tularensis type A as F.

tularensis type B and vice versa may occur when identification is based on the immunological detection of the LPS capsule or biochemical tests. In the past, such misidentification led to laboratory infections and resulted in the temporary shutdown of laboratories for cost-intensive decontamination [45]. The sensitivity of the new method is intriguing, since we were able to detect artificial contamination of type B strains with F. tularensis MLN2238 supplier type A as low as 0.1% of the total bacterial population. Moreover, FISH could prove relevant for the rapid identification of mutations in 16S or 23S rRNA gene regions which are associated with or causative for antibiotic resistance of bacterial pathogens against aminoglycosides or macrolides [46]. This investigation showed that Francisella cells infecting different mouse or primate tissues carry sufficient

numbers of ribosomes to be detected with fluorochrome-labeled oligonucleotides. The probes readily penetrate tissue samples and bacterial cell walls. This technique is well suited to detect the location of a pathogen within the body, an advantage that can be further improved in combination with confocal laser scanning microscopy. This modification could compensate the comparatively low sensitivity of in situ GANT61 in vivo hybridization typically requiring about 105 cells per ml for a positive reaction [25]. “”Phylogenetic staining”" using fluorescence labeled hybridization probes was employed for several clinically relevant and also environmental bacterial species [27]. P-type ATPase For environmental studies, fluorescent in situ hybridization is used for the identification at genus, species and subspecies level especially for uncultivable species making FISH an extremely valuable tool to study ecological niches of bacterial species or symbiotic life styles in complex ecological systems. Future

studies will show whether in situ hybridization techniques are sufficiently sensitive to detect dormant or metabolically inactive Francisella cells intracellularly surviving within tissues or in environmental samples like water, soil or arthropod vectors. Conclusions The molecular methods investigated in this study offer alternatives to more traditional diagnostic methods for detection of tularemia in humans and animals. In particular, whole-cell hybridization is a promising, rapid, and cultivation-independent detection method for Francisellae in clinical samples but could also prove useful to detect and explore the newly recognized diversity of Francisella species or Francisella-like organisms in the environment. Authors’ informations WDS and ES direct the German Reference Laboratory for Tularemia, which was repeatedly appointed by the Germany Federal Ministry of Health to provide specialist AZD5153 datasheet expertise in the field of tularemia.