Dramatic increase of third-generation cephalosporin-resistant E. coli in German intensive care units: secular trends in antibiotic drug use and bacterial resistance, 2001 to 2008.
BACKGROUND
The objective of the present study was to analyse secular trends in antibiotic consumption and resistance data from a network of 53 intensive care units (ICUs).


METHODS
The study involved prospective unit and laboratory-based surveillance in 53 German ICUs from 2001 through 2008. Data were calculated on the basis of proportions of nonduplicate resistant isolates, resistance densities (that is, the number of resistant isolates of a species per 1,000 patient-days) and an antimicrobial usage density (AD) expressed as daily defined doses (DDD) and normalised per 1,000 patient-days.


RESULTS
Total mean antibiotic use remained stable over time and amounted to 1,172 DDD/1,000 patient-days (range 531 to 2,471). Carbapenem use almost doubled to an AD of 151 in 2008. Significant increases were also calculated for quinolone (AD of 163 in 2008) and third-generation and fourth-generation cephalosporin use (AD of 117 in 2008). Aminoglycoside consumption decreased substantially (AD of 86 in 2001 and 24 in 2008). Resistance proportions were as follows in 2001 and 2008, respectively: methicillin-resistant Staphylococcus aureus (MRSA) 26% and 20% (P = 0.006; trend test showed a significant decrease), vancomycin-resistant enterococcus (VRE) faecium 2.3% and 8.2% (P = 0.008), third-generation cephalosporin (3GC)-resistant Escherichia. coli 1.2% and 19.7% (P < 0.001), 3GC-resistant Klebsiella pneumoniae 3.8% and 25.5% (P < 0.001), imipenem-resistant Acinetobacter baumannii 1.1% and 4.5% (P = 0.002), and imipenem-resistant K. pneumoniae 0.4% and 1.1%. The resistance densities did not change for MRSA but increased significantly for VRE faecium and 3GC-resistant E. coli and K. pneumoniae. In 2008, the resistance density for MRSA was 3.73, 0.48 for VRE, 1.39 for 3GC-resistant E. coli and 0.82 for K. pneumoniae.


CONCLUSIONS
Although total antibiotic use did not change over time in German ICUs, carbapenem use doubled. This is probably due to the rise in 3GC-resistant E. coli and K. pneumoniae. Increased carbapenem consumption was associated with carbapenem-resistant K. pneumoniae carbapenemase-producing bacteria and imipenem-resistant A. baumannii.
Meyer
Elisabeth
E
Institute of Hygiene and Environmental Medicine, Charité-University Medicine Berlin, Hindenburgdamm 27, 12203 Berlin, Germany. elisabeth.meyer@charite.de
Schwab
Frank
F
Schroeren-Boersch
Barbara
B
Gastmeier
Petra
P
D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D016470:Bacteremia / Q000188:drug therapy; D002511:Cephalosporins / Q000494:pharmacology / Q000627:therapeutic use*; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects*; D005858:Germany; D006801:Humans; D007362:Intensive Care Units; D011159:Population Surveillance; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data
D000900:Anti-Bacterial Agents; D002511:Cephalosporins