Prevalence of antibiotic resistance of the commensal flora in Dutch nursing homes

Objectives: To determine the prevalence of antibiotic resistance and multiresistance of Escherichia coli and Staphylococcus aureus in nursing homes and to determine which factors are associated with this prevalence. Design: Cohort study. Setting: Nursing homes. Participants: Residents of long-stay somatic care wards and rehabilitation patients were recruited from five nursing homes and two rehabilitation wards in hospitals in the central region of the Netherlands. Measurements: From each included patient, an anal swab was analyzed for E. coli and its antibiotic susceptibility and extended spectrum beta-lactamase-producing Enterobacteriaceae. Nasal swabs were analyzed for S. aureus and its susceptibility, including methicillin-resistant S. aureus (MRSA). Associations were determined between resistance of E. coli to amoxicillin/co-amoxiclav and recent use (previous 6 months) of these antibiotics, hospital admission (previous 3 months), and presence of a urinary catheter. Results: A total of 125 patients were included in the study. The resistance and intermediate susceptibility of E. coli varied from 4% (ceftriaxone) to 43% (amoxicillin). Extended spectrum beta-lactamase-producing Enterobacteriaceae were found in 6% of the patients. Amoxicillin and/or co-amoxiclav users were significantly more resistant to these antibiotics (69%) than nonusers (38%). No associations were found between amoxicillin and/or co-amoxiclav resistance and hospital admission or presence of a urine catheter. The resistance of S. aureus varied from 0% to 69% (penicillin). No MRSA was found. The ciprofloxacin resistance in E. coli and S. aureus was 14% and 39%, respectively. Conclusion: The prevalence of antibiotic-resistant E. coli and S. aureus in nursing homes was considerably high in this study, although no MRSA was found. This may lead to failing of empiric therapy of infections in patients in nursing homes. In particular, the high resistance to ciprofloxacin may make empiric quinolone therapy unreliable. Antibiotic use was associated with antibiotic resistance of E. coli. Therefore, antibiotic use should be restricted as much as possible. Analysis of risk factors for antibiotic resistance should be extended to be able to prevent further development of antibiotic resistance in nursing homes