The sixth ASM<i>Candida</i>and candidiasis conference

The interest of the scientific community in Candida species continues to grow in order to match the increased incidence of infections caused by these species. Representative of this was the fact that over 300 delegates attended the sixth American Society for Microbiology conference on ‘Candida and candidiasis’ held at the Hyatt Regency Hotel in downtown Tampa, FL, USA, between January 13th and 17th 2002. This meeting goes from strength to strength and is currently the most important forum for Candida biologists to discuss their recent research. The main organisers of the meeting were LaJean Chaffin from Texas Tech University and Bill Merz from Johns Hopkins University and the meeting was dedicated to the memory of Helen Buckley, from Temple University, a long-time worker in the field who passed away in 2001. The Candida field now encompasses a broad range of scientific disciplines most of which were represented in the 11 dedicated sessions. To the most informative of these sessions belonged the opening and closing session chaired by Frank Odds (University of Aberdeen) which incorporated a questionnaire designed to canvas delegates’ opinions on candidal virulence. The range of opinions on a variety of issues, including the definition of what constitutes a virulence factor and how these should be studied, was striking (with a particular divergence noticeable between molecular biologists and microbiologists). A special workshop was also organised (chaired by Aaron Mitchell, Columbia University) in response to the fact that the Candida albicans genome sequencing project has almost been completed. As a result of this, a committee of Candida biologists has been drawn up to implement a much needed universal gene annotation system for the C. albicans genome. Of course it is impossible to describe all of the presentations given at the meeting in a short review such as this and indeed everyone in the field has specific interests. However, the following represents some of the highlights of the meeting as judged by this author. One of the most interesting sessions, perhaps not surprisingly, was the session entitled ‘Genetics and genomics’, in which Pete Magee (University of Minnesota) and Sandy Johnson (UCSF) both described the hot topic of Candida and sex. Particularly intriguing was the mention by Sandy Johnson that there may be some link between mating gene expression and the opaque phase switch phenotype. In combination with other presentations in this session by Vincent Bruno (Columbia University) and Mike Lorenz (Whitehead Institute) it is clear that C. albicans has now entered the ‘post-genomic age’. The next session on ‘Epidemiology and population studies’ was designed to put in perspective the reasons why many of us have an interest in Candida biology. Rana Hajjeh (Centers for Disease Control) and Michael Pfaller (University of Iowa) described the increased prevalence of candidal infections and noted the continued emergence of other Candida species (e. g. C. glabrata and C. parapsilosis) as important human pathogens. From these presentations it was also made clear that surveillance studies to monitor epidemiological changes and the emergence of antifungal resistance are essential. In the next session the increasingly interesting topic was tackled of ‘Cell wall and surface molecules’, in which Paula Sundstrom (Ohio State University) described the role of the transglutaminase substrate protein Hwp1 in oesophageal candidiasis. Also in this session, Neil Gow (University of Aberdeen) discussed the importance of surface protein glycosylation in adherence, cell signalling and morphogenesis and consequently in virulence. A note of caution was introduced by Bill Fonzi (Georgetown University) who observed that increased filamentation in reconstituted C. albicansΔhwp1 mutants was due to URA3 expression (perhaps as a result of transcriptional interference) rather than complementation. Since the vast majority of knock out mutants in C. albicans have been generated using the ura-blaster method, this has considerable implications in many of the virulence studies performed to date and suggests that some of the results from these studies may have to be reinvestigated. A session dedicated to the ‘Host response’ included presentations on the immune responses to systemic infections (by Scott Filler, UCLA) and to oropharyngeal infections (by Louis de Repentigny, Hospital Sainte Justine, Montreal, QC, Canada). Specific vaginal and oral mucosal defenses were described by Paul Fidel (Louisiana State University) and the role of the innate immune responses was described by Luigina Romani (University of Perugia). The increasingly complex area of ‘Signalling and morphogenesis’ was addressed by some of the world experts in the field. Aspects of the pathways responsible for the yeast to hypha transition involving the EFG1 and CPH1 genes were discussed by Al Brown (University of Aberdeen) who described the role of the GCN4 gene and Joachim Ernst (Universität Düsseldorf) who described the role of the TPK1 and 2 genes. David Soll (University of Iowa) described recent data from his laboratory on phenotypic switching, while Judy Berman (University of Minnesota) presented some very interesting data (with the help of some stunning movies) on the roles of two B-cyclins (Cyb1p and Cyb99p), suggesting that regulation of the cell cycle may be involved in morphogenesis. The growing relevance of Candida species other than C. albicans was noted by the inclusion of a session on ‘Non-albicans virulence’. In this session Brendan Cormack (Johns Hopkins University) eloquently described a family of four GPI cell wall proteins (one of which has been designated Epa1p) implicated in the adherence of C. glabrata in a murine systemic infection model. Ken Haynes (Imperial College London) described a C. glabrata mutant (generated using signature-tagged mutagenesis) which surprisingly appears to have a hypervirulent phenotype in the mouse systemic infection model. Also in this session Michel Monod (CHUV, Lausanne, Switzerland) described aspartyl protease maturation in Candida tropicalis, while David Coleman (Trinity College Dublin) reviewed recent data available on the virulence of the recently identified species Candida dubliniensis. The penultimate session described the recently identified ‘Involvement of Candida species in biofilms’. As part of this, José Lopez-Ribot (University of Texas, San Antonio, TX, USA) provided a link to the final session on antifungal resistance in which Ted White (Seattle Biomedical Research Institute), Dominique Sanglard (University Hospital Lausanne), Steve Kelly (University of Wales), Joachim Morschhauser (Universitat Würzburg) and Martine Raymond (Institut des Recherches Cliniques de Montreal) described recent developments on common mechanisms (e. g. MDR1, CDR1, CDR2 overexpression and ERG11 and ERG3 mutation) of resistance and tolerance to antifungal agents. The discovery by Dominique Sanglard that calcineurin appears to play a role in C. albicans tolerance of antifungal agents was particularly interesting and suggests that resistance and tolerance are separate phenomena. In conclusion, this meeting was a great success. Our understanding of the biology and pathogenicity of Candida species has increased dramatically since the fifth Candida and candidiasis meeting held in Charleston, SC, USA, in 1999. Indeed the field is changing so rapidly that a poll of the delegates suggested that the meeting should be held every 2 years instead of three. So roll on 2004 for the next installment in our unravelling of the mysteries of Candida! January 2002

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