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Correlation between Mutations in
<i>liaFSR</i>
of Enterococcus faecium and MIC of Daptomycin: Revisiting Daptomycin Breakpoints
(2012)
MUNITA SEPULVEDA, JOSE MANUEL
;
Diana Panesso
;
Lorena Diaz
;
Truc T. Tran
;
Jinnethe Reyes
Mutations in liaFSR, a three-component regulatory system controlling cell-envelope stress response, were recently linked with the emergence of daptomycin (DAP) resistance in enterococci. Our previous work showed that a liaF mutation increased the DAP MIC of a vancomycin-resistant Enterococcus faecalis strain from 1 to 3 μg/ml (the DAP breakpoint is 4 μg/ml), suggesting that mutations in the liaFSR system could be a pivotal initial event in the development of DAP resistance. With the hypothesis that clinical enterococcal isolates with DAP MICs between 3 and 4 μg/ml might harbor mutations in liaFSR, we studied 38 Enterococcus faecium bloodstream isolates, of which 8 had DAP MICs between 3 and 4 μg/ml by Etest in Mueller-Hinton agar. Interestingly, 6 of these 8 isolates had predicted amino acid changes in the LiaFSR system. Moreover, we previously showed that among 6 DAP-resistant E. faecium isolates (MICs of >4 μg/ml), 5 had mutations in liaFSR. In contrast, none of 16 E. faecium isolates with a DAP MIC of ≤2 μg/ml harbored mutations in this system (P<0.0001). All but one isolate with liaFSR changes exhibited DAP MICs of ≥16 μg/ml by Etest using brain heart infusion agar (BHIA), a medium that better supports enterococcal growth. Our findings provide a strong association between DAP MICs within the upper susceptibility range and mutations in the liaFSR system. Concomitant susceptibility testing on BHIA may be useful for identifying these E. faecium first-step mutants. Our results also suggest that the current DAP breakpoint for E. faecium may need to be reevaluated
14Scopus© Citations 104
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A liaF Codon Deletion Abolishes Daptomycin Bactericidal Activity against Vancomycin-Resistant Enterococcus faecalis
(2013)
MUNITA SEPULVEDA, JOSE MANUEL
;
Truc T. Tran
;
Lorena Diaz
;
Diana Panesso
;
Jinnethe Reyes
The genetic bases for antibiotic tolerance are obscure. Daptomycin (DAP) is a lipopeptide antibiotic with bactericidal activity against enterococci. Using time-kill assays, we provide evidence for the first time that a deletion of isoleucine in position 177 of LiaF, a member of the three-component regulatory system LiaFSR involved in the cell envelope response to antimicrobials, is directly responsible for a DAP-tolerant phenotype and is likely to negatively affect response to DAP therapy.
4Scopus© Citations 66
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Complexity defying macroeconomics
(2023)
PANIAGUA PRIETO, PABLO IGNACIO
<jats:title>Abstract</jats:title> <jats:p>This article contributes to the literature on complexity and macroeconomic models by exploring the analytical relationship and tensions between complex phenomena and macroeconomics. By evaluating the properties of organised complexity, this article suggests alternative strategies for analysing the macroeconomy. Drawing on F. A. Hayek’s notion of organised complexity, I examine how its causal properties relate to the analytical criteria and assumptions that contemporary macroeconomic models use. The purpose is twofold: first, I associate the properties of complexity to the idea of the macroeconomy as an emergent totality arising from the causal interplay between individuals and the organising structure. This conceptually challenges modern macro and frames analytical tensions between complexity and macroeconomic analysis. Second, introducing complexity facilitates breaking away from current analytical and conceptual straitjackets in macroeconomics. Economic inquiry requires looking for alternative ways beyond standard models to analyse the macroeconomy as an emergent totality. This suggests stepping away from current formalistic methods and radical reductionism, in favour of unconventional strategies and approaches that are sensitive to rules, structures, and the causal properties of organised complexity.</jats:p>
Scopus© Citations 11 4
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Diversity emerging: from competitive exclusion to neutral coexistence in ecosystems
(2011)
Juan E. Keymer
;
Miguel A. Fuentes
;
Pablo A. Marquet
6Scopus© Citations 6
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Network Effects of Demographic Transition
(2019)
Tamas David-Barrett
<jats:title>Abstract</jats:title><jats:p>Traditional human societies use two of biology’s solutions to reduce free-riding: by collaborating with relatives, they rely on the mechanism of kin-selection, and by forming highly clustered social kin-networks, they can efficiently use reputation dynamics. Both of these solutions assume the presence of relatives. This paper shows how social networks change during demographic transition. With falling fertility, there are fewer children that could be relatives to one another. As the missing kin are replaced by non-kin friends, local clustering in the social network drops. This effect is compounded by increasing population size, characteristic of demographic transition. The paper also shows that the speed at which reputation spreads in the network slows down due to both falling fertility and increasing group size. Thus, demographic transition weakens both mechanisms for eliminating free-riders: there are fewer relatives around, and reputation spreads slower. This new link between falling fertility and the altered structure of the social network offers novel interpretations of the origins of legal institutions, the Small World phenomenon, the social impact of urbanisation, and the birds-of-a-feather friendship choice heuristic.</jats:p>
1Scopus© Citations 26
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The political economy of complexity: The case of cyber-communism
(2022)
Vicente Moreno-Casas
;
ESPINOSA LOYOLA, VICTOR IGNACIO
;
William Hongsong Wang
Scopus© Citations 12 4
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Methicillin-Susceptible, Vancomycin-Resistant Staphylococcus aureus, Brazil
(2015)
Diana Panesso
;
Paul J. Planet
;
Lorena Diaz
;
Jean-Emmanuel Hugonnet
;
Truc T. Tran
1Scopus© Citations 42 1

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