Bacteremia in a Veterans Administration Medical Center (1961-1981).

Laboratory data on blood cultures were reviewed for the period 1961-1981. Blood cultures accounted for 18% of all bacterial cultures. Nine percent of all blood cultures were positive for growth, including pathogens and contaminants. Of these, 21% wer contaiminants. Staphylococcus epidermidis was the most common contaminant while Escherichia coli and Staphylococcus aureus were the most frequently occurring pathogens, respectively. Four percent of all positive blood cultures, involving pathogens, had multiple organisms with E. coli the most common. There was no drastic change in the frequency of occurrence of Gram negative or positive isolates over the years, but certain pathogens like Proteus mirabilis, Serratia sp. and Group A Streptococci were more common from 1971-81 than 1961-70. One percent of all patients with positive blood cultures had the same organism for two months or longer. Analysis of these longer occurring infections yielded a mean of 15, median of 7 and range of 2-87 months. E. coli was the most common pathogen in these chronic infections, followed by S. aureus and Streptococcus pneumoniae, respectively.