title: Characteristics of serogroup 20 S.pneumoniae isolates from Brazil.
abstract: Although serogroup 20 is not part of any conjugate pneumococcal vaccine, its serotype 20A, but not 20B, belongs to the polysaccharide 23-valent formula. Little is known about its clinical, laboratorial and epidemiological characteristics.
  
  
  
  The purpose of this study was to evaluate the bacterial genotypes (by PFGE and MLST), clinical characteristics of patients (from review of medical records) and antimicrobial susceptibility of serogroup 20 isolates which were recovered from patients with invasive pneumococcal disease (IPD) from 2007 to 2012. Subtyping to determine 20A and 20B types was also performed by sequencing the genes of the cps locus.
  
  
  
  Sixteen isolates were genotyped and were highly related. All pneumococci were resistant to tetracycline and 31 % were non-susceptible to trimethoprim/sulfamethoxazole. Penicillin MIC ranged from 0.004 to 1 μg/mL and non-susceptibility (MIC ≥ 0.12 μg/mL) was observed in 5/16 isolates (31 %). All isolates belonged to subtype 20B. Most patients were male with a median age of 62 years and presented at least one underlying disease (mostly respiratory conditions). All isolates belonged to ST8889 and to a unique PFGE clone.
  
  
  
  A high clonal occurrence of serotype 20B pneumococci recovered from patients with IPD in Brazil was observed. As a non-PCV10 serotype, selective pressure may be responsible for this unusual occurrence of serogroup 20. However, temporal variation effect should not be underestimated; therefore it is an issue that warrants continued monitoring.
authors.affiliation: Basic Health Department, Federal University of Health Science of Porto Alegre, Porto Alegre, Brazil. julianaca@ufcspa.edu.br.
authors.forename: Juliana
authors.initials: J
authors.lastname: Caierão
authors.affiliation: Genetic Departament, Bioscience Institute, Center of Agricultural Microbiology Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Fernando Hayashi
authors.initials: FH
authors.lastname: Sant'Anna
authors.affiliation: Rollins School of Public Health, Emory University, Atlanta, USA.
authors.forename: Paulina
authors.initials: P
authors.lastname: Hawkins
authors.affiliation: Basic Health Department, Federal University of Health Science of Porto Alegre, Porto Alegre, Brazil.
authors.forename: Gabriela Rosa
authors.initials: GR
authors.lastname: Cunha
authors.affiliation: Basic Health Department, Federal University of Health Science of Porto Alegre, Porto Alegre, Brazil.
authors.forename: Mariana
authors.initials: M
authors.lastname: Mott
authors.affiliation: Conceição Hospital Group, Porto Alegre, Brazil.
authors.forename: Diego Rodrigues
authors.initials: DR
authors.lastname: Falci
authors.affiliation: Basic Health Department, Federal University of Health Science of Porto Alegre, Porto Alegre, Brazil.
authors.forename: Pedro Alves
authors.initials: PA
authors.lastname: d'Azevedo
authors.affiliation: Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, USA.
authors.forename: Lesley
authors.initials: L
authors.lastname: McGee
authors.affiliation: Basic Health Department, Federal University of Health Science of Porto Alegre, Porto Alegre, Brazil.
authors.forename: Cícero
authors.initials: C
authors.lastname: Dias
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D001938:Brazil; D002555:Cerebrospinal Fluid / Q000382:microbiology; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D011008:Pneumococcal Infections / Q000175:diagnosis / Q000382:microbiology*; D065288:Serogroup; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000302:isolation & purification; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D013752:Tetracycline
keywords: Invasive pneumococcal disease; Molecular epidemiology; Serogroup 20; Streptococcus pneumoniae