scacm.org/index.htm). The biochemical identification of this organism is problematic due to unstable phenotypic

reactions. For example, results of the 42 °C (Celsius temperature) growth test led to disagreement between researchers; Lawson [30] described a negative result but Kiehlbauch et al. [57] reported a positive result. The results of the alkaline-phosphatase test are difficult to read because the gradual color changes are dependent on the incubation time and certain strains give only the faintest hint of color [58]. Selleckchem BIBW2992 Due to these unstable phenotypic reactions and a lack of substantial data sets, commercially available identification kits do not produce reliable results. Therefore, identification has been based on nucleotide sequence or species-specific polymerase chain reaction (PCR). We have Natural Product Library cost developed a nested PCR system with high specificity and sensitivity (c.a. 102 CFU/ml) for detecting H. cinaedi based on the sequence of the known virulence factor gene, cdtB [37]. By using this cdtB gene-based PCR detection system, we identified more than 200 isolates received from various hospitals across the country. Another advantage of using PCR techniques is that culture is unnecessary. Since the culture of H. cinaedi isolates is very difficult and sometimes, as mentioned above,

cells fail to even grow, the present DNA detection test is convenient, as it can be directly performed even in these cases from the contents of a culture bottle using PCR. Analysis of 16S rRNA gene sequences is one of Cediranib (AZD2171) the most common approaches for investigating the phylogenetic positions of bacterial strains; however, Vandamme et al. [59] reported a problem due to misidentification of H. cinaedi using 16S rRNA gene sequences. The isolate believed to be H. cinaedi was located some distance from the phylogenetic cluster of the type strain, it is required careful consideration. Yet almost all isolates that we found were located within or very close to the type strain’s cluster, and were correctly identified using 16S rRNA gene phylogenetic

analysis. As described above, the species H. cinaedi includes at least two genetically diverse microorganisms, and Vandamme et al. [59] used certain strains such as the previously named “Helicobacter sp. strain Mainz”, or certain canine isolates; therefore, the antecedents of the strains should be clarified. Kuhnert and Burnens [60] highlight another potential source of error in the identification of H. cinaedi. ATCC 35863 was designated and distributed as a type strain of H. cinaedi but is actually H. fennelliae. Identification operations involve matching data sets obtained from unknown isolates with those of previously described taxa, so any mislabeling of the latter can result in unknown isolates being misidentified [60].