27th Meeting of the EPPO Panel on Diagnostics in Bacteriology

Paris, 2025-11-18/20

The EPPO Panel on Diagnostics in Bacteriology met in Paris, France. This Panel serves as EPPO’s technical body responsible for preparing and reviewing Diagnostic Standards for bacteria. The meeting was attended by 21 Panel members and one observer, and was chaired by Ms Trontin (EPPO Secretariat), with the support Mr Aoutil (EPPO Secretariat) and Mr Giovani (EPPO Secretariat).

Revised EPPO Diagnostic Standards reviewed during the meeting

The Panel reviewed four revised Diagnostic Standards.

PM 7/022 Xanthomonas arboricola pv. corylina

The Panel reviewed the comments received during the first stage of country consultation on the revised Diagnostic Standard and the changes proposed by the drafting team composed of experts from University of Tuscia (IT). The main discussions focused on the addition of new pictures, clarifications regarding the sample requirements for symptomatic and asymptomatic samples, and the validation data for the recommended tests. A new version that takes into account the discussions of the Panel will be prepared, further reviewed by the Panel by email and sent for the second stage of country consultation.

PM 7/102 Curtobacterium flaccumfaciens pv. flaccumfaciens

The Panel reviewed the draft of the Standard prepared by an expert from ILVO (BE). The main discussion points included the changes in taxonomy, the flow diagram, and the removal of the appendix on DNA barcoding. A new version that takes into account the discussions of the Panel will be prepared, further reviewed by the Panel by email and sent for the first stage of country consultation.

PM 7/042 Clavibacter michiganensis

The Panel reviewed the draft of the Standard prepared by experts from ANSES (FR), CREA (IT), FERA (GB), GEVES (FR) and ILVO (BE). The main discussion points included the flow diagram, the addition of guidance on testing asymptomatic plants, and the inclusion of information on molecular tests used for the detection of the pest in plant material. A new version that takes into account the discussions of the Panel will be prepared, further reviewed by the Panel by email and sent for the first stage of country consultation.

PM 7/121 'Candidatus Liberibacter africanus’, ‘Candidatus Liberibacter americanus’ and ‘Candidatus Liberibacter asiaticus’

The Panel reviewed the draft of the Standard prepared by experts from ANSES (FR), IPN (PT), INIAV (PT), and IVIA (ES). The main discussion points included the harmonisation of terminology, clarifications on some of the recommended molecular tests and their validation data, and the deletion of the biological indexing section. A new version that takes into account the discussions of the Panel will be prepared, further reviewed by the Panel by email and sent for the first stage of country consultation.

The progress made on the following Standards were also discussed:

PM 7/096 Xylophilus ampelinus: An expert from NIB (SI) shared the results of different research projects on the development and validation of diagnostic tests. Additionally, the expert outlined the reasons for revising the current standard. A draft Standard will be prepared for the next Panel meeting.

PM 7/080 Xanthomonas oryzae: An expert from CNR (IT) updated the Panel on the progress made in evaluating the performance of several detection and identification tests. An expert from NVWA-NIVIP (NL) highlighted the difficulties to isolate the bacterium on media. A draft Standard will be prepared for the next Panel meeting.

PM 7/127 Acidovorax citrulli: An expert from the University of Modena and Reggio Emilia (IT) presented the ongoing work on drafting the IPPC Protocol for this bacterium, and the differences with the EPPO Diagnostic Standard. The revision of the EPPO Diagnostic Standard will be rediscussed once the IPPC Standard is published.

PM 7/060 Pantoea stewartii subsp. stewartii: An expert from NIB (SI) shared the outcome of the work performed at national level, by the EURL and in the framework of the MapQuest project focusing on the improvements of molecular testing and the challenges of isolating the bacterium. A draft Standard will be prepared for the next Panel meeting.

PM 7/021 Ralstonia solanacearum, R. pseudosolanacearum and R. syzygii (Ralstonia solanacearum species complex): Experts from NVWA-NIVIP presented the progress made in developing a TaqMan PCR test for detecting Ralstonia solanacearum and R. pseudosolanacearum. They also informed the Panel about the results of recent phylogenetic studies and on the development of molecular tests for R. syzygii. Two experts from ILVO (BE) presented their investigations into the epidemiology of R. solanacearum, R. pseudosolanacearum and R. syzygii. A draft Standard will be prepared for the next Panel meeting.

New EPPO Diagnostic Standards reviewed during the meeting

The Panel reviewed four new Diagnostic Standards.

PM 7/NEW Matrix Assisted Laser Desorption/Ionisation Time-Of-Flight (MALDI-TOF) Mass Spectrometry (MS) for the identification of plant pathogenic bacteria

The Panel reviewed the revised draft of the Standard prepared by experts from INRAE (FR), ZHAW (CH), NVWA-NIVIP (NL), and JKI (DE) to answer the comments received during the first stage of country consultation. The main points discussed included the clarification of the culture conditions used for MALDI-TOF MS, the addition of a warning regarding the need to verify the possibility to use Mass Spectrometry profiles generated in other laboratories, the addition of guidance on the use of negative controls, the provision of new examples of result sheets, and the inclusion of information on Xanthomonas citri and X. oryzae. A new version of the Standard that takes into account the discussions of the Panel will be prepared and resent for the first stage of country consultation.

PM 7/NEW Curtobacterium spp. pathogenic on Euphorbia pulcherrima

The Panel reviewed the comments received during the first stage of country consultation and the changes proposed by the expert from ILVO (BE). The main discussion points included changes in taxonomy, revisions to the flow diagram, and clarifications on the molecular tests recommended and on DNA barcoding. A new version that takes into account the discussions of the Panel will be prepared and sent for the second stage of country consultation.

PM 7/NEW Xanthomonas phaseoli pv. phaseoli and Xanthomonas citri pv. fuscans

The Panel reviewed the comments received during the first stage of country consultation and the changes proposed by the drafting team composed of experts from ILVO (BE), GEVES (FR) and NIB (SI). The Panel agreed to delete the immunofluorescence test and further clarified the use of spiking controls for treated seeds, and provided additional clarifications on the validation data. A new version that takes into account the discussions of the Panel will be prepared and sent for the second stage of country consultation.

PM 7/NEW DNA barcoding as an identification tool for a number of regulated bacteria

The Panel reviewed the comments received from the Panel and EPPO-Q-bank curators on the draft Standard prepared by experts from Agroscope (CH), INIAV (PT), JKI (DE), Fera (GB) and NVWA-NIVIP (NL). The main discussion points included the inclusion of new DNA barcoding tests for Erwinia and Xylella, as well as the addition of information on alternative DNA extraction procedures. A new version that takes into account the discussions of the Panel will be prepared and sent for country consultation.

Plans for future revisions of Diagnostic Standards

The Panel agreed to revise the Standard PM 7/059 Clavibacter sepedonicus and to prepare an addendum on PM 7/064 (2) Xanthomonas arboricola pv. pruni. The need to revise PM 7/097 Indirect immunofluorescence test for plant pathogenic bacteria was also discussed. Depending on the changes needed a revision of the Standard or an addendum/corrigendum will be prepared.

27th Meeting of the EPPO Panel on Diagnostics in Bacteriology

Paris, 2025-11-18/20

Revised EPPO Diagnostic Standards reviewed during the meeting

New EPPO Diagnostic Standards reviewed during the meeting

Plans for future revisions of Diagnostic Standards

Other topics