Beyond the Abstract - The changing pattern of antimicrobial resistance within 42033 Escherichia coli isolates from nosocomial, community and urology patient-specific urinary tract infections, Dublin, 1999-2009, by Ivor Cullen

BERKELEY, CA ( - E.coli infection is the most causative pathogen in urinary tract infections, accounting for 70-80% in the community and 50-60% in the hospital setting.

A retrospective analysis of the 42,033 positive E.coli urine infections from the 11-year period 1999–2009 in Tallaght hospital (AMNCH) was performed. The origins of the urine samples were stratified into three groups: inpatients with nosocomial (hospital acquired) UTIs, urine originating from the emergency department and general practice (community UTIs), and UTIs in urology patients.

As expected, the resistance rates to commonly used antibiotics are highest for hospital inpatients as these patients have often had recent surgery/intervention and often have had previous exposure to antibiotics. Also it is well understood that organisms isolated within the hospitals are inherently more resistant to antibiotics.

Our research suggests that first line therapy in the community should change to nitrofurantoin or a cephalosporin and we suggest caution prescribing co-amoxyclav (augmentin) and ciprofloxacin where we are seeing significant rising trends in resistance to these agents. Our analysis confirms that within the community, ampicillin and trimethoprim no longer represent suitable first line choice antibiotics (they traditionally had been used in this setting). Ciprofloxacin resistance approaches 20% in the nosocomial (hospital) UTI population and approaches 30% in the urology population, indicating they are no longer suitable first line antibiotic choices in these populations. We have also identified the overall gentamicin resistance rate was 3.4% and is climbing at a rate of 0.7% per year (P <0.001). This is particularly concerning as this agent would be a first line choice for unwell hospital patients with UTIs. Within the urology patient population the resistance rate was 6.4%.

Ineffective treatment of UTI with inappropriate antibiotic agents has serious repercussions. The patients may be exposed to multiple courses of antibiotics (as the first choices are ineffective) and it also leads to further evolution of resistant strains within the community and the hospital. There is an obvious monetary cost to ineffective prescribing.

This research will promote evidence based effective prescribing within the hospital and the local community and has been incorporated into recent hospital prescribing guidelines and guidelines issued from the Irish College of General Practitioners. This is the largest study of its nature performed to date.

It was recently presented at the Annual Irish Society of Urology Scientific Meeting , and was presented at the European Association of Urology and the American Association of Urology meetings in 2011.

Antibiotic resistance rates do vary between countries, and indeed regions, within countries. We recommend similar analyses should be performed in all regions to ensure effective evidence based prescribing occurs throughout the country.


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Ivor Cullen as part of Beyond the Abstract on This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.


The changing pattern of antimicrobial resistance within 42033 Escherichia coli isolates from nosocomial, community and urology patient-specific urinary tract infections, Dublin, 1999-2009 - Abstract

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