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High prevalence and persistence of the Streptococcus pneumoniae Taiwan19F-14 clone among children in Greece

Abstract number: 1733_491

Mavroidi A., Paraskakis I., Pangalis A., Kirikou E., Charisiadou A., Athanasiou T., Tassios P., Tzouvelekis L.

Objectives: Molecular characterisation of the multi-drug resistant serotype 19F Streptococcus pneumoniae strains, prevalent amongst Greek children during 2001–2006, i.e. before and after introduction of the heptavalent vaccine in 2004.

Methods: A representative subset of 143 of 241 (34%) serotype 19F pneumococci from invasive (IPD), non-invasive infections (NIPD) and healthy children during January 2001–April 2006 were studied with respect to antimicrobial susceptibility (penicillin, amoxicillin, cefotaxime, erythromycin, clindamycin, co-trimoxazole, tetracycline, chloramphenicol, rifampicin, ofloxacin), by disk diffusion and E-test, and subtyped by PFGE and MLST.

Results: Serotype 19F – representing 31.8% and 26.0% of all pneumococcal isolates from children during 2001–2004 and 2005–2006, respectively – was a leading cause of NIPD in both periods, and more important in IPD in the second (19% vs. 6.5%; chi2 = 6.51, p < 0.02). Apart from 18 fully susceptible isolates, the remaining 125 (87.4%) were resistant to three or more antimicrobial classes (MDR). PFGE yielded 18 types (a total of 55 subtypes); 93% of all isolates belonged to only eight types. The dominant type, G (110 isolates, of which 55 belonged to one of 30 subtypes), had been seen first in 1996, in a common UK-Greek erythromycin-resistant clone. All type G isolates were MDR (including resistant to erythromycin and non-susceptible to penicillin (PNS)), in contrast to only 15 (45%) of the remaining 33 isolates (chi2 = 68.64, p < 0.001). Thirteen (12%) of the PNS isolates also showed decreased susceptibility or resistance to cefotaxime (MIC 2–8 mg/L). MLST followed by eBURST analysis identified 12 STs – of which five were novel – grouped in six clonal complexes (CC). PFGE type G isolates were either ST236, corresponding to the Taiwan19F-14 (CC271) international clone, or one of four new single locus variants (SLV). A novel SLV of ST177 was also found.

Conclusion: First observed in Greece in 1996, the Taiwan19F-14 (CC271) international clone – so far considered minor in Europe – has now become dominant amongst Greek paediatric S. pneumoniae, even after introduction of the heptavalent vaccine in 2004. Over 75% of these isolates belonged to CC271 and a single PFGE type, yet both phenotypic and genotypic variation suggest a locally actively evolving clone.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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