In vitro activity and selection of disk content for disk diffusion susceptibility tests with trovafloxacin

1996 ◽  
Vol 15 (8) ◽  
pp. 678-682 ◽  
Author(s):  
P. C. Fuchs ◽  
A. L. Barry ◽  
S. D. Brown ◽  
D. L. Sewell
Keyword(s):  
Vitro Activity ◽  
Disk Diffusion ◽  
In Vitro Activity ◽  
Susceptibility Tests ◽  
Selection Of

3-0-demethyl fortimicin A: In vitro activity and interpretive zone standards for disk diffusion susceptibility tests

1984 ◽  
Vol 3 (6) ◽  
pp. 531-537
Author(s):  
A. L. Barry ◽  
R. N. Jones ◽  
C. Thornsberry ◽  
T. L. Gavan ◽  
E. H. Gerlach ◽  
...  
Keyword(s):  
Vitro Activity ◽  
Disk Diffusion ◽  
In Vitro Activity ◽  
Susceptibility Tests

scholarly journals 598. In Vitro Activity of Aztreonam in Combination with Ceftazidime–Avibactam, Amoxicillin–Clavulanate, and Piperacillin–Tazobactam vs. NDM-Producing Escherichia coli and Klebsiella pneumoniae Clinical Isolates

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S281-S281
Author(s):  
Andrew Walkty ◽  
James Karlowsky
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Vitro Activity ◽  
Clinical Isolates ◽  
Disk Diffusion ◽  
In Vitro Activity ◽  
Zone Diameter ◽  
Amoxicillin Clavulanate ◽  
Lactamase Inhibitor

Abstract Background There are limited options available for the treatment of infections caused by Enterobacteriaceae that produce an NDM metallo-β-lactamase. The purpose of this study was to compare the in vitro activity of aztreonam in combination with three different β-lactam/β-lactamase inhibitors (ceftazidime–avibactam, amoxicillin-clavulanate, piperacillin–tazobactam) vs. NDM-positive Enterobacteriaceae clinical isolates. Methods Seven Escherichia coli and three Klebsiella pneumoniae clinical isolates (all NDM-positive by PCR) were included in this study. The in vitro activities of ceftazidime–avibactam, amoxicillin-clavulanate, piperacillin–tazobactam, and aztreonam were determined by disk diffusion as described by CLSI. For synergy testing, disks containing a β-lactamase inhibitor (ceftazidime–avibactam, amoxicillin-clavulanate, piperacillin tazobactam) were applied to Mueller–Hinton agar plates inoculated with the test organisms, and the plates were incubated for 1 hour. The disks were then removed and aztreonam disks were dropped on the previous disk sites. The plates were then incubated as per standard CLSI recommendations for disk diffusion testing. Results All ten isolates demonstrated phenotypic resistance to aztreonam, amoxicillin-clavulanate, and piperacillin–tazobactam, and eight were resistant to ceftazidime–avibactam (CLSI breakpoints). The zone diameter observed for aztreonam in combination with ceftazidime–avibactam was greater than for either antimicrobial on its own for nine isolates. Seven isolates (70%) had susceptibility to aztreonam restored (zone diameter ≥21 mm) in the presence of avibactam. Aztreonam in combination with amoxicillin-clavulanate demonstrated in increase in zone diameter for all isolates relative to the zone for each antimicrobial alone, but only two (20%) had aztreonam susceptibility restored. Aztreonam susceptibility was not restored for any of the isolates in combination with piperacillin–tazobactam. Conclusion Of the three β-lactam/β-lactamase inhibitor-aztreonam combinations evaluated, ceftazidime–avibactam plus aztreonam demonstrated the greatest in vitro activity vs. NDM-producing Enterobacteriaceae. Disclosures All authors: No reported disclosures.

In vitro activity of the aryl-fluoroquinolones A-56619 and A-56620 and evaluation of disk susceptibility tests

1986 ◽  
Vol 5 (1) ◽  
pp. 18-22 ◽  
Author(s):  
A. L. Barry ◽  
R. N. Jones ◽  
C. Thornsberry ◽  
L. W. Ayers ◽  
T. L. Gavan ◽  
...  
Keyword(s):  
Vitro Activity ◽  
In Vitro Activity ◽  
Susceptibility Tests ◽  
Disk Susceptibility

scholarly journals Comparison of Two Methods and Three End Points in Determination of In Vitro Activity of Micafungin against Aspergillus spp

2003 ◽  
Vol 47 (8) ◽  
pp. 2640-2643 ◽  
Author(s):  
Sevtap Arikan ◽  
Pınar Yurdakul ◽  
Gulsen Hascelik
Keyword(s):  
Vitro Activity ◽  
Disk Diffusion ◽  
In Vitro Activity ◽  
End Points ◽  
Minimum Effective Concentration ◽  
Disk Diffusion Assay ◽  
Diffusion Assay

ABSTRACT We investigated the in vitro activity of micafungin against clinical Aspergillus isolates (n = 37) (Aspergillusfumigatus [n = 21], Aspergillusflavus [n = 14], and Aspergillus niger [n = 2]) by using NCCLS M38A microdilution and an investigational disk diffusion assay. Microdilution assay results were evaluated by using the end points of a MIC-2 (measured in micrograms per milliliter) and minimum effective concentration (MEC, measured in micrograms per milliliter; the lowest concentration of micafungin that produces short and aberrant hyphal branchings microscopically). Disk diffusion results were interpreted by measuring the zone(s) of inhibition (ZOI, measured in millimeters). Micafungin proved to be similarly active against all Aspergillus species tested. At 24 h, MIC-2s and MECs were identical. At 48 h, however, MIC-2s increased unpredictably, leading to the loss of a consistent correlation between the two end points. MECs and ZOI remained consistent and correlated at both reading times, suggesting their use as relevant end points in susceptibility testing of micafungin against Aspergillus. All Aspergillus isolates yielded intrazonal growth on disk diffusion agar plates. The intrazonal colonies contained short, aberrant hyphal branchings microscopically. The in vivo significance of these findings remains to be further investigated.

scholarly journals Selection of Retapamulin, a Novel Pleuromutilin for Topical Use

2006 ◽  
Vol 50 (11) ◽  
pp. 3882-3885 ◽  
Author(s):  
Stephen Rittenhouse ◽  
Sanjoy Biswas ◽  
John Broskey ◽  
Lynn McCloskey ◽  
Terrance Moore ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pyogenes ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Postantibiotic Effect ◽  
Selection Of

ABSTRACT The in vitro activity of retapamulin was determined and compared to that of topical and community antibiotics. The MIC90s of retapamulin against Staphylococcus aureus and Streptococcus pyogenes were 0.12 μg/ml and 0.016 μg/ml, respectively. Retapamulin has a low propensity to select resistance and produces an in vitro postantibiotic effect.

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