Legionella in two days instead of ten — and what the comparison with the reference method shows
The MICA method labels the bacterial cell wall and counts microcolonies automatically. Agreement with culture to ISO 11731:2017 was 82.4 % and sensitivity 67.4 % — a faster result, but not yet an equivalent one.
- The method uses click chemistry: bacteria incorporate a labelled sugar molecule into the cell wall, which allows fluorescent labelling and automatic counting already at the microcolony stage.
- A result is available after two days against up to ten days for the culture method; the limit of detection of both methods was the same at 50 colony forming units per litre.
- In the comparison 15 samples positive by the standard were negative by MICA and 4 negative by the standard came out positive — the difference in counts reached 0.4 to 0.6 of an order of magnitude in favour of culture.
- The authors state plainly that the method needs further refinement, including longer incubation for some strains; the paper appeared in MicrobiologyOpen on 12 June 2026.