Diagnostic des pneumonies aiguës communautaires aux urgences et distinction entre étiologie virale ou bactérienne

La pandémie actuelle liée à l’émergence du SARSCoV-2 en 2019 a considérablement modifié la perception des médecins de l’impact des virus respiratoires et de leur rôle dans les pneumonies aiguës communautaires (PAC). Alors que plus de 25 % des tableaux de PAC chez l’adulte étaient d’origine virale, les virus respiratoires étaient souvent perçus comme des agents pathogènes peu graves. Devant le défi que représente encore à nos jours la documentation microbiologique d’une PAC, l’instauration d’un traitement empirique par antibiotiques est souvent réalisée aux urgences. La pandémie de COVID-19 a surtout mis en exergue le rôle déterminant de la biologie moléculaire et du scanner thoracique dans l’algorithme diagnostique de la PAC. En effet, un diagnostic rapide et fiable est la clé pour améliorer les mesures de précaution et réduire la prescription inutile d’antibiotiques. Du fait de prises en charges très différentes, il est nécessaire de distinguer l’étiologie virale de la bactérienne d’une PAC.

Comparison of Four Streptococcus pneumoniae Urinary Antigen Tests Using Automated Readers

Streptococcus pneumoniae urinary antigen tests (UATs) may be interpreted using automatic readers to potentially automate sample incubation and provide standardized results reading. Here, we evaluated four UATs the BinaxNOW S. pneumoniae Antigen Card (Abbott, Chicago, IL, USA), ImmuView S. pneumoniae and Legionella (SSI Diagnostica, Hillerød, Denmark), STANDARD F S. pneumoniae Ag FIA (SD Biosensor, Gyeonggi, South Korea), and Sofia S. pneumoniae FIA (Quidel Corporation, San Diego, CA, USA) with their respective benchtop readers for their ability to detect S. pneumoniae urinary antigen. We found that these assays had a sensitivity of 76.9–86.5%, and specificity of 84.2–89.7%, with no significant difference found among the four UATs. The assays had a high level of agreement with each other, with 84.5% of samples testing consistently across all four assays. The automatically and visually read test results from the two immunochromatographic assays, BinaxNOW and ImmuView, were compared and showed excellent agreement between the two types of reading. Immunofluorescent-based assays, Sofia and STANDARD F, had significantly less time to detect compared to the two immunochromatographic assays due to having less assay setup procedures and shorter sample incubation times. In conclusion, the four UATs performed similarly in the detection of S. pneumoniae urinary antigen, and readers can bring increased flexibility to running UATs in the clinical routine.

Rapid diagnostic tests for infectious diseases in the emergency department

Background

Rapid diagnostic tests (RDTs) for infectious diseases, with a turnaround time of less than 2 hours, are promising tools that could improve patient care, antimicrobial stewardship and infection prevention in the emergency department (ED) setting. Numerous RDTs have been developed, although not necessarily for the ED environment. Their successful implementation in the ED relies on their performance and impact on patient management.

Objectives

The aim of this narrative review was to provide an overview of currently available RDTs for infectious diseases in the ED.

Sources

PubMed was searched through August 2019 for available studies on RDTs for infectious diseases. Inclusion criteria included: commercial tests approved by the US Food and Drug Administration (FDA) or Conformité Européenne (CE) in vitro diagnostic devices with data on clinical samples, ability to run on fully automated systems and result delivery within 2 hours.

Content

A nonexhaustive list of representative commercially available FDA- or CE-approved assays was categorized by clinical syndrome: pharyngitis and upper respiratory tract infection, lower respiratory tract infection, gastrointestinal infection, meningitis and encephalitis, fever in returning travellers and sexually transmitted infection, including HIV. The performance of tests was described on the basis of clinical validation studies. Further, their impact on clinical outcomes and anti-infective use was discussed with a focus on ED-based studies.

Implications

Clinicians should be familiar with the distinctive features of each RDT and individual performance characteristics for each target. Their integration into ED work flow should be preplanned considering local constraints of given settings. Additional clinical studies are needed to further evaluate their clinical effectiveness and cost-effectiveness.