Authors:Konstantin Tanida, Lars Koste, Christian Koenig, Werner Wenzel, Andreas Fritsch and Hagen Frickmann
To evaluate the automated cartridge-based PCR approach ARIES SARS-CoV-2 Assay targeting the ORF-sequence and the N-gene of SARS-CoV-2.
In line with the suggestions by Rabenau and colleagues, the automated ARIES SARS-CoV-2 Assay was challenged with strongly positive samples, weakly positive samples and negative samples. Further, intra-assay and inter-assay precision as well as the limit-of-detection (lod) were defined with quantified target RNA and DNA. The Cepheid Xpert Xpress SARS-Cov-2 Assay was used as gold standard.
Concordance between the ARIES assay and the Cepheid assay was 100% for strongly positive samples and for negative samples, respectively. For weakly positive samples as confirmed applying the Cepheid assay, a relevant minority of 4 out of 15 samples (26.7%) went undetected by the ARIES assay. Intra- and inter-assay precision were satisfactory, while the lod was in the 103 DNA copies/reaction-range, in the 103 virus copies/reaction-range, or in the 103–104 free RNA copies/reaction-range in our hands.
The automated ARIES assay shows comparable test characteristics as the Cepheid assay focusing on strongly positive and negative samples but a slightly reduced sensitivity with weakly positive samples. Decisions on diagnostic use should include considerations on the lod.
Authors:Hagen Frickmann, Thomas Köller, Ralf Matthias Hagen, Klaus-Peter Ebert, Martin Müller, Werner Wenzel, Renate Gatzer, Ulrich Schotte, Alfred Binder, Romy Skusa, Philipp Warnke, Andreas Podbielski, Christian Rückert and Bernd Kreikemeyer
Introduction: We assessed the molecular epidemiology of multidrug-resistant bacteria colonizing or infecting war-injured patients from Libya and Syria who were treated at the Bundeswehr hospitals Hamburg and Westerstede, Germany.
Methods: Enterobacteriaceae and Gram-negative rod-shaped nonfermentative bacteria with resistance against third-generation methoxyimino cephalosporins or carbapenems as well as methicillin-resistant Staphylococcus aureus (MRSA) from war-injured patients from Libya and Syria were assessed by molecular typing, i.e., spa typing for MRSA strains and rep-PCR and next-generation sequencing (NGS) for Gram-negative isolates.
Results: A total of 66 isolates were assessed – comprising 44 Enterobacteriaceae, 16 nonfermentative rod-shaped bacteria, and 6 MRSA from 22 patients – and 8 strains from an assessment of the patient environment comprising 5 Enterobacteriaceae and 3 nonfermentative rod-shaped bacteria. Although 24 out of 66 patient strains were isolated more than 3 days after hospital admission, molecular typing suggested only 7 likely transmission events in the hospitals. Identified clonal clusters primarily suggested transmission events in the country of origin or during the medical evacuation flights.
Conclusions: Nosocomial transmissions in hospital can be efficiently prevented by hygiene precautions in spite of heavy colonization. Transmission prior to hospital admission like on evacuation flights or in crises zones needs further assessment.