Authors:M. Szász, Nóra Lehotkai, Katalin Kristóf, Dóra Szabó, and K. Nagy
The predominant causative agent of urinary tract infections in children and adults is
, but it is necessary to appreciate the importance of other Gram-negative rods, especially in newborns. Antibiotic resistance rates are also different in children and in adult care units due to many factors and therapeutical guidelines.The aim of this retrospective study was to show the local prevalence and resistance patterns of uropathogens in certain clinics of university and present the distribution of uropathogens in different age groups. Therefore, 4833 positive samples were analysed.
was found to be the highest prevalent causative agent in every adult care unit, but some differences in other causative agents could have been detected. Three types of antimicrobial agents showed decreasing susceptibility rates: trimethoprim/sulfamethoxasole, cephalosporins and quinolones; but there were differences in resistance among the 8 investigated inpatient wards.
Authors:B. Kádár, M. Szász, Katalin Kristóf, Natasa Pesti, G. Krizsán, Julianna Szentandrássy, L. Rókusz, K. Nagy, and Dóra Szabó
The aim of the study was to investigate the biofilm-production of 60 Pseudomonas aeruginosa strains isolated from clinical samples and to examine the effect of different antimicrobials and their combinations with clarithromycin on biofilm-formation.The minimal inhibitory concentrations (MICs), minimal biofilm inhibitory concentrations (MBICs), and antibiotic synergy by calculating the fractional inhibitory concentration (FIC) index were determined for the following antibiotics: ceftazidime, cefepime, piperacillin/tazobactam, imipenem, meropenem, levofloxacin, ciprofloxacin, gentamicin, amikacin, tobramycin, netilmicin and clarithromycin.A total of 14 (23.3%) isolates out of 60 isolates of P. aeruginosa were biofilm positive. Cefepime, imipenem and meropenem had the lowest MIC90 values. Piperacillin/tazobactam and clarithromycin had the highest MIC90 values. Imipenem, meropenem, piperacillin/tazobactam and clarithromycin had the lowest MBIC90 values.For biofilm-forming P. aeruginosa strains 2-fold to 128-fold higher MBIC values than MIC values were obtained for ceftazidime, cefepime, imipenem, amikacin and netilmicin. The MBIC was 2-fold to 512-fold lower then the MIC values in the case of piperacillin/tazobactam, ciprofloxacin, levofloxacin and clarithromycin.Synergy was generally demonstrated for clarithromycin in combination with aminoglycosides, fluoroquinolones or ceftazidime. However, surprisingly it was found that combinations of clarithromycin with carbapenems or cefepime led to an antagonistic interaction: combination of clarithromycin with imipenem, meropenem or ertapenem showed antagonism in 37.5%, 50% and 62.5% of the strains tested whereas its combination with cefepime expressed antagonism in 75% of the strains, respectively. To the best of our knowledge no one has previously described this phenomenon so far.