Rapid Emergence of Daptomycin Resistance in Nonstriatum Corynebacterium Species: A Multicenter Study

2019 ◽  
Vol 152 (Supplement_1) ◽  
pp. S32-S33
Author(s):  
Kaitlin Mitchell ◽  
Erin McElvania ◽  
Meghan Wallace ◽  
Amy Robertson ◽  
Lars Westblade ◽  
...  
Keyword(s):  
Multicenter Study ◽  
Tertiary Care ◽  
Total N ◽  
Gradient Diffusion ◽  
Corynebacterium Species ◽  
Short Period ◽  
High Level ◽  
Level Resistance

Abstract Members of the genus Corynebacterium are increasingly recognized as causes of opportunistic infection; some species can be multidrug resistant, posing a treatment challenge. Daptomycin is frequently used as therapy of last resort in this setting, but previous work from our group demonstrated the ability of C striatum clinical isolates to rapidly develop high-level resistance to daptomycin, both in vivo and in vitro. Here, our objective was to expand this investigation into a multicenter study evaluating multiple Corynebacterium species. Corynebacterium strains from three tertiary-care academic medical centers (total, n = 76; site 1, n = 44; site 2, n = 15; site 3, n = 17) were evaluated, representing 16 species. Isolates were identified during routine clinical testing and reported to species level in accordance with each laboratory’s standard operating procedures. Identification of each species was confirmed using both VITEK MS and Bruker BioTyper MALDI-TOF MS. MICs to daptomycin (Etest), vancomycin (Etest), and telavancin (Liofilchem) at baseline were determined using gradient diffusion methods on Mueller-Hinton agar with blood (Hardy Diagnostics). Each isolate was then inoculated in duplicate to 5 mL Tryptic Soy Broth. A daptomycin Etest was submerged in one tube from each pair, and growth was observed after 24-hour incubation. If turbidity was observed in the tube with daptomycin, MICs for each of the 3 antimicrobials were reassessed. High-level daptomycin resistance emerged in 24 strains: C aurimucosum (1/1 isolate tested), C bovis (1/2), C jeikeium (2/11), C macginleyi (3/3), C resistens (1/1), C simulans (1/1), C striatum (14/14 isolates), and C ulcerans (1/1). The majority of these isolates had MIC values >256 µg/mL following exposure to daptomycin. Forty-eight other isolates remained susceptible to daptomycin: C afermentans (1/1), C amycolatum (19/20), C diphtheriae (1/1), C jeikeium (7/11), C kroppenstedtii (2/2), C propinquum (3/3), C pseudodiphtheriticum (6/6), C tuberculostearicum (0/6), and C urealyticum (0/3). Many of these isolates did not undergo MIC testing postdaptomycin exposure in broth due to complete lack of growth. Among those that did (n = 19), the median daptomycin MIC was 0.38 µg/mL (mean 0.42 µg/mL; range 0.023-1.0 µg/mL). One isolate of C bovis and two isolates of C jeikeium yielded variable susceptibility to daptomycin; a subset of resistant colonies grew adjacent to the gradient diffusion strip. Upon isolation and further MIC testing, these colonies maintained high-level resistance. In addition, one isolate of C amycolatum exhibited high-level daptomycin resistance (MIC >256 µg/mL) prior to in vitro exposure. All isolates in the cohort were susceptible to vancomycin and telavancin, both before and after daptomycin exposure. Our findings suggest that multiple Corynebacterium species can rapidly develop high-level daptomycin resistance after a short period of exposure to this antimicrobial. This finding has important clinical implications, especially in the treatment of invasive infections or infections of indwelling medical devices.

scholarly journals Efficacy of Ampicillin plus Ceftriaxone in Treatment of Experimental Endocarditis Due to Enterococcus faecalis Strains Highly Resistant to Aminoglycosides

1999 ◽  
Vol 43 (3) ◽  
pp. 639-646 ◽  
Author(s):  
Joan Gavaldà ◽  
Carmen Torres ◽  
Carmen Tenorio ◽  
Pedro López ◽  
Myriam Zaragoza ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Enterococcus Faecalis ◽  
Pharmacokinetic Parameters ◽  
Initial Inoculum ◽  
High Level ◽  
Time Kill ◽  
Disk Method ◽  
Level Resistance

The purpose of this work was to evaluate the in vitro possibilities of ampicillin-ceftriaxone combinations for 10 Enterococcus faecalis strains with high-level resistance to aminoglycosides (HLRAg) and to assess the efficacy of ampicillin plus ceftriaxone, both administered with humanlike pharmacokinetics, for the treatment of experimental endocarditis due to HLRAg E. faecalis. A reduction of 1 to 4 dilutions in MICs of ampicillin was obtained when ampicillin was combined with a fixed subinhibitory ceftriaxone concentration of 4 μg/ml. This potentiating effect was also observed by the double disk method with all 10 strains. Time-kill studies performed with 1 and 2 μg of ampicillin alone per ml or in combination with 5, 10, 20, 40, and 60 μg of ceftriaxone per ml showed a ≥2 log10 reduction in CFU per milliliter with respect to ampicillin alone and to the initial inoculum for all 10E. faecalis strains studied. This effect was obtained for seven strains with the combination of 2 μg of ampicillin per ml plus 10 μg of ceftriaxone per ml and for six strains with 5 μg of ceftriaxone per ml. Animals with catheter-induced endocarditis were infected intravenously with 108 CFU of E. faecalis V48 or 105 CFU of E. faecalisV45 and were treated for 3 days with humanlike pharmacokinetics of 2 g of ampicillin every 4 h, alone or combined with 2 g of ceftriaxone every 12 h. The levels in serum and the pharmacokinetic parameters of the humanlike pharmacokinetics of ampicillin or ceftriaxone in rabbits were similar to those found in humans treated with 2 g of ampicillin or ceftriaxone intravenously. Results of the therapy for experimental endocarditis caused by E. faecalis V48 or V45 showed that the residual bacterial titers in aortic valve vegetations were significantly lower in the animals treated with the combinations of ampicillin plus ceftriaxone than in those treated with ampicillin alone (P < 0.001). The combination of ampicillin and ceftriaxone showed in vitro and in vivo synergism against HLRAgE. faecalis.

scholarly journals Efficacy of vancomycin and teicoplanin alone and in combination with streptomycin in experimental, low-level vancomycin-resistant, VanB-type Enterococcus faecalis endocarditis.

1996 ◽  
Vol 40 (1) ◽  
pp. 55-60 ◽  
Author(s):  
D P Nicolau ◽  
M N Marangos ◽  
C H Nightingale ◽  
K B Patel ◽  
B W Cooper ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Resistant Strain ◽  
Low Level ◽  
Vancomycin Resistant ◽  
Low Levels ◽  
High Level ◽  
Isogenic Strains ◽  
Level Resistance

The efficacy of vancomycin (VM) and teicoplanin (TE), alone and in combination with streptomycin (SM), against enterococci that express low-level VanB-type VM resistance was investigated in experimental endocarditis using isogenic strains of Enterococcus faecalis susceptible to glycopeptides and aminoglycosides or inducibly resistant to low levels of VM (MIC = 16 micrograms/ml). VM was significantly less active against the resistant strain than against the susceptible strain, establishing that low-level VanB-type VM resistance can influence therapeutic efficacy. By contrast, TE had equally good activity against both strains. VM or TE combined with SM was synergistic and bactericidal against the resistant strain in vitro. While both combinations were efficient in reducing bacterial density in vivo, TE plus SM was significantly superior to VM plus SM if valve sterilization was considered. These data suggest that despite the presence of low-level VanB-type resistance, combination therapy with a glycopeptide and SM (and presumably other aminoglycosides to which there is not high-level resistance) will nevertheless provide effective bactericidal activity.

scholarly journals Low-Level Resistance to Rifampin in Streptococcus pneumoniae

2003 ◽  
Vol 47 (3) ◽  
pp. 863-868 ◽  
Author(s):  
Patricia Stutzmann Meier ◽  
Silvia Utz ◽  
Suzanne Aebi ◽  
Kathrin Mühlemann
Keyword(s):  
Streptococcus Pneumoniae ◽  
Point Mutations ◽  
Low Level ◽  
Development Of Resistance ◽  
Rifampin Resistance ◽  
High Level ◽  
Tissue Compartments ◽  
Level Resistance

ABSTRACT Rifampin is recommended for combination therapy of meningitis due to β-lactam-resistant Streptococcus pneumoniae. High-level rifampin resistance (MIC, ≥4 mg/liter) has been mapped to point mutations in clusters I and III of rpoB of the pneumococcus. The molecular basis of low-level resistance (MICs, ≥0.5 and <4 mg/liter) was analyzed. Spontaneous mutants of clinical pneumococcal isolates were selected on Columbia sheep blood agar plates containing rifampin at 0.5, 4, 10, or 50 mg/liter. Low-level resistance could be assigned to mutations in cluster II (I545N, I545L). Sensitive (MIC, <0.048 mg/liter) wild-type strains acquired low-level resistance at a rate approximately 10 times higher than that at which they acquired high-level resistance (average mutation frequencies, 2.4 × 10−7 for low-level resistance versus 2.9 × 10−8 for high-level resistance [P < 0.0001]). In second-step experiments, the frequencies of mutations from low- to high-level resistance were over 10 times higher than the frequencies of mutations from susceptibility to high-level resistance (average mutation frequencies, 7.2 × 10−7 versus 5.0 × 10−8 [P < 0.001]). Mutants with low-level resistance were stable upon passage. Sequencing of a clinical isolate with low-level resistance (MIC, 0.5 mg/liter) revealed a Q150R mutation upstream of cluster I. The frequencies of mutations to high-level resistance for this strain were even higher than the rates observed for the in vitro mutants. Therefore, a resistance-mediating mutation located outside clusters I, II, and III has been described for the first time in the pneumococcus. In vitro low-level rifampin resistance in S. pneumoniae could be mapped to cluster II of rpoB. Mutants of pneumococcus with low-level resistance may be selected in vivo during therapy in tissue compartments with low antibiotic concentrations and play a role in the development of resistance.

scholarly journals The Phytotoxin Albicidin is a Novel Inhibitor of DNA Gyrase

2007 ◽  
Vol 51 (1) ◽  
pp. 181-187 ◽  
Author(s):  
Saeed M. Hashimi ◽  
Melisa K. Wall ◽  
Andrew B. Smith ◽  
Anthony Maxwell ◽  
Robert G. Birch
Keyword(s):  
Dna Gyrase ◽  
Topoisomerase Iv ◽  
Gene Encoding ◽  
Interacting Protein ◽  
Routine Assay ◽  
High Level ◽  
Self Protection ◽  
Level Resistance

ABSTRACT Xanthomonas albilineans produces a family of polyketide-peptide compounds called albicidins which are highly potent antibiotics and phytotoxins as a result of their inhibition of prokaryotic DNA replication. Here we show that albicidin is a potent inhibitor of the supercoiling activity of bacterial and plant DNA gyrases, with 50% inhibitory concentrations (40 to 50 nM) less than those of most coumarins and quinolones. Albicidin blocks the religation of the cleaved DNA intermediate during the gyrase catalytic sequence and also inhibits the relaxation of supercoiled DNA by gyrase and topoisomerase IV. Unlike the coumarins, albicidin does not inhibit the ATPase activity of gyrase. In contrast to the quinolones, the albicidin concentration required to stabilize the gyrase cleavage complex increases 100-fold in the absence of ATP. The slow peptide poisons microcin B17 and CcdB also access ATP-dependent conformations of gyrase to block religation, but in contrast to albicidin, they do not inhibit supercoiling under routine assay conditions. Some mutations in gyrA, known to confer high-level resistance to quinolones or CcdB, confer low-level resistance or hypersensitivity to albicidin in Escherichia coli. Within the albicidin biosynthesis region in X. albilineans is a gene encoding a pentapeptide repeat protein designated AlbG that binds to E. coli DNA gyrase and that confers a sixfold increase in the level of resistance to albicidin in vitro and in vivo. These results demonstrate that DNA gyrase is the molecular target of albicidin and that X. albilineans encodes a gyrase-interacting protein for self-protection. The novel features of the gyrase-albicidin interaction indicate the potential for the development of new antibacterial drugs.

scholarly journals Carbapenems drive the collateral resistance to ceftaroline in cystic fibrosis patients with MRSA

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Maria Celeste Varela ◽  
Melanie Roch ◽  
Agustina Taglialegna ◽  
Scott W. Long ◽  
Matthew Ojeda Saavedra ◽  
...  
Keyword(s):  
Risk Factors ◽  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Therapeutic Strategies ◽  
Penicillin Binding Protein ◽  
Molecular Relationships ◽  
High Level ◽  
Level Resistance

Abstract Chronic airways infection with methicillin-resistant Staphylococcus aureus (MRSA) is associated with worse respiratory disease cystic fibrosis (CF) patients. Ceftaroline is a cephalosporin that inhibits the penicillin-binding protein (PBP2a) uniquely produced by MRSA. We analyzed 335 S. aureus isolates from CF sputum samples collected at three US centers between 2015–2018. Molecular relationships demonstrated that high-level resistance of preceding isolates to carbapenems were associated with subsequent isolation of ceftaroline resistant CF MRSA. In vitro evolution experiments showed that pre-exposure of CF MRSA to meropenem with further selection with ceftaroline implied mutations in mecA and additional mutations in pbp1 and pbp2, targets of carbapenems; no effects were achieved by other β-lactams. An in vivo pneumonia mouse model showed the potential therapeutic efficacy of ceftaroline/meropenem combination against ceftaroline-resistant CF MRSA infections. Thus, the present findings highlight risk factors and potential therapeutic strategies offering an opportunity to both prevent and address antibiotic resistance in this patient population.

scholarly journals Relationship between the Level of Acquired Resistance to Gentamicin and Synergism with Amoxicillin in Enterococcus faecalis

2005 ◽  
Vol 49 (10) ◽  
pp. 4144-4148 ◽  
Author(s):  
Elisabeth Aslangul ◽  
Raymond Ruimy ◽  
Françoise Chau ◽  
Louis Garry ◽  
Antoine Andremont ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Acquired Resistance ◽  
Bactericidal Effect ◽  
A Cell ◽  
Enzymatic Inactivation ◽  
High Level ◽  
The Impact ◽  
Level Resistance

ABSTRACT In enterococci, intrinsic low-level resistance to gentamicin does not abolish synergism with a cell wall-active antibiotic while high-level resistance due to acquired aminoglycoside-modifying enzymes does. To study the impact of intermediate levels of resistance to gentamicin (64 < MIC < 500 μg/ml), we selected in vitro three consecutive generations of mutants of Enterococcus faecalis JH2-2 with MICs of gentamicin at 128 μg/ml for G1-1477, 256 μg/ml for G2-1573, and 512 μg/ml for G3-1688. E. faecalis 102, which is highly resistant to gentamicin by enzymatic inactivation was used as control. In in vitro killing curves experiments, gentamicin concentrations allowing bactericidal activity and synergism in combination with amoxicillin increased from 4 μg/ml (1/16th the MIC), 16 μg/ml (one-eighth the MIC), 64 μg/ml (one-quarter the MIC), and 256 μg/ml (one-half the MIC) for strains JH2-2, G1-1477, G2-1573 and G3-1688, respectively. As expected, no bactericidal effect of the combination or synergism could be obtained with strain 102. In rabbits with aortic endocarditis caused by strain G1-1477 or G2-1573, combination therapy with amoxicillin and gentamicin was significantly more active than amoxicillin alone (P < 0.05) but not in those infected with the strains G3-1688 and 102. Thus, intermediate levels of resistance to gentamicin was not associated with a loss of a beneficial effect of the gentamicin-amoxicillin combination in vivo even though higher concentrations of gentamicin were necessary to achieve in vitro synergism. Therefore, the use of an MIC of 500 μg/ml as a clinical cutoff limit to predict in vivo benefit of the combination remains a simple and effective tool.

scholarly journals Characterization of Saccharomyces cerevisiae strains displaying high-level or low-level resistance to trichothecene antibiotics

1990 ◽  
Vol 267 (3) ◽  
pp. 709-713 ◽  
Author(s):  
M Fernandez-Lobato ◽  
M Cannon ◽  
J A Mitlin ◽  
R C Mount ◽  
A Jimenez
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ribosome Biogenesis ◽  
Gene Encoding ◽  
Ribosomal Subunits ◽  
Low Level ◽  
Ribosomal Protein L3 ◽  
High Level ◽  
Level Resistance

Biochemical and genetic analyses have been carried out on Saccharomyces cerevisiae strains characterized in vivo as sensitive, low-level-resistant or high-level-resistant to trichothecene antibiotics. Levels of drug resistance in vitro were determined for each strain and for suitable diploids derived from them. Ribosome biogenesis was also studied in selected haploids. It is suggested that resistance in all cases results from a mutation in the gene encoding ribosomal protein L3. If this is indeed the situation, then different mutations in this same gene not only can cause low-level or high-level resistance to trichothecene antibiotics but also can affect the maturation of either 40 S or 60 S ribosomal subunits.

Significance of In-Vitro and In-Vivo Correlation in Drug Delivery System

2018 ◽  
Vol 4 (4) ◽  
pp. 523-531
Author(s):  
Hina Mumtaz ◽  
Muhammad Asim Farooq ◽  
Zainab Batool ◽  
Anam Ahsan ◽  
Ashikujaman Syed
Keyword(s):  
Dosage Form ◽  
Pharmaceutical Preparations ◽  
Pharmacokinetic Profile ◽  
In Vitro Dissolution ◽  
Time Saving ◽  
Pharmaceutical Dosage Form ◽  
Short Period ◽  
Form Development

The main purpose of development pharmaceutical dosage form is to find out the in vivo and in vitro behavior of dosage form. This challenge is overcome by implementation of in-vivo and in-vitro correlation. Application of this technique is economical and time saving in dosage form development. It shortens the period of development dosage form as well as improves product quality. IVIVC reduce the experimental study on human because IVIVC involves the in vivo relevant media utilization in vitro specifications. The key goal of IVIVC is to serve as alternate for in vivo bioavailability studies and serve as justification for bio waivers. IVIVC follows the specifications and relevant quality control parameters that lead to improvement in pharmaceutical dosage form development in short period of time. Recently in-vivo in-vitro correlation (IVIVC) has found application to predict the pharmacokinetic behaviour of pharmaceutical preparations. It has emerged as a reliable tool to find the mode of absorption of several dosage forms. It is used to correlate the in-vitro dissolution with in vivo pharmacokinetic profile. IVIVC made use to predict the bioavailability of the drug of particular dosage form. IVIVC is satisfactory for the therapeutic release profile specifications of the formulation. IVIVC model has capability to predict plasma drug concentration from in vitro dissolution media.

scholarly journals Mutations in fbiD (Rv2983) as a Novel Determinant of Resistance to Pretomanid and Delamanid in Mycobacterium tuberculosis

2020 ◽  
Vol 65 (1) ◽  
pp. e01948-20
Author(s):  
Dalin Rifat ◽  
Si-Yang Li ◽  
Thomas Ioerger ◽  
Keshav Shah ◽  
Jean-Philippe Lanoix ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Clinical Evidence ◽  
Clinical Samples ◽  
Loss Of Function ◽  
Wild Type ◽  
Content Type ◽  
Solid Media ◽  
High Level ◽  
Level Resistance

ABSTRACTThe nitroimidazole prodrugs delamanid and pretomanid comprise one of only two new antimicrobial classes approved to treat tuberculosis (TB) in 50 years. Prior in vitro studies suggest a relatively low barrier to nitroimidazole resistance in Mycobacterium tuberculosis, but clinical evidence is limited to date. We selected pretomanid-resistant M. tuberculosis mutants in two mouse models of TB using a range of pretomanid doses. The frequency of spontaneous resistance was approximately 10−5 CFU. Whole-genome sequencing of 161 resistant isolates from 47 mice revealed 99 unique mutations, of which 91% occurred in 1 of 5 genes previously associated with nitroimidazole activation and resistance, namely, fbiC (56%), fbiA (15%), ddn (12%), fgd (4%), and fbiB (4%). Nearly all mutations were unique to a single mouse and not previously identified. The remaining 9% of resistant mutants harbored mutations in Rv2983 (fbiD), a gene not previously associated with nitroimidazole resistance but recently shown to be a guanylyltransferase necessary for cofactor F420 synthesis. Most mutants exhibited high-level resistance to pretomanid and delamanid, although Rv2983 and fbiB mutants exhibited high-level pretomanid resistance but relatively small changes in delamanid susceptibility. Complementing an Rv2983 mutant with wild-type Rv2983 restored susceptibility to pretomanid and delamanid. By quantifying intracellular F420 and its precursor Fo in overexpressing and loss-of-function mutants, we provide further evidence that Rv2983 is necessary for F420 biosynthesis. Finally, Rv2983 mutants and other F420H2-deficient mutants displayed hypersusceptibility to some antibiotics and to concentrations of malachite green found in solid media used to isolate and propagate mycobacteria from clinical samples.

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