CONTROLLED COMPARATIVE-EVALUATION OF BACT ALERT FAN AND ESP 80A AEROBIC MEDIA AS MEANS FOR DETECTING BACTEREMIA AND FUNGEMIA/

During a one-year period, a total of 6,305 blood cultures were process ed in a tertiary-care teaching hospital; 6 to 12 ml of blood was inocu lated into both a BacT/Alert Pan aerobic bottle and an ESP 80A aerobic bottle, The FAN aerobic bottle contains an antimicrobial-absorbing ma terial; the 80A aerobic bottle does not, Bottles were processed on the ir respective continuous-monitoring blood culture instruments for np t o five days of incubation. Four hundred thirty-three cultures (6.9%) r epresenting 301 septic episodes in 235 different patients yielded 490 bacteria or yeasts thought to be clinically significant. Two hundred s eventy-five of the 433 presumed clinically significant positive cultur es (63.5%) representing 195 septic episodes and yielding 301 isolates were positive in both FAN and 80A bottles. One hundred nine significan t positive cultures (25.2%) (i,e,, cultures positive with an organism judged to be of probable clinical significance) from 70 septic episode s yielded 126 isolates only in FAN bottles, Conversely, the 80A bottle was exclusively positive in 49 instances (11.3%), representing 36 sep tic episodes and yielding 63 isolates, The higher rates of significant positive blood cultures, numbers of septic episodes documented, and n umbers of isolates recovered in FAN bottles versus 80A bottles were al l statistically significant (P < 0.05), Enhanced rates of detection of presumed clinically significant isolates in FAN bottles were largely accounted for by Staphylococcus aureus, members of the Enterobacteriac eae, and non-Pseudomonas aeruginosa miscellaneous gram-negative bacill i from patients receiving antimicrobial therapy at the time blood cult ures were obtained. Enhanced recovery of one organism group, the P-hem olytic streptococci, occurred in 80A. With one exception, detection ti mes were essentially equivalent in the two systems. The single excepti on pertained to streptococci and enterococci, which were recovered sig nificantly faster in 80A bottles. Three hundred thirty-eight of the 6, 305 blood cultures evaluated in this study (5.4%) were judged likely t o be contaminated. The percentages of probable contaminated cultures w ere as follows: 26.6% FAN and 80A; 42.3% FAN only; 31.1% 80A only (P < 0.05), Finally, the instrument false-positive rates for the two syste ms were 0.7% with FAN and 3.0% with 80A (P < 0.05), We conclude that w hile contamination sates were slightly higher with FAN than with 80A, use of PAN aerobic bottles in conjunction with the BacT/Alert system w ill yield significantly higher numbers of clinically significant blood culture isolates than 80A bottles and the ESP system. Furthermore, th is enhanced detection Is most conspicuous in patients receiving antimi crobial therapy at the time blood cultures are performed, probably due to the presence of an antimicrobial-absorbing material in FAN aerobic bottles.