Molecular characterisation of linezolid resistance in two vancomycin-resistant (VanB) Enterococcus faecium isolates using Pyrosequencing™

SUMMARYDuring 2004 and at the start of 2005 a university hospital in Southwest Germany was affected by an extensive outbreak of vancomycin-resistantEnterococcus faecium(VRE). Although the outbreak was contained, linezolid-resistant enterococci emerged during and after the outbreak as the usage of linezolid became more common. Linezolid resistance was no longer limited to VRE. Nosocomial spread of linezolid-resistant but vancomycin-susceptibleE. faeciumwas detected and these strains also emerged in patients without prior drug exposure. Linezolid should therefore be used with caution and the susceptibility of isolates monitored over time. Isolation precautions and screening of contacts should be considered to avoid spread of resistant isolates.

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Molecular Characterisation of Vancomycin-Resistant Enterococcus faecium Isolates Belonging to the Lineage ST117/CT24 Causing Hospital Outbreaks

Frontiers in Microbiology ◽

10.3389/fmicb.2021.728356 ◽

2021 ◽

Vol 12 ◽

Author(s):

Paola Lisotto ◽

Natacha Couto ◽

Sigrid Rosema ◽

Mariëtte Lokate ◽

Xuewei Zhou ◽

...

Keyword(s):

Detailed Analysis ◽

Resistance Genes ◽

Enterococcus Faecium ◽

Genetic Background ◽

Core Genome ◽

Discriminatory Power ◽

Molecular Characterisation ◽

Accessory Genes ◽

Antimicrobial Resistance Genes ◽

Vancomycin Resistant

Background: Vancomycin-resistant Enterococcus faecium (VREfm) is a successful nosocomial pathogen. The current molecular method recommended in the Netherlands for VREfm typing is based on core genome Multilocus sequence typing (cgMLST), however, the rapid emergence of specific VREfm lineages challenges distinguishing outbreak isolates solely based on their core genome. Here, we explored if a detailed molecular characterisation of mobile genetic elements (MGEs) and accessory genes could support and expand the current molecular typing of VREfm isolates sharing the same genetic background, enhancing the discriminatory power of the analysis.Materials/Methods: The genomes of 39 VREfm and three vancomycin-susceptible E. faecium (VSEfm) isolates belonging to ST117/CT24, as assessed by cgMLST, were retrospectively analysed. The isolates were collected from patients and environmental samples from 2011 to 2017, and their genomes were analysed using short-read sequencing. Pangenome analysis was performed on de novo assemblies, which were also screened for known predicted virulence factors, antimicrobial resistance genes, bacteriocins, and prophages. Two representative isolates were also sequenced using long-read sequencing, which allowed a detailed analysis of their plasmid content.Results: The cgMLST analysis showed that the isolates were closely related, with a minimal allelic difference of 10 between each cluster’s closest related isolates. The vanB-carrying transposon Tn1549 was present in all VREfm isolates. However, in our data, we observed independent acquisitions of this transposon. The pangenome analysis revealed differences in the accessory genes related to prophages and bacteriocins content, whilst a similar profile was observed for known predicted virulence and resistance genes.Conclusion: In the case of closely related isolates sharing a similar genetic background, a detailed analysis of MGEs and the integration point of the vanB-carrying transposon allow to increase the discriminatory power compared to the use of cgMLST alone. Thus, enabling the identification of epidemiological links amongst hospitalised patients.

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Low Proportion of Linezolid and Daptomycin Resistance Among Bloodborne Vancomycin-Resistant Enterococcus faecium and Methicillin-Resistant Staphylococcus aureus Infections in Europe

Frontiers in Microbiology ◽

10.3389/fmicb.2021.664199 ◽

2021 ◽

Vol 12 ◽

Author(s):

Robby Markwart ◽

Niklas Willrich ◽

Tim Eckmanns ◽

Guido Werner ◽

Olaniyi Ayobami

Keyword(s):

Staphylococcus Aureus ◽

Enterococcus Faecium ◽

Methicillin Resistant Staphylococcus Aureus ◽

Temporal Change ◽

Methicillin Resistant ◽

Linezolid Resistance ◽

Multivariable Regression ◽

Vancomycin Resistant ◽

Significant Health ◽

The Eu

Vancomycin-resistant Enterococcus faecium (VREF) and methicillin-resistant Staphylococcus aureus (MRSA) are associated with significant health burden. We investigated linezolid and daptomycin resistance among VREF and MRSA in the EU/EEA between 2014 and 2018. Descriptive statistics and multivariable logistic regression were used to analyze 6,949 VREF and 35,131 MRSA blood isolates from patients with bloodstream infection. The population-weighted mean proportion of linezolid resistance in VREF and MRSA between 2014 and 2018 was 1.6% (95% CI 1.33–2.03%) and 0.28% (95% CI 0.32–0.38%), respectively. Daptomycin resistance in MRSA isolates was similarly low [1.1% (95% CI 0.75–1.6%)]. On the European level, there was no temporal change of daptomycin and linezolid resistance in MRSA and VREF. Multivariable regression analyses showed that there was a higher likelihood of linezolid and daptomycin resistance in MRSA (aOR: 2.74, p < 0.001; aOR: 2.25, p < 0.001) and linezolid in VREF (aOR: 1.99, p < 0.001) compared to their sensitive isolates. The low proportion of linezolid and daptomycin resistance in VREF and MRSA suggests that these last-resort antibiotics remain effective and will continue to play an important role in the clinical management of these infections in Europe. However, regional and national efforts to contain antimicrobial resistance should continue to monitor the trend through strengthened surveillance that includes genomic surveillance for early warning and action.

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Linezolid Resistance in Vancomycin-Resistant Enterococcus faecalis and Enterococcus faecium Isolates in a Brazilian Hospital

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02399-14 ◽

2014 ◽

Vol 58 (5) ◽

pp. 2993-2994 ◽

Cited By ~ 15

Author(s):

L. M. de Almeida ◽

M. R. E. de Araujo ◽

M. F. Iwasaki ◽

A. G. Sacramento ◽

D. Rocha ◽

...

Keyword(s):

Enterococcus Faecalis ◽

Enterococcus Faecium ◽

Vancomycin Resistant Enterococcus ◽

Linezolid Resistance ◽

Vancomycin Resistant

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Increasing Incidence of Linezolid-Intermediate or -Resistant, Vancomycin-Resistant Enterococcus faecium Strains Parallels Increasing Linezolid Consumption

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00070-08 ◽

2008 ◽

Vol 52 (6) ◽

pp. 2256-2259 ◽

Cited By ~ 65

Author(s):

Marc H. Scheetz ◽

Stephanie A. Knechtel ◽

Michael Malczynski ◽

Michael J. Postelnick ◽

Chao Qi

Keyword(s):

Enterococcus Faecium ◽

Vancomycin Resistant Enterococcus ◽

Linezolid Resistance ◽

Current Trends ◽

Vancomycin Resistant

ABSTRACT Clinical enterococcal resistance to linezolid is defined by the presence of the G2576T mutation. We evaluated the incidence of genetically proven linezolid resistance among vancomycin-resistant Enterococcus faecium strains and linezolid consumption for a possible association. A relationship was found (r 2 = 0.73, P = 0.03) and predicts increasing resistance with current trends of linezolid use.

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Virulence of Vancomycin-Resistant Enterococcus faecium According to Linezolid Resistance and Clinical Outbreak Status

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00192-13 ◽

2013 ◽

Vol 57 (8) ◽

pp. 3923-3927 ◽

Cited By ~ 5

Author(s):

Milena McLaughlin ◽

Michael Malczynski ◽

Chao Qi ◽

Grace Barajas ◽

Jordan Radetski ◽

...

Keyword(s):

Enterococcus Faecium ◽

Galleria Mellonella ◽

Interaction Model ◽

Content Type ◽

Host Interaction ◽

Linezolid Resistance ◽

Related Pair ◽

Significant Difference ◽

Vancomycin Resistant ◽

Poor Outcomes

ABSTRACTAssessing clinical virulence differences between vancomycin-resistantEnterococcus faecium(VREF) strains resistant to linezolid (LRVRE) and linezolid-susceptible VRE (LSVRE) strains is difficult due to confounding patient variables.Galleria mellonellais a validated host interaction model allowing straightforward organism virulence assessment. The objective of this study was to assess the virulence of VREF inG. mellonellaaccording to linezolid resistance and clinical outbreak status. A genetically related pair of VREF strains with and without genotypically confirmed linezolid resistance was selected for analysis. Additionally, six strains of LSVRE and two strains of LRVRE were selected according to epidemiologic outbreak status. Mortality ofG. mellonellawas assessed daily over a 5-day period and analyzed using Kaplan-Meier survival curves and log rank tests. Linezolid resistance did not have a significant effect onG. mellonellamortality in the genetically related pair (P= 0.93). There was no significant difference in mortality over time between strains (non-outbreak [i.e., no patient transmissions were recorded] [n= 2] versus outbreak [i.e., transmission occurred between 3 or more patients in a period of 30 days] [n= 6],P= 0.84; extensive transmission [i.e., the isolate was transmitted between at least 80 patients] [n= 2] versus limited transmission [i.e., the isolate was transmitted between fewer than 10 patients] [n= 4],P= 0.78). These results suggest that patients infected with LRVRE or outbreak strains of VREF are at no greater risk of poor outcomes mediated by organism virulence than those infected with LSVRE or non-outbreak strains.

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