Rapid Identification of Microorganisms from Sterile Body Fluids by Use of FilmArray

Abstract

Early detection and rapid identification of microorganisms are crucial the for appropriate management of infections of normally sterile body fluids (SBF) (1-3). Previously, SBF other than blood were cultured on solid medium (4). Larger volumes were processed through centrifugation and filtration in order to concentrate and improve the detection of microorganisms. Nonetheless, the microorganism recovery from SBF was unsatisfactory until the introduction of blood culture (BC) bottles. The introduction of BC bottles resulted in increased microorganism recovery in addition to decreased time to detection (5-10). However, the identification of microorganisms from positive bottles with conventional methods may still take up to 48 h for many microorganisms and even longer for others, such as slow-growing bacteria and yeasts (11). Several methods have been evaluated for rapid identification of microorganisms directly from positive blood cultures (12)(13)(14). In contrast, the data on the performance of rapid microbiological methods in diagnostics of SBF are scarce. The aim of the present study was to evaluate the performance of the FilmArray blood culture identification (BCID) panel in the identification of microorganisms directly from positive blood culture bottles inoculated with clinical SBF specimens.This study was performed at Karolinska University Hospital, Huddinge, Sweden. SBF specimens were collected in the clinical wards using standard protocols. Specimen volumes of 1 to 2 ml were inoculated in BacT/Alert pediatric/PF plus (bioMérieux, Durham, NC, USA), and volumes of Ͼ2 ml in BacT/Alert aerobic/FA plus and anaerobic/FN plus bottles (bioMérieux). All bottles were incubated in the BacT/Alert 3D blood culture system (bioMérieux) until they gave a positive signal or for a maximum incubation time of 5 days.Positive BC bottles with SBF were processed as follows. Gram staining was performed immediately after bottles signaled positivity. All positive bottles were subcultured onto a Columbia blood agar plate (aerobic and anaerobic), a cystinelactose-electrolyte-deficient plate (CLED) agar, and a chocolate agar plate. After an incubation time of 48 h, we analyzed the growth morphology on the agar plates. Identification of microorganisms was done by conventional methods, including matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS; Bruker Daltonics, Bremen, Germany) and Vitek2 XL (bioMérieux). Susceptibility testing was performed by the disc diffusion method according to EUCAST guidelines (http://www.eucast.org/). Methicillin resistance in Staphylococcus spp. was evaluated by the cefoxitin disc diffusion method. Similarly, imipenem and meropenem disc diffusion methods were used in order to determine/confirm the absence of Klebsiella pneumoniae carbapenemase (KPC). FilmArray (FA; bioFire, Salt Lake City, UT) analyses were performed as previously described (13). Results that were discrepant between the reference method and the FilmArray were evaluated further. According to the discre...

Syndromic Panel-Based Testing in Clinical Microbiology

“…Altun et al (90) evaluated the performance of the FilmArray BCID panel for the identification of organisms from positive blood culture bottles that had been inoculated with normally sterile body fluids (including pleural [n ϭ 51], synovial [n ϭ 38], abscess [n ϭ 10], dialysis [n ϭ 9], cerebrospinal [n ϭ 7], and bile [n ϭ 1] fluids). Those authors reported that the BCID panel accurately identified 100% (84/84) of organisms in monomicrobial infections and 75% (18/24) of targets if multiple organisms were recovered by routine culture (90). Of note, the FilmArray BCID panel is not FDA approved/cleared for direct testing of clinical specimens or of specimens other than blood in positive blood culture bottles.…”

Pneumococcal Disease in the Era of Pneumococcal Conjugate Vaccine

“…These approaches comprise a potential point-of-care diagnostic tool with high sensitivity and specificity in direct identification of pneumococci especially from positive blood culture bottles. 52 However further studies analyzing the clinical significance of positive results in samples from patients with pneumococcal infections are warranted.…”

Comparison of rapid BACpro® II, Sepsityper® kit and in-house preparation methods for direct identification of bacteria from blood cultures by MALDI-TOF MS with and without Sepsityper® module analysis

“…Many molecular assays have been developed to improve the turnaround time (TAT) of blood cultures using PCR and microarray technologies. Some of these assays are highly sensitive and reduce the TAT significantly and have been used by many clinical laboratories [10]. However, there are important limitations to these assays.…”