Purpose: The aim of this study was to describe the clinical and microbiological characteristics of recurrent invasive pneumococcal disease (RIPD) cases identified in the Region of Madrid between January 2007 and December 2011.
Methods: Streptococcus pneumoniae serotyping was performed by Pneumotest-Latex and Quellung reaction. Molecular typing was carried out by pulsed-field gel electrophoresis (PFGE). A relapse was defined as any case of RIPD caused by strains with similar PFGE profile. Re-infections were defined by detection of recurrent episodes caused by strains with different PFGE patterns.
Results: During the study period, 2,929 S. pneumoniae strains isolated from 2,858 patients with invasive pneumococcal disease (IPD) were studied. In 61 patients (2.1 %), 132 episodes of RIPD were detected (two episodes in 52 patients, three in 8 and four in 1). Twelve patients had relapses, 47 had re-infections and two had re-infections followed by relapses. Common risk factors to developing RIPD were HIV (42.6 %) and haematological malignancies (16.4 %). The most frequent serotypes were 8 (16 episodes) and 19A (15 episodes). Fourteen strains that were resistant to levofloxacin were also resistant to erythromycin. The proportion of strains co-resistant to erythromycin and levofloxacin was significantly higher in relapses (11/29) than in re-infections (3/103).
Conclusions: The occurrence of repeated episodes of IPD in the same patient over the time is not an exceptional issue. Some underlying conditions that may favour these recurrences, mainly immunosuppression, need to be considered in patients having an episode of IPD.