The slide was placed on a cold plate in the refrigerator (4°C) for 5 min to allow the agarose to produce a microgel with the trapped intact cells

inside. The coverslip PF-04929113 molecular weight was removed gently, and the slide was immediately immersed horizontally in 10 ml of the lysing solution for 5 min at 37°C for gram-positive bacteria or at room temperature (22°C) in case of gram-negative bacteria. The slide was washed horizontally in a tray with abundant distilled water for 3 min, dehydrated by incubating horizontally in cold (-20°C) ethanol of increasing concentration (70%, 90%, and 100%) for 3 min each, and air-dried in an oven. The dried slide was incubated in a microwave oven at 750 W for 4 min, and the DNA was stained with 25 μl of the fluorochrome SYBR Gold (Molecular Probes, Eugene, OR, USA) diluted 1:400 in TBE buffer (0.09 M Tris-borate, 0.002 M EDTA, pH 7.5) for 2 min in the dark, with a glass coverslip. MK-4827 concentration After a brief wash in phosphate buffer pH 6.88 (Merck, Darmstadt, Germany), a 24 × 60 mm coverlisp was added and the slides visualized under fluorescence

microscopy. In situ digestion with proteinase K and with DNase I Many cultures sensitive to beta-lactams showed a diffuse microgranular-fibrilar background. To investigate the nature of this background, in situ digestion with enzymes and Fluorescence In Situ Hybridization (FISH) with a whole genome probe were performed. One strain of E. coli susceptible to ampicillin, isolated from an urine sample, was incubated with this antibiotic (32 μg/ml) and another strain of A. baumannii, isolated from a respiratory sample, ever was incubated with imipenem (0.76 μg/ml), in Mueller-Hinton broth at 37°C for 60 min, with aeration and shaking. Afterwards, three microgels (18 × 18 mm) on each slide were prepared for each microorganism, as described before, but without the lysis step. One microgel corresponded to the control culture without antibiotic, and the other two, to the culture incubated with the antibiotic. Some slides were washed by immersion in proteinase K buffer (SDS 1%, EDTA 2 mM, pH 7.5) and some slides were washed

in DNase I buffer (Tris-HCl 20 mM, MgCl2 2 mM, pH 8.3), three times, 5 min each. In the first case, whereas one of the microgels from the culture treated with the antibiotic was only incubated with the proteinase K buffer, the other microgel was incubated with proteinase K in buffer (2 mg/ml). In the case of the slides washed with the DNase I buffer, one of the microgels from the culture treated with the antibiotic was only incubated with the DNase I buffer and the other microgel was incubated with 2.5 U DNase I in buffer. Incubations were performed after covering with a glass coverslip, at 37°C, 30 min, in a humid chamber. Finally, the slides were washed in distilled water, dehydrated in increasing ethanol baths (70%-90%-100%) 5 min each, air dried and stained with SYBR Gold (1:400).