DDI - Capítulos (ou partes) de livros
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Browsing DDI - Capítulos (ou partes) de livros by Author "Caniça, Manuela"
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- Bacterial resistancesPublication . Manageiro, Vera; Salgueiro, Vanessa; Ferreira, Eugénia; Caniça, ManuelaHere we review several factors involved in the emergence of antibiotic resistance. They are numerous, and the constant adaptation of microorganisms to the selective pressure exerted by antibiotics is extraordinary. The monitoring systems to assess antibiotic resistance levels and the extent of dissemination were highlighted. In addition, the success of spread of certain bacterial lineages and resistant mechanisms remains sometimes difficult to determine. The need to enlarge research in the area of antibiotic resistance was also stated, not only to better understand the dynamics of dissemination of resistance between different bacteria and different ecosystems, but also to enlarge the pharmaceutical pipeline of antibacterials against multidrug-resistant pathogens. It is manifest the severe consequences of antibiotic resistances to humans, animals and environment, constituting a global public health priority. In consequence, it should be tackled on all fronts in view to the essential concept of “One World-One Medicine-One Health”.
- Molecular epidemiology of carbapenemase resistant Klebsiella pneumoniaePublication . Jones-Dias, Daniela; Caniça, Manuela; Manageiro, VeraCarbapenem-resistant Klebsiella pneumoniae have emerged as a class of pathogens that pose a significant threat to patients admitted to healthcare facilities. This phenotype is mostly due to the production of carbapenemases, which constitute the group of β-lactamases capable of hydrolysing all β-lactam antibiotics, including carbapenems. However, the successful worldwide dissemination of carbapenem resistant K. pneumoniae has been linked to the emergence of a specific type of carbapenemase: KPC (K. pneumoniae carbapenemase). Although this carbapenemase has been identified in several sequence-types (STs), the pandemic seems to be mainly driven by the spread of KPC-producing K. pneumoniae from ST258. Apart from the triumph of the clonal spread, there is a considerable variability in the number of mobile genetic elements that KPC-producing K. pneumoniae might harbour, and that contribute to the mobilization and transference of the KPC-encoding gene (blaKPC). This transmission can be mediated by different molecular mechanisms that include the mobilization of minor genetic elements and the horizontal transfer of different conjugative plasmids. Tn4401 transposon is highly involved in the horizontal dissemination of blaKPC. This transposon can even assume different isoforms that, in turn, may become associated with multiple blaKPC-bearing plasmids. Although many plasmids have been linked to the dissemination of blaKPC gene, the incompatibility groups enclosing Tn4401 seem to be predominant. In K. pneumoniae, other carbapenem resistance determinants have been identified throughout the years but none has disseminated to the extent of KPC. Its spread and success seems to be multifactorial with virulence factors, antibiotic resistance determinants and mobile genetic elements playing major roles. Only the early detection of these factors may ease their establishment worldwide and prevent their emergence in non endemic countries.
- Polyclonal KPC-3-producing Enterobacteriaceae in PortugalPublication . Manageiro, Vera; Ferreira, Eugénia; Louro, Deolinda; The Antimicrobial Resistance Surveillance Program in Portugal; Caniça, ManuelaAll 6 KPC-3-producing Enterobacteriaceae isolates (5 K. pneumoniae and 1 Enterobacter cloacae), identified among 61 isolates, from different Portuguese health institutions (March 2010 to December 2011) were multidrug resistant, showing susceptibility only to colistin. The blaKPC-3 gene, conferring resistance to carbapenemes, was present alone or in combination with other bla genes: blaSHV-26, blaCTX-M-15, and the ESBL blaSHV-164, here firstly described. The Tn4401-harbouring blaKPC-3 encountered in all isolates, showed a 68 bp deletion upstream of the bla gene. All but two KPC-3-containing plasmids revealed the following types: IncFrepB plus IncFIIs (n=3) and IncFrepB plus IncP (n=1). Dissemination of blaKPC seems to be due to carriage of similar KPC-harbouring plasmids within genetically distinct K. pneumoniae (ST14, ST34, ST59, ST416 and the novel ST960, by MLST) and E. cloacae clinical strains.