Susceptibility in Parenteral Antibiotics in Streptococcus pneumoniae Isolated from Children with Invasive Pneumococcal Disease

Abstract

Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of commonly used clinical antimicrobial drugs were examined for 76 strains of Streptococcus pneumoniae isolated between 2006 and 2011 from pediatric patients with invasive pneumococcal infection. Patients from whom bacterial strains were isolated ranged from 4 months to 6 years old and included 50 infants (65.8％) 1 year old and 10 (13.2％) less than 1 year old, i.e., 79.1％ of all patients studied. In diagnosis, 38 (50.0％) had occult bacteremia, 34 (44.7％) pneumonia, 3 (3.9％) meningitis, and 1 (1.3％) sepsis. Infections in all but one case who died of sepsis were treated without sequelae. The most frequent capsular serotype among isolates was 6B (20 strains,26.3％), followed by 19 F (13 strains, 17.1％) and 14 (9 strains, 11.8％). Serotypes for 55 strains (72.4％) corresponded to those contained in heptavalent pneumococcal conjugate vaccine. In classification by resistance based on mutations in penicillin-binding protein genes, 32 were penicillin-resistant S. pneumoniae (42.1％), 35 penicillin intermediate-resistant S. pneumoniae (46.1％), and 11 penicillin-susceptible S. pneumoniae (11.8％). MIC₉₀/MBC₉₀ of drugs were as follows : ampicillin 4/4μg/mL, cefotaxime 0.5/0.5μg/mL, ceftriaxone 1/2μg/mL, panipenem 0.125/0.125μg/mL, meropenem 0.5/0.5μg/mL, and doripenem 0.25/0.25μg/mL.