Journal article
Activity of cefepime against ceftazidime-resistant gram-negative bacilli using low and high inocula
Journal of antimicrobial chemotherapy, v 35(6), pp 765-773
Jun 1995
PMID: 7559188
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Cefepime is a broad-spectrum cephalosporin that is reported to have enhanced activity against ceftazidime-resistant Gram-negative bacilli. In this study the effects of varying inoculum size on in-vitro susceptibility to cefepime and other selected antimicrobial agents were determined by agar dilution MICs and in time-kill studies. Among strains of Pseudomonas aeruginosa (n = 55) and Enterobacter spp (n = 56) that had previously been identified as ceftazidime-resistant, 73% and 96% were susceptible to cefepime (MIC < or = 16 mg/L), respectively, when tested with an inoculum of 10(4) cfu. However, with an inoculum of 10(7) cfu, 98% and 100% of strains were resistant, respectively. Furthermore, the bactericidal activity of cefepime against ceftazidime-resistant isolates was also inoculum-dependent. In time-kill studies, bactericidal action was obtained only at the lowest concentration of organisms (10(4) cfu/mL). beta-Lactamase extracted from an isolate of P. aeruginosa that demonstrated an inoculum effect had a lower affinity for cefepime than for ceftazidime. Overall, cefepime proved to be more resistant to hydrolysis by the beta-lactamase. However, differences in kinetics of the beta-lactamase against cefepime or ceftazidime do not appear to be of consequence in determining susceptibility of P. aeruginosa and Enterobacter spp. at high bacterial densities, since most strains with chromosomally-mediated beta-lactamase are highly resistant.
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Details
- Title
- Activity of cefepime against ceftazidime-resistant gram-negative bacilli using low and high inocula
- Creators
- C C Johnson - Medical College of Pennsylvania, Philadelphia, USAL LivorneseM J GoldP G PitsakisS TaylorM E Levison
- Publication Details
- Journal of antimicrobial chemotherapy, v 35(6), pp 765-773
- Publisher
- Oxford University Press; England
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Infectious Diseases (and HIV Medicine)
- Web of Science ID
- WOS:A1995RG28800005
- Scopus ID
- 2-s2.0-0029090188
- Other Identifier
- 991014878360504721
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InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Infectious Diseases
- Microbiology
- Pharmacology & Pharmacy