Caracterização fenotípica e molecular de isolados de Acinetobacter spp. Produtores de oxa-carbapenemases provenientes de diferentes reservatórios

• Ano de defesa: 2019
• Autor(a) principal: Barbosa, Ana Clara Narciso [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• dARK ID: ark:/48912/00130000252dv
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Resistência Bacteriana No Meio Ambiente; Disseminação Da Resistência Bacteriana; OXA-Carbapenemase; Acinetobacter. spp.
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=7643367; https://repositorio.unifesp.br/handle/11600/59212

The genus Acinetobacter comprises a set of bacterial species capable of causing infections in both humans and animals. High rates of carbapenem resistance have been reported among Acinetobacter spp. from worldwide, usually due to the production of carbapenemases. We evaluated isolates of Acinetobacter spp. producers of CHDL recovered from different reservoirs (human and animal). The Acinetobacter spp. isolated from birds were obtained from a surveillance study performed in collaboration with the São Paulo Zoo. Choanal and cloacal swabs from Anseriformes birds (captive and migratory) recovered at the São Paulo Zoo lake (Attachment 3). Subsequently, a microbiological screening was performed to select gram-negative bacilli with reduced sensitivity to carbapenems (Attachment 4). Those identified by MALDI-TOF MS as Acinetobacter spp. were selected. The results of this study were presented in two manuscripts: Article 1 - Published in November 2017 in the journal Antimicrobial Agents and Chemotherapy (Impact Factor: 4,302). The OXA-58-producing A. seiferttii AC12.1 isolate was recovered from the C. melancoryphus microbiota. The isolate showed high MICs for most β-lactams, amikacin, and polymyxin B. The quinolones, tigecycline, gentamicin, minocycline, and sulfamethoxazole/trimethoprim showed good in vitro activity against this isolate. AC12.1 showed a PFGE pattern and a plasmid profile identical to that of isolate previously identified from a patient diagnosed with bloodstream infection in the 1990s. In both bacterial isolates, a ~59 Kb plasmid was detected carrying blaOXA-58 gene, which has been not transferred by electroporation assays. Isolate AC12.1 was subjected to genetic analysis by walking sequencing and revealed that an ISAba825 was inserted upstream of blaOXA-58. Both structures were flanked by two copies of truncated ISAba3. Article 2 - Not submitted yet. The objective was to characterize isolates of OXA-72 producing A. baumannii recovered from captive and migratory Anseriformes from São Paulo Zoo. Additionally, we compare clinical isolates recovered from patients hospitalized at Hospital São Paulo between 2000 and 2017. All isolates were highly resistant to carbapenems and showed high MICs for other β-lactams. In contrast, all isolates showed low MICs for polymyxin B, minocycline, and tigecycline. Two clonal patterns were determined by PFGE (A and B). The pattern A was composed by human and Anseriformes isolates, and pattern B was composed exclusively by human isolates. According to the clonal pattern, distinct subtypes of both groups were selected for MLST (PubMLST) experiments. Clonal complex 79 was the most frequent one observed. All isolates carried a ~16 Kb plasmid with, which was transferred to ATCC19606 by electroporation. The plasmid location of blaOXA-72 was confirmed. Two representative isolates that showed the same genetic characteristics; however, recovered from different reservoirs were selected for whole genome sequencing by the Illumina MiSeq. Analyzes demonstrate that both isolates had the same 16,673 bp plasmid called pAC1-BRL. In addition to blaOXA-72, a macrolide resistance gene was detected, both flanked by the XerC / XerD recombination sites. Comparison with genetically related plasmids showed that pAC1-BRL is related to plasmids detected from different countries encoding different OXAs-carbapenemases. Interestingly, some plasmids considered genetically related did not carry CHDL-encoding genes. We conclude that the results presented in this dissertation expose information about the relationship of birds present in the FPZSP with the dissemination of microorganisms of clinical importance. This relation elucidates important genetic characteristics in these isolates and evidence a possible network of contamination / dissemination among different environments.