Oral lactam activity against recent (November2008June2009) penicillin non-susceptible serotype19A Streptococcus pneumoniae isolates in Spain
Abstract number: P1679
Fenoll A., Aguilar L., Gimenez M.J., Vicioso M.D., Robledo O., Granizo J.J., Coronel P.
Objective: To explore susceptibility to oral b-lactams vs. cefotaxime of penicillin (PEN) non-susceptible serotype 19A isolates since in Spain this serotype has significantly increased in last years after introduction of the 7-valent pneumococcal conjugate vaccine, with significant reduction in PEN susceptibility.
Methods: 268 successive PEN non-susceptible (MIC 0.12 mg/l) serotype 19A isolates received from November 2008 to June 2009 in the Spanish Reference Pneumococcal Laboratory were tested. Susceptibility was determined by agar dilution following CLSI, using Mueller-Hinton agar supplemented with 5% sheep blood, incubating under 5% CO2 atmosphere. CLSI breakpoints (oral for PEN and cefuroxime; non-meningitis for amoxicillin and cefotaxime) were used.
Results: MIC50, MIC90 (mg/l), range and percentage (%) of susceptible (S), intermediate (I) and resistant (R) isolates are shown in the table.
Conclusions: Cefditoren exhibited the highest intrinsic activity in terms of MIC50 and MIC90, with values four times lower than those of cefotaxime. Non-susceptibility (intermediate + resistant) rates to oral b-lactams with current CLSI breakpoints were high, ranging from 33.2% for amoxicillin to 98.9% for cefaclor.
|Session name:||Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Vienna, Austria, 10 - 13 April 2010|
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