Abstract
Understanding local susceptibility patterns is important when selecting antimicrobials for initial empirical antibiotic-therapy of bloodstream infections. Because the determination of susceptibility is dependent on the breakpoints used, the aim of the study was to compare the antimicrobial susceptibility results to different classes of antibiotics of 512 strains of Enterobacteriaceae (200 ESβL positive) isolated from bloodstream using CLSI 2013 and current EUCAST 2013 guidelines to evaluate the impact of break-point discrepancies. The results of the study showed that statistically significant discrepancies (p ≤ 0.001) were found for amoxicillin/clavulanic acid, piperacillin alone or with tazobac-tam, imipenem, meropenem, cefepime (only ESβL negative isolates), amikacin and gentamicin using current CLSI or EUCAST interpretive criteria. Further harmonization of CLSI and EUCAST breakpoints is warranted. This study could give useful information to physicians for managing bloodstream infections caused by Enterobacteriaceae.
Highlights
Bloodstream infections (BSI) are a leading cause of morbidity and mortality
For amoxicillin/clavulanic acid and ampicillin European Committee on Antimicrobial Susceptibility Testing (EUCAST) includes, in the resistant category, the MIC values classified as intermediate by Clinical and Laboratory Standard Institute (CLSI), but different percentage of resistance was only observed for amoxicillin/clavulanic acid (70% and 64% respectively)
Susceptibility breakpoints according to CLSI are ≤ 8 mg/l for cefepime, ≤ 1 mg/l for cefotaxime and ≤ 4 mg/l for ceftazidime; susceptibility EUCAST breakpoint is ≤ 1 mg/l for the three cephalosporins
Summary
Bloodstream infections (BSI) are a leading cause of morbidity and mortality. In addition there is an emergence of extended spectrum β-lactamase (ESβL) producers along with an alarming increase and spread of multidrug-resistance among BSI pathogens [1,2,3,4,5,6]. Antimicrobial resistance surveillance of the local epidemiology is indispensable for the initial antibiotic therapy that in bloodstream infections is always empirical [7]. From 2010 the European Committee on Antimicrobial Susceptibility Testing (EUCAST) [8] and the Clinical and Laboratory Standard Institute (CLSI) [9] published lower susceptibility breakpoints for third-generation cephalosporins to differentiate ESβL-positive from ESβLnegative isolates of Enterobacteriaceae. Breakpoint values of other classes of antibiotics mainly for Gram-negative species, were reviewed [8,9]. Changed CLSI guidelines or the use of EUCAST guidelines have led differences in susceptibility rates, mainly for cefalosporins, and conflicting results in literature [10,11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
