Microbiological aspects of a Streptococcus pyogenes outbreak causing invasive disease in children attending a day care centre in Cantabria, Spain
Abstract number: 1733_922
Agüero J., Ortega M., Cano M., González de Aledo A., Calvo J., Viloria L., Mellado P., Pelayo T., Martínez-Martínez L.
Objectives: To study microbiological aspects of S. pyogenes isolates cultured from children (5 to 40 month old) attending a day care centre in Cantabria (Northern Spain), and to compare these isolates with those from contacts of the affected children and with epidemiologically unrelated isolates from the same area.
Methods: Pharyngotonsillar swabs from 40 children, 4 day care staff and 258 contacts were cultured according to standard methods. Samples from multiple organs were cultured from a child who died from streptococcal toxic shock syndrome (STSS). Blood cultures were obtained from 2 other children with STSS. Nine S. pyogenes isolated from pharyngotonsillar samples unrelated with the outbreak were included for comparison. Clonal relationship of the isolates was assessed by PFGE. Protein M typing was performed by sequencing of the region of the emm gene coding for the N-terminal zone of the protein. Susceptibility testing was performed with Etest strips on Mueller-Hinton blood agar plates. A multiplex PCR was used for detecting the presence of genes: speA, speB, speC, speF, speG, speH, speJ, ssa and smeZ.
Results:S. pyogenes was isolated from pharyngotonsillar samples of 11 children and 14 contacts, and from invasive samples of 2 out of 3 children with STSS. All isolates from children at the day care centre were of emm type 4, presented the same PFGE pattern and contained speB, speC, speF, ssa and smeZ. Isolates from contacts corresponded to emm types 1, 2, 12 or 22 and to 5 PFGE patterns unrelated to that of the children isolates. Isolates from epidemiologically unrelated patients were of emm types 3, 11, 12, 18 or 22 and presented 5 PFGE unrelated to that of the outbreak strain. All isolates were susceptible to penicillin, clindamycin, levofloxacin and tetracycline and, except 1 isolate from an unrelated patient, to erythromycin.
Conclusions: A strain of S. pyogenes of emm type 4 caused an outbreak in children attending a day care centre. The organism was also cultured from two children who developed STSS, one of which died. This strain was unrelated to other S. pyogenes isolated from contacts of the children or from epidemiologically unrelated patients from the same area
|Session name:||European Society of Clinical Microbiology and Infectious Diseases|
|Location:||ICC, Munich, Germany|
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