Ping-Chin Chang1, Chi-Chung Chen2, Ying Chen Lu3, Chih-Cheng Lai4, Hui-Ling Huang5, Yin-Ching Chuang6, Hung-Jen Tang7. 1. Department of Internal Medicine, Chi Mei Medical Center, Liouying, Tainan, Taiwan. 2. Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan; Department of Food Science, National Chiayi University, Chiayi, Taiwan. 3. Department of Food Science, National Chiayi University, Chiayi, Taiwan. 4. Department of Intensive Care Medicine, Chi Mei Medical Center, Liouying, Tainan, Taiwan. 5. Department of Health and Nutrition, Chia-Nan University of Pharmacy and Science, Tainan, Taiwan. 6. Department of Internal Medicine, Chi Mei Medical Center, Liouying, Tainan, Taiwan; Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan. 7. Department of Health and Nutrition, Chia-Nan University of Pharmacy and Science, Tainan, Taiwan; Department of Medicine, Chi Mei Medical Center, Tainan, Taiwan. Electronic address: 8409d1@gmail.com.
Abstract
OBJECTIVES: This study aims to assess the in vitro activity of cefoperazone alone and different cefoperazone-sulbactam ratios against different inoculum sizes of multidrug resistant organisms. METHODS: Minimum inhibitory concentrations (MICs) of cefoperazone, cefoperazone-sulbactam at fixed ratio of 1:1 and 2:1 against a normal inoculum size of 5 × 105 CFU/ml and a high inoculum size of 5 × 107 CFU/ml were measured. RESULTS: Each 33 isolates of extended-spectrum β-lactamases (ESBL)-producing Escherichia coli, ESBL-producing Klebsiella pneumoniae, carbapenem-resistant E. coli, and carbapenem-resistant Pseudomonas aeruginosa and a total of 122 isolates of carbapenem-resistant Acinetobacter baumannii were collected. After the addition of sulbactam at a 1:1 ratio, most MIC50 and MIC90 values decreased. Cefoperazone-sulbactam at a 1:1 ratio had a higher susceptibility rate against ESBL-producing E. coli, carbapenem-resistant E. coli, and carbapenem-resistant A. baumannii than cefoperazone-sulbactam at a 2:1 ratio (all P < 0.05). For ESBL-producing E. coli, the susceptibility rate of cefoperazone-sulbactam at ratios of (1:1) and (2:1) decreased from 97.0 to 87.9% and 90.9 to 60.6%, for normal to high inoculum, respectively. For ESBL-producing K. pneumoniae, both susceptibility rate of cefoperazone-sulbactam at ratios of (1:1) and (2:1) decreased from 75.8%, and 63.6% at normal inoculum to 51.5% and 42.4% at high inoculum. CONCLUSIONS: Cefoperazone-sulbactam at a 1:1 ratio has greater in vitro activity against most multidrug resistant organisms than cefoperazone-sulbactam at a 2:1 ratio. Such combinations were not influenced by the inoculum size of ESBL-producing E. coli and K. pneumoniae and could be a therapeutic option for treating severe infections.
OBJECTIVES: This study aims to assess the in vitro activity of cefoperazone alone and different cefoperazone-sulbactam ratios against different inoculum sizes of multidrug resistant organisms. METHODS: Minimum inhibitory concentrations (MICs) of cefoperazone, cefoperazone-sulbactam at fixed ratio of 1:1 and 2:1 against a normal inoculum size of 5 × 105 CFU/ml and a high inoculum size of 5 × 107 CFU/ml were measured. RESULTS: Each 33 isolates of extended-spectrum β-lactamases (ESBL)-producing Escherichia coli, ESBL-producing Klebsiella pneumoniae, carbapenem-resistant E. coli, and carbapenem-resistant Pseudomonas aeruginosa and a total of 122 isolates of carbapenem-resistant Acinetobacter baumannii were collected. After the addition of sulbactam at a 1:1 ratio, most MIC50 and MIC90 values decreased. Cefoperazone-sulbactam at a 1:1 ratio had a higher susceptibility rate against ESBL-producing E. coli, carbapenem-resistant E. coli, and carbapenem-resistant A. baumannii than cefoperazone-sulbactam at a 2:1 ratio (all P < 0.05). For ESBL-producing E. coli, the susceptibility rate of cefoperazone-sulbactam at ratios of (1:1) and (2:1) decreased from 97.0 to 87.9% and 90.9 to 60.6%, for normal to high inoculum, respectively. For ESBL-producing K. pneumoniae, both susceptibility rate of cefoperazone-sulbactam at ratios of (1:1) and (2:1) decreased from 75.8%, and 63.6% at normal inoculum to 51.5% and 42.4% at high inoculum. CONCLUSIONS:Cefoperazone-sulbactam at a 1:1 ratio has greater in vitro activity against most multidrug resistant organisms than cefoperazone-sulbactam at a 2:1 ratio. Such combinations were not influenced by the inoculum size of ESBL-producing E. coli and K. pneumoniae and could be a therapeutic option for treating severe infections.