O394 Abstract (oral session) Serotype 5 pneumococci causing invasive pneumococcal disease (IPD) outbreaks in Barcelona (1997-2011) D. Rolo*, A. Fenoll, D. Fontanals, N. Larrosa, M. Giménez, R. Pallares, J. Liñares, C. Ardanuy (Barcelona, Madrid, Sabadell, Badalona, ES)

Objectives: The aim of this study was to analyze trends in invasive serotype 5 (Ser5), describing clinical data of patients and molecular characterization of isolates. Methods: All invasive pneumococci were prospectively collected in four hospitals in the Barcelona area during 1997-2011 period. Antimicrobial susceptibility (microdilution) and molecular typing (PFGE and MLST) of Ser5 pneumococci were performed. Clinical data of patients was analysed. Results: Among 5,093 invasive pneumococci collected, 134 (2.6%) of them were Ser5. The majority of them (88.1%) were isolated from blood. Most of Ser5 pneumococci (47.0%) were isolated from young adults (18-64 years), 35.1% from the elderly (over 64 years) and 17.9% from children (<18 years). Although the overall incidence of Ser5 IPD was low (0.25 cases/100.000 inhabitants), 3 incidence peaks were detected: 0.63/100.000 in 1999, 1.15/100.000 in 2005 and 0.37/100.000 in 2009. Rates of Ser5-IPD were higher among young and older adults in the first two peaks, while it was higher among children in 2009. All but one child were healthy. Comparing young and older adults: 51.6% vs 19.1% were healthy, 20.6% vs 38.3% had COPD, and 11.1% vs 38.3% had cardiovascular diseases. The majority (88.8%) of patients had pneumonia. The overall 30-day mortality rate was low (4.5%). Ser5 pneumococci were fully susceptible to penicillin, cefotaxime, erythromycin, and ciprofloxacin. Sixty-five (48.5%) isolates were cotrimoxazole-resistant, and 7 of them were also resistant to tetracycline and chloramphenicol. A single PFGE cluster related to Colombia5- ST289 clone was found. Two major related sequence types (STs) were detected: ST1223 (n=65), and ST289 (n=61). ST289 clone was responsible for all the cases of the Ser5 outbreak in 1999, while ST1223 clone accounted for 73.8% and 61.5% of isolates in 2005 and 2009, respectively. Conclusion: Serotype 5 pneumococci are a frequent cause of invasive pneumococcal disease outbreaks. The expansion of a single locus variant (ST1223) of Colombia5-ST289 clone was responsible of a major outbreak in 2005 in Barcelona area. Outbreaks of invasive serotype 5 may be prevented by the implementation of the new pneumococcal conjugated- vaccines (PCV10 and PCV13).