Outcome of Severe Bacterial Pneumonia in the Era of Pneumococcal Vaccination

Abstract

<b>Introduction:</b> After the introduction of pneumococcal conjugate vaccines, community-acquired pneumonia (CAP) caused by <i>Streptococcus pneumoniae</i> has decreased whereas <i>Staphylococcus aureus</i> and <i>Streptococcus pyogenes</i> could be increasing. These bacteria have been associated with high rates of complications. <b>Aims:</b> (1) To describe the characteristics of pediatric bacterial CAP requiring hospitalization. (2) To compare outcomes according to causative microorganisms. (3) To analyze changes in bacterial CAP rate and etiology over time. <b>Patients and Methods:</b> Retrospective single-center study of inpatients aged 1 month-16 years with culture-confirmed bacterial CAP in 2010-2018 in Madrid, Spain. <b>Results:</b> We included 64 cases (42 <i>S. pneumoniae</i>, 13 <i>S. pyogenes</i> and 9 <i>S. aureus</i>). Culture-confirmed CAP represented 1.48-2.33/1,000 all-cause pediatric hospital admissions, and its rate did not vary over time. However, there was a significant decrease in pneumococcal CAP in the last 3 years of the study (78% of CAP in 2010-2015 vs. 48% in 2016-18, <i>p</i> = 0.017). Median hospital stay was 10.5 days (interquartile range 5-19.5), 38 patients (59%) developed complications and 28 (44%) were admitted to the intensive care unit. Outcomes were similar among children with <i>S. pneumoniae</i> and <i>S. aureus</i> CAP, whereas <i>S. pyogenes</i> was associated with a higher risk for complications (OR 8 [95%CI 1.1-57.2]) and ICU admission (OR 7.1 [95%CI 1.7-29.1]) compared with pneumococcal CAP. <b>Conclusion:</b> In a setting with high PCV coverage, culture-confirmed bacterial CAP did not decrease over time and there was a relative increase of <i>S. pyogenes</i> and <i>S. aureus</i>. Children with CAP caused by <i>S. pyogenes</i> were more likely to develop complications.