Phenotypical and genotypical differences of Streptococcus pneumoniae carried by healthy children attending day care centres in big cities versus small communities of Hungary
Abstract number: P1055
Tóthpál A., Kardos S., Amyes S.G., Nagy K., Dobay O.
Objectives:Streptococcus pneumoniae is a pathogen causing a wide spectrum of severe diseases, which can be carried in the nasopharynx of healthy individuals, especially children attending community centres. In the present study, we have compared the carriage observed in day-care centres of big cities versus small villages in Hungary.
Methods: Nasal swabs were collected from 187 children (age 36 years) from 6 day-care centres (4 big cities and 2 small villages) in different parts of Hungary. The pneumococci were selected from the normal flora, and their identity was confirmed by optochin sensitivity and the presence of the lytA gene. Serotyping was done by the combination of the conventional method (antisera) and a PCR-based method. The antibiotic sensitivity was determined by E-tests, and the genetic relatedness of the strains was examined by PFGE.
Results: The pneumococcus carriage rate was 39.5% (n = 74). On one occasion, we could detect the simultaneous carriage of 2 pneumococcal strains. We could determine the serotype of 64 strains. The serotype distribution showed that in the villages only 2 or 3 serotypes were represented, while in the cities the diversity was much wider. The serotypes in ranking order were: 14 (35.6%), 6 (24.1%, 6A > 6B), 19F (9.2%), 15, 23F, 18C, 3, 19A, 13, 7. The strains were generally very sensitive to antibiotics, except for macrolides. In the villages we detected slightly lower penicillin MICs, but none of the strains were resistant (R) to penicillin. The highest MICs (0.51 mg/L) were detected in sero 14, 23F, 19F, and 18C (all part of the Prevenar vaccine). 18 strains showed high-level R to erythromycin, these were of different serotypes, and 14 carried the ermB gene. We could identify the presence of very distinct PFGE clones at the individual nurseries, e.g. different clones of serotype 14 strains from the different places.
Conclusions: There was no difference in the carriage rate between cities and villages, and little in antibiotic sensitivity. The difference lay in the serotype distribution. Based on our data and taking the relevant cross-protections into account, Prevenar (serotypes 4, 6B, 9V, 14, 18C, 19F, 23F) would cover 77.0% of the total isolates, but 100% in the villages. On the other hand, there was only one single strain, protection to which is not provided by Pneumovax. We could clearly show the presence of discrete clones within the nurseries, indicating the intensive exchange of bacteria between children.
|Session name:||Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Vienna, Austria, 10 - 13 April 2010|
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