In vitro activity of cefoperazone and cefoperazone-sulbactam against carbapenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa

In vitro activity of cefoperazone and cefoperazone-sulbactam against carbapenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa

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Chih-Cheng Lai,1 Chi-Chung Chen,2,3 Ying-Chen Lu,3 Yin-Ching Chuang,2,4 Hung-Jen Tang5,6 1Department of Intensive Care Medicine, Chi Mei Medical Center, Liouying, Tainan, Taiwan; 2Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan; 3Department of Food Science, National Chiayi University, Chiayi, Taiwan; 4Department of Internal Medicine, Chi Mei Medical Center, Liouying, Tainan, Taiwan; 5Department of Medicine, Chi Mei Medical Center, Tainan, Taiwan; 6Department of Health and Nutrition, Chia-Nan University of Pharmacy and Science, Tainan, Taiwan Background: This study aimed to investigate the in vitro activity of cefoperazone–sulbactam against carbapenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa, and to evaluate the antibiotic resistance mechanisms of these bacteria.Materials and methods: In total, 21 isolates of carbapenem-resistant P.aeruginosa and 15 isolates of carbapenem-resistant A.baumannii with different pulsed-field gel electrophoresis types were collected for assessment of the michael harris ii headband in vitro antibacterial activities of cefoperazone and cefoperazone–sulbactam and the associated resistance mechanisms of the bacteria.

Results: For carbapenem-resistant P.aeruginosa, the minimum inhibitory concentration (MIC) value and antibiotic susceptibility rate were similar for cefoperazone and cefoperazone–sulbactam (at 1:1 and 2:1 ratios).In contrast, for carbapenem-resistant A.baumannii, the MIC values, including the MIC range, MIC that inhibited 50% of isolates (MIC50) and MIC that inhibited 90% of isolates (MIC90), were reduced after treatment with sulbactam and cefoperazone.

We screened resistance genes, including VIM-2, OXA-2 and OXA-10, in 21 carbapenem-resistant P.aeruginosa isolates.Only one (4.8%) of the isolates showed expression of VIM-2, and neither the OXA-2 nor the OXA-10 gene was detected.

However, 20 (95.2%) isolates among the carbapenem-resistant P.aeruginosa isolates selected for oprD sequencing showed the phenomenon of nucleotide substitution or deletion.Among 15 carbapenem-resistant A.

baumannii isolates, we found that ten (66.7%) isolates had concomitant expression of the OXA-23 and ISAba1-OXA-23 genes, and six (40.0%) isolates had expression of the OXA-24-like gene.All 15 isolates had OXA-51-like gene expression, and only 1 (6.

7%) isolate dr dabber boost evo atomizer replacement had ISAba1-OXA-51-like gene expression.None of the isolates contained the IMP-1, IMP-8, KPC, NDM, VIM-1 or OXA-48 genes.Conclusion: The in vitro antibacterial activity of cefoperazone against carbapenem-resistant A.baumannii can be enhanced by adding sulbactam to cefoperazone, but the addition does not affect carbapenem-resistant P.

aeruginosa.This significant difference can be explained by the different resistance mechanisms of carbapenem-resistant A.baumannii and P.aeruginosa.

Keywords: cefoperazone–sulbactam, Acinetobacter baumannii, Pseudomonas aeruginosa.