Klebsiella pneumoniae 20022007: multi-class resistance and changing patterns of resistance to carbapenems and third-generation cephalosporins

Abstract number: P637

Mera R.M., Miller L.A., Amrine-Madsen H., Sahm D.F.

Objectives: To describe the changes over time of K. pneumoniae resistance to several antimicrobial classes in a statistical model that adequately adjusts for changes over time and the effect of several risk factors.

Methods: The surveillance study consisted of 186,819 US isolates from the TSN Network® surveillance database (Eurofins Medinet) for the period 2002–2007. Covariates available for analysis were time, age, sex, state, location (Ward or ICU) and source (blood, sputum, etc). Antimicrobial classes considered in the model were carbapenems, 3rd generation cephalosporins, aminoglycosides and fluoroquinolones. Multi-class or multiple resistance was defined as non susceptibility to three or more antimicrobial classes. Odds of resistance and 95% confidence intervals around rates were obtained using a logistic regression model.

Results: Non susceptibility to carbapenems was not observed in this data set in 2002 but reached 3% for Meropenem in 2007. 3rd Generation cephalosporins such as Ceftazidime showed a continuous increase from 8.9% in 2002 to 14.2% in 2007, with 70% of the latter being multiply resistant compared to 50% in 2002 (p < 0.001). Levofloxacin resistance had a similar increase from 7.6% in 2002 to 14.5% in 2007, with 69% of the latter also being multiply resistant. Although there is a tendency toward a plateau for aminoglycosides, such as Gentamicin and Amikacin, multiple resistance has increased 2.9 fold (2.7–3.2) in five years of surveillance from 3.9% in 2002 to 10.7% in 2007. A multivariate model for multiple resistance has it increasing 2.1% (0.5–3.7%) every year (p = 0.001), with a 2.4% (0.8–3.4%) significant difference between ICU and Ward independent of time. Subjects under 18 years had a significantly lower rate (7.8%, 7.4–8.2%) in 2007 than those over 65 years old (11.2%, 10.9–11.6%).

Conclusion:K. pneumoniae non susceptibility to several antimicrobial classes has shown a marked increase during the surveillance period. Resistance to three or more antimicrobial classes has been amplified despite relatively low levels of carbapenem resistance and a plateau in aminoglycoside resistance.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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