Real time PCR detection of Piscirickettsia salmonis from formalin-fixed paraffin-embedded tissues.

Piscirickettsia salmonis is the causative agent of piscirickettsiosis, a transmissible disease of salmonid fish. Diagnosis of piscirickettsiosis has traditionally been based upon identification of typical pathological changes by histological investigation, with confirmation by immunohistochemistry on formalin-fixed, paraffin-embedded tissues. However, implementation of more rapid confirmatory techniques, preferably with higher levels of sensitivity and possibilities for quantification, is desirable. A real-time polymerase chain reaction (PCR) assay was designed for specific detection of P. salmonis and tested on samples extracted from formalin-fixed paraffin-embedded material. Construction of a PCR-target mimic allowed determination of detection limits, linearity of the real-time PCR and quantitative detection of P. salmonis. The present study demonstrates the capability of the described real time PCR assay for detection of P. salmonis from paraffin-embedded material with a high degree of sensitivity and specificity. Implementation of this assay constitutes an important development for a rapid and secure diagnosis of piscirickettsiosis.

Francisella philomiragia subsp. noatunensis subsp. nov., isolated from farmed Atlantic cod (Gadus morhua L.).

Seven bacterial isolates from farmed Atlantic cod displaying chronic granulomatous disease were characterized by phenotypic and molecular taxonomic methods. The isolates were Gram-negative, facultatively intracellular, non-motile, strictly aerobic coccobacilli which produced H(2)S from cysteine-supplemented media and are therefore phenotypically consistent with members of the genus Francisella. Comparison of 16S rRNA gene sequences and six partial housekeeping gene sequences (groEL, shdA, rpoB, rpoA, pgm and atpA) confirmed the organism as a member of the genus Francisella, with Francisella philomiragia as its closest relative (99.3 % 16S rRNA gene sequence similarity, 92.2-99.0 % housekeeping gene sequence similarity). Despite the close relationship with F. philomiragia, isolates from Atlantic cod could be readily distinguished phenotypically and genetically from F. philomiragia ATCC 25015(T). DNA-DNA hybridization studies revealed a mean reassociation value of 68 %. Thus, on the basis of phenotypic and molecular genetic evidence, we propose that the strains isolated from Atlantic cod should be recognized as Francisella philomiragia subsp. noatunensis subsp. nov. with the type strain 2005/50/F292-6C(T) (=NCIMB 14265(T)=LMG 23800(T)). Francisella philomiragia ATCC 25015(T) (=DSM 735(T)) is reclassified as Francisella philomiragia subsp. philomiragia subsp. nov.

[The value of C-reactive protein testing in suspected lower respiratory tract infections. A study from general practice on the effect of a rapid test on antibiotic research and course of the disease in adults]. / Nytten av å teste C-reaktivt protein ved mulig nedre luftveisinfeksjon. En undersøkelse fra allmennpraksis av en hurtigtests innvirkning på antibiotikaforskrivning og sykdomsforløp hos voksne.

We wanted to assess whether routine use of a rapid test for C-reactive protein (CRP) could reduce prescription of antibiotics for adults with possible lower respiratory tract infection. 239 patients were randomized into a CRP group, tested with the rapid test (n = 108) and a control group (n = 121). Before knowing to which group the patient belonged the doctors made a preliminary decision about antibacterial treatment. The C-reactive protein value was then released if the patient belonged to the CRP group, and the therapy could be adjusted in light of the result. Antibacterial courses prescribed during the consultations and in the following three weeks were registered. The clinical course was evaluated by interview after one week and again after three weeks. Antibiotics were prescribed for altogether 56% of the patients in the CRP group and 60% in the control group. The difference was not statistically significant. Prescription of antibiotics was strongly associated with the finding of crackles and wheezes, but not with cough, dyspnoea or chest pain. Slow recovery was associated with high age, absence of fever and a normal value of C-reactive protein. No significant benefit of the CRP test was demonstrated. We discuss whether the doctors made full practical use of the information provided by the test. Bronchial obstruction should probably be considered to be the problem more often in coughing patients with a normal CRP value.