Limited performance of MALDI-TOF for identification of fish Aeromonas isolates at species level

The aim of this study was to evaluate the usefulness of the MALDI-TOF MS to identify 151 isolates of Aeromonas obtained mostly from diseased fish. MALDI-TOF MS correctly identified all isolates to the genus level but important differences in the percentage of isolates correctly identified depending on the species were observed. Considering exclusively the first identification option, Aeromonas bestiarum, Aeromonas hydrophila, Aeromonas salmonicida, Aeromonas veronii and Aeromonas sobria were the best identified with results >95%. However, considering the first and second identification options, the only species that showed values >90% was A. hydrophila. Overall, when the database was supplemented with 14 new spectra, the number of accurate identifications increased (41% vs. 55%) and the number of inconclusive identifications decreased (45% vs. 29%), but great differences in the success of species-level identifications were found. Species-distinctive mass peaks were identified only for A. hydrophila and A. bestiarum (5003 and 7360 m/z in 95.5% and 94.1% of their isolates, respectively). This work demonstrates the utility of MALDI-TOF MS for Aeromonas identification to the genus level, but there is no consistency for the accurate identification of some of the most prevalent species implicated in fish disease.

Detection of steroid receptors in breast cancer: relationship between EIA and IHC methods

The efficiency of EIA and IHC (frozen tissue) in the detection of ER and PR in 51 breast cancers were compared. ER were detected in 51% of cases by IHC and in 49% of tumours by EIA. PR were detected in 56.8% of cases by IHC and in 54.8% of tumours by EIA. Concordance of the results of IHC and EIA reached 78.4% in ER and 82.4% in PR detection. Discordance between IHC and EIA seems to be related to minor changes in sensibility of methods, but we cannot conclude that one of the two techniques is superior to the other in the detection of hormonal receptors. There is a common trend of association between low grade of histologic or nuclear malignancy and a high expression of hormonal receptors.