Minutes of the closed meeting, 23 February 2011, Ascona, Switzerland
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Minute 1. Call to order.
The Secretary and Acting Chairman, G. Greub, called the meeting to order at 20 : 00 on 23 February 2011, in the Salon Mandala of the Hotel Monte Verita at Ascona, Switzerland
Minute 2. Record of attendance.
The members present were Gilbert Greub (Secretary and Acting Chairman), Patrik Bavoil, Bernhard Kaltenböck, Mathias Maass, Andreas Pospischil, Konrad Sachse and Daisy Vanrompay. Apologies for absence were received from Gerald Byrne, Gunna Christiansen, Daniele Corsaro, Deborah Dean, Pierre-Edouard Fournier, Grazia Greco, Ted Hackstadt, Matthias Horn, Simone Magnino, Richard Stephens and Peter Timms.
Minute 3. Agenda.
The proposed agenda was approved.
Minute 4. Minutes of the previous meeting.
The minutes of the previous meeting (21st June 2010) held in Salzburg (Austria) were approved.
Minute 5. Recent taxonomic developments within the order Chlamydiales.
Since the previous meeting held in June 2010 in Salzburg (Austria), no new species have been reported in the literature. Volume 4 of the 2nd edition of Bergey’s Manual of Systematic Bacteriology has just been published. This 4th volume includes the chapter dedicated to chlamydial taxonomy [M. Horn (2011). Phylum XXIV. Chlamydiae Garrity and Holt 2001. In Bergey’s Manual of Systematic Bacteriology, 2nd edition]. In line with the proposals of the subcommittee on the taxonomy of the Chlamydiae [G. Greub, Int J Syst Evol Microbiol 60 (2010), 2691–2693; G. Greub, Int J Syst Evol Microbiol 60 (2010), 2694], a single genus (Chlamydia) is considered in the Chlamydiaceae family in this 2nd edition of Bergey’s Manual of Systematic Bacteriology. This issue of Bergey’s Manual of Systematic Bacteriology also clarifies the taxonomic affiliation of ‘Candidatus Clavichlamydia salmonicola’, by proposing that it represents a representing Candidatus species of a new family-level lineage ‘Candidatus Clavichlamydiaceae’. This makes sense given the phylogenetic relationship and genetic distance of this candidate species with its closest relatives, the genus Chlamydia. Please note that it was originally reported as Clavochlamydia and then renamed Clavichlamydia by Horn et al. [M. Horn (2011). Phylum XXIV. Chlamydiae Garrity and Holt 2001. In Bergey’s Manual of Systematic Bacteriology, 2nd edition].
Minutes 6. Minimal standards for description of new species within the order Chlamydiales.
All members of the subcommittee on the taxonomy of chlamydiae considered that special standards are needed for the description of new species within the order Chlamydiales, given the strict intracellular nature of these bacteria. Thus, as an example, only a single strain is sufficient to describe a new species (whereas five strains are needed for other clades). This strain should be available in pure culture [in any cell culture system including amoebal co-culture; see Minute 8 of the Little Rock meeting; G. Greub. Int J Syst Evol Microbiol 60 (2010), 2691–2693]. Moreover, this strain should be extensively studied and its affiliation supported (i) by sequencing part (>500 bp) of a minimum of 5 to 8 genes and (ii) by providing sufficient phenotypic information [E. Stackebrandt et al. Int J Syst Evol Microbiol 52 (2002), 1043–1047].
The genes that should be sequenced should at least include the 16S and 23S rRNA genes since cut-offs are available [K. D. Everett et al. Int J Syst Bacteriol 49 (1999), 415–440]. Other core genes (such as gyrA, rpoB and secY) are, however, important to precisely determine the taxonomic affiliation of new species since these core genes are less conserved and more discriminative than genes encoding rRNA. The taxogenomic work currently done by Bertelli and Greub will help define which core genes are well suited for such genetic and phylogenetic analyses.
Regarding phenotypic analysis, the subcommittee recommends the provision of electron-microscopy images that confirm the presence of a biphasic or multiphasic life cycle with infectious elementary bodies and replicating reticulate bodies and to provide ideally a profiling of whole-cell proteins by SDS-PAGE or MALDI-TOF MS, as recently done for Estrella lausannensis [J. Lienard et al. Microbes Infect 13 (2011), 1232–1241]. Serological differentiation index is an alternative; however, this is not recommended given its low discriminative power. Of course, naming of new species is only valid upon publication in IJSEM (as an original article or by the validation list when species description has been published elsewhere) and it is suggested that authors contact the subcommittee of taxonomy of Chlamydiae for advice prior to submission of their article. Members of the subcommittee are also available to the Editors of IJSEM for any help during the review process.
Minutes 7. Communication policy.
Decisions taken during the subcommittee have been presented orally to all the chlamydial community present in Ascona on 25th February and to chlamydiologists present at the meeting of the Chlamydia Basic Research Society (CBRS) in Los Angeles, USA, in March 2011. Moreover, these decisions are communicated through the Minutes published in IJSEM.
Minute 8. Current membership.
The members of the subcommittee are as follows: Patrik Bavoil (USA); Robert Brunham (Canada); Gerald Byrne (USA); Gunna Christiansen (Denmark); Daniele Corsaro (France) ; Deborah Dean (USA); Pierre-Edouard Fournier (France); Grazia Greco (Italy); Gilbert Greub, Secretary and Acting Chairman (Switzerland); Ted Hackstadt (USA); Mathias Horn (Austria); Bernhard Kaltenböck (USA); Matthias Maass (Austria); Simone Magnino (Italy); Garry Myers (USA); Andreas Pospischil (Switzerland); Konrad Sachse (Germany); Richard Stephens (USA); Peter Timms (Australia); and Daisy Vanrompay (Belgium).
It has been decided that members who are not present at four consecutive meeting of the subcommittee will be contacted to check their ongoing interest in Chlamydiales taxonomy and in absence of a positive answer will be excluded from the subcommittee. New members may join the subcommittee up to a maximum of 20 members. To be nominated, putative new members should be supported by at least two active members of the subcommittee and should summarize their motivation in a short letter.
Minute 9. Next meeting.
The next closed meeting of the subcommittee will be held during the next European Chlamydia meeting that will take place in Amsterdam in Spring 2012.
Minute 10. Adjournment.
The meeting was adjourned at 21 : 35 on 23 February 2011.