A COMPARATIVE STUDY ON CONVENTIONAL AND AUTOMATED BLOOD CULTURE IN THE EARLY DETECTION OF BACTERIAL PATHOGENS.

Corresponding Author:
Dr. Lekshmi L. Rajan,
Assistant Professor,
Department of Transfusion Medicine & Immunohematology,
Government Medical College,
Kottayam, Kerala.
E-mail: lekshmraj@gmail.com

ABSTRACT

BACKGROUND

Blood culture is a critical tool in the microbiological laboratory, which detects and identifies microorganisms in the blood along with antibiotic susceptibility and has considerable prognostic significance by suggesting appropriate antibiotic therapy. Automated blood culture systems are replacing conventional methods and must be comparatively studied to elucidate the benefits and advantages. The present study compares a recently installed BacT/ALERT automated system with the conventional method with regard to rate of detection and time to detection of microorganisms.

This prospective observational study was conducted in a Medical College, a tertiary care centre in Kerala among patients with suspected bacteraemia and sepsis.

MATERIALS AND METHODS

Two samples were drawn from each of the 248 subjects and subjected to conventional and automated blood cultures using standardised techniques. The rate of detection and the time to detection of microorganisms were compared.

RESULTS

Overall, 27.8% and 21.3% of the samples showed positive growths by the automated and conventional methods. The automated system detected 96.9% of the single isolates compared to 80% for the conventional method (p value < 0.01). The automated system detected 72.5% of the cases within 24 hours and 98.6% cases within 48 hours. In comparison, the conventional system detected none within 24 hours and only 34% within 48 hours. The mean time to detection by the automated method was 22.8, 18.24 and 23 hours for Gram positive bacteria, Gram negative bacteria and fungi respectively.

CONCLUSION

Automated blood culture systems are a reliable alternative to conventional blood culture systems with better performance in rate of detection and time to detection of micro-organisms in our settings. Early availability of results facilitates the timely initiation of appropriate antibiotic therapy.

KEYWORDS                           

Blood Culture, Automated Blood Culture Systems, Bacteraemia, Sepsis.