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Phenotypic and genotypic characterisation of multiple antibiotic-resistant Staphylococcus aureus exposed to subinhibitory levels of oxacillin and levofloxacin

BACKGROUND: The emergence and spread of multidrug resistant methicillin-resistant Staphylococcus aureus (MDR-MRSA) has serious health consequences in the presence of sub-MIC antibiotics. Therefore, this study was designed to evaluate β-lactamase activity, efflux activity, biofilm formation, and gene...

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Autores principales: Jo, Ara, Ahn, Juhee
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4966875/
https://www.ncbi.nlm.nih.gov/pubmed/27473500
http://dx.doi.org/10.1186/s12866-016-0791-7
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author Jo, Ara
Ahn, Juhee
author_facet Jo, Ara
Ahn, Juhee
author_sort Jo, Ara
collection PubMed
description BACKGROUND: The emergence and spread of multidrug resistant methicillin-resistant Staphylococcus aureus (MDR-MRSA) has serious health consequences in the presence of sub-MIC antibiotics. Therefore, this study was designed to evaluate β-lactamase activity, efflux activity, biofilm formation, and gene expression pattern in Staphylococcus aureus KACC 10778, S. aureus ATCC 15564, and S. aureus CCARM 3080 exposed to sublethal concentrations of levofloxacin and oxacillin. RESULTS: The decreased MICs were observed in S. aureus KACC and S. aureus ATCC when exposed to levofloxacin and oxacillin, while and S. aureus CCARM remained resistance to streptomycin (512 μg/mL) in the presence of levofloxacin and imipenem (>512 μg/mL) in the presence of oxacillin. The considerable increase in extracellular and membrane-bound β-lactamase activities was observed in S. aureus ATCC exposed to oxacillin (>26 μmol/min/mL). The antibiotic susceptibility of all strains exposed to EPIs (CCCP and PAβN) varied depending on the classes of antibiotics. The relative expression levels of adhesion-related genes (clfA, clfB, fnbA, fnnB, and icaD), efflux-related genes (norB, norC, and qacA/B), and enterotoxin gene (sec) were increased more than 5-fold in S. aureus CCARM. The eno and qacA/B genes were highly overexpressed by more than 12- and 9-folds, respectively, in S. aureus CCARM exposed to levofloxacin. The antibiotic susceptibility, lactamase activity, biofilm-forming ability, efflux activity, and gene expression pattern varied with the intrinsic antibiotic resistance of S. aureus KACC, S. aureus ATCC, and S. aureus CCARM exposed to levofloxacin and oxacillin. CONCLUSIONS: This study would provide useful information for better understating of combination therapy related to antibiotic resistance mechanisms and open the door for designing effective antibiotic treatment protocols to prevent excessive use of antibiotics in clinical practice. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12866-016-0791-7) contains supplementary material, which is available to authorized users.
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spelling pubmed-49668752016-07-30 Phenotypic and genotypic characterisation of multiple antibiotic-resistant Staphylococcus aureus exposed to subinhibitory levels of oxacillin and levofloxacin Jo, Ara Ahn, Juhee BMC Microbiol Research Article BACKGROUND: The emergence and spread of multidrug resistant methicillin-resistant Staphylococcus aureus (MDR-MRSA) has serious health consequences in the presence of sub-MIC antibiotics. Therefore, this study was designed to evaluate β-lactamase activity, efflux activity, biofilm formation, and gene expression pattern in Staphylococcus aureus KACC 10778, S. aureus ATCC 15564, and S. aureus CCARM 3080 exposed to sublethal concentrations of levofloxacin and oxacillin. RESULTS: The decreased MICs were observed in S. aureus KACC and S. aureus ATCC when exposed to levofloxacin and oxacillin, while and S. aureus CCARM remained resistance to streptomycin (512 μg/mL) in the presence of levofloxacin and imipenem (>512 μg/mL) in the presence of oxacillin. The considerable increase in extracellular and membrane-bound β-lactamase activities was observed in S. aureus ATCC exposed to oxacillin (>26 μmol/min/mL). The antibiotic susceptibility of all strains exposed to EPIs (CCCP and PAβN) varied depending on the classes of antibiotics. The relative expression levels of adhesion-related genes (clfA, clfB, fnbA, fnnB, and icaD), efflux-related genes (norB, norC, and qacA/B), and enterotoxin gene (sec) were increased more than 5-fold in S. aureus CCARM. The eno and qacA/B genes were highly overexpressed by more than 12- and 9-folds, respectively, in S. aureus CCARM exposed to levofloxacin. The antibiotic susceptibility, lactamase activity, biofilm-forming ability, efflux activity, and gene expression pattern varied with the intrinsic antibiotic resistance of S. aureus KACC, S. aureus ATCC, and S. aureus CCARM exposed to levofloxacin and oxacillin. CONCLUSIONS: This study would provide useful information for better understating of combination therapy related to antibiotic resistance mechanisms and open the door for designing effective antibiotic treatment protocols to prevent excessive use of antibiotics in clinical practice. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12866-016-0791-7) contains supplementary material, which is available to authorized users. BioMed Central 2016-07-29 /pmc/articles/PMC4966875/ /pubmed/27473500 http://dx.doi.org/10.1186/s12866-016-0791-7 Text en © The Author(s). 2016 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Jo, Ara
Ahn, Juhee
Phenotypic and genotypic characterisation of multiple antibiotic-resistant Staphylococcus aureus exposed to subinhibitory levels of oxacillin and levofloxacin
title Phenotypic and genotypic characterisation of multiple antibiotic-resistant Staphylococcus aureus exposed to subinhibitory levels of oxacillin and levofloxacin
title_full Phenotypic and genotypic characterisation of multiple antibiotic-resistant Staphylococcus aureus exposed to subinhibitory levels of oxacillin and levofloxacin
title_fullStr Phenotypic and genotypic characterisation of multiple antibiotic-resistant Staphylococcus aureus exposed to subinhibitory levels of oxacillin and levofloxacin
title_full_unstemmed Phenotypic and genotypic characterisation of multiple antibiotic-resistant Staphylococcus aureus exposed to subinhibitory levels of oxacillin and levofloxacin
title_short Phenotypic and genotypic characterisation of multiple antibiotic-resistant Staphylococcus aureus exposed to subinhibitory levels of oxacillin and levofloxacin
title_sort phenotypic and genotypic characterisation of multiple antibiotic-resistant staphylococcus aureus exposed to subinhibitory levels of oxacillin and levofloxacin
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4966875/
https://www.ncbi.nlm.nih.gov/pubmed/27473500
http://dx.doi.org/10.1186/s12866-016-0791-7
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