TABLE 1.
Microorganisms recovered from aerobic BCs performed with BacT/Alert and Bactec culture mediaa
| Microorganism (no.) | No. (%) of isolates recovered from indicated aerobic BC bottles |
Pc | ||
|---|---|---|---|---|
| BacT/Alert and Bactecb | BacT/Alert only | Bactec only | ||
| Gram negative (65) | 58 (89.2) | 0 | 7 (10.8) | 0.006 |
| Escherichia coli (22) | 19 (86.4) | 0 | 3 (13.6) | NS |
| Klebsiella pneumoniae (14) | 13 (92.9) | 0 | 1 (7.1 | NS |
| Morganella morganii (2) | 2 | 0 | 0 | NA |
| Proteus mirabilis (3) | 2 | 0 | 1 | NA |
| Pseudomonas aeruginosa (23) | 21 (91.3) | 0 | 2 (8.7) | NS |
| Stenotrophomonas maltophilia (1) | 1 | 0 | 0 | NA |
| Gram positive (48) | 37 (77.1) | 9 (18.7) | 2 (4.2) | 0.024 |
| Enterococcus faecalis (3) | 1 (33.3) | 2 (66.6) | 0 | NA |
| Staphylococcus aureus (19) | 14 (73.7) | 3 (15.8) | 2 (10.5) | NS |
| Coagulase-negative staphylococci (19)d | 17 (89.5) | 2 (10.5) | 0 | NS |
| Streptococcus anginosus (3) | 2 | 1 | 0 | NA |
| Streptococcus constellatus (1) | 1 | 0 | 0 | NA |
| Streptococcus pneumoniae (3) | 2 | 1 | 0 | NA |
| Yeasts (10) | 7 (70) | 1 | 2 | NS |
| Candida albicans (7) | 5 | 0 | 2 | NS |
| Candida parapsilosis (1) | 0 | 1 | 0 | NA |
| Candida tropicalis (2) | 2 | 0 | 0 | NA |
| Total isolates (123) | 102 (82.9) | 10 (8.1) | 11 (8.9) | NS |
| Treatment positive (32) | 31 | 0 | 1 | NS |
| Treatment negative (91) | 71 | 10 | 10 | NS |
Analysis was limited to the 212 aerobic BCs (BacT/Alert FA Plus and Bactec Plus Aerobic/F) that grew clinically relevant microbial species. The terms treatment negative and treatment positive refer to cultures drawn before and after initiation of empirical antimicrobial therapy, respectively (see Materials and Methods). Abbreviations: BC, blood culture; NS, not significant; NA, not applicable. Percentages were not calculated when ≤5 microorganisms were isolated.
Isolates of the same species recovered from BacT/Alert and Bactec bottles in a given episode were counted as 1 isolate.
Statistical significance was assessed by comparing the percentage of isolates recovered from BacT/Alert bottles (column 2 + column 3/column 2 +column 3 + column 4) versus percentage of isolates recovered from Bactec bottles (column 2 + column 4/column 2 +column 3 + column 4) (two-sample test of proportions).
Includes Staphylococcus epidermidis (n = 16), Staphylococcus haemolyticus (n = 2), and Staphylococcus hominis (n = 1).