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Título:
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Novel insights into the classification of staphylococcal ?-lactamases in relation to the cefazolin inoculum effect
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Autores:
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Carvajal, Lina P. ;
Rincon, Sandra ;
Echeverri, Aura M. ;
Porras, Jessica ;
Rios, Rafael ;
Ordoñez, Karen M. ;
Seas, Carlos ;
Gomez-Villegas, Sara I. ;
Diaz, Lorena ;
Arias, Cesar A. ;
Reyes, Jinnethe
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Tipo de documento:
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texto impreso
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Editorial:
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American Society for Microbiology, 2020-07-14T00:01:02Z
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Nota general:
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info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es
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Idiomas:
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Inglés
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Palabras clave:
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Editados por otras instituciones
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Artículos
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Artículos en revistas indizadas
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Resumen:
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Cefazolin has become a prominent therapy for methicillin-susceptible Staphylococcus aureus (MSSA) infections. However, an important concern is the cefazolin inoculum effect (CzIE), a phenomenon mediated by staphylococcal ?-lactamases. Four variants of staphylococcal ?-lactamases have been described based on serological methodologies and limited sequence information. Here, we sought to reassess the classification of staphylococcal ?-lactamases and their correlation with the CzIE. We included a large collection of 690 contemporary bloodstream MSSA isolates recovered from Latin America, a region with a high prevalence of the CzIE. We determined cefazolin MICs at standard and high inoculums by broth microdilution. Whole-genome sequencing was performed to classify the ?-lactamase in each isolate based on the predicted full sequence of BlaZ. We used the classical schemes for ?-lactamase classification and compared it to BlaZ allotypes found in unique sequences using the genomic information. Phylogenetic analyses were performed based on the BlaZ and core-genome sequences. The overall prevalence of the CzIE was 40%. Among 641 genomes, type C was the most predominant ?-lactamase (37%), followed by type A (33%). We found 29 allotypes and 43 different substitutions in BlaZ. A single allotype, designated BlaZ-2, showed a robust and statistically significant association with the CzIE. Two other allotypes (BlaZ-3 and BlaZ-5) were associated with a lack of the CzIE. Three amino acid substitutions (A9V, E112A, and G145E) showed statistically significant association with the CzIE (P ?
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En línea:
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http://repositorio.upch.edu.pe/handle/upch/8257
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