive cocci, 51% to Gram negative bacilli, 5% to anaerobes and 2% to yeasts. When seasonal patterns were categorized, most were bi- or multiphasic except Streptococcus pneumoniae and Staphylococcus aureus which yielded mono- and aphasic patterns, respectively. These results show the occurrence of certain pathogens, like S. pneumoniae, to be linked with seasons or months of the year.