Increasing penicillin resistance in pneumococci isolated from cerebrospinal fluid samples: Fifteen-year experience from a teaching hospital

Abstract

Objective: There have been prominent changes in evaluation of resistance patterns of pneumococci and breakpoint values in recent years. We aimed to investigate the penicillin sensitivity of pneumococcal strains isolated from the cesrebrospinal fluid specimens between the years 1997-2011 in our hospital and determine the MIC values under the light of these changes. Methods: Identification of pneumococci was made with conventional methods in patients with meningitis. MIC values for penicillin G were investigated by E test method in all strains. MIC values of pneumococci strains were evaluated acscording to values determined by CLSI for meningitis isolates in 2008. Results: A total of 57 strains were investigated in this study. The MIC range for penicillin was 0.016 - 0.75 mg/ml in S. pneumoniae strains. Seventy five percent of the strains were sensitive and eight strains (14%) had resistance. MIC50 value was sensitive, and a MIC90 value was resistant. The first resistant strain was detected in 2000, and three strains were resistant in the last year. When examined over the years increased resistance was 5.3% in the first five-year period seems to be 28.6% in the last five-year period. Conclusions: Knowledge on penicillin resistance patterns and surveillance is very important in the empirical treatment in pneumococcal meningitis.