Streptococcus pneumoniae isolates in paediatric population: evaluation of emerging serotypes in the era of 7valent pneumococcal conjugate vaccine and their antibiotic susceptibility

Abstract number: R2390

Bandettini R., Pescetto L., Ricagni L., Ansaldi F., Canepa P., Icardi G., Santolini M., Turello V., Diana M.C.

Objectives: To estimate the serotype distribution of pneumococci and their antibiotic susceptibility patterns among paediatric patients.

Methods: Clinical isolates were obtained from 84 children, aged 4 months to 8 years, between March and October 2009. Vaccination with 7-valent pneumococcal conjugate vaccine (PCV7) was considered appropriate if it was done according to the following scheme: a three-dose series if starting vaccination at leqslant R: less-than-or-eq, slant12 months of age; a two-dose series if starting vaccination at 12–24 months of age; and one-dose series if starting vaccination at geqslant R: gt-or-equal, slanted24 months of age. Streptococcus pneumoniae strains were collected from the following clinical cases: acute otitis media (69.0%), pneumonia (14.3%), sepsis (7.1%), conjunctivitis (2.4%), acute tracheitis (2.4%), acute sinusitis (1.2%), acute tonsillitis (1.2%), bronchiectasis (1.2%). Antimicrobial susceptibility of all isolates was tested by the disk diffusion method in accordance with the guidelines of CLSI, against erythromycin, clindamycin, vancomycin. Penicillin and ceftriaxone MICs were determined by E-test. Pneumococci were serotyped by primer specific PCR.

Results: Of 84 children, 73 (87.0%) were vaccinated with PCV7, 9 (10.7%) were not vaccinated, 2 (2.3%) dropped-out. Of 84 strains, 61 (72.6%) were serotyped and 4 of them (6.5%) belonged to vaccine type (4, 9V, 14, 23F). A total of 10 (16.4%) isolates were serotype 19A, all susceptible to penicillin, while 4 of them were resistant to erythromycin and clindamycin (phenotype C). A total of 7 (11.5%) were resistant to penicillin, erythromycin and clindamycin and belonged to 7 different non-vaccine types. All isolates were susceptible to vancomycin and ceftriaxone.

Conclusions: Pneumococcus is a leading cause of invasive and non-invasive infection among children and its seriousness is the increasing prevalence of drug-resistant strains. As reported in literature although the widespread PCV7 vaccination, an increase in non-vaccine types has been observed also in our study. Moreover the proportion of resistant pneumococci was higher among non-vaccine types. This study could be the a platform for future surveillance.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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