[Streptococcus pneumoniae: serotype evolution and patterns of antimicrobial susceptibility in invasive isolates from...

Streptococcus pneumoniae is an important cause of morbidity and mortality in children and adults in the world.

Analysis of data from laboratory surveillance of S. pneumoniae, invasive isolates recovered from 1994 to 2004.

Database of invasive isolates of S. pneumoniae, sent to the Microbiology Group through the national surveillance laboratory network of acute bacterial meningitis and acute respiratory infections, from 1994 to 2004. The isolates had epidemiological data, serotyping, antimicrobial susceptibility patterns and some of them molecular typing.

The data of 2,022 isolates from 120 hospitals of different regions of the country were analyzed. The isolates were recovered mainly from blood cultures (50.7%) and cerebrospinal fluid (42%). The most important serotypes were 14, 6B, 23F, 1, 5, 6A, 19F, 18C y 9V, which account for 83.6% of isolates obtained from children under 6 years of age, 74% from the 6 -14 year age group and 61.4% from children over 14 years of age. Overall, 29.8% of isolates presented diminished susceptibility to penicillin (DSP), 44.3% to trimethoprim-sulphamethoxazole, 32.4% to tetracycline, 8.2% to chloramphenicol and 3.8% to erythromycin. All isolates were susceptible to vancomycin and 13% were multiresistant. Six hundred two DSP isolates were molecularly typed, 27 (4.5%), were related with the Spain23F-1 clone, 38 (6.3%) with the Spain6B-2, 301 (50%) with the Spain9V-3 and 75 (12.5%) with the Colombia23F-26 clone. Moreover, all 138 isolates with capsular type 5 were related to the Colombia5-19 clone.

The results provide basic information necessary to design and implement strategies for prevention of pneumococcal disease.