Bacterial Density, Serotype Distribution and Antibiotic Resistance of Pneumococcal Strains from the Nasopharynx of Peruvian Children Before and After Pneumococcal Conjugate Vaccine 7

• Type of Material: Article
• Authors: Carla Berg, Emory University; Christiane R. Hanke, Emory University; Carlos G. Grijalva, Vanderbilt University; Sopio Chochua, Emory University; Mathias W. Pletz, Jena University Hospital; Claudia Hornberg, University of Bielefeld; Kathryn M. Edwards, Vanderbilt University; Marie R. Griffin, Vanderbilt University; Hector Verastegui, Instituto de Investigación Nutricional; Ana I. Gil, Instituto de Investigación Nutricional; Claudio F. Lanata, Instituto de Investigación Nutricional; Keith Klugman, Emory University; Jorge Vidal Graniel, Emory University
• Language: English
• Date: 2016-04-01
• Publisher: Lippincott, Williams & Wilkins
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
• Final Published Version (URL): http://dx.doi.org/10.1097/INF.0000000000001030
• Title of Journal or Parent Work: Pediatric Infectious Disease Journal
• ISSN: 0891-3668
• Volume: 35
• Issue: 4
• Start Page: 432
• End Page: 439
• Grant/Funding Information: This work was supported by research grants from Pfizer, investigator-initiated research grant [IIR WS1898786 (0887X1-4492)] to CGG and [IIR WS2079099] to JEV.; This study was also partially funded by a Thrasher Research Fund [02832-9]; and a Vanderbilt University CTSA grant [UL1 RR024975] from the National Institutes of Health. Christiane Hanke received a scholarship from the ARGUS foundation, Germany (Gemeinnützige Stiftung für den Erhalt und die Entwicklung von Infektionstherapeutika, 2005-2013). Mathias Pletz was supported by a grant from the German Ministry for Science and Education [01KI1204].
• Keywords: DISEASE; PREVALENCE; 6C; STREPTOCOCCUS-PNEUMONIAE; DYNAMICS; Pediatrics; PCV7; Immunology; nasopharyngeal colonization; serotype replacement; CARRIAGE; Life Sciences & Biomedicine; antibiotic resistance; YOUNGER; Science & Technology; IMPACT; Streptococcus pneumoniae; Infectious Diseases; IMMUNIZATION; COLONIZATION
• Research Categories: Health Sciences, Public Health

Abstract

Background: Pneumococcal conjugate vaccines (PCV) have decreased nasopharyngeal carriage of vaccine types but little data exist from rural areas. We investigated bacterial density, serotype distribution and antibiotic resistance of pneumococcal strains within the nasopharynx of young children in the Peruvian Andes, 2 years after PCV7 was introduced. Methods: Pneumococcal strains were isolated from a subset of 125 children from our Peruvian cohort, who entered the study in 2009 and had pneumococcus detected in the nasopharynx in both 2009 and during follow-up in 2011. Strains were Quellung-serotyped and tested for susceptibility to antibiotics. Bacterial density was determined by quantitative polymerase chain reaction. Results: The prevalence of PCV7 strains decreased from 48% in 2009 to 28.8% in 2011, whereas non-PCV7 types increased from 52% to 71.2% (P = 0.002). There was a 3.5-fold increase in carriage of serotype 6C in 2011 (P = 0.026). Vaccination with PCV7 did not affect pneumococcal density in children colonized by a PCV7 type but did increase density in those colonized with a non-PCV7 type. Antibiotic resistance did not change after vaccine introduction; strains were nonsusceptible to tetracycline (97.2%), trimethoprim-sulfamethoxazole (56.4%), penicillin (34%), erythromycin (22.4%), chloramphenicol (18.8%) and clindamycin (12.4%). Conclusions: Serotype replacement was observed post-PCV7 vaccination with a concomitant, not previously recognized, increased nasopharyngeal density.