Performance of two blood culture systems to detect anaerobic bacteria. Is there any difference?

• Published in: Anaerobe 2017-06, Vol.45, p.59-64
• Main Authors: Mueller-Premru, Manica, Jeverica, Samo, Papst, Lea, Nagy, Elisabeth
• Format: Article
• Language: English
• Subjects: Anaerobe; Bacteremia - diagnosis; Bacteria, Anaerobic - isolation & purification; Blood Culture - methods; Blood culture system; Detection rate; Humans; Sensitivity and Specificity; Time Factors; Time-to-positivity
• ISSN: 1075-9964; 1095-8274
• DOI: 10.1016/j.anaerobe.2017.03.006

We studied the performance characteristics of two blood culture (BC) bottles/systems, (i) BacT/ALERT-FN Plus/3D (bioMérieux, Marcy l’Étoile, France) and (ii) BACTEC-Lytic/9000 (Becton Dickinson, Sparks, USA) for detection of growth and time-to-positivity (TTP) against a balanced and diverse collection of anaerobic bacterial strains (n = 48) that included reference strains (n = 19) and clinical isolates (n = 29) of 32 species (15 Gram-negative and 17 Gram-positive). Standard suspension of bacteria was inoculated to each bottle in duplicates and incubated in the corresponding system. Overall, 62.5% (n = 30) of strains were detected by both BC bottle types. Comparing the two, 70.8% (n = 34) and 79.2% (n = 38) of strains were detected by BacT/ALERT-FN Plus and BACTEC-Lytic bottles, respectively (p = 0.38). Among Gram-negative anaerobes (n = 25) the detection rate was 76.0% (n = 19) vs. 92.0% (n = 23) (p = 0.22), respectively. Among Gram-positive anaerobes (n = 23) the detection rate was 65.2% (n = 15) in both bottles (p = 1). The average TTP per bottle was calculated only for the strains detected by both systems (n = 30) and was 40.85 h and 28.08 h for BacT/ALERT-FN Plus and BACTEC-Lytic, respectively (p