The relationship between primary care antibiotic prescribing and bacterial resistance in adults in the community: a controlled observational study using individual patient data.
ABSTRACT To examine the relationship between primary care prescribed antibiotics and the development of antibiotic resistance in perineal flora contaminating unselected urinary isolates from a large sample of asymptomatic adults representative of the general community.
Escherichia coli isolates contaminating urine samples were obtained from asymptomatic adults aged >16 years registered with general practices in the former Avon and Gloucestershire health authority areas. Data on antibiotic exposure during the 12 months prior to providing the urine samples were collected from the primary care electronic and paper medical records. The main outcome measure was resistance to amoxicillin or trimethoprim or both.
Two thousand nine hundred and forty-three adults submitted urine samples. Susceptibility among E. coli isolates and antibiotic prescribing data were available from 618 patients. We found no evidence of an association between resistance and patients' exposure to any antibiotic prescribed in primary care in the previous 12 months [adjusted odds ratio (OR) 1.12, 95% confidence interval 0.77-1.65, P = 0.52]. Secondary analyses demonstrated greater resistance in patients exposed to antibiotics within 2 months (adjusted OR 1.95, 1.08-3.49, P = 0.03), a dose-response relationship to increasing exposure to trimethoprim in the previous 12 months (adjusted OR 1.01, 1.01-1.02, P = 0.001) and that individuals who had been prescribed any beta-lactam antibiotic in the previous 12 months had amoxicillin MICs more than twice (adjusted 95% CI 1.23-3.31, P = 0.009) that of those who had not been prescribed any beta-lactams.
Whether or not adults receive a prescription for any antibiotic during a 12 month period does not appear to influence the antimicrobial resistance of perineal flora. However, the temporal and dose-response relationships found may be suggestive of a causative association and should be the focus of further research.
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ABSTRACT: To assess the effect of previous antibiotic use on the risk of a resistant Escherichia coli urinary tract infection (UTI), we undertook a case-control study with prospective measurement of outcomes in 10 general practices in the UK. Urinary samples from all patients with symptoms suggestive of UTIs were sought, and those with a laboratory-proven E. coli infection were interviewed and their medical records examined. Case patients were those with ampicillin- or trimethoprim-resistant infections and control patients had infections that were susceptible to antibiotics, including ampicillin and trimethoprim. Risk of ampicillin-resistant E. coli infection in 903 patients was associated with amoxicillin prescriptions of >or=7 days duration in the previous 1 month [odds ratio (OR)=3.91, 95% CI 1.64-9.34] and previous 2-3 months (2.29, 1.12-4.70) before illness onset. For prescriptions <7 days duration, there was no statistically significant association. Higher doses of amoxicillin were associated with lower risk of ampicillin resistance. For trimethoprim-resistant E. coli infections, the OR was 8.44 (3.12-22.86) for prescriptions of trimethoprim of >or=7 days in the previous month and 13.91 (3.32-58.31) for the previous 2-3 months. For trimethoprim prescriptions of <7 days, the OR was 4.03 (1.69-9.59) for the previous month but prescribing in earlier periods was not significantly associated with resistance. Within the community setting, exposure to antibiotics is a strong risk factor for a resistant E. coli UTI. High-dose, shorter-duration antibiotic regimens may reduce the pressure on the emergence of antibiotic resistance.Journal of Antimicrobial Chemotherapy 08/2007; 60(1):92-9. · 5.34 Impact Factor
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ABSTRACT: Rapid influenza diagnostic testing is potentially a useful means to decrease inappropriate prescription of antibiotics. We studied the impact of access to rapid influenza test results on antibiotic prescribing and other patient management practices for outpatients with influenza-like illness (ILI) in a rural province in Eastern Thailand. A medical record review was performed for 300 patients of all ages selected from five outpatient departments using a 1:2 ratio of ILI cases with and without influenza infection identified by the QuickVue rapid test. Chi-square analysis or Fisher's exact test was used to compare patient management practices (antibiotic prescriptions, individual treatments administered, additional tests ordered, and related hospitalization) between rapid test positive and negative patients. Logistic regression was used to evaluate the effect of rapid test results on patient management practices for ILI. Eighty-two percent of all patients with ILI were prescribed antibiotics. Patients with a positive rapid test were less likely to be prescribed antibiotics than those with a negative result (73% vs. 87%, respectively, p=0.003). The likelihood of antibiotic prescription for influenza positive patients was 0.41 times the likelihood for influenza negative patients (95% CI 0.23-0.74, p=0.003). There was no significant difference in the frequency of other patient management practices between influenza positive and negative patients. Thai outpatients with ILI are prescribed antibiotics at a frequency approximately twice that reported in the USA. Having access to a rapid influenza test result was associated with a significant decrease in antibiotic prescription. Improved access to rapid influenza testing and expanded physician education may reduce inappropriate antibiotic use and improve patient care.International Journal of Infectious Diseases 08/2007; 11(4):355-9. · 2.36 Impact Factor
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ABSTRACT: ABSTRACT: BACKGROUND: Urinary tract infections (UTIs) are the second most common bacterial infections in general practice and a frequent indication for prescription of antimicrobials. Increasing concern about the association between the use of antimicrobials and acquired antimicrobial resistance has highlighted the need for rational pharmacotherapy of common infections in general practice. METHODS: Management of urinary tract infections in general practice was studied prospectively over 8 weeks. Patients presenting with suspected UTI submitted a urine sample and were enrolled with an opt-out methodology. Data were collected on demographic variables, previous antimicrobial use and urine samples. Appropriateness of different treatment scenarios was assessed by comparing treatment with the laboratory report of the urine sample. RESULTS: A total of 22 practices participated in the study and included 866 patients. Bacteriuria was established for 21% of the patients, pyuria without bacteriuria for 9% and 70% showed no laboratory evidence of UTI. An antimicrobial agent was prescribed to 56% (481) of the patients, of whom 33% had an isolate, 11% with pyuria only and 56% without laboratory evidence of UTI. When taking all patients into account, 14% patients had an isolate identified and were prescribed an antimicrobial to which the isolate was susceptible. The agents most commonly prescribed for UTI were co-amoxyclav (33%), trimethoprim (26%) and fluoroquinolones (17%). Variation between practices in antimicrobial prescribing as well as in their preference for certain antimicrobials, was observed. Treatment as prescribed by the GP was interpreted as appropriate for 55% of the patients. Three different treatment scenarios were simulated, i.e. if all patients who received an antimicrobial were treated with nitrofurantoin, trimethoprim or ciprofloxacin only. Treatment as prescribed by the GP was no more effective than treatment with nitrofurantoin for all patients given an antimicrobial or treatment with ciprofloxacin in all patients. Prescribing cost was lower for nitrofurantoin. Empirical treatment of all patients with trimethoprim only was less effective due to the higher resistance levels. CONCLUSIONS: There appears to be considerable scope to reduce the frequency and increase the quality of antimicrobial prescribing for patients with suspected UTI.BMC Family Practice 10/2011; 12(1):108. · 1.61 Impact Factor