Caracterização molecular de isolados pertencentes ao complexo Acinetobacter calcoaceticus-Acinetobacter baumannii obtidos de amostras clínicas e ambientais
Data
2022-05-27
Autores
Alves, Rebeca Lobato 
Orientadores
Minarini, Luciene Andrade da Rocha
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Este estudo teve como objetivo caracterizar molecularmente isolados de Acinetobacter spp. obtidos de amostras clínicas de pacientes atendidos no Hospital Municipal e em Serviços de Saúde na comunidade de Diadema, no período de maio a dezembro de 2019, e de importantes reservatórios de água da Região Metropolitana de São Paulo em 2021. A identificação dos isolados clínicos e ambientais foi realizada por MALDI-TOF MS e a concentração inibitória mínima para os principais antimicrobianos foi determinada por diluição em ágar. Os genes que codificam mecanismos de resistência aos β-lactâmicos, incluindo carbapenêmicos, determinantes plasmidiais de resistência à colistina e às quinolonas foram investigados por PCR. A análise de similaridade genética foi realizada por REP-PCR. Ao todo, 53 isolados clínicos pertencentes ao complexo Acinetobacter calcoaceticus-Acinetobacter baumannii foram incluídos no estudo, sendo 52 A. baumannii e um A. pittii. Foi observado 86,79% e 22,65% de isolados resistente ao imipenem e à colistina, respectivamente. A maior parte dos isolados clínicos (41, 83,68%) foi obtida de pacientes internados no Hospital Municipal, causando principalmente infecções no trato respiratório inferior (14, 26,42%). Os genes encontrados foram blaOXA-23-like, blaOXA-24/40-like, em 32 (60,37%) e 16 (30,18%) isolados, respectivamente. O gene blaOXA-51-like foi detectado em todos os isolados identificados como A. baumannii. Além disso, foram evidenciados 20 grupos clonais nos isolados clínicos do complexo. Nas amostras de água, 25 isolados de Acinetobacter spp. foram recuperados, sendo sete A. calcoaceticus, dois A. pittii, um A. baumannii e 15 A. baylyi. Os isolados de água foram provenientes de um único ponto de coleta da Represa Billings. Ao todo, 14 isolados de A. baylyi apresentaram o gene blaOXA-24/40-like, dos quais 12 demonstraram resistência ao imipenem. Além disso, cinco isolados de A. baylyi apresentaram genes de resistência às quinolonas, sendo o gene qnrA o mais frequente. Os resultados obtidos nesse estudo reforçam a necessidade de manter constante vigilância e o monitoramento dos isolados de Acinetobacter spp.
This study aimed to characterize molecular mechanisms of Acinetobacter spp. obtained from clinical samples of patients attended at the Municipal Hospital and Health Services in the community of Diadema, from May to December 2019, and from important water reservoirs in the Metropolitan Region of São Paulo in 2021. The identification of clinical and environmental isolates was performed by MALDI-TOF MS and the minimum inhibitory concentration for the main antimicrobials was determined by agar dilution. The genes that encode mechanisms of resistance to β-lactams, including carbapenems, plasmid-mediated colistin and quinolones resistance were investigated by PCR. Genetic similarity analysis was performed by REP-PCR. In all, 53 clinical isolates belonging to the Acinetobacter calcoaceticus-Acinetobacter baumannii complex were included in the study, being 52 A. baumannii and one A. pittii. It was observed 86.79% and 22.65% of isolates resistant to imipenem and colistin, respectively. Most of the clinical isolates (41, 83.68%) were obtained from patients admitted to the Municipal Hospital, causing mainly infections in the lower respiratory tract (14, 26.42%). The genes found were blaOXA-23-like, blaOXA-24/40-like, in 32 (60.37%) and 16 (30.18%) isolates, respectively. The blaOXA-51-like gene was detected in all isolates identified as A. baumannii. In addition, 20 clonal groups were evidenced in the clinical isolates among the complex. In the water samples, 25 Acinetobacter spp. were recovered, being seven A. calcoaceticus, two A. pittii, one A. baumannii and 15 A. baylyi. The water isolates came from a single collection point at the Billings Reservoir. Altogether, 14 A. baylyi isolates showed the blaOXA-24/40-like gene, of which 12 showed resistance to imipenem. In addition, five A. baylyi isolates showed quinolone resistance genes, with the qnrA gene being the most frequent. The results obtained in this study reinforce the need for constant surveillance and monitoring of Acinetobacter spp.
This study aimed to characterize molecular mechanisms of Acinetobacter spp. obtained from clinical samples of patients attended at the Municipal Hospital and Health Services in the community of Diadema, from May to December 2019, and from important water reservoirs in the Metropolitan Region of São Paulo in 2021. The identification of clinical and environmental isolates was performed by MALDI-TOF MS and the minimum inhibitory concentration for the main antimicrobials was determined by agar dilution. The genes that encode mechanisms of resistance to β-lactams, including carbapenems, plasmid-mediated colistin and quinolones resistance were investigated by PCR. Genetic similarity analysis was performed by REP-PCR. In all, 53 clinical isolates belonging to the Acinetobacter calcoaceticus-Acinetobacter baumannii complex were included in the study, being 52 A. baumannii and one A. pittii. It was observed 86.79% and 22.65% of isolates resistant to imipenem and colistin, respectively. Most of the clinical isolates (41, 83.68%) were obtained from patients admitted to the Municipal Hospital, causing mainly infections in the lower respiratory tract (14, 26.42%). The genes found were blaOXA-23-like, blaOXA-24/40-like, in 32 (60.37%) and 16 (30.18%) isolates, respectively. The blaOXA-51-like gene was detected in all isolates identified as A. baumannii. In addition, 20 clonal groups were evidenced in the clinical isolates among the complex. In the water samples, 25 Acinetobacter spp. were recovered, being seven A. calcoaceticus, two A. pittii, one A. baumannii and 15 A. baylyi. The water isolates came from a single collection point at the Billings Reservoir. Altogether, 14 A. baylyi isolates showed the blaOXA-24/40-like gene, of which 12 showed resistance to imipenem. In addition, five A. baylyi isolates showed quinolone resistance genes, with the qnrA gene being the most frequent. The results obtained in this study reinforce the need for constant surveillance and monitoring of Acinetobacter spp.