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Infections due to antibiotic-resistant bacteria diagnosed at hospital admission. Incidence and risk factors

Abstract number: P2063

Tacconelli E., Iannotti N., Venturiello S., Cataldo M., Muscatello A., Spanu T., Fadda G., Cauda R.

Objectives: In recent years a rising incidence of antibiotic resistant bacteria (ARB) isolated at hospital admission (HA) has been reported. Little is known about the epidemiological characteristics of patients (pts) suffering from infections due to ARB at HA. Therefore, objective of the study was to analyse risk factors for these infections.

Methods: A one-year cohort study was planned. ARB included: meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum b-lactamase (ESBL)-producing bacteria, ciprofloxacin-resistant Escherichia coli or multi-drug-resistant (MDR) Gram-negative bacteria (>3 resistance to common used antibiotics) isolated within 72 hours of HA. For the risk factors analysis, a nested case-control study was done comparing the first consecutive 100 pts with infection due to ARB to 200 randomised pts with no infections due to ARB diagnosed throughout hospital stay.

Results: In the cohort study, infections caused by ARB were diagnosed in 398 pts representing 7 cases per 1,000 hospital admissions. Twenty-two percent of isolates were ESBL-producing bacteria, 17% MRSA, 10% carbapenems-resistant Pseudomonas aeruginosa and 2% VRE. According to the 2007 Centers for Disease Control criteria, among 100 infections, 94% were healthcare associated and 6% were community acquired. Independent risk factors (P < 0.05) included: urinary catheter (odds ratio [OR] 5.7), Charlson score >3 (OR 3), antibiotic therapy within 30 days (OR 2.7) and age >60 years (OR 2.2). The presence of all risk factors was associated with the strongest evidence to rule in diagnosis of infections due to ARB at HA (likelihood ratio=12). Analysis of previous therapy revealed that glycopeptides and penicillins were predictive for meticillin resistance in S. aureus (area under receiver operator characteristic [ROC] curve), 65%); quinolones and penicillins for ciprofloxacin-resistance in E. coli (area under ROC curve, 68%); penicillins for ESBL production (area under ROC curve, 59%), for MDR-resistance in Gram-negative bacteria (area under ROC curve, 58%) and for vancomycin-resistance in enterococci (area under ROC curve, 71%).

Conclusion: Pts aged >60 yrs with clinical signs of bacterial infections at HA and urinary catheter, previous use of antibiotics, and severe underlying conditions are at increased risk for having infections caused by ARB. Recognition of these risk factors may influence the selection of empirical treatment.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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