Effect of Meropenem-Colistin and Meropenem-Amikacin Combinations against Carbapenem-Resistant Pseudomonas aeruginosa Isolates in Suez Canal University Hospitals

Document Type : Original Article


1 Microbiology And Immunology Department, Faculty Of Medicine, Suez Canal University Round Road 4.5km

2 Medical microbiology and immunology faculty of medicine Suez Canal University, Egypt


Background: Healthcare associated infections (HAIs) caused by carbapenem-resistant P. aeruginosa are considered as an overwhelming problem in hospitals due to its resistance to most effective antibiotic classes. Consequently, various antimicrobial combinations have been suggested as an alternative in clinical practice. So, our aim was to improve the antibiotic policy in Suez Canal University Hospitals (SCUHs) in the treatment of carbapenem-resistant Pseudomonas aeruginosa infections and to reduce morbidity and mortality rates due to these infections.
Materials and methods: A cross-sectional descriptive study was carried out on 36 Carbapenem-resistant Pseudomonas aeruginosa strains collected from different wards in SCUHs. A checkerboard assay was carried on these strains to assess the effect of meropenem colistin and meropenem-amikacin combination.
Results: the synergy testing of the meropenem-amikacin combination on Carbapenem-resistant Pseudomonas aeruginosa showed 50% synergy, 8.3% addition, 36% indifference and 5.7% antagonism. For the meropenem-colistin combination, it showed 39% synergism, 30.5% addition and 30.5% indifference with no antagonism was observed. Although, the mean FIC value of meropenem was higher in the meropenem-amikacin combination than in the meropenem-colistin combination, the difference was statistically insignificant.
Conclusions: Both combinations (meropenem colistin and meropenem-amikacin) showed high rates of synergy and reduction of meropenem MICs against Carbapenem-Resistant Pseudomonas aeruginosa Isolates and can offer good alternatives in the clinical practice for treatment of CRPA strains.


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