Continuous Monitoring Blood Culture System Research Articles

Review on evaluations of currently available blood-culture systems.

Review on evaluations of currently available blood-culture systems.

The use of continuous monitoring blood culture systems in the diagnosis of catheter related sepsis.

AIM: To assess whether the information provided by automated continuous monitoring blood culture systems could aid in the diagnosis of catheter related sepsis. METHODS: Serial dilutions of a strain of...

Four-day incubation period for blood culture bottles processed with the Difco ESP blood culture system.

Blood culture records from 1994 to 1995 from five U.S. medical centers all using the Difco ESP continuous monitoring blood culture system were reviewed retrospectively. Among a total of 7,362 isolates of bacteria and yeasts, only 0.1% of possibly significant isolates would have been missed had blood cultures been routinely incubated for 4 days instead of the 5 days recommended by the manufacturer. Conversely, numerous contaminants, detected only on day 5, would have been eliminated by a 4-day incubation period.

Comparison of DNA Probe Technology and Automated Continuous-Monitoring Blood Culture Systems in the Detection of Neonatal Bacteremia. † 1314

The rapid detection of microorganisms from blood culture is important because of its impact on appropriate selection and duration of antimicrobial therapy. The present study compared the ability of a rapid DNA probe assay to detect bacterial growth in blood culture specimens to their detection by continuous-monitoring blood culture systems (CMBCS). A total of 1700 blood cultures collected from 3 intensive care nurseries were analyzed. A 3cc aliquot of blood was removed from each culture during early incubation (mean 14 hrs), processed and analyzed by the DNA probe.

Current Blood Culture Methods and Systems: Clinical Concepts, Technology, and Interpretation of Results

Since the mid-1970s there has been a number of advances in blood culture practices and technology; these advances have been based largely on well-designed controlled clinical evaluations of blood culture systems and media. Thus, a sound scientific basis for the fundamental principles of blood culturing now exists. In this article. I will address issues of clinical and technical importance with regard to blood culturing; these issues include skin antisepsis, the number and timing of blood cultures, the appropriate volume of blood for culture, culture media and additives, length and atmosphere of incubation, and interpretation of positive blood culture results. Finally, I will discuss the currently available blood culture systems, with an emphasis on the newer continuous-monitoring blood culture systems.

Factors involved in the selection of a continuous monitoring blood culture system

A new generation of blood culture systems has become available in the last few years. These systems use the principle of continuous monitoring of a blood/broth mixture to detect organisms. All have different detection systems and have many optional and differing features, for example the types of culture media available. The use of these systems has significant implications for laboratories concerning cost and working practices. It is important that purchasers make the best choice for their particular requirements. Factors to be considered when choosing a blood culture system include performance in terms of sensitivity, specificity and the speed of detection of organisms. Capital and consumable costs, the software (including data management options), and the amount of regular user maintenance that is required also merit consideration.

Comparison of Difco ESP and Organon Teknika BacT/Alert continuous-monitoring blood culture systems

The Difco ESP and Organon Teknika BacT/Alert (BTA) systems were evaluated in a clinical study of 5,421 aerobic and 5,035 anaerobic blood cultures. Of 405 clinically significant positive cultures evaluated, 272 grew in both systems, 86 grew in ESP only, and 47 grew in BTA only (P < 0.005). Of 320 organisms detected in aerobic bottles, 208 grew in both systems, 68 grew in ESP only and 45 grew in BTA only (P < 0.05), with Staphylococcus aureus the only organism showing a statistically significant difference. The ESP anaerobic bottle also detected more anaerobes (16 of 17 versus 4 of 17, P < 0.005) and more organisms overall (57 versus 34, P < 0.05). However, with the exception of patients with anaerobic bacteremia (12 of 13 for ESP and 4 of 13 for BTA, P < 0.05), there was no statistical difference in the detection of patient episodes. Average detection time of matched aerobic bottles was 18.3 h for ESP and 22.0 h for BTA (P < 0.001). For matched pairs of anaerobic bottles, the average detection time was faster in the BTA bottles (P < 0.001), because of the growth of facultative organisms. To explore the differences in anaerobic detection more fully, 20 sets of anaerobic bottles were seeded with 12 anaerobic species mixed with human blood. ESP grew more organisms (17 of 20 versus 10 of 20, P < 0.025), and the average time to detection for the 10 paired positive cultures was 21.6 h for ESP and 50.8 h for BTA (P < 0.05). Times for loading and unloading bottles were similar for both systems.

Multicenter clinical evaluation of a continuous monitoring blood culture system using fluorescent-sensor technology (BACTEC 9240)

The BACTEC 9240 (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md.) is a new continuous-monitoring blood culture system that uses internal, fluorescent-CO2 sensors. In a multicenter clinical trial, organism yield and times to detection with the prototype BACTEC 9240 system were compared with those of the BACTEC NR 660 system. Equal volumes of blood were inoculated into the bottles included in the study blood culture sets (aerobic and anaerobic 9240 and NR6A and NR7A bottles). A total of 9,391 aerobic and 8,951 anaerobic bottle pairs were inoculated with 9,801 blood specimens. A total of 587 clinically significant positive blood cultures and 415 cases of sepsis were studied. The standard 9240 aerobic bottle detected significantly more Staphylococcus aureus (P < 0.05), coagulase-negative staphylococci (P < 0.01), and total microorganisms (P < 0.001) than the NR6A bottle. The standard 9240 anaerobic bottle detected significantly more coagulase-negative staphylococci (P < 0.001), members of the family Enterobacteriaceae (P < 0.01), and total microorganisms (P < 0.001) than the NR7A bottle. A total of 420 positive cultures were detected in both systems; for 284, the time to detection was equivalent with both systems (within 12 h); for 123, the 9240 system was faster; and for 13, the NR 660 system was faster (P < 0.001). The average times to detection for the 9240 and the NR 660 systems were 20.2 and 27.5 h, respectively. Ninety-nine cultures were positive only in the 9240 system, and 68 cultures were positive only in the NR 660 system (P < 0.02). The 9240 system also detected significantly more episodes of bacteremia (P < 0.001). The false-positive rates for the 9240 and NR 660 systems were 2.2 and 2.3%, respectively. The false-negative rates for the two systems after 5 days of incubation did not differ significantly. The contamination rates for the 9240 and NR 660 systems were 1.9 and 1.5%, respectively (P < 0.05). In conclusion, the prototype 9240 system detected more clinically significant positive blood cultures and did so sooner than the NR 660 system, with the additional advantages of full automation, continuous monitoring, and noninvasive sampling.