scholarly journals In vitro susceptibility to quinine and microsatellite variations of the Plasmodium falciparum Na+/H+ exchanger (Pfnhe-1) gene: the absence of association in clinical isolates from the Republic of Congo

2011 ◽  
Vol 10 (1) ◽  
pp. 37 ◽  
Author(s):  
Sébastien Briolant ◽  
Stéphane Pelleau ◽  
Hervé Bogreau ◽  
Philippe Hovette ◽  
Agnès Zettor ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Clinical Isolates ◽  
In Vitro Susceptibility ◽  
Republic Of Congo ◽  
The Republic

In vitro susceptibility of clinical isolates ofBacteroides fragilis andBacteroides thetaiotaomicron in Japan

1992 ◽  
Vol 11 (11) ◽  
pp. 1069-1073 ◽  
Author(s):  
K. Watanabe ◽  
K. Ueno ◽  
N. Kato ◽  
Y. Muto ◽  
K. Bandoh ◽  
...  
Keyword(s):  
Clinical Isolates ◽  
In Vitro Susceptibility

scholarly journals In Vitro Activities of Daptomycin against 2,789 Clinical Isolates from 11 North American Medical Centers

2001 ◽  
Vol 45 (6) ◽  
pp. 1919-1922 ◽  
Author(s):  
Arthur L. Barry ◽  
Peter C. Fuchs ◽  
Steven D. Brown
Keyword(s):  
Clinical Isolates ◽  
In Vitro Activity ◽  
Broth Microdilution ◽  
In Vitro Susceptibility ◽  
Medical Centers ◽  
Mueller Hinton ◽  
Calcium Cations ◽  
Important Exception ◽  
Mueller Hinton Broth

ABSTRACT The in vitro activity of daptomycin is affected by the concentration of calcium cations in the test medium. Mueller-Hinton broth is currently adjusted to contain 10 to 12.5 mg of magnesium per liter and 20 to 25 mg of calcium per liter, but for testing of daptomycin, greater concentrations of calcium (50 mg/liter) are recommended to better resemble the normal concentration of ionized calcium in human serum. Two levels of calcium were used for broth microdilution tests of 2,789 recent clinical isolates of gram-positive bacterial pathogens. MICs of daptomycin were two- to fourfold lower when the broth contained additional calcium. For most species, however, the percentages of strains that were inhibited by 2.0 μg of daptomycin per ml were essentially identical with the two broth media. Enterococci were the important exception; i.e., 92% were inhibited when tested in calcium-supplemented broth but only 35% were inhibited by 2.0 μg/ml without the additional calcium. This type of information should be considered when selecting criteria for defining in vitro susceptibility to daptomycin.

scholarly journals 1593. Antimicrobial Activity of Ceftazidime-Avibactam and Comparator Agents Against OXA-48 β-lactamase–Producing Enterobacterales Collected in International Medical Centers, Including the United States, in 2017–2018

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S793-S793
Author(s):  
Lynn-Yao Lin ◽  
Dmitri Debabov ◽  
William Chang
Keyword(s):  
Antimicrobial Agents ◽  
The United States ◽  
Resistance Mechanisms ◽  
Clinical Isolates ◽  
Surveillance Program ◽  
Multiple Resistance ◽  
In Vitro Susceptibility ◽  
Medical Centers ◽  
Custom Made

Abstract Background OXA-48 is a carbapenemase with low-level hydrolytic activity toward cephalosporins. This study evaluated in vitro activities of ceftazidime-avibactam (CAZ-AVI), meropenem (MEM), meropenem-vaborbactam (MVB), ceftolozane-tazobactam (C/T), and other antimicrobial agents against 113 OXA-48-producing Enterobacterales with multiple resistance mechanisms collected in a 2017–2018 global surveillance program. Methods Nonduplicate clinical isolates of 113 Enterobacterales were collected from medical centers in 25 countries in 2017–2018. In vitro susceptibility tests were performed by broth microdilution with a custom-made panel consisting of CAZ-AVI, ceftazidime (CAZ), MEM, MVB, C/T, colistin (COL), gentamicin (GEN), levofloxacin (LEV), and amikacin (AMK). Whole genome sequencing or quantitative PCR data were used to analyze resistance mechanisms, such as OXA-48, extended-spectrum β-lactamase (ESBL), original-spectrum β-lactamase (OSBL), and AmpC β-lactamase. Clinical and Laboratory Standards Institute breakpoints were applied for susceptibility interpretations. Results Of 113 OXA-48–producing clinical isolates, 20 carried OXA-48 alone. The remaining 93 isolates carried additional β-lactamases, including 63 with ESBL (CTX-M-15) + OSBL (SHV, TEM), 15 with AmpC (DHA, AAC, CMY) + ESBL (CTX-M-15), and 15 with OSBL (SHV, TEM). 99.1% (all but 1) of all isolates tested were susceptible to CAZ-AVI, whereas 71.7%, 17.7%, and 14.2% were susceptible to MVB, MEM, and C/T, respectively. Among isolates harboring multiple resistance mechanisms (OXA-48 + ESBL + OSBL; n=63), 98.4%, 69.8%, 11.1%, and 7.9% were susceptible to CAZ-AVI, MVB, MEM, and C/T, respectively. Among isolates carrying OXA-48 + AmpC + ESBL + OSBL (n=15), 100%, 66.7%, 13.3%, and 13.3% were susceptible to CAZ-AVI, MVB, MEM, and C/T, respectively (Table). Aminoglycosides (AMK and GEN) and other β-lactams (eg, CAZ) were 20%–90% active against these isolates. COL was the second most effective comparator, inhibiting 83.2% of these isolates. Table Conclusion CAZ-AVI was the most effective agent in this study compared with other antibiotics, including β-lactams, β-lactam–β-lactamase inhibitor combinations, aminoglycosides, and COL, against OXA-48-producing Enterobacterales carrying multiple β-lactamases. Disclosures Lynn-Yao Lin, MS, AbbVie (Employee) Dmitri Debabov, PhD, AbbVie (Employee) William Chang, BS, AbbVie (Employee)

Meropenem/vaborbactam activity in vitro: a new option for Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae treatment

2021 ◽  
Author(s):  
Federica Romanelli ◽  
Stefania Stolfa ◽  
Anna Morea ◽  
Luigi Ronga ◽  
Raffaele Del Prete ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Turning Point ◽  
Treatment Strategies ◽  
Blood Cultures ◽  
Clinical Isolates ◽  
In Vitro Susceptibility ◽  
Klebsiella Pneumoniae Carbapenemase ◽  
Lactamase Inhibitor

Aim: Infections by Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae represent a major challenge because of limited treatment strategies. New β-lactam/β-lactamase inhibitor associations may help to deal with this challenge. The aim of this study is to evaluate the in vitro susceptibility of KPC-producing K. pneumoniae for meropenem/vaborbactam in comparison with ceftazidime/avibactam against. Materials and methods: Twenty-eight strains isolated from blood cultures were evaluated. Testing for susceptibility to meropenem/vaborbactam and ceftazidime/avibactam was performed by E-test gradient strip. Results: All the clinical isolates were susceptible to meropenem/vaborbactam, while one strain was resistant to ceftazidime/avibactam with a MIC of 32 μg/ml. The median MIC of ceftazidime/avibactam evaluated after standardization was higher compared with that of meropenem/vaborbactam. Conclusion: Meropenem/vaborbactam could be an important turning point in the treatment of KPC-producing K. pneumoniae infections, especially considering the emergence of ceftazidime/avibactam resistance.

scholarly journals Effect of Fluorescent Dyes onIn Vitro-Differentiated, Late-Stage Plasmodium falciparum Gametocytes

2014 ◽  
Vol 58 (12) ◽  
pp. 7398-7404 ◽  
Author(s):  
Tamirat Gebru ◽  
Benjamin Mordmüller ◽  
Jana Held
Keyword(s):  
Plasmodium Falciparum ◽  
Late Stage ◽  
Fluorescent Dyes ◽  
Clinical Symptoms ◽  
Laboratory Strain ◽  
Clinical Isolates ◽  
Synthetic Dyes ◽  
Content Type ◽  
Highly Active

ABSTRACTPlasmodium falciparumgametocytes are not associated with clinical symptoms, but they are responsible for transmitting the pathogen to mosquitoes. Therefore, gametocytocidal interventions are important for malaria control and resistance containment. Currently available drugs and vaccines are not well suited for that purpose. Several dyes have potent antimicrobial activity, but their use against gametocytes has not been investigated systematically. The gametocytocidal activity of nine synthetic dyes and four control compounds was tested against stage V gametocytes of the laboratory strain 3D7 and three clinical isolates ofP. falciparumwith a bioluminescence assay. Five of the fluorescent dyes had submicromolar 50% inhibitory concentration (IC50) values against mature gametocytes. Three mitochondrial dyes, MitoRed, dihexyloxacarbocyanine iodide (DiOC6), and rhodamine B, were highly active (IC50s < 200 nM). MitoRed showed the highest activity against gametocytes, with IC50s of 70 nM against 3D7 and 120 to 210 nM against clinical isolates. All compounds were more active against the laboratory strain 3D7 than against clinical isolates. In particular, the endoperoxides artesunate and dihydroartemisinin showed a 10-fold higher activity against 3D7 than against clinical isolates. In contrast to all clinically used antimalarials, several fluorescent dyes had surprisingly highin vitroactivity against late-stage gametocytes. Since they also act against asexual blood stages, they shall be considered starting points for the development of new antimalarial lead compounds.

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