FATORES DE RISCO E EPIDEMIOLOGIA MOLECULAR DE Streptococcus pneumoniae NÃO SUSCETÍVEIS À PENICILINA ISOLADOS DE NASOFARINGE DE CRIANÇAS QUE FREQUENTAM CRECHES EM GOIÂNIA-GO, BRASIL
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2009-02-17
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Universidade Federal de Goiás
Resumo
Objectives: (i) to identify risk factors for S. pneumoniae penicillin nonsusceptible
isolates (PNSp) in children attending day-care centers (DCCs) in Goiânia, Brazil and to
assess the genetic patterns of pneumococcal isolates; (ii) to estimate the coverage for
carriage serotypes for the 7-valente (PCV7) pneumococcal conjugate vaccine, and for
the investigational 10 (PCV10) and 13-valent (PCV13) vaccines; (iii) to assess the
genetic relatedeness between isolates expressing capsular type 14 and those non(sero)-
typeable isolates (NTPn); (iv) to investigate if carriage isolates match genetically to any
international pneumococcal clone (PMEN network).
Methods: A cross-sectional survey of carriage PNSp was conducted among 1.192
children, 2 months to 5 years of age, attending 62 DCCs in Central Brazil. Capsular
typing was performed in PNSp isolates (CLSI, 2007) and in a sample of isolates
susceptible to penicillin (PSSp) matched to PNSp and DCCs whenever possible.
Serotyping was performed by Quellung reactions and confirmed by multibead assay.
NTPn isolates and serotype 14 were tested by PCR for capsule genes. Odds ratio for
PNSp carriage and respective 95% confidence interval (95%CI) were assessed by
logistic regression. Pulsed field gel electrophoresis (PFGE) was applied to assess the
genetic similarity between PNSp serotype 14 and NTPn isolates. PCR was performed
for the presence of pneumococcal capsule gene locus. For comparison purpose we also
evaluated the genetic profile of PNSp serotype 14 invasive strains derived from the
current pneumococcal invasive disease surveillance for the same pediatric population.
Isolates were epidemiologically related if they shared ≥80% similarity on the
dendrogram (Dice coefficient). A cluster was defined as three or more related isolates.
Results: A total of 686 pneumococci were isolated for a colonization rate of 57.6% and
178 (25.8%) were PNSp. Among the PNSp isolates the usual common types were
found: 14 (53%), 23F (10.2%), 6B (6%), 19F (4.8%) and 19A (4.2%). PSSp isolates
displayed 30 different serotypes although serotype 14 was the most common. Overall a
high prevalence of NTPn (11.1%) was observed with 62.9% PNSp. Serotypes coverage
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for the PCV7, PCV10 and PCV13 vaccines were 55.2%, 55.9% and 65.1%,
respectively. Being less than 24 months of age (OR=1.79; p=0.006), hospitalization in
the previous three months (OR=2.19; p=0.025), and recurrent acute otitis media
(OR=2.89; p=0.013) were independently associated with PNSp in a multivariate model.
Among the 123 PNSp submitted to PFGE (106/carriage and 17/ invasive isolates) a
major group of 34 serotype 14 strains (8 invasive and 26 carriage) was identified and
found to be genetically related to the global pneumococcal clone Spain 9V-3 (82.7%
similarity). All NTPn presented capsule gene locus and 10 (45.4%) of them presented
capsule gene locus to type 14.
Conclusions: (i) DCC attendees with history of recurrent AOM could significantly
contribute to the spread of nasopharyngeal PNSp strains into the community; (ii)
epidemiologic and molecular evidences support the findings that pneumococcal
nonypeable carriage isolates are genetically similar to carriage and invasive isolates
expressing capsular type 14; (iii) carriage and invasive isolates circulating in Goiânia
belong to a serotype 14 variant of the Spain 9V -3 clone and play a critical role in the
spread of PNSp strains to the entire pediatric community of Goiânia
Descrição
Palavras-chave
Streptococcus pneumoniae, portador de pneumococo, fatores de risco, epidemiologia
molecular, pneumococo sorotipo 14, clone Spain9V-3, creches, S. pneumoniae não
tipáveis , Streptococcus pneumoniae carriage, nonsusceptible pneumococcal carriage, risk
factors for pneumococcal carriage, day care centers, molecular epidemiology,
non(sero)-typeable S. pneumoniae, pneumococ
Citação
FRANCO, Cáritas Marquez. Risk factors and molecular epidemiology of penicillin nonsusceptible Streptococcus
pneumoniae isolates in nasopharynx of children attending day-care centers in Goiânia-
GO, Brazil. 2009. 156 f. Tese (Doutorado em Ciências da Saúde) - Universidade Federal de Goiás, Goiânia, 2009.