Renata Tejkalová

Biofilm detection and the clinical significance ofStaphylococcus epidermidis isolates

The ability ofStaphylococcus epidermidis to produce biofilm was compared in 147 clinically significant strains repeatedly isolated from blood cultures of patients with bloodstream infection and in 147 strains isolated from skin. The strains were examined for the presence ofica operone, for the ability to form biofilm by Christensen’s test-tube method and for the production of slime by Congo Red agar method. Theica operone was found in 92 (62.6 %) blood isolates and in 44 (29.9) isolates from skin. Christensen’s test-tube method was positive in 79 (53.7) and 33 (22.4), Congo Red agar method in 64 (43.5) and 31 (21.1) of blood and skin isolates, respectively. All three methods were more frequently positive in clinically significant isolates from blood than in strains isolated from skin. The detection ofica operone and the Christensen’s test-tube method showed better correlation with the clinical significance than the Congo Red agar method.

Importance of biofilm in Candida parapsilosis and evaluation of its susceptibility to antifungal agents by colorimetric method.

The ability ofC. parapsilosis (an important cause of nosocomial infections) to produce biofilm was evaluated in 32 bloodstream isolates and 85 strains isolated from skin. The biofilm formation was found in 19 (59%) blood isolates and only in 33 (39%) isolates from skin. The antifungal susceptibility was assessed for amphotericin B, itraconazole and voriconazole in planktonic and biofilm form of the 19 biofilm-positive bloodstream strains by broth microdilution method according toNCCLS standards. The method was modified by the use of resazurin as a colorimetric indicator of the metabolically active cells which makes the determination of the effect of antifungal agents easier. Biofilm forms of all strains were more resistant than their planktonic form.

Molecular characterization of metallo-β-lactamase-producing Pseudomonas aeruginosa in a Czech hospital (2009-2011).

Metallo-b-lactamases (MbLs) are the most commonly acquired carbapenemases in Pseudomonas aeruginosa (Mesaros et al., 2007). The first report, to the best of our knowledge, on MbL-producing bacteria in the Czech Republic appeared in 2009 and concerned two P. aeruginosa isolates producing IMP-7 (Hrabak et al., 2009). In this study, we present the molecular characterization of MbL-producing P. aeruginosa isolates derived from a Czech hospital.

LightCycler SeptiFast technology in patients with solid malignancies: clinical utility for rapid etiologic diagnosis of sepsis

We retrospectively evaluated 54 results of the SeptiFast test from patients with solid malignancy admitted to the ICU between June 2009 and August 2011. Specimens from suspected bloodstream infection were analyzed using LightCycler SeptiFast (Roche Molecular Diagnostics according to the manufacturers instruction and evaluated in comparison with blood culture results obtained from blood sampled no longer than 24 hours before or after sampling for SeptiFast. Blood culturing and identification were performed according to the routine diagnostic procedures. The total number of blood cultures analyzed was 85, and finding a microorganism by either of the two tests was evaluated as positive. Consistently, negative results from SeptiFast and blood culture were obtained in 21 (39%) cases.