RESUMO
Convergence of virulence and antibiotic-resistance has been reported in Klebsiella pneumoniae, but not in Klebsiella variicola. We, hereby, report the detection and genomic characterization of hypervirulent and hypermucoviscous K. pneumoniae and K.variicola recovered in Chile from health-care associated infections, which displayed resistance to broad-spectrum cephalosporins. One hundred forty-six K. pneumoniae complex isolates were screened by hypermucoviscosity by the "string test." Two hypermucoid isolates, one hypermucoviscous K. pneumoniae (hmKp) and one K. variicola (hmKv), were further investigated by whole-genome sequencing. In vivo virulence was analyzed by the Galleria mellonella killing assay. In silico analysis of hmKp UCO-494 and hmKv UCO-495 revealed the presence of multiple antibiotic-resistance genes, such as blaCTX-M-1, blaDHA-1 and blaLEN-25 among others clinically relevant resistance determinants, including mutations in a two-component regulatory system related to colistin resistance. These genetic features confer a multidrug-resistant (MDR) phenotype in both strains. Moreover, virulome in silico analysis confirmed the presence of the aerobactin gene iutA, in addition to yersiniabactin and/or colicin V encoding genes, which are normally associated to high virulence in humans. Furthermore, both isolates were able to kill G. mellonella and displayed higher virulence in comparison with the control strain. In summary, the convergence of virulence and the MDR-phenotype in K. pneumoniae complex members is reported for the first time in Chile, denoting a clinical problem that deserves special attention and continuous surveillance in South America.
Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/patogenicidade , Klebsiella/genética , Klebsiella/patogenicidade , Animais , Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Chile , Genoma Bacteriano/genética , Humanos , Klebsiella/enzimologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/enzimologia , Larva/microbiologia , Testes de Sensibilidade Microbiana , Mariposas/microbiologia , Fatores de Virulência/genética , Sequenciamento Completo do GenomaRESUMO
The study on the toxicity of chitosan diethyl phosphate (ChDP), a controlled release insecticide, on the activities of butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) in rainbow trout exposed to this pesticide was carried out. It was found that ChDP reduced BuChE activity in O. mykiss by a factor of eight at 6 days, with high fluctuation to the end of the exposition time at 12 days. The in vitro analysis of brain AChE treated with ChDP and Phenamiphos showed that it was competitively inhibited by both organophosphates. The values obtained for Km and Vmax for the AChE-ChDP (Km: 21.23 microM; Vmax: 43.10 micromol/min/g) and AChE-Phenamiphos (Km: 38.62 microM; Vmax: 38.91 micromol/min/g) systems were relatively low compared to values of the AChE (control) system (Km: 62.99 microM; Vmax: 63.29 micromol/min/g). Results reported in this study confirmed that chitosan diethyl phosphate performs similarly to organophosphate pesticides, producing inhibition in cholinesterases in rainbow trout.