Rapid identification of pathogens from positive blood cultures by multiplex polymerase chain reaction using the FilmArray system

Sepsis is a leading cause of death. Rapid and accurate identification of pathogens and antimicrobial resistance directly from blood culture could improve patient outcomes. The FilmArray® (FA; Idaho Technology, Salt Lake City, UT, USA) Blood Culture (BC) panel can identify >25 pathogens and 4 antibiotic resistance genes from positive blood cultures in 1 h. We compared a development version of the panel to conventional culture and susceptibility testing on 102 archived blood cultures from adults and children with bacteremia. Of 109 pathogens identified by culture, 95% were identified by FA. Among 111 prospectively collected blood cultures, the FA identified 84 (91%) of 92 pathogens covered by the panel. Among 25 Staphylococcus aureus and 21 Enterococcus species detected, FA identified all culture-proven methicillin-resistant S. aureus and vancomycin-resistant enterococci. The FA BC panel is an accurate method for the rapid identification of pathogens and resistance genes from blood culture.     

Usefulness of the FilmArray blood culture identification panel for identifying causative pathogens of bone and joint infections

As bone and joint infections (BJIs) require long-term treatment, identifying their causative pathogens is vital. However, the detection rate of conventional culturing remains inadequate. This study aimed to evaluate the usefulness of the FilmArray blood culture identification (BCID) panel for identifying causative pathogens in patients with BJIs. We tested a BCID panel using collected samples, in addition to conventional cultures. The primary outcome was to evaluate the diagnostic performance of the BCID panel, calculated using conventional culturing methods. A total of 44 patients who underwent BJI-related specimen collection were enrolled. Of the 44 patients, 22 were diagnosed with a BJI. Conventional culture identified 15 of 22 organisms (68.2%), whereas the BCID panel identified 14 of 22 organisms (63.4%). The overall sensitivity and specificity of the BCID panel were 73.3% and 57.1%, respectively, compared to those of the conventional culture. However, the sensitivity reached 100% when only pathogens included in the BCID panel were considered. In seven culture-negative cases, the BCID panel identified three organisms (42.9%). The BCID panel also indicated the appropriate therapy against a BJI caused by methicillin-resistant Staphylococcus aureus by detecting the mecA gene. This study demonstrated that the BCID panel has the potential for early and accurate diagnosis of the causative organism of BJI using specimens such as joint fluid and bone tissue. Our results suggest that BCID panels, in addition to routine culture, may improve our ability to diagnose the causative microorganisms of BJI in clinical practice, thereby contributing to the selection of appropriate antimicrobial agents.     

How do we reduce acyclovir overuse? Impact of FilmArray meningitis/encephalitis panel tests for pediatric patients

BackgroundFew Japanese hospitals can perform in-house cerebrospinal fluid (CSF) polymerase chain reaction (PCR) to screen for herpes simplex virus, leading to patients being administered acyclovir (ACV) for several days. The FilmArray Meningitis/Encephalitis Panel (ME Panel) is a multiplex PCR test that can identify 14 major pathogens within 1 h. We aimed to investigate the efficacy of the ME Panel in children admitted with central nervous system infections in Japan.MethodsWe conducted a single-center, quasi-experimental study. The ME panel was introduced in April 2020. We outsourced the CSF samples to a laboratory during the pre-intervention period (April 2016 to March 2020) and performed the ME panel at our hospital during the post-intervention period (April 2020 to December 2021). Duration and dose of ACV and antibiotic use, length of stay (LOS) in the pediatric intensive care unit (PICU), and total LOS after testing were compared using the Mann-Whitney U test.ResultsThe number of cases in the pre- and post-intervention periods was 67 and 22 cases, respectively. The median duration of ACV decreased significantly from 6 days to 0 day (p < 0.001), and the median dose of ACV use decreased significantly from 14 vials to 0 vial (p < 0.001). No significant differences were noted in the total duration and dose of antibiotic use, LOS in PICU, and the total LOS after testing.ConclusionThe introduction of ME panel may contribute to appropriate ACV use; however, there was no significant change in the duration and dose of antibiotic use or LOS.     

Rapid and visual detection of Group B streptococcus using recombinase polymerase amplification combined with lateral flow strips

Conventional culture method for detecting Group B streptococcus (GBS), a common pathogen of neonatal meningitis and sepsis, is time-consuming and unsensitive. Even though real-time fluorescence PCR-based molecular method is more accurate, it need special instrument and elaborate protocol. Here, we established a novel molecular method combining recombinase polymerase amplification with lateral flow strips for detecting GBS. The cAMP factor (cfb) gene is a highly specific and sensitive biomarker to identify GBS and is detectable by using 100 genomic copies as the amplification template. Clinical performance of this assay was evaluated by testing 130 samples, in comparison with culture method and real-time fluorescence PCR, and the results achieved 100% accuracy, which were the same with those of real-time fluorescence PCR, and were better than those of culture method with false-negative detection. This study provides a rapid and visual method, with clinical potential, for the detection of GBS infection of patients.