Thesis (M.Sc.) - Cairo University - Faculty of Medicine - Department of Microbiology and Immunology

Introduction: The purpose of this study was to evaluate the sensitivity of cefepime /tazobactam combination against ESBL- and/or AmpC-producing Gram-negative bacilli. Materials and method: The study was conducted on 100 Gram-negative bacilli. ESBL production was screened by using the disc diffusion test and was confirmed by the combined disc confirmatory test, screening of AmpC production was done by cefoxitin disc test and confirmation was done by AmpC disc test. Isolates confirmed positive for ESBL and/ or AmpC production were investigated for their susceptibility to the following antibiotics: cefepime, imipenem, ertapenem, meropenem, piperacillin/tazobactam, cefoperazone/sulbactam and cefepime/tazobactam. Results: Among 100 Gram-negative bacilli, 56 isolates screened positive for ESBL production by the disc diffusion test and 44 were confirmed as ESBL producers by the combined disc confirmatory test. Thirty-two isolates were screened positive for AmpC production by cefoxitin disc test and 9 isolates were confirmed as AmpC producers by AmpC disc test. Using MAST D68C set, 32 isolates were ESBL producers, 3 were AmpC producers, and 4 isolates were both ESBL and AmpC producers. Forty-three isolates were sensitive to cefepime/tazobactam combination, 10 isolates were sensitive to cefoperazone/sulbactam, 13 isolates were sensitive to piperacillin/tazobactam, 37 isolates were sensitive to meropenem, 32 isolates were sensitive to ertapenem, 37 isolates were sensitive to imipenem and 8 isolates were sensitive to cefepime. Conclusion: Cefepime/tazobactam revealed excellent activity against ESBL and/or AmpC-producing Gram-negative bacilli and may be considered as a therapeutic alternative to carbapenems in infections caused by these organisms

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