Work

Inclusivity and Exclusivity of a Highly Multiplexed Polymerase Chain Reaction System for the Detection and Quantification of Lower Respiratory Tract Pathogens

Year: 2016

Type: article

Abstract: Background. Identification of etiological agents of lower respiratory tract infections (LRTIs) is a diagnostic challenge because multiple bacteria, viruses, and fungi are implicated. Some of these bacteria are also commensals of the upper respiratory tract and require quantification to differentiate between pathogenic and contaminating loads. The FilmArray LRTI Panel (FA LRTI Panel) (BioFire Diagnostics, LLC) is being developed to provide rapid (∼1 hours), sensitive, and specific identification of key pathogens and select antibiotic resistance markers, as well as relative quantification of commensal bacteria. This study evaluated the exclusivity and inclusivity of a prototype FA LRTI Panel to detect 40 analytes. Methods. A total of 526 isolates were tested across 3 sites by multiple operators. These included viruses, fungi, and bacteria, some of which contained antibiotic resistance markers. Inclusivity was assessed at a concentration of 105 CFU/mL and specificity at 108 CFU/mL. In addition, quantitative accuracy and consistency among strains were evaluated for commensal bacterial targets. Results. Panel exclusivity was assessed using 232 species of on-panel organisms, phylogenetic-neighbors, and a representative subset of normal oropharyngeal flora, with 100% specificity observed for 38 of 40 targets. Inclusivity was confirmed for 194 of 194 qualitative target analytes, including antibiotic resistance markers, and for 190 of 190 quantitative target analytes. The FA LRTI Panel quantification was within 0.5 log units of the test concentration for the majority of quantitative analytes across multiple strains. Titers of strains quantified above or below the expected level were concordant with titer estimates by other molecular methods. Conclusion. These results indicate that the FA LRTI Panel will be able to identify numerous pathogens implicated in LRTI with a high degree of specificity. This study suggests that the FA LRTI Panel will be able to provide accurate quantification that is comparable to traditional microbiological methods. (Note: The FilmArray LRTI Panel has not been evaluated by the US Food and Drug Administration or other regulatory agencies for In Vitro Diagnostic use.) Disclosures. J. Antosch, BioFire Diagnostics: Employee, Salary; U. Spaulding, BioFire Diagnostics: Employee, Salary; C. Li, BioFire Diagnostics: Employee, Salary; D. Nicholes, BioFire Diagnostics: Employee, Salary; E. Bonar, BioFire Diagnostics: Employee, Salary; C. Alberti-Segui, bioMerieux: Employee, Salary; C. Weber, bioMerieux: Employee, Salary; M. Casse, bioMerieux: Employee, Salary; M. Rogatcheva, BioFire Diagnostics: Employee, Salary

Source: Open Forum Infectious Diseases

DOI: 10.1093/ofid/ofw172.40