Sequential steps of daptomycin resistance in<i>Enterococcus faecium</i>and reversion to hypersusceptibility through IS-mediated inactivation of the<i>liaFSR</i>operon

Sinel, Clara; Cosquer, Thibaud; Auzou, Michel; Goux, Didier; Giard, Jean‐Christophe; Cattoir, Vincent

doi:10.1093/jac/dkw229

Cited by 18 publications

(12 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In fact, 35 genes responded in opposite directions in the shift to biofilm growth for the WT and the mutant (i.e., expression was up for the WT, down for the mutant, or vice versa), and 25 genes were divergently expressed for the relA mutant under biofilm and planktonic growth conditions. Some of these genes with divergent expression provide potential mechanistic explanations for the biofilm-dependent resistance observed, including liaS , a major target of mutations causing resistance to daptomycin (36), which was upregulated in the WT biofilm relative to WT planktonic culture, but downregulated in the relA biofilm relative to planktonic relA cells. A small group of genes were uniquely upregulated in the relA biofilm, including genes with chaperone functions, such as greA (EFAU004_01358) and cspA (EFAU004_01491), which would presumably enhance stress tolerance.…”

Section: Resultsmentioning

confidence: 99%

RelA Mutant Enterococcus faecium with Multiantibiotic Tolerance Arising in an Immunocompromised Host

Honsa

Cooper

Mhaissen

et al. 2017

mBio

View full text Add to dashboard Cite

Serious bacterial infections in immunocompromised patients require highly effective antibacterial therapy for cure, and thus, this setting may reveal novel mechanisms by which bacteria circumvent antibiotics in the absence of immune pressure. Here, an infant with leukemia developed vancomycin-resistant Enterococcus faecium (VRE) bacteremia that persisted for 26 days despite appropriate antibiotic therapy. Sequencing of 22 consecutive VRE isolates identified the emergence of a single missense mutation (L152F) in relA, which constitutively activated the stringent response, resulting in elevated baseline levels of the alarmone guanosine tetraphosphate (ppGpp). Although the mutant remained susceptible to both linezolid and daptomycin in clinical MIC testing and during planktonic growth, it demonstrated tolerance to high doses of both antibiotics when growing in a biofilm. This biofilm-specific gain in resistance was reflected in the broad shift in transcript levels caused by the mutation. Only an experimental biofilm-targeting ClpP-activating antibiotic was able to kill the mutant strain in an established biofilm. The relA mutation was associated with a fitness trade-off, forming smaller and less-well-populated biofilms on biological surfaces. We conclude that clinically relevant relA mutations can emerge during prolonged VRE infection, causing baseline activation of the stringent response, subsequent antibiotic tolerance, and delayed eradication in an immunocompromised state.

show abstract

Section: Resultsmentioning

confidence: 99%

RelA Mutant Enterococcus faecium with Multiantibiotic Tolerance Arising in an Immunocompromised Host

Honsa

Cooper

Mhaissen

et al. 2017

mBio

View full text Add to dashboard Cite

show abstract

“…These mutants were previously obtained in vitro from E . faecium strain Aus0004 and have daptomycin MICs ranging from between 4 to 128 mg/L, while the MIC of the parental strain was 2 mg/L 17 . After extracting total RNAs at the LE phase, we studied the expression of these nine sRNAs with qPCR.…”

Section: Resultsmentioning

confidence: 99%

“…faecium Aus0004 with increasing daptomycin MICs (4, 8, 18, 32, 64, and 128 μg/mL vs . 2 μg/mL for the parental strain) 17 was tested. qRT-PCR experiments were performed in triplicates on RNAs extracted from cells collected at an OD 600 nm of 1.6 (late exponential growth phase).…”

Section: Resultsmentioning

confidence: 99%

“…However, genes involved in daptomycin resistance, such as liaFSR and cls 16 had some degree of changes in expression (Supplementary Table S4 ). It is noteworthy since expression level of the liaFSR operon is linked to daptomycin resistance levels 17 .…”

Section: Discussionmentioning

confidence: 99%

“…Although several genes (e.g. liaFSR , yycFGHIJ , and cls ) are known to be involved in the development of daptomycin resistance 16 , the different steps of resistance acquisition remain unclear, particularly those related to the selection of low-level resistant mutants 17 . Moreover, nothing is currently known about the stress response of E .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Small RNAs in vancomycin-resistant Enterococcus faecium involved in daptomycin response and resistance

Sinel

Augagneur

Sassi

et al. 2017

Sci Rep

Self Cite

View full text Add to dashboard Cite

Vancomycin-resistant Enterococcus faecium is a leading cause of hospital-acquired infections and outbreaks. Regulatory RNAs (sRNAs) are major players in adaptive responses, including antibiotic resistance. They were extensively studied in gram-negative bacteria, but less information is available for gram-positive pathogens. No sRNAs are described in E. faecium. We sought to identify a set of sRNAs expressed in vancomycin-resistant E. faecium Aus0004 strain to assess their roles in daptomycin response and resistance. Genomic and transcriptomic analyses revealed a set of 61 sRNA candidates, including 10 that were further tested and validated by Northern and qPCR. RNA-seq was performed with and without subinhibitory concentrations (SICs) of daptomycin, an antibiotic used to treat enterococcal infections. After daptomycin SIC exposure, the expression of 260 coding and srna genes was altered, with 80 upregulated and 180 downregulated, including 51% involved in carbohydrate and transport metabolisms. Daptomycin SIC exposure significantly affected the expression of seven sRNAs, including one experimentally confirmed, sRNA_0160. We studied sRNA expression in isogenic mutants with increasing levels of daptomycin resistance and observed that expression of several sRNAs, including sRNA_0160, was modified in the stepwise mutants. This first genome-wide sRNA identification in E. faecium suggests that some sRNAs are linked to antibiotic stress response and resistance.

show abstract

Antimicrobial tolerance and its role in the development of resistance: Lessons from enterococci

Darnell

Paxie

Rose

et al. 2022

Advances in Microbial Physiology

View full text Add to dashboard Cite

Sequential steps of daptomycin resistance inEnterococcus faeciumand reversion to hypersusceptibility through IS-mediated inactivation of theliaFSRoperon

Abstract: We demonstrated the stepwise and sequential acquisition of mutations in liaS and in cls leading to daptomycin resistance in E. faecium, and the instability of daptomycin resistance as well as the role of liaFSR inactivation in reversion to daptomycin hypersusceptibility.

Cited by 18 publications

References 20 publications

RelA Mutant Enterococcus faecium with Multiantibiotic Tolerance Arising in an Immunocompromised Host

RelA Mutant Enterococcus faecium with Multiantibiotic Tolerance Arising in an Immunocompromised Host

Small RNAs in vancomycin-resistant Enterococcus faecium involved in daptomycin response and resistance

Antimicrobial tolerance and its role in the development of resistance: Lessons from enterococci

Contact Info

Product

Resources

About