Non-typeable Streptococcus pneumoniae carriage isolates genetically similar to invasive and carriage isolates expressing capsular type 14 in Brazilian infants.
OBJECTIVE
We have recently found a high prevalence of non-typeable pneumococcal isolates (NTPn) circulating in day-care centers in Central Brazil, besides serotype 14 isolates. We therefore examined the genetic relationship among NTPn and serotype 14 from carriage and invasive pneumococcal isolates obtained from children attending emergency rooms enrolled in a population-based surveillance.


METHODS
The isolates were characterized by Quellung reaction serotyping, PCR for the presence of pneumolysin and the loci for a capsule gene (cpsA) and the type 14 gene (cps14H) in all NTPn, and by multilocus sequence typing and pulsed field gel electrophoresis.


RESULTS
87.2% of the isolates were clustered into nine clusters. The major cluster included 41 pneumococcal serotype 14 (28 carriage and 13 invasive isolates) and two NTPn related to the global pneumococcal clone Spain(9V)-3. Overall, 95.4% of the NTPn carriage strains were genetically related to carriage or invasive strains expressing serotype 14. A dominant NTPn lineage was found, that grouped 14 pneumococcal strains. Almost half of the multidrug-resistant isolates grouped into the NTPn cluster.


CONCLUSIONS
These findings provide baseline data to assess the impact of the pneumococcal vaccination on the molecular epidemiology of Streptococcus pneumoniae. Changes in frequency of NTPn isolates and also genetic changes should be carefully monitored post vaccination, to detect potential vaccine-escape or replacement disease by capsule switched strains, especially in areas where colonization with NTPn has been frequently observed.
Andrade
Ana Lucia S
AL
Department of Community Health, Federal University of Goiás, Goiânia, Brazil. ana@iptsp.ufg.br
Franco
Cáritas M
CM
Lamaro-Cardoso
Juliana
J
André
Maria Cláudia D P B
MC
Oliveira
Leandro L G
LL
Kipnis
André
A
Rocha
Cristyane G B B
CG
Andrade
João G
JG
Alves
Sueli L A
SL
Park
In H
IH
Nahm
Moon H
MH
Almeida
Samanta G
SG
Brandileone
Maria Cristina C
MC
D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D001938:Brazil / Q000453:epidemiology; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology*; D002675:Child, Preschool; D016172:DNA Fingerprinting; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D017720:Molecular Epidemiology; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D022242:Pneumococcal Vaccines / Q000276:immunology; D016133:Polymerase Chain Reaction; D015995:Prevalence; D017422:Sequence Analysis, DNA; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D013301:Streptolysins / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics
D001426:Bacterial Proteins; C500439:CpsA protein, Streptococcus pneumoniae; D022242:Pneumococcal Vaccines; D013301:Streptolysins; D037521:Virulence Factors; C032290:plY protein, Streptococcus pneumoniae