Comparative evaluation of the BCB Roche and Oxoid Signal blood culture systems

Abstract

The agar-slide blood culture system BCB Roche was compared with the Oxoid Signal blood culture system using 2,266 paired blood cultures. A total of 271 (12%) paired sets were culture-positive, including 222 (9.8%) yielding pathogens associated with septicemia and 50 (2.2%) yielding likely contaminants. In the recovery of the total 235 isolates considered as pathogens, the BCB Roche system yielded 202 (85.9%), the Oxoid Signal 211 (89.8%); 178 (75.7%) were cultured by both systems. There was no statistically significant difference between the two systems in their sensitivity, contamination-rate and detection time, except for gram-positive organisms, which were detected earlier by the Oxoid Signal system. Both systems performed well and were easy to handle.

Review on evaluations of currently available blood-culture systems

“…about 10 mL per adult patient [17, 57]. At the University Hospital Geneva, we found that the Signal system detected facultatively and strictly anaerobic bacteria well, which was complementary to the Septi‐Chek aerobic system [8, 9, 42, 43]. Similar findings were also reported elsewhere [39].…”

“… Yield of pathogens and contamination rate of 10 498 manual aerobic blood‐culture vials (Septi‐Chek BHI, Signal and Hémoline) related to the volume of blood cultured. On average, 9±2.8 mL of blood was inoculated during the studies performed at the University Hospital Geneva [8, 9]. …”

Evaluation of the new improved BHI-lysis blood culture medium for the BCB roche system

“…Results of evaluation of the commercially available blood culture systems BCB Roche (Hoffmann-La Roche, Switzerland) and Oxoid Signal (Oxoid, UK) have been favourable, the two systems constituting a valuable blood culture set for detection of aerobic and anaerobic microorganisms (1,2). With the intention of improving the detection rate of the BHI-S broth in the BCB Roche system, we reasoned that certain microorganisms, especially when intracelluIar, would grow better in BHI-S broth supplemented with a lysing agent such as saponin (BCB release).…”

Methods used in the United Kingdom for the culture of micro-organisms from blood.

“…In other laboratories the number of days' incubation (number of laboratories) was less than 5 (3), 5-6 (39), 8-10 (32), [14][15][16][17][18][19][20][21] (16). In five laboratories the incubation time depended on the type of bottle and in 14 the incubation period was not stated.…”