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Mutant prevention concentration of colistin alone and in combination with rifampicin for multidrug-resistant Acinetobacter baumannii
Colistin-susceptible isolates of Acinetobacter baumannii often contain subpopulations that are resistant to colistin. Monotherapy with colistin can lead to selective growth of these subpopulations and emergence of colistin-resistant strains. Our objectives were to explore the susceptibility pattern...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Springer Berlin Heidelberg
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5059421/ https://www.ncbi.nlm.nih.gov/pubmed/27510182 http://dx.doi.org/10.1007/s10096-016-2736-3 |
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author | Nordqvist, H. Nilsson, L. E. Claesson, C. |
author_facet | Nordqvist, H. Nilsson, L. E. Claesson, C. |
author_sort | Nordqvist, H. |
collection | PubMed |
description | Colistin-susceptible isolates of Acinetobacter baumannii often contain subpopulations that are resistant to colistin. Monotherapy with colistin can lead to selective growth of these subpopulations and emergence of colistin-resistant strains. Our objectives were to explore the susceptibility pattern of colistin-resistant subpopulations and investigate if combining colistin with a second antibiotic could prevent their selective growth. Four colistin-susceptible clinical isolates of A. baumannii and one reference isolate were used. The mutant prevention concentration (MPC) of colistin, i.e. the concentration required to block growth of all single-step-mutant subpopulations, was determined by plating an inoculum of 10(9) CFU on Mueller Hinton agar (MHA)-plates containing 2-fold dilutions of colistin (0.125–128 mg/L). Susceptibility testing of colistin-resistant subpopulations, obtained in the MPC assay, was performed with Etest. The MPC of colistin, in combination with rifampicin, was determined by plating an inoculum of 10(9) CFU on MHA-plates containing colistin (0.125–128 mg/L) and fixed concentrations of rifampicin (1.1 mg/L or 4.4 mg/L). The colistin-resistant subpopulations demonstrated increased susceptibility to a number of agents compared to their main populations. These subpopulations were even susceptible to agents that normally are inactive against gram-negative bacteria and all had rifampicin MICs of < 0.002 mg/L. The combination of colistin and rifampicin completely inhibited the growth of all colistin-resistant subpopulations and significantly lowered the MPC of colistin for A. baumannii. Combining colistin with rifampicin could be a way to prevent selective growth of colistin-resistant subpopulations of A. baumannii and possibly the emergence of colistin-resistant strains. |
format | Online Article Text |
id | pubmed-5059421 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Springer Berlin Heidelberg |
record_format | MEDLINE/PubMed |
spelling | pubmed-50594212016-10-26 Mutant prevention concentration of colistin alone and in combination with rifampicin for multidrug-resistant Acinetobacter baumannii Nordqvist, H. Nilsson, L. E. Claesson, C. Eur J Clin Microbiol Infect Dis Original Article Colistin-susceptible isolates of Acinetobacter baumannii often contain subpopulations that are resistant to colistin. Monotherapy with colistin can lead to selective growth of these subpopulations and emergence of colistin-resistant strains. Our objectives were to explore the susceptibility pattern of colistin-resistant subpopulations and investigate if combining colistin with a second antibiotic could prevent their selective growth. Four colistin-susceptible clinical isolates of A. baumannii and one reference isolate were used. The mutant prevention concentration (MPC) of colistin, i.e. the concentration required to block growth of all single-step-mutant subpopulations, was determined by plating an inoculum of 10(9) CFU on Mueller Hinton agar (MHA)-plates containing 2-fold dilutions of colistin (0.125–128 mg/L). Susceptibility testing of colistin-resistant subpopulations, obtained in the MPC assay, was performed with Etest. The MPC of colistin, in combination with rifampicin, was determined by plating an inoculum of 10(9) CFU on MHA-plates containing colistin (0.125–128 mg/L) and fixed concentrations of rifampicin (1.1 mg/L or 4.4 mg/L). The colistin-resistant subpopulations demonstrated increased susceptibility to a number of agents compared to their main populations. These subpopulations were even susceptible to agents that normally are inactive against gram-negative bacteria and all had rifampicin MICs of < 0.002 mg/L. The combination of colistin and rifampicin completely inhibited the growth of all colistin-resistant subpopulations and significantly lowered the MPC of colistin for A. baumannii. Combining colistin with rifampicin could be a way to prevent selective growth of colistin-resistant subpopulations of A. baumannii and possibly the emergence of colistin-resistant strains. Springer Berlin Heidelberg 2016-08-10 2016 /pmc/articles/PMC5059421/ /pubmed/27510182 http://dx.doi.org/10.1007/s10096-016-2736-3 Text en © The Author(s) 2016 Open Access This 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. |
spellingShingle | Original Article Nordqvist, H. Nilsson, L. E. Claesson, C. Mutant prevention concentration of colistin alone and in combination with rifampicin for multidrug-resistant Acinetobacter baumannii |
title | Mutant prevention concentration of colistin alone and in combination with rifampicin for multidrug-resistant Acinetobacter baumannii |
title_full | Mutant prevention concentration of colistin alone and in combination with rifampicin for multidrug-resistant Acinetobacter baumannii |
title_fullStr | Mutant prevention concentration of colistin alone and in combination with rifampicin for multidrug-resistant Acinetobacter baumannii |
title_full_unstemmed | Mutant prevention concentration of colistin alone and in combination with rifampicin for multidrug-resistant Acinetobacter baumannii |
title_short | Mutant prevention concentration of colistin alone and in combination with rifampicin for multidrug-resistant Acinetobacter baumannii |
title_sort | mutant prevention concentration of colistin alone and in combination with rifampicin for multidrug-resistant acinetobacter baumannii |
topic | Original Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5059421/ https://www.ncbi.nlm.nih.gov/pubmed/27510182 http://dx.doi.org/10.1007/s10096-016-2736-3 |
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