TABLE 2.

False-positive rates for organisms that frequently represent contamination

Organism(s)Source
1,585 blood culture-positive episodes from 3 U.S. hospitalsa497,134 blood cultures from 640 U.S. institutionsb
% of all positive cultures (n = 1,585)Contamination rate (%)% of all positive culturesContamination rate (%)
Coagulase-negative staphylococci44.382Not reported62-63
Corynebacterium spp. (other than C. jeikieum)33.496Not reported68-78
Bacillus spp.0.891.7Not reported68-70 (other than B. anthracis)
Propionibacterium acnes 3.0100Not reported84-85
Viridans group streptococci4.549.3Not reported32-33
Clostridiium perfringens 0.876.9Not reportedNot reported
  • a Data are from reference 155.

  • b Data are from reference 113.