Impact of BioFire blood culture ID panel on empiric antimicrobial therapy for sepsis cases: a retrospective study

Introduction

Sepsis is a fatal and often challenging condition, contributing to the morbidity and mortality of critically ill patients. Early clinical diagnosis and effective empirical antibiotic therapy play an immense role in their survival. Blood culture may take 48–72 hours to report the organism though traditional methods. However, the BioFire FilmArray blood culture identification (BCID) panel is an FDA-approved polymerase chain reaction assay that enables prompt and accurate identification of the organism within 1 hour, thus enabling early appropriate treatment and reducing morbidity, mortality and delayed hospital stay. This study evaluated the impact of a BCID panel on the empiric antibiotic therapy in critically ill patients in the intensive care unit (ICU) setting.

Materials and methods

This was a retrospective study on patients admitted to the ICU with positive blood cultures and ifor whom BioFire FilmArray (BCID) was done. Data were collected from patient case records in the health information system (HIS) and drug charts. Patients for whom BCID was not done were excluded from this study. The initial positive time, time to positivity, preliminary critical time, BCID ID, BCID resistance, isolated organism, resistance pattern, final critical informing time, empirical antibiotic, date and time of antibiotic modification and patient outcomes were collected.

Result and discussion

Out of the 45 patients with positive blood cultures, four (8.89%) samples were non-identifiable in BCID. These were non-fermenter, Gram-negative organisms other than Pseudomonas species or Acinetobacter species. The initial results of the BCID panel were available to clinicians within a short laboratory turnaround time of 3.2 hours, similar to other studies.1, 2 Empirical antimicrobials were modified based on BCID reports within an average time of 8.4 hours in 16 (39.02%) of the 41 patients with identifiable samples. 28 (68.30%) of these patients were found to have Gram-negative bacilli, of which the panel also helped in identification of significant number of isolates (34.50%) with resistance genes, enabling earlier additional infection prevention and control practices. Four patients had one more isolate additionally identified by routine culture methods (blood and MacConkey agar) that were not identified by the BCID panel. Among these, only one patient had an Enterococcus species isolated for which antibiotic therapy was not adequate. As a result of contaminated blood culture reports with contamination rates above 5%, patients receive unnecessary harmful antimicrobials.³ One potential drawback of the BCID panel was its inability to detect organisms other than coagulase-negative staphylococci, such as Bacillus species, diphtheroids and micrococci, which have been included in the upgraded panel of the BCID2.⁴ Overall patient mortality was 17 (41.46%) and five (12.20%) of all-cause mortality in the drug-modified group. Similar studies have revealed that sepsis increases the risk of death by 30–80%.⁵

Conclusion

BCID helps with earlier and accurate empirical choice of antibiotics for patients with bloodstream infections compared with conventional or phenotypic methods.