Mean time to detection (hours) of residual contamination of organ culture medium by the three methods: visual, conventional and blood bottles. Of 14 bacteria initially inoculated, five were fully eradicated by the antibiotics in the organ culture medium and therefore did not appear in this table. Of the remaining nine bacteria and three fungi, only the inocula presenting residual growth after the 48 hour incubation in the organ culture medium are presented. Detection times corresponded to the interval between inoculation and detection of a change in turbidity and/or colour using the visual method and the conventional microbiological method, and to automat detection of growth using the blood bottle method. Identification of micro-organisms required each time a further 24–48 hours. All three methods detected contamination of the fungi, but the quickest results were obtained by the fungal or aerobic blood bottles
| Time between inoculation and positivity (hours) | |||
|---|---|---|---|
| Micro-organism Inoculum | Visual method (aspect of the medium) | Conventional method (mean, triplicate) | Blood bottle method (mean, triplicate) |
| No = no detection. | |||
| Methicillin resistant Staphylococcus aureus | |||
| 107 | 48 (turbid) | 48 (48–48–48) | 17.7 (19–17–17) |
| 105 | no | 80 (72–48–120) | 19.3 (13–22–23) |
| 103 | no | no | 36 (28–48–32) |
| 102 | no | no | 39.3 (38–37–43) |
| Methicillin sensitive Staphylococcus aureus | |||
| 107 | no | no | 19.7 (16–25–18) |
| 105 | no | no | 37.7 (33–52–28) |
| Staphylococcus epidermidis | |||
| 107 | 24 (yellow) | 24 (24–24–24) | 3 (3–3–3) |
| 105 | 72 (yellow) | 24 (24–24–24) | 16 (21–4–23) |
| Staphylococcus haemolyticus | |||
| 107 | no | no | 43.3 (38–40–52) |
| Pseudomonas aeruginosa | |||
| 107 | 24 (turbid) | 24 (24–24–24) | 3.3 (3–3–4) |
| 105 | 24 (turbid) | 24 (24–24–24) | 8.6 (7–4–15) |
| Acinetobacter baumannii | |||
| 107 | 24 (turbid) | 32 (48–24–24) | 5 (3–8–4) |
| 105 | 24 (turbid) | 32 (48–24–24) | 4 (3–4–5) |
| Bacillus subtilis | |||
| 107 | 96 (yellow) | 48 (48–48–48) | 13 (12–14–13) |
| Klebsiella pneumoniae | |||
| 107 | no | 48 (24–72–48) | 14.7 (20–13–11) |
| 105 | no | no | 20.7 (24–18–20) |
| Enterococcus faecalis | |||
| 107 | 48 (yellow) | 48 (48–48–48) | 14.7 (25–15–4) |
| 105 | no | no | 35 (30–25–50) |
| Candida albicans | |||
| 107 | 24 (orange) | 24 (24–24–24) | 3 (3–3–3) |
| 105 | 24 (orange) | 24 (24–24–24) | 3 (3–3–3) |
| 103 | 24 (orange) | 24 (24–24–24) | 3 (3–3–3) |
| 102 | 24 (orange) | 24 (24–24–24) | 3 (4–2–3) |
| Candida krusei | |||
| 107 | 24 (yellow) | 24 (24–24–24) | 2.7 (2–3–3) |
| 105 | 24 (yellow) | 24 (24–24–24) | 3 (3–3–3) |
| 103 | 24 (yellow) | 24 (24–24–24) | 3 (3–3–3) |
| 102 | 24 (orange) | 24 (24–24–24) | 3.3 (4–3–3) |
| Aspergillus fumigatus | |||
| 107 | 48 (turbid) | 24 (24–24–24) | 11.3 (13–15–6) |
| 105 | 48 (turbid) | 24 (24–24–24) | 15.7 (17–15–15) |
| 103 | 48 (turbid) | 24 (24–24–24) | 20 (20–17–23) |
| 102 | 48 (turbid) | 40 (24–72–24) | 27.7 (17–50–16) |