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Caraterização das estirpes de Streptococcus pneumoniae responsáveis por infeção não invasiva no adulto entre 2016 e 2018
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Abstract(s)
Streptococcus pneumoniae é um microrganismo comensal da nasofaringe humana. Apesar da relação de colonização, este agente pode apresentar-se como patogénico e causar infeções invasivas e não invasivas, com maior incidência nas crianças e nos idosos. Em Portugal, as vacinas pneumocócicas conjugadas (PCVs) estão disponíveis desde 2001. A vacina PCV13 foi introduzida no Plano Nacional de Vacinação (PNV) em 2015. Este trabalho pretendeu caraterizar as estirpes isoladas de pneumonia pneumocócica não invasiva em adultos, depois da introdução da PCV13 no PNV infantil. Assim, foi realizada uma caraterização fenotípica – serotipagem e determinação de suscetibilidade antimicrobiana – e genotípica – determinação de perfis alélicos de “multilocus sequence type” (MLST) – de estirpes pneumocócicas responsáveis por provocar pneumonia pneumocócica não invasiva (PPNI) na população adulta, entre 2016 a 2018, em Portugal. Os resultados obtidos foram comparados com estudos anteriores, de modo a avaliar o efeito da vacinação na distribuição de serotipos, resistência antimicrobiana e linhagens genéticas. Foram encontrados 52 serotipos diferentes, sendo o serotipo 3 (14.6%) a principal causa de PPNI. Os serotipos PCV13 foram responsáveis por 29.6% dos casos, enquanto os serotipos não vacinais representaram 38.6%. Os serotipos adicionais pertencentes à PPV23 expressaram 31.8% dos casos de PPNI. A não suscetibilidade à penicilina e eritromicina foi observada em 18.4% e 21.1% dos casos, enquanto a não suscetibilidade às duas classes antimicrobianas foi observada em 11.9% dos casos. A análise por MLST identificou 110 sequence types (STs) agrupados em 45 complexos clonais (CCs). Os CCs mais frequentes foram o CC180, o CC179, o CC439, o CC97 e o CC66, responsáveis por 41.2% dos casos de PPNI. Apesar da diminuição dos serotipos vacinais, é importante continuar a monitorização e os estudos epidemiológicos no futuro para avaliar a evolução da população pneumocócica com a distribuição de serotipos, resistência antimicrobiana e identificar possíveis evoluções genéticas e trocas capsulares.
Streptococcus pneumoniae is a commensal microorganism of the human nasopharynx. Despite the colonization relationship, this agent can present as a pathogen and cause invasive and non-invasive infections, with greater incidence in children and the elderly. In Portugal, pneumococcal conjugate vaccines (PCV) have been available since 2001. In 2015, the PCV13 vaccine was introduced in the National Immunization Plan. This work aimed to characterize the isolated strains of non-invasive pneumococcal pneumonia in adults, after the introduction of PCV13 in children’s PNV. In this sense, a phenotypic characterization – serotyping and determination of t antimicrobial susceptibility – and genotypic – determination of the allelic profiles of "multilocus sequence type" (MLST) – of pneumococcal strains responsible for causing non-invasive pneumococcal pneumonia (NIPP) in adult population, between 2016 to 2018, in Portugal. The results obtained were compared with previous studies, in order to assess the effect of vaccination on the distribution of serotypes, antimicrobial resistance and genetic strains. 52 different serotypes were found, with serotype 3 (14.6%) being the main cause of NIPP. Serotypes belonging to PCV13 were responsible for 50.2% of the cases of infection, while non-vaccine serotypes accounted for 38.6%. Non-susceptibility to penicillin and erythromycin was observed in 18.4% and 21.1% of cases, and non susceptibility to the two antimicrobial classes was observed in 11.9% of cases. MLST analysis identified 110 sequence types (ST) grouped into 45 clonal complexes (CC). The most frequent CCs were CC180, CC179, CC439, CC97 and CC66, responsible for 41.2% of NIPP cases. Despite the decrease in vaccine serotypes, it is important to continue monitoring and perform epidemiological studies in the future to assess the evolution of the pneumococcal population with serotype distribution, antimicrobial resistance and to identify possible genetic evolutions and capsular exchanges.
Streptococcus pneumoniae is a commensal microorganism of the human nasopharynx. Despite the colonization relationship, this agent can present as a pathogen and cause invasive and non-invasive infections, with greater incidence in children and the elderly. In Portugal, pneumococcal conjugate vaccines (PCV) have been available since 2001. In 2015, the PCV13 vaccine was introduced in the National Immunization Plan. This work aimed to characterize the isolated strains of non-invasive pneumococcal pneumonia in adults, after the introduction of PCV13 in children’s PNV. In this sense, a phenotypic characterization – serotyping and determination of t antimicrobial susceptibility – and genotypic – determination of the allelic profiles of "multilocus sequence type" (MLST) – of pneumococcal strains responsible for causing non-invasive pneumococcal pneumonia (NIPP) in adult population, between 2016 to 2018, in Portugal. The results obtained were compared with previous studies, in order to assess the effect of vaccination on the distribution of serotypes, antimicrobial resistance and genetic strains. 52 different serotypes were found, with serotype 3 (14.6%) being the main cause of NIPP. Serotypes belonging to PCV13 were responsible for 50.2% of the cases of infection, while non-vaccine serotypes accounted for 38.6%. Non-susceptibility to penicillin and erythromycin was observed in 18.4% and 21.1% of cases, and non susceptibility to the two antimicrobial classes was observed in 11.9% of cases. MLST analysis identified 110 sequence types (ST) grouped into 45 clonal complexes (CC). The most frequent CCs were CC180, CC179, CC439, CC97 and CC66, responsible for 41.2% of NIPP cases. Despite the decrease in vaccine serotypes, it is important to continue monitoring and perform epidemiological studies in the future to assess the evolution of the pneumococcal population with serotype distribution, antimicrobial resistance and to identify possible genetic evolutions and capsular exchanges.
Description
Tese de mestrado, Microbiologia Clínica e Doenças Infecciosas Emergentes, Universidade de Lisboa, Faculdade de Medicina, 2022
Keywords
Streptococcus pneumoniae Estirpe Pneumonia pneumocócica não invasiva Resistência antimicrobiana Linhagens genéticas Teses de mestrado - 2022