Antibiotic resistance in Enterobacteriacea in Austrian intensive care units

Abstract number: P2097

Metz-Gercek S., Pointner C., Polonyi M., Krziwanek K., Mittermayer H.

Background: Infections with resistant Gram-negative (GN) bacteria in intensive care settings have become a threat to modern medicine in recent years. Increasing resistance against first line drugs such as fluoroquinolones (FQ) or 3rd generation cephalosporines (3C), the appearance of metallo-betalactamase resistance (MBL) in some countries e.g. Greece and Great Britain and the lack of new drug developments with activity against GN pathogens are the main factors for increasing complexity of patient management. In the present study we analysed the current situation and time trends of in vitro activity of vital substances in intensive care units (ICUs) of 33 hospitals in Austria.

Methods: Susceptibility to 9 antibiotics of 1.125 consecutive enterobacteriacea strains isolated in clinical specimen in ICUs all over Austria during the periods January to May 2005 and January to May 2007 was determined at the National Reference Center for Nosocomial Infections and Antibiotic Resistance in Linz. Besides that data on patient characteristics, epidemiology and culturing practice were collected to set resistance prevalence in relation to factors of patient characteristics and clinical activity. Data from the European surveillance network EARSS has been used for comparison and to bring the findings in a larger context.

Results: For the most frequent GN pathogen E. coli (eco) rising resistance for FQ, 3C, and 4th generation Cephalosporins (4C) as well as an increase of ESBL-producing strains were found in Austrian ICUs. In contrast to that, the activity of Carbapenems (C) as well as the activity of the recently introduced drug tigecycline (T) was still very high. In Klebsiella species (ksp) no rising trend in resistance for FQ, 3C, 4C and rates of ESBL-producing strains were detected. This is in accordance with findings in EARSS where resistance rates of FQ and 3C for invasive eco isolates has also risen substantially (FQ: 7% to 27%; 3C: 0% to 8%) between 2001 and 2007. Resistance rates for FQ (12%/12%), 3C (6%/5%) and C (0%/0%) for K. pneumoniae (kpn) have on the other hand remained stable since the beginning of the EARSS data collection in 2005.

Conclusions: There is still in vitro activity of a number of substances especially the reserve drugs C and T against eco and kpn/ksp. It is surprising that typical nosocomial pathogens such as ksp and kpn show no change in resistance over time unlike eco which shows an enormous increase in resistance against firstline therapeutic options.