Saatja: "Vladimira Hinic" <
[email protected]>
Saaja: "Vladimira Hinic" <
[email protected]>
Teema: Invitation: International EQA for C. diphtheriae Diagnostics
Kuupäev: 2025-08-27 10:21
Dear Colleagues,
We would like to invite you to take part in our upcoming international
External Quality Assessment for Corynebacterium diphtheriae diagnostics.
All relevant details regarding the assessment, including objectives,
procedures, and timelines, are provided in the attached letter.
We would greatly appreciate your participation in the assessment and are
looking forward to your feedback.
With kind regards,
Prof. Andreas Sing and Dr. Anja Berger
LGL, WHO Collaborating Centre, Germany
Dr. Stefanie Schindler
AGES, Austrian Reference Centre, Austria
Dr. Vladimira Hinic and Prof. Adrian Egli
IMM, University of Zurich, Switzerland
Subject: Invitation to participate in an international External Quality Assessment for
Corynebacterium diphtheriae diagnostics
Dear Colleague,
We are pleased to invite your laboratory to participate in an international External Quality
Assessment (EQA) focused on the diagnostics of C. diphtheriae. This EQA initiative is jointly
organized by Professor Andreas Sing and Dr. Anja Berger from the Bavarian Health and Food Safety
Authority (LGL) and the WHO Collaborating Centre for Diphtheria, Dr. Stefanie Schindler from the
Austrian Agency for Health and Food Safety (AGES, Austrian Reference Centre), and Dr. Vladimira
Hinic and Prof. Adrian Egli from the Institute of Medical Microbiology, University of Zurich (IMM UZH).
The primary aim of this international EQA is to standardize and improve the diagnostic capabilities for
C. diphtheriae, a critical undertaking given the occurrence of intermittent large-scale outbreaks, and C.
ulcerans as an emerging and potentially toxigenic zoonotic pathogen. Participating laboratories will
receive a set of 13 isolates, including ten clinical isolates of C. diphtheriae and C. ulcerans and three
negative control strains. The assessment will benchmark essential diagnostic methods such as
bacterial culture, organism identification, PCR for toxin detection, the Elek test, and whole-genome
sequencing (WGS). To participate effectively, laboratories should be able to culture and identify C.
diphtheriae and C. ulcerans and perform toxin detection (either PCR or Elek test).
Participants will be provided with a dedicated form to submit their results, which will subsequently
undergo comparative analysis. Each participating center will receive individualized feedback and
have the opportunity to discuss their diagnostics with our organizing team. Additionally, a webinar
will be hosted to present and discuss the aggregated results and methodological insights. Findings from
this EQA are planned for presentation at an upcoming ESCMID conference, and we aim to publish the
comprehensive results in a peer-reviewed scientific journal.
Participation in this EQA will play a vital role in enhancing laboratory preparedness, harmonizing
global diagnostic standards, and strengthening capacity to respond effectively to diphtheria
outbreaks. We sincerely hope that your laboratory will join this important initiative.
Should you have any questions or require further clarification, please do not hesitate to contact any
member of our organizing team directly.
We kindly ask you to confirm your participation by 19th September 2025 via email (
[email protected]),
so we may finalize the necessary logistical arrangements.
Thank you very much for considering this invitation. We look forward to your valuable participation.
Yours sincerely,
Prof. Andreas Sing Dr. Anja Berger
LGL, WHO Collaborating Centre, Germany
Dr. Stefanie Schindler
AGES, Austrian Reference Centre, Austria
Dr. Vladimira Hinic Prof. Adrian Egli
IMM, University of Zurich, Switzerland