The influence of antibiotic use on the occurrence of vancomycin-resistant enterococci.
BACKGROUND
Several studies have documented the influence of antibiotic selective pressure, mainly from the use of glycopeptides, third-generation cephalosporins, quinolones and lincosamides, on the frequency of vancomycin-resistant enterococci (VRE) occurrence in hospitals. The aim of this study was to evaluate the relationship between VRE occurrence and antibiotic use in the Department of Hemato-Oncology of the Teaching Hospital in Olomouc (DHO), Czech Republic, over a 6-year period under standard and unchanged hygienic and epidemiological conditions.


METHODS
During the period of 1998-2003, Enterococcus sp. strains and VRE were isolated by standard methods from clinical samples taken from DHO in-patients. The frequency of VRE occurrence was expressed as the number of isolated strains per 100 bed-days/year. DHO antibiotic consumption data were processed according to the anatomical therapeutic chemical (ATC)/defined daily dose (DDD) system valid in 2003 and expressed in defined daily dose per 100 bed-days (DDD/100 bed-days) for each year of the period.


RESULTS
Since 1998, the occurrence of VRE decreased significantly (from 0.28 to 0.17 VRE/100 bed-days in 2001). Between 2001 and 2003, a significant (P < 0.05) increase from 0.17 to 0.38 was observed. The antibiotic use decreased from 205.2 in 1998 to 161.0 DDD/100 bed-days in 1999 and after an increase in 2001 (to 181.8 DDD/100 bed-days) it remained relatively stable. A significant decrease was observed in third-generation cephalosporins and quinolones (from 29.5 to 9.7 and from 42.2 to 30.2 DDD/100 bed-days respectively) between 1998 and 1999. In 2002-2003, the use of third-generation cephalosporins and glycopeptides increased substantially (from 10.1 to 13.9 and from 11.3 to 15.2 DDD/100 bed-days respectively). The Pearson correlation value was significantly positive (P < 0.05) for VRE occurrence and the use of glycopeptides and third-generation cephalosporins.


CONCLUSIONS
While our study confirms the effect of use of glycopeptides and third-generation cephalosporins on occurrence of VRE, no influence of quinolones and lincosamides over the 6-year period was shown.
Kolar
M
M
Department of Microbiology, Medical Faculty, Palacky University, Hnĕvotínská 3, 775-15 Olomouc, Czech Republic. kolar@fnol.cz
Urbanek
K
K
Vagnerova
I
I
Koukalova
D
D
D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001424:Bacterial Infections / Q000188:drug therapy; D018153:Czech Republic / Q000453:epidemiology; D004363:Drug Utilization / Q000706:statistics & numerical data; D016983:Enterococcus / Q000187:drug effects / Q000302:isolation & purification*; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D017720:Molecular Epidemiology; D020713:Vancomycin Resistance
D000900:Anti-Bacterial Agents