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Emergence of a clone of Streptococcus pneumoniae serotype 19A in children in Murcia, Spain

Abstract number: P1344

Yague G., Martinez-Toldos C., Iborra A., Alfayate S., Ruiz J., Segovia M.

Background: Serotype 19A is know to have risen as important cause of invasive pneumococcal disease (IPD) after the introduction of the heptavalent pneumococcal conjugate vaccine (PCV7). During routine surveillance of serotype distribution of paediatric invasive S. pneumoniae isolates in Murcia (Spain), we detected an increased of 19A serotype. The objective of this study was to describe S. pneumoniae serotype distribution in our geographic area in children <11 years with emphasis on serotype 19A.

Methods: From March 2006 to April 2008 we studied 40 isolates of S. pneumoniae obtained from a normally sterile site (IPD) from children attending in Hospital Virgen Arrixaca, Murcia. Serotyping was made by Quellung reaction. Susceptibility to penicillin (P), cefotaxime (CTX), erythromycin (ER), levofloxacin (LV), chloranphenicol (C), tetracycline (TE) and vancomycin (VA) was determined by E-test and interpreted according to CLSI guidelines. Molecular typing of 19A isolates was performed by Pulsed Field Gel Electrophoresis (PFGE) using SmaI endonuclease.

Results: The most common serotypes were the non-PCV7 serotype 19A (8, 20%) and the PCV7 cover serotype14 (8, 20%). The distribution of the rest were as follows: serotype 1, 12.5%; 3 and 7F, 10%;19F, 23B, and 9V, 5%;9N, 18C, 23F and 23A 2.5% respectively. Non-PCV7 serotypes caused 67.5% of IPD. The first isolate of serotype 19A was detected on February 07 then, six 19A strains were isolated in a four month period (October-2007/January-2008). Pulsed field gel electrophoresis patterns of these six 19A isolates were indistinguishable and different to the first isolate. Illnesses of the related 19A strains included empyema (67.6%), pneumonia whit bacteraemia (16.7%) and bacteraemia (16.7%). Respect antibiotic susceptibility, within the entire S. pneumoniae population (n = 40), a 45% were non susceptible to P (defined as a penicillin MIC of geqslant R: gt-or-equal, slanted0.12). Among 19A strains 75% were considered as non susceptible. The proportion of CTX susceptible S. pneumoniae was 80% all isolates/87.5% 19A strains. Resistant rates (%all/%19A strains) among non-b-lactam agents were as follows: E 25/37.5; TE 25/62.5; C 5/0. No resistance to VA or LV was observed

Conclusion: In our area the recent increase in serotype 19A could be explain by introduction of a specific clone responsible of an outbreak of IPD. The proportion of 19A isolates that are nonsusceptible to commoly used antimicrobial was greater than the proportion for other serotypes.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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