Bacteremia develops during some infections and various bacteria. including
opportunistic pathogens, are usually involved. Blood cultures aid etiologic diagnosis and
guide treatment by determining antibiotic susceptibility of isolates. Lately, the most
frequently isolated organisms are known to be grain-negative bacilli, staphylococci and
enterococci, while frequent isolates during the preantibtotic era were well known
pathogens such as beta-hemolytic streptococcus, pneumococcus and meningococcus.
In this study, laboratory data on blood cultures the years 1969-1973 at Severance
hospital were analyzed to determine trends of bacteria isolation. During the 5-year
period, 9705 blood cultures from an undetermined number of patients were made and
1,194 positive cultures (799 patients) were obtained.
1. Frequently isolated bacteria in decreasing order were Sal. typhi, Enterobacteriaceae,
S.aureus, P. aeruginosa, alpha-hemolytic streptococcus, and enterococcus.
2. Ratio of annual isolation of Enterobacteriaceae to total positive cultures showed a
tendency of the organism to increase.
3. Frequently isolated bacteria from pediatric patients were Enterobacteriaceae and S.
aureus. In Patients in the 6-49 age group, Sal. typhi was most frequently found and
in patients of 50 years and over, it was Enterobacteriaceae.
4. Monthly isolation rate of Sal. typhi showed two peaks; one in June-July and another
in November.
5. Polymicroblal bacteremia were found in 2.4% of patients with positive blood cultures.
Most of the organisms concerned were those belonging to Enterobacteriaceae.
6. None of the Sal. typhi tested were resistant to chloramphenicol or to ampicillin with
Kirby-Bauer disc diffusion method. Many of the isolates of S.aureus and
Enerobacteriaceae were resistant to the routinely tested antibiotics.
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