Activity of cefditoren versus seven other antimicrobials against amoxicillin non-susceptible Streptococcus pneumoniae
Abstract number: 1733_1524
Perez-Trallero E., Marimon J., Erzibengoa M., Gimenez M., Coronel P., Aguilar L.
Objective: Amoxicillin has the highest intrinsic activity against S. pneumoniae but amoxicillin non-susceptibility is not rarely found among penicillin-resistant isolates. Antibiotic susceptibility testing against these isolates can be considered the workhorse to test new and old compounds.
Methods: Susceptibility to penicillin (PEN), amoxicillin/clavulanic acid (2:1) (AMC), cefuroxime (CXM), cefpodoxime (CPD), cefotaxime (CTX), cefditoren (CDN), erythromycin (ERY), and levofloxacin (LVX) was determined by microdilution with Mueller-Hinton broth supplemented with 3% lysed horse blood according to CLSI guidelines, against 244 isolates exhibiting non-susceptibility to amoxicillin (MIC ≥4mg/mL) and higher amoxicillin vs. penicillin MIC. CLSI susceptibility breakpoints (mg/mL) were considered.
Results: MIC distribution of the antimicrobials tested: no. of isolates inhibited (cumulative percentage) at concentration (mg/mL) are shown in the Table.
Conclusions: On a MIC90 basis, CDN (1mg/mL) exhibited the highest intrinsic activity followed by CTX (2mg/mL), AMC, CPD and LVX (8mg/mL), with a clear inadequacy of CXM and ERY (≥16mg/mL). CDN activity (twice that of CTX) may be useful against amoxicillin non-susceptible strains where only CTX and LVX offer significant activity (7090% susceptibility rates).
|Session name:||European Society of Clinical Microbiology and Infectious Diseases|
|Location:||ICC, Munich, Germany|
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