Lancet 2001,357(9269):1674–1675.PubMedCrossRef Competing interests The authors declared that they have no competing interest. Authors’ contributions Pritelivir AL, EOA and LAV conceived of the study and participated in its design. AL and LAV participated in the coordination and helped to draft the manuscript. EOA carried out the phenotypic and molecular characterization of the isolates and drafted the manuscript. LAV and DP participated in the molecular genetic studies. MP participated in the co-ordination of the study. All authors read and approved the final manuscript.”
“Background Flavobacteria are non-fermentative, catalase and oxidase positive, gram negative, yellow rods frequently isolated from different ecosystems

[1–3]. Some species, in particular Flavobacterium branchiophilum, F. columnare and F. psychrophilum

are feared fish pathogens responsible for disease outbreaks in fish farms worldwide [4–9]. F. psychrophilum cause either skin, gills and fin lesions Doramapimod as well as systemic disease in internal fish organs, the so called Bacterial Cold Water disease (BCW) and Rainbow Trout Fry Syndrome (RTFS), which can both lead to high mortality in the populations affected [4, 10]. Diagnosis of F. psychrophilum infections relies mainly on macroscopic symptoms, microscopic examination of fresh samples of fish spleens, and cultures of samples from tissues on non-selective agar medium [11–14]. Due to the often only superficial location of the disease on the fish as well as low densities and slow growth of the pathogen, early stages of infection are easily overlooked. This can lead to false negative results,

thus increasing the number of incorrect diagnoses [15]. Fluorescent in situ hybridization (FISH) has recently been described to diagnose F. psychrophilum infections in fish: the method is fast, reliable, and allows detection of F. psychrophilum concentrations of >105 cells/ml in water and spleen samples [16]. In some cases FISH provide quantitative results [17], but this F. psychrophilum specific FISH, allows only a qualitative Obatoclax Mesylate (GX15-070) detection but no quantification of the pathogen [16]. In the past few years, PCR methods have been described to detect and diagnose F. psychrophilum infections [18, 19]. PCR, as well as nested PCR, are highly sensitive, fast, and could allow simultaneous detection of different pathogens [20, 21]. Currently available PCR techniques can be used to detect F. psychrophilum in a sample [18, 19]. Real time quantitative PCR (qPCR) has been used in several studies to improve sensitivity of methods of detection and quantification of bacteria [22]. Due to its high sensitivity, this technique has widely been used to discover low amounts of pathogen DNA in the environment or in an organism during infection, to monitor its spread as well as to study healthy carriers as pathogen reservoirs [22–24]. Recently two qPCR for F.