Mutations in Ribosomal Protein L3 Are Associated with Oxazolidinone Resistance in Staphylococci of Clinical Origin

Locke, Jeffrey B.; Hilgers, M.T.; Shaw, Karen Joy

doi:10.1128/aac.01032-09

Cited by 115 publications

(89 citation statements)

References 27 publications

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“…The results suggest that TR-701 would exhibit an efficacy similar to the efficacy of lin- ezolid for S. aureus pneumonia. An unanswered question in the current study is whether TR-701 would be expected to have the same efficacy for a linezolid-resistant isolate, as has been suggested by in vitro results (32,33,46,49). The results suggest further study of TR-701 in clinical trials of pneumonia due to S. aureus is warranted and may be especially useful given the increased burden of MSSA and MRSA pneumonia in the health care setting.…”

Section: Discussionmentioning

confidence: 84%

Comparative Pharmacodynamics of the New Oxazolidinone Tedizolid Phosphate and Linezolid in a Neutropenic Murine Staphylococcus aureus Pneumonia Model

Lepak

Marchillo

Pichereau

et al. 2012

Antimicrob Agents Chemother

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Staphylococcus aureus has become a leading cause of community-and hospital-acquired pneumonia. Furthermore, infection with community-and health care-acquired strains of methicillinresistant S. aureus (MRSA) is increasingly common and limits antimicrobial options (13,25,29,31). Tedizolid phosphate (TR-701) is a novel oxazolidinone prodrug. The active moiety, tedizolid (TR-700), exhibits potent activity against Gram-positive bacteria, including MRSA (48). The goals of our studies were to identify the pharmacodynamic (PD) target (AUC/MIC ratio) for TR-700 against methicillin-susceptible S. aureus (MSSA) and MRSA strains in a neutropenic murine pneumonia model and compare the PD targets of TR-700 to that of the only FDA-approved oxazolidinone antibiotic, linezolid. MATERIALS AND METHODSBacteria, media, and antibiotics. Eleven isolates of S. aureus were utilized for these experiments. The strains included four MSSA strains (ATCC 6538P, ATCC 25923, ATCC 29213, and ATCC Smith), one hospital-acquired MRSA strain (ATCC 33591), and six community-acquired MRSA strains (MW2, R2527, 04-045, 04-154, 05-051, and UW 307109). Organisms were grown, subcultured, and quantified in Mueller-Hinton broth (Difco Laboratories, Detroit, MI) and Mueller-Hinton agar (Difco Laboratories, Detroit, MI). Linezolid was obtained from the University of Wisconsin pharmacy. Tedizolid (TR-700) and tedizolid phosphate (TR-701) were supplied by the manufacturer (Trius Therapeutics, San Diego, CA). Prior to in vivo treatment studies, TR-701 was dissolved in sterile water at the appropriate drug concentrations. TR-700 was dissolved in sterile dimethyl sulfoxide (DMSO) and diluted with medium to the appropriate concentration for in vitro susceptibility testing.In vitro susceptibility studies. The MICs of linezolid and TR-700 were determined three times in duplicate using Clinical and Laboratory Standards Institute (CLSI) microdilution methods M07-A8 (15). The duplicates were identical, and the final results were reported as the median value of the three MIC tests (see Table 1).Murine infection model. All animal studies were approved by the Animal Research Committees of the University of Wisconsin and William S. Middleton Memorial VA Hospital. Six-week-old, specific-pathogenfree, female ICR/Swiss mice weighing between 24 and 27 g (Harlan Sprague-Dawley, Indianapolis, IN) were used for all studies. Three mice were utilized for each treatment and control group. Mice were rendered neutropenic (absolute neutrophil count of Ͻ100/mm 3 ) by injecting cyclophosphamide (Mead Johnson Pharmaceuticals, Evansville, IN) intraperitoneally 4 days (150 mg/kg of body weight) and 1 day (100 mg/kg) prior to experimental infection. Previous studies have shown that this regimen produces persistent neutropenia in this animal model for 5 days (3). Broth cultures of freshly plated bacteria were grown to logarithmic phase. The inoculum for each organism was diluted to a 0.3 absorbance at 580 nm. Viable plate count confirmation of the inoculum ranged from 10 6 to 10 7 CFU/ml. Anima...

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Section: Discussionmentioning

confidence: 84%

Comparative Pharmacodynamics of the New Oxazolidinone Tedizolid Phosphate and Linezolid in a Neutropenic Murine Staphylococcus aureus Pneumonia Model

Lepak

Marchillo

Pichereau

et al. 2012

Antimicrob Agents Chemother

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“…Mutations in these proteins have only recently been described, and their association with resistance is less certain than that of mutations found in the 23S rRNA gene. Initially, in vitro studies suggested that these mutations conferred reduced susceptibility to linezolid (20). Since that time, though, few studies have confirmed the association between these mutations and linezolid resistance, making this only a minor limitation of our study.…”

Section: Discussionmentioning

confidence: 87%

Investigation of Linezolid Resistance in Staphylococci and Enterococci

et al. 2016

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The objective of this study was to investigate an apparent increase in linezolid-nonsusceptible staphylococci and enterococci following a laboratory change in antimicrobial susceptibility testing from disk diffusion to an automated susceptibility testing system. Isolates with nonsusceptible results (n ‫؍‬ 27) from Vitek2 were subjected to a battery of confirmatory testing which included disk diffusion, Microscan broth microdilution, Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution, gradient diffusion (Etest), 23S rRNA gene sequencing, and cfr PCR. Our results show that there is poor correlation between methods and that only 70 to 75% of isolates were confirmed as linezolid resistant with alternative phenotypic testing methods (disk diffusion, Microscan broth microdilution, CLSI broth microdilution, and Etest). 23S rRNA gene sequencing identified mutations previously associated with linezolid resistance in 16 (59.3%) isolates, and the cfr gene was detected in 3 (11.1%) isolates. Mutations located at positions 2576 and 2534 of the 23S rRNA gene were most common. In addition, two previously undescribed variants (at positions 2083 and 2345 of the 23S rRNA gene) were also identified and may contribute to linezolid resistance.

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“…The L3 Leu101Val substitution was previously detected in a linezolid-susceptible clinical isolate (data on file, JMI Laboratories). However, Gly155 and Ala157 were previously implicated in disturbing linezolid binding (8,9). Thus, due to the proximity of these amino acid substitutions to those found in this study, the L3 mutations coupled with cfr may act synergistically and possibly contribute to the elevated linezolid MIC results.…”

mentioning

confidence: 70%

First Report of Staphylococcal Clinical Isolates in Mexico with Linezolid Resistance Caused by cfr : Evidence of In Vivo cfr Mobilization

Mendes

Deshpande

Noriega³

et al. 2010

J Clin Microbiol

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Mutations in Ribosomal Protein L3 Are Associated with Oxazolidinone Resistance in Staphylococci of Clinical Origin

Cited by 115 publications

References 27 publications

Comparative Pharmacodynamics of the New Oxazolidinone Tedizolid Phosphate and Linezolid in a Neutropenic Murine Staphylococcus aureus Pneumonia Model

Comparative Pharmacodynamics of the New Oxazolidinone Tedizolid Phosphate and Linezolid in a Neutropenic Murine Staphylococcus aureus Pneumonia Model

Investigation of Linezolid Resistance in Staphylococci and Enterococci

First Report of Staphylococcal Clinical Isolates in Mexico with Linezolid Resistance Caused by cfr : Evidence of In Vivo cfr Mobilization

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