Serotyping and antibiotic resistance of Streptococcus pneumoniae isolated from pediatric infections in central Greece.

OBJECTIVE

To determine the distribution of serogroups/serotypes and antibiotic resistance pattern of Streptococcus pneumoniae isolated from pediatric infections in central Greece.

METHODS

In total, 306 S. pneumoniae strains isolated from children, aged from 18 days to 14 years (median 18 months), during a 21-month period, from different specimen sources, were studied. Susceptibility testing was carried out by the Kirby---Bauer method and by the Etest, and serotyping by the Quellung reaction.

RESULTS

Of the S. pneumoniae isolates, 3.9% were highly resistant to penicillin (PR), while 17.6% were intermediately resistant (IPR). PR and IPR isolates were found to be, in general, more resistant to other antibiotics than penicillin-susceptible isolates. The PR and IPR isolates belonged to the serogroup/serotypes 19, 23, 9, 6 and 14 (in descending order of frequency). The penicillin-susceptible isolates belonged to 20 different groups/serotypes, the most common being 19, 6, 14, 9, 3, 23 and 1 (in descending order of frequency). Serogroup 23 was often found to be multiresistant.

CONCLUSIONS

Resistance to penicillin in S. pneumoniae isolates is relatively low and differs according to the specimen type. All the pneumococcal serogroups/serotypes isolated from the children were found to be included in the 23-valent polysaccharide vaccine. Most of the children with a pneumococcal infection, however, were less than 2 years old and could not be protected by the existing vaccine.