Epidemiology and Infection

Bacterial infections

Serotype distribution of Streptococcus pneumoniae causing invasive disease in the Republic of Ireland

I. VICKERSa1a2 c1, M. FITZGERALDa3, S. MURCHANa3, S. COTTERa3, D. O'FLANAGANa3, M. CAFFERKEYa1a2 and H. HUMPHREYSa2a4

a1 Epidemiology and Molecular Biology Unit and Irish Meningococcal and Meningitis Reference Laboratory, Children's University Hospital, Dublin, Ireland

a2 Department of Clinical Microbiology, RCSI Education and Research Centre, Beaumont Hospital, Dublin, Ireland

a3 Health Protection Surveillance Centre, Dublin, Ireland

a4 Department of Microbiology, Beaumont Hospital, Dublin, Ireland

SUMMARY

The 7-valent pneumococcal conjugate vaccine (PCV7) was included in the routine infant immunization schedule in Ireland in September 2008. We determined the serotype of 977 S. pneumoniae isolates causing invasive disease between 2000–2002 and 2007–2008, assessed for the presence of the recently described serotype 6C and determined the susceptibility of isolates during 2007–2008 to penicillin and cefotaxime. Serotype 14 was the most common serotype during both periods and 7·7% of isolates previously typed as serotype 6A were serotype 6C. During 2000–2002 and 2007–2008, PCV7 could potentially have prevented 85% and 74% of invasive pneumococcal disease in the target population (i.e. children aged <2 years), respectively. The level of penicillin non-susceptibility was 17% in 2007–2008. Ongoing surveillance of serotypes is required to determine the impact of PCV7 in the Irish population and to assess the potential of new vaccines with expanded valency.

(Accepted June 25 2010)

(Online publication July 19 2010)

Correspondence:

c1 Author for correspondence: Dr I. Vickers, Epidemiology and Molecular Biology Unit and Irish Meningococcal and Meningitis Reference Laboratory, Children's University Hospital, Temple St, Dublin, Ireland. (Email: imelda.vickers@cuh.ie)

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