Trends in Pediatric Pneumococcal Pleural Empyema Following Pneumococcal Conjugate 13-Valent Vaccination: 10 Years of Active Surveillance in a Mexican Hospital

Abstract

Background. We have previously published the first Mexican study showing a decrease in pneumococcal invasive disease following implementation of the 13-valent pneumococcal conjugate vaccine (PCV13); however, the impact of this vaccine on pneumococcal pleural empyema (PPE), serotypes distribution, and appearance by other non-pneumococcal bacteria has not been yet published. The Tijuana, Mexico and San Diego, California border is considered the most transited border in the world. Methods. Since October 2005 until September 2015, active surveillance for pleural empyema (PE) in children <16 years old was performed in the Tijuana, Mexico, General Hospital (TGH). Diagnosis of PE was established by Lyell criteria of a pleural effusion with a community acquired pneumonia +- bacterial isolation. For Streptococcus pneumoniae isolates serotype identification was performed using the Quellung reaction (Statens Serum Institute, Copenhagen, Denmark). A descriptive analysis for all PPE was performed. Results. A total of 48 PE were diagnosed. Bacterial identification was possible in 35 (73%) cases. Among these, 26 (74.28%) were caused by S. pneumoniae. Median age for PPE was of 3.91 years (4 months -15 years), pleural decortication was performed in 10 patients (38.5%), and one patient died. Before PCV13 implementation (a period of 77 months), the total number of PPE were of 21 (3.27 cases per year), with serotypes 3, 19A and 6A/C accounting for 64.3% of cases since PCV13 introduction. Following PCV13 implementation (43 months period), PPE dropped to 5 cases (1.4 cases per year), with isolation of serotypes 6A/C, 7B, 15, 3 and 24F (one each). Appearance of non-PPE started to appear since 2010 with two cases, but have increased since implementation of PCV13 (seven cases). Non-pneumococcal isolates have been Staphylococcus aureus (3), Streptococcus pyogenes (2), and Streptococcus salivarus, Group Milleri Streptococcus, Klebsiella oxytoca and Pseudomonas aeruginosa (one each). Conclusion. (1) Following PCV13 universal vaccination, all PPE cases have decreased, with a trend on decrease on serotypes 6A/C, 3 and 19A. (2) This study shows an impact of PCV13 on PPE; however, early appearance of non-pneumococcal bacteria causing PE is present. (3) Continuous active surveillance for PE is mandatory.