Background: Escherichia coli is the main GNB causing infections in patients. Antimicrobial
resistance (AR) to commonly prescribed drugs menaces its effectiveness for the
treatment of those infections. Monitoring of national rates and trends and
understanding the factors associated to AR infections can help to develop
national guidelines to control this problem.
Objective: To identify rates and time trends in AR of E. coli infections in hospitalized patients in Spain and To identify main characteristics associated to AR.
Methods: A series or annual prevalence surveys of infections performed at a national level.Spanish hospitals are invited to participate annually to survey hospitalized patients in a point prevalence study. Demographics, infection characteristics, and patient data are abstracted by trained nurses and doctors. For this study all E. coli infections were selected. AR to third generation cephalosporins (3GC) and fluorquinolones (FQ) as reported to clinicians by the microbiology laboratory were recorded. Data pertaining to the period from 1999 through 2007 was included for analysis. Time trends were identified by univariate logistic regressions. Main factors associated to AR infections were selected by multistep multivariate logistic regression analysis.
Results: Up to 266 hospitals participated every year. A total of 13,564 E. coli infections were identified. 54% of them were identified in females. Infections were localized in the urinary tract (6,953, 54%), the surgical site (15%), blood-stream (BSI) (12%), and respiratory tract (RTI) (5%). Only 973 infections (7.2%) pertained to ICU patients. Most infections were diagnosed in patients older than 65 years (59%), and were community onset (55%).
Antimicrobial resistance to FQ and 3GC increased throughout the study period from 15.9% to 31.1% and from 4.6% to 12.7% respectively (p<0.01). Main factors associated to 3GC resistance were nosocomial onset (OR 1.64), ICU setting (OR 1.15), RTI or BSI (OR 1.34 and 1.27), renal failure (OR 1.19), diabetes (OR 1.21), chronic lung disease (CLD) (OR 1.28), decubitus ulcer (OR 1.34), immunosuppression (OR 1.46), sedation (OR 1.37), and urinary catheter (OR 1.2). Main factors associated to FQ resistance were nosocomial onset (OR 1.14), renal failure (OR 1.27), diabetes (OR 1.21), malignancy (OR 1.15), CLD (OR 1.48), neutropenia (OR 1.45), decubitus ulcer (OR 1.62), immunosuppression (OR 1.43), and urinary catheter (OR 1.4).
Conclusions: Rates of resistance of E. coli to 3GC are high and have increased dramatically in Spain in the last years. Several host and infection factors have been identified associated to antimicrobial resistance.
The study was granted by FIS PI07/90255.
Figure. Rate of antimicrobial resistance for E. coli infections in hospitalized patients. Spain, 1999-2007