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Caracterização genómica de Staphylococcus aureus isolados de infeção invasiva em idade pediátrica em Portugal
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Staphylococcus aureus são cocos Gram-positivos da família Micrococcaceae, podendo
ser comensais ou patogénicos no ser humano. Atualmente, é um dos principais agentes infeciosos na comunidade e em ambiente hospitalar. Este estudo procurou identificar as principais linhagens responsáveis por infeções invasivas pediátricas (<18 anos) em Portugal, avaliando a suscetibilidade a antimicrobianos e a distribuição de genes de virulência. Um total de 205 estirpes de S. aureus foram isoladas de amostras de sangue (n=180), líquido sinovial (n=12) ou outros fluidos/tecidos normalmente estéreis (n=13) em 10 hospitais portugueses entre 2015 e 2020. A partir das sequências genómicas (Illumina) obtidas para todas as estirpes, identificaram-se perfis de multilocus sequence typing (MLST), genes de virulência e de resistência a antimicrobianos. Foi determinada a suscetibilidade a 14 agentes antimicrobianos.
As estirpes pertenciam a 36 tipos de sequência agrupados em 17 complexos clonais (CCs) e um singleton. CC398 (16.6%), CC30 (16.1%), CC5 (13.7%) e CC45 (10.7%) foram os mais frequentes. A resistência à penicilina foi de 87.3% (n=179) e as estirpes de S. aureus resistentes à meticilina (MRSA) representaram 17.1% (n=35) das estirpes, com os tipos SCCmec IV (n=17), VI (n=8) e II (n=8) identificados. As estirpes de MRSA pertenciam aos CC5 (51.4%), CC22 (31.4%), CC8 (11.4%), CC72 (2.9%) e CC152 (2.9%). Foi também detetada resistência à eritromicina (29.8%), clindamicina (28.8%), norfloxacina (15.1%), ácido fusídico (7.3%) e à gentamicina (6.8%). Os genes da leucocidina de Panton-Valentine (PVL) foram detetados em 10 estirpes (4.9%), incluindo duas estirpes MRSA. O gene da toxina-1 da síndrome do choque tóxico foi encontrado em 15.6% (n=32) das estirpes, enquanto os genes das toxinas esfoliativas ETA (2.9%) e ETB (2.4%) estavam presentes numa minoria, apesar da severidade de alguns casos. As estirpes de S. aureus responsáveis por infeções invasivas pediátricas em Portugal apresentaram uma diversidade considerável, apesar da identificação de linhagens amplamente disseminadas.
Staphylococcus aureus is a Gram-positive cocci in the Micrococcaceae family, that can be found as a commensal or pathogenic agent in humans. Nowadays, S. aureus is recognized as one of the main agents of community and hospital infections. This study aimed at identifying the main S. aureus lineages causing pediatric (<18 years) invasive infections in Portugal, evaluating antimicrobial susceptibility and the distribution of virulence genes. A total of 205 isolates were recovered from blood (n=180), synovial fluid (n=12) or other normally sterile fluids/tissues (n=13) in 10 Portuguese hospitals between 2015 and 2020. Genomic sequences (Illumina) were obtained for all isolates. Multilocus sequence typing (MLST) profiles, virulence and antimicrobial resistance genes were identified from the genomic sequences. Antimicrobial susceptibility to fourteen antimicrobial agents was determined by disk diffusion or E-test.. Isolates belonged to 36 sequence types grouped into 17 clonal complexes (CCs) and one singleton. CC398 (16.6%), CC30 (16.1%), CC5 (13.7%) and CC45 (10.7%) were the most frequent CCs. Overall penicillin resistance was 87.3% and methicillin-resistant S. aureus (MRSA) strains accounted for 17.1% (n=35) of the isolates, with SCCmec types IV (n=17), VI (n=8) and II (n=8) being identified. MRSA isolates belonged to CC5 (51.4%), CC22 (31.4%), CC8 (11.4%), CC72 and CC152 (2.9% each). Resistance to other antimicrobial agents included erythromycin (29.8%), clindamycin (28.8%), norfloxacin (15.1%), fusidic acid (7.3%) or gentamicin (6.8%). Panton-Valentine leucocidin (PVL) genes were detected in 10 isolates (4.9%), including two MRSA. Toxic shock syndrome toxin-1 gene was found in 15.6% (n=32) of the isolates while exfoliative toxins ETA (2.9%) and ETB (2.4%) genes were carried by a minority of isolates, despite the severity of some cases. S. aureus causing pediatric invasive infections in Portugal showed considerable diversity, albeit representing widely disseminated lineages.
Staphylococcus aureus is a Gram-positive cocci in the Micrococcaceae family, that can be found as a commensal or pathogenic agent in humans. Nowadays, S. aureus is recognized as one of the main agents of community and hospital infections. This study aimed at identifying the main S. aureus lineages causing pediatric (<18 years) invasive infections in Portugal, evaluating antimicrobial susceptibility and the distribution of virulence genes. A total of 205 isolates were recovered from blood (n=180), synovial fluid (n=12) or other normally sterile fluids/tissues (n=13) in 10 Portuguese hospitals between 2015 and 2020. Genomic sequences (Illumina) were obtained for all isolates. Multilocus sequence typing (MLST) profiles, virulence and antimicrobial resistance genes were identified from the genomic sequences. Antimicrobial susceptibility to fourteen antimicrobial agents was determined by disk diffusion or E-test.. Isolates belonged to 36 sequence types grouped into 17 clonal complexes (CCs) and one singleton. CC398 (16.6%), CC30 (16.1%), CC5 (13.7%) and CC45 (10.7%) were the most frequent CCs. Overall penicillin resistance was 87.3% and methicillin-resistant S. aureus (MRSA) strains accounted for 17.1% (n=35) of the isolates, with SCCmec types IV (n=17), VI (n=8) and II (n=8) being identified. MRSA isolates belonged to CC5 (51.4%), CC22 (31.4%), CC8 (11.4%), CC72 and CC152 (2.9% each). Resistance to other antimicrobial agents included erythromycin (29.8%), clindamycin (28.8%), norfloxacin (15.1%), fusidic acid (7.3%) or gentamicin (6.8%). Panton-Valentine leucocidin (PVL) genes were detected in 10 isolates (4.9%), including two MRSA. Toxic shock syndrome toxin-1 gene was found in 15.6% (n=32) of the isolates while exfoliative toxins ETA (2.9%) and ETB (2.4%) genes were carried by a minority of isolates, despite the severity of some cases. S. aureus causing pediatric invasive infections in Portugal showed considerable diversity, albeit representing widely disseminated lineages.
Descrição
Tese de mestrado, Microbiologia Clínica e Doenças Infeciosas Emergentes, Universidade de Lisboa, Faculdade de Medicina, 2024
Palavras-chave
Staphylococcus aureus Infeção pediátrica invasiva Resistência antimicrobiana Staphylococcus aureus resistente à meticilina (MRSA) Staphylococcus aureus suscetível à meticilina (MSSA) Teses de mestrado - 2024