The present study investigated regional variations in antibiotic use for the treatment of hospital-acquired infections (HAIs) in France by means of a multilevel analysis, to identify targets for quality improvement.

Data were obtained from the 2001 and 2006 French national point-prevalence surveys of HAIs and antibiotic use. The present study was conducted using data from 393 nonteaching public hospitals. Data included patient characteristics calculated at the hospital level (mean age and proportion of patients with the following: HAI, presence of a vascular catheter, presence of a urinary catheter, surgical procedure, and immunodeficiency) and hospital characteristics (size and presence of an intensive care unit). The regional effect was measured using a random intercept on a regional variable.

Overall, the prevalence of antibiotic use was 5.35% for both study years. The most commonly used antibiotics for HAIs were fluoroquinolones (2001, 1.33%; 2006, 1.35%) and combinations of penicillins with a β-lactamase inhibitor (2001, 0.92%; 2006, 1.02%). Mapping of antibiotic use showed wide variation between regions. The regional effect explained 3% of antibiotic variation in the unadjusted analysis. In the multivariable analysis, hospital size, high prevalence of patients with immunodeficiency, and infection characteristics explained 45% of the variability in antibiotic use. The regional effect was not retained in the final model.

The pattern of antibiotic use for HAIs differed over time, and regional variations were mostly explained by patient characteristics; there was no regional effect. Models that take data hierarchy into account are essential to better approach antibiotic use and develop relevant strategies for improvement.

To investigate relationships between rates of antimicrobial consumption and the incidence of antimicrobial resistance in Staphylococcus aureus and Pseudomonas aeruginosa isolates from hospitals.

We conducted an observational study that used retrospective data from 2002 and linear regression to model relationships. Hospitals were asked to collect data on consecutive S. aureus and P. aeruginosa isolates, consumption rates for antibiotics (ie, anti-infectives for systemic use as defined by Anatomical Therapeutic Chemical class J01), and hospital characteristics, including infection control policies. Rates of methicillin resistance in S. aureus and rates of ceftazidime and ciprofloxacin resistance in P. aeruginosa were expressed as the percentage of isolates that were nonsusceptible (ie, either resistant or intermediately susceptible) and as the incidence of nonsuceptible isolates (ie, the number of nonsuceptible isolates recovered per 1,000 patient-days). The rate of antimicrobial consumption was expressed as the number of defined daily doses per 1,000 patient-days.

Data were obtained from 47 French hospitals, and a total of 12,188 S. aureus isolates and 6,370 P. aeruginosa isolates were tested.

In the multivariate analysis, fewer antimicrobials showed a significant association between the consumption rate and the percentage of isolates that were resistant than an association between the consumption rate and the incidence of resistance. The overall rate of antibiotic consumption, not including the antibiotics used to treat methicillin-resistant S. aureus infection, explained 13% of the variance between hospitals in the incidence of methicillin resistance among S. aureus isolates. The incidence of methicillin resistance in S. aureus isolates increased with the use of ciprofloxacin and levofloxacin and with the percentage of the hospital's beds located in intensive care units (adjusted multivariate coefficient of determination [aR2], 0.30). For P. aeruginosa, the incidence of ceftazidime resistance was greater in hospitals with higher consumption rates for ceftazidime, levofloxacin, and gentamicin (aR2, 0.37). The incidence of ciprofloxacin resistance increased with the use of fluoroquinolones and with the percentage of a hospital's beds located in intensive care (aR2, 0.28).

A statistically significant relationship existed between the rate of fluoroquinolone use and the rate of antimicrobial resistance among S. aureus and P. aeruginosa isolates. The incidence of resistant isolates showed a stronger association with the rate of antimicrobial use than did the percentage of isolates with resistance.