Immunofluorescence testing by fluorescence microscopy. 5 μg/mL 1°Ab and 20 μg/mL R-PE conjugated 2°Ab were used representative microscopic images for (A) B. cepacia, (B) P. aerugino sa and (C) S. aureus in exponential growth phase (t = 2 h) from pure cultures. Laser Scanning Microscopy was employed (LSM 510, Carl Zeiss AG, Oberkochen, Germany). R-PE fluorescence was excited by 1 mW 543 nm Helium-Neon Laser and collected through a 585 nm long pass filter. Images are magnified 1000 x.