scholarly journals Treatment of Polymicrobial Osteomyelitis with Ceftolozane-Tazobactam: Case Report and Sensitivity Testing of Isolates

2016 ◽  
Vol 2016 ◽  
pp. 1-4 ◽  
Author(s):  
Jeffrey C. Jolliff ◽  
Jackie Ho ◽  
Jeremiah Joson ◽  
Arash Heidari ◽  
Royce Johnson
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Case Reports ◽  
Opportunistic Pathogen ◽  
Generation Cephalosporin ◽  
Multidrug Resistant ◽  
Mechanisms Of Resistance ◽  
Sensitivity Testing ◽  
Lactamase Inhibitor

Stenotrophomonas maltophiliais an inherently multidrug resistant (MDR) opportunistic pathogen with many mechanisms of resistance. SENTRY studies reveal decreasing sensitivities ofS. maltophiliato trimethoprim-sulfamethoxazole and fluoroquinolones. Ceftolozane-tazobactam (Zerbaxa, Merck & Co., Inc.) a novel intravenous combination agent of a third-generation cephalosporin andβ-lactamase inhibitor was demonstrated to havein vitroactivity against many Gram-positive, Gram-negative, and MDR organisms. Data for ceftolozane-tazobactam’s use outside of Food and Drug Administration (FDA) approved indications has been limited thus far to two case reports which demonstrated its efficacy in pan-resistantPseudomonas aeruginosapneumonia. Herein, we describe the first published case of treatment of MDRS. maltophiliain polymicrobial osteomyelitis with long-term (>14 days) ceftolozane-tazobactam and metronidazole. Ceftolozane-tazobactam may offer a possible alternative for clinicians faced with limited options in the treatment of resistant pathogens including MDRS. maltophilia.

scholarly journals Avibactam Restores the Susceptibility of Clinical Isolates of Stenotrophomonas maltophilia to Aztreonam

2017 ◽  
Vol 61 (10) ◽  
Author(s):  
Maria F. Mojica ◽  
Krisztina M. Papp-Wallace ◽  
Magdalena A. Taracila ◽  
Melissa D. Barnes ◽  
Joseph D. Rutter ◽  
...  
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Opportunistic Pathogen ◽  
Multidrug Resistant ◽  
World Health ◽  
Combination Therapies ◽  
Content Type ◽  
Medical Need ◽  
The World ◽  
Health Organization

ABSTRACT Stenotrophomonas maltophilia is an emerging opportunistic pathogen, classified by the World Health Organization as one of the leading multidrug-resistant organisms in hospital settings. The need to discover novel compounds and/or combination therapies for S. maltophilia is urgent. We demonstrate the in vitro efficacy of aztreonam-avibactam (ATM-AVI) against S. maltophilia and kinetically characterize the inhibition of the L2 β-lactamase by avibactam. ATM-AVI overcomes aztreonam resistance in selected clinical strains of S. maltophilia, addressing an unmet medical need.

scholarly journals In VitroDrug Combination Studies of Letermovir (AIC246, MK-8228) with Approved Anti-Human Cytomegalovirus (HCMV) and Anti-HIV Compounds in Inhibition of HCMV and HIV Replication

2015 ◽  
Vol 59 (6) ◽  
pp. 3140-3148 ◽  
Author(s):  
Steffen Wildum ◽  
Holger Zimmermann ◽  
Peter Lischka
Keyword(s):  
Human Cytomegalovirus ◽  
Treatment Strategies ◽  
Opportunistic Pathogen ◽  
Multidrug Resistant ◽  
Severe Toxicity ◽  
Transplant Recipients ◽  
Hiv Drugs ◽  
Anti Hiv

ABSTRACTDespite modern prevention and treatment strategies, human cytomegalovirus (HCMV) remains a common opportunistic pathogen associated with serious morbidity and mortality in immunocompromised individuals, such as transplant recipients and AIDS patients. All drugs currently licensed for the treatment of HCMV infection target the viral DNA polymerase and are associated with severe toxicity issues and the emergence of drug resistance. Letermovir (AIC246, MK-8228) is a new anti-HCMV agent in clinical development that acts via a novel mode of action and has demonstrated anti-HCMV activityin vitroandin vivo. For the future, drug combination therapies, including letermovir, might be indicated under special medical conditions, such as the emergence of multidrug-resistant virus strains in transplant recipients or in HCMV-HIV-coinfected patients. Accordingly, knowledge of the compatibility of letermovir with other HCMV or HIV antivirals is of medical importance. Here, we evaluated the inhibition of HCMV replication by letermovir in combination with all currently approved HCMV antivirals using cell culture checkerboard assays. In addition, the effects of letermovir on the antiviral activities of selected HIV drugs, and vice versa, were analyzed. Using two different mathematical techniques to analyze the experimental data, (i) additive effects were observed for the combination of letermovir with anti-HCMV drugs and (ii) no interaction was found between letermovir and anti-HIV drugs. Since none of the tested drug combinations significantly antagonized letermovir efficacy (or vice versa), our findings suggest that letermovir may offer the potential for combination therapy with the tested HCMV and HIV drugs.

scholarly journals 2287. Real-world Use of Tedizolid Phosphate: A Case Series of Long-Term Tolerability

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S784-S784
Author(s):  
Taylor Morrisette ◽  
Beatriz Da Silva ◽  
Scott W Mueller ◽  
Laura Damioli ◽  
Martin Krsak ◽  
...  
Keyword(s):  
White Blood Cells ◽  
Case Series ◽  
Multidrug Resistant ◽  
Primary Objective ◽  
Term Therapy ◽  
Gram Positive ◽  
Safe Alternative ◽  
Term Tolerability

Abstract Background Tedizolid is an oxazolidinone antibiotic with broad-spectrum Gram-positive activity approved for the treatment of skin and skin structure infections with a 6-day course. Oxazolidinone antibiotics represent appealing options for prolonged antimicrobial therapy due to their available oral formulations with excellent bioavailability and potent in vitro activity against various multidrug-resistant Gram-positive organisms, Mycobacterium spp., and Nocardia spp. Although tedizolid and linezolid offer a similar clinical spectrum based on antimicrobial activity alone, long-term use of linezolid is often limited by serious adverse effects. Preliminary assessments have suggested better tolerability with tedizolid; however, these are limited by shorter exposure duration. The objective of this study was to evaluate the long-term safety and tolerability of tedizolid. Methods Retrospective cohort of adult patients receiving tedizolid for ≥ 28 days, with baseline complete blood cell (CBC) indices available, and CBC indices drawn ≥ 14 days into tedizolid course. The primary objective was to evaluate the long-term tolerability of tedizolid. Results 13 patients met inclusion criteria: median age 61 years (IQR, 51–64 years), 69% male, 85% Caucasian. The majority of patients utilized tedizolid for suppression (85%), and the median duration of tedizolid was 113 days (IQR, 71–204 days). There were no differences in CBC indices when comparing baseline to last laboratory draw throughout tedizolid exposure: platelets (baseline: 203 x 109/L (IQR, 186–283 x 109/L) vs. last: 196 x 109/L (IQR, 161–303 x 109/L; p = 0.65), hemoglobin (baseline: 9.8 g/dL (IQR, 8.8–11.1 g/dL) vs. last: 11.7 g/dL (IQR, 11.0–13.1 g/dL; p = 0.10), and white blood cells (baseline: 6.2 x 109/L (IQR, 5.6–7.6 x 109/L) vs. last: 6.5 x 109/L (IQR, 6.3–7.3 x 109/L; p = 0.45). The final laboratory draws were obtained a median of 78 days (IQR, 44–119 days) into therapy. No patients experienced peripheral neuropathy, optic neuritis/visual changes, or serotonin syndrome during treatment/suppression with tedizolid during the period evaluated. Conclusion Long-term therapy with tedizolid appears to be well-tolerated. Treatment and suppression with tedizolid seems to be a safe alternative to linezolid. Disclosures All authors: No reported disclosures.

scholarly journals In Vitro Bactericidal Activity of Human β-Defensin 3 against Multidrug-Resistant Nosocomial Strains

2006 ◽  
Vol 50 (2) ◽  
pp. 806-809 ◽  
Author(s):  
Giuseppantonio Maisetta ◽  
Giovanna Batoni ◽  
Semih Esin ◽  
Walter Florio ◽  
Daria Bottai ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Bactericidal Activity ◽  
Stenotrophomonas Maltophilia ◽  
Bactericidal Effect ◽  
Multidrug Resistant ◽  
Bacterial Strains ◽  
Gram Negative

ABSTRACT The antimicrobial activity of human β-defensin 3 (hBD-3) against multidrug-resistant clinical isolates of Staphylococcus aureus, Enterococcus faecium, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Acinetobacter baumannii was evaluated. A fast bactericidal effect (within 20 min) against all bacterial strains tested was observed. The presence of 20% human serum abolished the bactericidal activity of hBD-3 against gram-negative strains and reduced the activity of the peptide against gram-positive strains.

scholarly journals Contribution of Resistance-Nodulation-Division Efflux Pump OperonsmeU1-V-W-U2-Xto Multidrug Resistance of Stenotrophomonas maltophilia

2011 ◽  
Vol 55 (12) ◽  
pp. 5826-5833 ◽  
Author(s):  
Chao-Hsien Chen ◽  
Chiang-Ching Huang ◽  
Tsao-Chuen Chung ◽  
Rouh-Mei Hu ◽  
Yi-Wei Huang ◽  
...  
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Efflux Pump ◽  
Acquired Resistance ◽  
Type Systems ◽  
Resistant Mutant ◽  
Multidrug Resistant ◽  
Content Type ◽  
Membrane Fusion Protein ◽  
Resistance Nodulation Division

ABSTRACTKJ09C, a multidrug-resistant mutant ofStenotrophomonas maltophiliaKJ, was generated byin vitroselection with chloramphenicol. The multidrug-resistant phenotype of KJ09C was attributed to overexpression of a resistance nodulation division (RND)-type efflux system encoded by an operon consisting of five genes:smeU1,smeV,smeW,smeU2, andsmeX. Proteins encoded bysmeV,smeW, andsmeXwere similar to the membrane fusion protein, RND transporter, and outer membrane protein, respectively, of known RND-type systems. The proteins encoded bysmeU1andsmeU2were found to belong to the family of short-chain dehydrogenases/reductases. Mutant KJ09C exhibited increased resistance to chloramphenicol, quinolones, and tetracyclines and susceptibility to aminoglycosides; susceptibility to β-lactams and erythromycin was not affected. The expression of thesmeU1-V-W-U2-Xoperon was regulated by the divergently transcribed LysR-type regulator genesmeRv. Overexpression of the SmeVWX pump contributed to the acquired resistance to chloramphenicol, quinolones, and tetracyclines. Inactivation ofsmeVandsmeWcompletely abolished the activity of the SmeVWX pump, whereas inactivation ofsmeXalone decreased the activity of the SmeVWX pump. The enhanced aminoglycoside susceptibility observed in KJ09C resulted from SmeX overexpression.

Stroma-free long-term growth of primary acute myeloid leukemia (AML) cells.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e18535-e18535
Author(s):  
Jing Chen ◽  
Glorymar Ibanez Sanchez ◽  
Paul Calder ◽  
Mark G. Frattini
Keyword(s):  
Growth Factors ◽  
Conditioned Medium ◽  
Stromal Cells ◽  
Drug Sensitivity ◽  
Growth Conditions ◽  
Leukemic Cells ◽  
Sensitivity Testing ◽  
Drug Sensitivity Testing

e18535 Background: To individualize therapy for relapsed/refractory AML patients, optimal in-vitro culture conditions to support primary leukemic cells are essential for drug sensitivity testing. Our lab has validated a high throughput chemosensitivity assay with primary AML cells maintained by growth factors (cytokines); however, growth factors have not been shown to support long-term assays of primary AML cells. Stromal cells of the tumor microenvironment are crucial to maintain normal hematopoiesis and leukemic cells and have been shown to support long term in-vitro expansion of primary AML cells. However, there is little information characterizing these growth conditions. The aim of this study was to compare long-term proliferation and phenotypes of primary AML cells with growth factors or stromal support to best determine their utility as a platform for drug sensitivity testing in functional assays. Methods: Patient-derived AML cells were cultured in 96-well plates in: 1) cell culture medium only 2) Human HS5 or HS27 stromal cells 3) HS5 or HS27 stroma-conditioned media or 4) cytokine cocktail. Viability readout by Guava ViaCount and leukemic cell surface phenotypes by fluorescently-conjugated antibodies were performed weekly over 3 weeks. Results: Primary AML cells cultured with only cytokines maintained proliferation at 3 weeks. In comparison, AML cells cultured in HS5 stroma-conditioned medium also maintained proliferation at a similar rate at 3 weeks, while co-culture with HS5 stromal cells demonstrated significantly higher proliferation. Leukemic immunophenotypes were maintained for all growth conditions over 3 weeks. Conclusions: Contrary to known data, primary AML cells with cytokines continued to expand at 3 weeks, at a similar rate to HS5 stroma-conditioned medium, a finding that has not been reported. Consistent with previous studies, we confirmed that stromal cells such as HS5 can provide long-term in-vitro expansion of primary AML cells, which cannot be substituted by stroma-conditioned medium. The ability to maintain long-term expansion of primary AML cells by both cytokines and stromal cells sets up a platform for a direct comparison of high throughput drug sensitivity testing under these growth conditions.

scholarly journals Characterization and PCR-Based Replicon Typing of Resistance Plasmids in Acinetobacter baumannii

2010 ◽  
Vol 54 (10) ◽  
pp. 4168-4177 ◽  
Author(s):  
Alessia Bertini ◽  
Laurent Poirel ◽  
Pauline D. Mugnier ◽  
Laura Villa ◽  
Patrice Nordmann ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Horizontal Transmission ◽  
Opportunistic Pathogen ◽  
Multidrug Resistant ◽  
Conjugative Plasmid ◽  
Homogeneous Groups ◽  
Nucleotide Homology ◽  
Carbapenemase Gene ◽  
Resistance Plasmids

ABSTRACT Acinetobacter baumannii is an opportunistic pathogen, especially in intensive care units, and multidrug-resistant isolates have increasingly been reported during the last decade. Despite recent progress in knowledge of antibiotic resistance mechanisms in A. baumannii, little is known about the genetic factors driving isolates toward multidrug resistance. In the present study, the A. baumannii plasmids were investigated through the analysis and classification of plasmid replication systems and the identification of A. baumannii-specific mobilization and addiction systems. Twenty-two replicons were identified by in silico analysis, and five other replicons were identified and cloned from previously uncharacterized A. baumannii resistance plasmids carrying the OXA-58 carbapenem-hydrolyzing oxacillinase. Replicons were classified into homology groups on the basis of their nucleotide homology. A novel PCR-based replicon typing scheme (the A. baumannii PCR-based replicon typing [AB-PBRT] method) was devised to categorize the A. baumannii plasmids into homogeneous groups on the basis of the nucleotide homology of their respective replicase genes. The AB-PBRT technique was applied to a collection of multidrug-resistant A. baumannii clinical isolates carrying the bla OXA-58 or bla OXA-23 carbapenemase gene. A putative complete conjugative apparatus was identified on one plasmid whose self-conjugative ability was demonstrated in vitro. We showed that this conjugative plasmid type was widely diffused in our collection, likely representing the most important vehicle promoting the horizontal transmission of A. baumannii resistance plasmids.

scholarly journals Mechanisms of Resistance to Structurally Diverse Antiestrogens Differ under Premenopausal and Postmenopausal Conditions: Evidence from in Vitro Breast Cancer Cell Models

Endocrinology ◽  
2009 ◽  
Vol 150 (5) ◽  
pp. 2036-2045 ◽  
Author(s):  
Ping Fan ◽  
Wei Yue ◽  
Ji-Ping Wang ◽  
Sarah Aiyar ◽  
Yan Li ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Lines ◽  
Egf Receptor ◽  
Estrogen Receptor Α ◽  
Cell Number ◽  
Mechanisms Of Resistance ◽  
Long Term Treatment ◽  
Resistant Cells

This study questioned whether the mechanisms of resistance to antiestrogens differ when acquired under premenopausal (Pre-M) vs. postmenopausal (PM) conditions and whether structurally diverse antiestrogens induce adaptation of differing signaling pathways. To address this issue, we conducted systematic studies under Pre-M vs. PM culture conditions with long-term exposure to different antiestrogens and examined the resultant “specific biologic signatures” of the various resistant cells. Estradiol stimulated growth and inhibited apoptosis of “pre-menopausal” antiestrogen-resistant cells but exerted opposite effects on their “post-menopausal” counterparts. Under Pre-M conditions, tamoxifen (TAM)-resistant cells exhibited a marked translocation of estrogen receptor α from the nucleus into the cytoplasm, whereas this occurred to a lesser extent under PM conditions. MCF-7 cells exposed to PM but not Pre-M conditions exhibited up-regulation of basal epidermal growth factor (EGF) receptor (EGFR) levels, an effect exaggerated in cells exposed to 4-hydroxytamoxifen. Differing effects occurred in response to structurally divergent antiestrogens. Long-term treatment with both 4-hydroxytamoxifen and ICI182,780 increased EGFR levels, but this was not seen in response to TAM. Surprisingly, EGF administration slightly increased cell number in TAM-resistant cells, whereas only increasing cell weight and decreasing cell number in EGFR overexpressing-resistant cells. To assess potential differences among various parental cell lines, we induced resistance in cell lines obtained from other laboratories and confirmed the results from our own parental cells with minor differences. Together, these data demonstrate that culture of breast cancer cells under Pre-M and PM conditions and structurally diverse antiestrogens results in adaptive responses with differing biological signatures.

scholarly journals Comparative evaluation of methods testing in vitro sensitivity to azithromycin in multi-drug resistant Pseudomonas aeruginosa isolated from cystic fibrosis patients

2020 ◽  
Author(s):  
Michael Soerensen ◽  
Dennis Nurjadi ◽  
Bakhodur Khakimov ◽  
Sébastien Boutin ◽  
Alexander H. Dalpke ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Therapeutic Option ◽  
Calf Serum ◽  
Multidrug Resistant ◽  
Term Treatment ◽  
In Vitro Sensitivity ◽  
Mueller Hinton ◽  
Long Term Treatment

Abstract Long-term treatment with azithromycin is a therapeutic option in Cystic Fibrosis (CF) patients chronically infected with P. aeruginosa . It was recently shown that azithromycin has direct antimicrobial activity when P. aeruginosa isolates are tested in Roswell Park Memorial Institute medium supplemented with fetal calf serum (RPMI 1640/FCS) by broth microdilution. We now investigated whether (i) azithromycin might also be active against multidrug resistant (MDR) P. aeruginosa isolated from CF patients and (ii) how in vitro sensitivity assays perform in synthetic cystic fibrosis sputum medium (SCFM), a medium that mimics the particular CF airway environment. In 17 (59%) out of 29 MDR P. aeruginosa CF isolates MICs for azithromycin ranged between 0.25 and 8 µg/ml and 12 isolates (41%) showed a MIC ≥512 µg/ml when measured in RPMI/FCS. In contrast, MICs were ≥256 µg/ml for all P. aeruginosa MDR isolates when tested in either SCFM or in conventional cation-adjusted Mueller Hinton Broth. High MIC values observed in CF adapted medium SCFM for both PAO1 and MDR P. aeruginosa CF isolates, as opposed to findings in RPMI, argue against routine azithromycin MIC testing of CF isolates.

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