Article

Correlation of cefpodoxime susceptibility with cephalothin and cefuroxime for urinary tract isolates

Eisenhower Army Medical Center.
Journal of Medical Microbiology (Impact Factor: 2.25). 11/2013; 63(Pt_2). DOI: 10.1099/jmm.0.063040-0
Source: PubMed

ABSTRACT

This study attempted to determine whether cefuroxime was superior to cephalothin as a surrogate marker for cefpodoxime among urinary tract isolates. The Microscan© system was used to determine susceptibility for cephalothin and cefuroxime on consecutive cultures with a colony count of > 50,000 organisms. Simultaneously, an E-test for cefpodoxime was conducted. The cefpodoxime interpretation was compared to that of the other 2 agents, and the categorical agreement was calculated, defined as the percentage of identical susceptibility interpretations. Cefuroxime (83%) had a significantly higher categorical agreement than cephalothin (63%) among 300 isolates (p < 0.01). The major error rate was 16% for cephalothin, and 3% for cefuroxime. The very major error rate was 7% for cephalothin and 14% for cefuroxime among the 14 cefpodoxime-resistant isolates. For E.coli. the major error rates were 15% and 1% for cephalothin and cefuroxime, respectively. Very major error rates were 9% for both agents. Cefuroxime was a better predictor of cefpodoxime susceptibility than cephalothin, and appears to be the preferred surrogate agent for the Microscan© system, particularly for E. coli.

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    ABSTRACT: Of the cephalosporins, cefpodoxime has the most published clinical data for the treatment of urinary tract infections. In 2014, the Clinical and Laboratory Standards Institute (CLSI) guidelines recommended that cefazolin should be used as the surrogate marker for cefpodoxime among urinary tract isolates, replacing cephalothin. This study attempted to determine how well cefazolin serves as the surrogate marker. Additionally, it investigated how cefuroxime compared to cefazolin as a surrogate marker. The MicroScan© Walkaway Plus system was used to determine susceptibility for cefazolin and cefuroxime on consecutive urine cultures with a colony count of > 50,000 organisms. Only Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis isolates were included per CLSI guidelines. Simultaneously, an Etest© for cefpodoxime was conducted. The cefpodoxime interpretation was compared to that of the other 2 agents, and the categorical agreement was calculated, defined as the percentage of identical susceptibility interpretations. Cefazolin (92%) had a significantly higher categorical agreement than cefuroxime (85%) among 284 isolates (p = 0.011). The major error rate was 4.4% for cefazolin, and 1.1% for cefuroxime. The very major error rate was 64% for cefazolin and 18% for cefuroxime among the 11 cefpodoxime-resistant isolates. Cefazolin was a better predictor of cefpodoxime susceptibility than the previously recommended agent cephalothin. However, cefuroxime had better major and very major error rates than cefazolin.
    No preview · Article · Jul 2015 · Journal of Medical Microbiology