Análise da diversidade de espécies de Acinetobacter spp. e do seu papel como reservatório de genes de resistência aos antimicrobianos em matrizes aquáticas e solos das diferentes regiões geográficas brasileiras
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2023-12-18
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A ecologia microbiana assume que os microrganismos, mesmo espécies não patogênicas, são reservatórios ambientais de genes de resistência aos antimicrobianos (ARGs). Bactérias ambientais, consideradas não patogênicas, estão expostas a múltiplos metabólitos com atividade antimicrobiana produzidos por outros microrganismos como forma de defesa e competição pelos nichos ecológicos em que habitam. Esses metabólitos ou bioativos permitiram o surgimento de ARGs com alta especificidade ao longo de milhares de anos, e sua localização dentro de elementos genéticos móveis facilitou sua transmissão para espécies bacterianas patogênicas. É fato que as infecções por Acinetobacter spp. estão se espalhando rapidamente em todo o mundo, principalmente em ambientes nosocomiais. O gênero Acinetobacter é altamente diverso e ubíquo, consistindo em cocobacilos gram-negativos não
fermentadores da glicose, catalase-positivos e oxidase-negativos. As espécies pertencentes a este gênero são majoritariamente ambientais e não patogênicas. Entretanto, A. baumannii é a espécie patogênica mais importante do gênero, e essa característica se deve à sua notável adaptabilidade a ambientes hospitalares e à sua multirresistência (MDR), o que acaba ofuscando as demais espécies do gênero. O objetivo geral deste estudo foi de avaliar a presença de cepas de Acinetobacter spp. resistentes aos antimicrobianos em matrizes aquáticas e solos das diferentes regiões geográficas brasileiras. Para o presente estudo, foram selecionados 106 isolados de Acinetobacter spp. recuperados de amostras de matrizes aquáticas e de solo dos estados do Pará (PA), Ceará (CE), São Paulo (SP), Santa Catarina (SC) e Mato Grosso do Sul (MS). Todos os isolados de Acinetobacter spp. tiveram sua identificação confirmada pela técnica de MALDI-TOF MS. Além disso, o perfil de sensibilidade
aos antimicrobianos foi determinado pela técnica de difusão em disco. Os ARGs aos β-lactâmicos, às fluoroquinolonas, aos aminoglicosídeos e às polimixinas foram submetidos a análise mediante a técnica de reação em cadeia da polimerase (PCR) convencional e multiplex utilizando primers específicos, empregando pools de amostras. Posteriormente, os pools que demonstraram positividade para algum dos ARGs triados, cada cepa dentro daquele pool foi verificada individualmente para o gene de interesse. Ao todo foram identificadas 12 espécies de Acinetobacter, sendo que A. baumannii (n=46; 43,4%) foi a espécie mais prevalente, seguida por A. pittii (n=16; 15,1%), A. nosocomialis (n=15; 14,1%) e A. seifertii (n=11; 10,4%). A maioria dos isolados de Acinetobacter spp. foram obtidos nos estados do PA (n=56; 52,8%) e CE (n=37; 34,9%). Além disso, uma maior diversidade de espécies de Acinetobacter foi verificada nesses dois estados comparados aos estados de SP, SC e MS. Dentre os ARGs triados, foram detectados os genes blaOXA-5-like (n=2 isolados), blaOXA-24/40-like (n=6 isolados), blaOXA-51-like (n=47 isolados), blaIMP-like (n=8 isolados) e blaSHVlike (n=6 isolados). A análise comparativa entre os diferentes estados avaliados revelou variações significativas na distribuição geográfica dos ARGs, com uma maior frequência entre os estados de CE e PA. Enquanto os genes blaIMP-like e blaSHV-like foram detectados somente em isolados de A. baumannii, os genes blaOXA-24/40-like e blaOXA-5-like foram encontrados em espécies de A. não-baumannii, como A. pittii e A. soli. A heterogeneidade na distribuição de
espécies e ARGs em amostras ambientais observada no presente estudo sugere uma
necessidade de abordagens de vigilância nacional e sob uma perspectiva de Saúde Única, de modo que possam ser fornecido um panorama real da resistência aos antimicrobianos nas diferentes regiões brasileiras e, assim, orientar a implementação de medidas eficazes no combate a emergência e disseminação de patógenos MDR e novos ARGs no país.
Microbial ecology assumes that microorganisms, even non-pathogenic species, are environmental reservoirs of antimicrobial resistance genes (ARGs). Environmental bacteria, considered non-pathogenic, are exposed to multiple metabolites with antimicrobial activity produced by other microorganisms as a form of defense and competition for the ecological niches in which they inhabit. These metabolites have allowed the emergence of ARGs with high specificity over thousands of years, and their location within mobile genetic elements has facilitated their transmission to pathogenic bacterial species. It is a fact that infections caused by Acinetobacter spp. are spreading rapidly across the world, particularly in hospital settings. The genus Acinetobacter is highly diverse and ubiquitous, consisting of non-glucosefermenting, catalase-positive, and oxidase-negative Gram-negative coccobacilli. The species belonging to this genus are mostly environmental and non-pathogenic. However, A. baumannii is the most important pathogenic species of the genus, and this characteristic is due to its remarkable adaptability to hospital environments and its multidrug resistance (MDR), which ends up overshadowing the other species of the genus. The general objective of this study was to evaluate the presence of Acinetobacter spp. resistant to antimicrobials in aquatic matrices and soils from different Brazilian geographic regions. For the present study, 106 isolates of Acinetobacter spp. were selected and recovered from samples of water and soil from the states of Pará (PA), Ceará (CE), São Paulo (SP), Santa Catarina (SC), and Mato Grosso do Sul (MS). All Acinetobacter spp. isolates have their identification confirmed by MALDI-TOF MS technique. Furthermore, the antimicrobial susceptibility profile was determined by the disk diffusion method. Finally, ARGs to β-lactams, fluoroquinolones, aminoglycosides, and polymyxins were subjected to analysis using the conventional and multiplex polymerase chain reaction (PCR) technique using specific primers, and pools of samples were initially tested. Subsequently, in the pools that demonstrated positivity for any of the screened ARGs, each strain within that pool was individually checked for the gene of interest. A total of 12 Acinetobacter species were identified, with A. baumannii (n=46; 43.4%) being the most prevalent species, followed by A. pittii (n=16; 15.1%), A. nosocomialis (n=15; 14.1%), and A. seifertii (n=11; 10.4%). Most of Acinetobacter spp. isolates were obtained in the states of PA (n=56; 52.8%) and CE (n=37; 34.9%). Furthermore, a greater diversity of Acinetobacter species was observed in these two states compared to the states of SP, SC, and MS. Among the ARGs screened, the genes blaOXA-5-like (n=2 isolates), blaOXA-24/40-like (n=6 isolates), blaOXA-51-like (n=47 isolates), blaIMP-like (n=8 isolates), and blaSHV-like (n=6 isolates). The comparative analysis between the different states evaluated revealed significant variations in the geographic distribution of ARGs, with a greater frequency between the states of CE and PA. While the blaIMP-like and blaSHV-like genes were detected only in A. baumannii isolates, the blaOXA-24/40-like and blaOXA-5-like genes were found in A. non-baumannii species, such as A. pittii and A. soli. The heterogeneity in the distribution of species and ARGs in environmental samples observed in the present study suggests a need for national surveillance approaches under a One Health perspective, so that a real panorama of antimicrobial resistance in different Brazilian regions can be provided and, thus, guide the implementation of effective measures to combat the emergence and spread of MDR pathogens and new ARGs in the country.
Microbial ecology assumes that microorganisms, even non-pathogenic species, are environmental reservoirs of antimicrobial resistance genes (ARGs). Environmental bacteria, considered non-pathogenic, are exposed to multiple metabolites with antimicrobial activity produced by other microorganisms as a form of defense and competition for the ecological niches in which they inhabit. These metabolites have allowed the emergence of ARGs with high specificity over thousands of years, and their location within mobile genetic elements has facilitated their transmission to pathogenic bacterial species. It is a fact that infections caused by Acinetobacter spp. are spreading rapidly across the world, particularly in hospital settings. The genus Acinetobacter is highly diverse and ubiquitous, consisting of non-glucosefermenting, catalase-positive, and oxidase-negative Gram-negative coccobacilli. The species belonging to this genus are mostly environmental and non-pathogenic. However, A. baumannii is the most important pathogenic species of the genus, and this characteristic is due to its remarkable adaptability to hospital environments and its multidrug resistance (MDR), which ends up overshadowing the other species of the genus. The general objective of this study was to evaluate the presence of Acinetobacter spp. resistant to antimicrobials in aquatic matrices and soils from different Brazilian geographic regions. For the present study, 106 isolates of Acinetobacter spp. were selected and recovered from samples of water and soil from the states of Pará (PA), Ceará (CE), São Paulo (SP), Santa Catarina (SC), and Mato Grosso do Sul (MS). All Acinetobacter spp. isolates have their identification confirmed by MALDI-TOF MS technique. Furthermore, the antimicrobial susceptibility profile was determined by the disk diffusion method. Finally, ARGs to β-lactams, fluoroquinolones, aminoglycosides, and polymyxins were subjected to analysis using the conventional and multiplex polymerase chain reaction (PCR) technique using specific primers, and pools of samples were initially tested. Subsequently, in the pools that demonstrated positivity for any of the screened ARGs, each strain within that pool was individually checked for the gene of interest. A total of 12 Acinetobacter species were identified, with A. baumannii (n=46; 43.4%) being the most prevalent species, followed by A. pittii (n=16; 15.1%), A. nosocomialis (n=15; 14.1%), and A. seifertii (n=11; 10.4%). Most of Acinetobacter spp. isolates were obtained in the states of PA (n=56; 52.8%) and CE (n=37; 34.9%). Furthermore, a greater diversity of Acinetobacter species was observed in these two states compared to the states of SP, SC, and MS. Among the ARGs screened, the genes blaOXA-5-like (n=2 isolates), blaOXA-24/40-like (n=6 isolates), blaOXA-51-like (n=47 isolates), blaIMP-like (n=8 isolates), and blaSHV-like (n=6 isolates). The comparative analysis between the different states evaluated revealed significant variations in the geographic distribution of ARGs, with a greater frequency between the states of CE and PA. While the blaIMP-like and blaSHV-like genes were detected only in A. baumannii isolates, the blaOXA-24/40-like and blaOXA-5-like genes were found in A. non-baumannii species, such as A. pittii and A. soli. The heterogeneity in the distribution of species and ARGs in environmental samples observed in the present study suggests a need for national surveillance approaches under a One Health perspective, so that a real panorama of antimicrobial resistance in different Brazilian regions can be provided and, thus, guide the implementation of effective measures to combat the emergence and spread of MDR pathogens and new ARGs in the country.