Evaluation of tedizolid Liofilchem MIC test strips:  a comparison to broth microdilution MIC results for Staphylococcus spp.

2016 ◽  
Author(s):  
Christopher Tan
Keyword(s):  
Broth Microdilution ◽  
Test Strips ◽  
Staphylococcus Spp

scholarly journals Performance of Ceftolozane-Tazobactam Etest, MIC Test Strips, and Disk Diffusion Compared to Reference Broth Microdilution for β-Lactam-Resistant Pseudomonas aeruginosa Isolates

2017 ◽  
Vol 56 (3) ◽  
Author(s):  
Romney M. Humphries ◽  
Janet A. Hindler ◽  
Paul Magnano ◽  
Annie Wong-Beringer ◽  
Robert Tibbetts ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Los Angeles ◽  
Performance Characteristics ◽  
Disk Diffusion ◽  
Broth Microdilution ◽  
Beta Lactam ◽  
Content Type ◽  
Test Strips ◽  
Santa Ana

ABSTRACT The performance characteristics of the ceftolozane-tazobactam (C-T) Etest (bioMérieux, Marcy l'Etoile, France), MIC test strips (MTS; Liofilchem, Italy), and disk diffusion (Hardy, Santa Ana, CA) were evaluated for a collection of 308 beta-lactam-resistant isolates of Pseudomonas aeruginosa recovered from three institutions in Los Angeles, CA. Reference testing was performed by the reference broth microdilution (rBMD) method. MIC and disk results were interpreted using Clinical and Laboratory Standards Institute breakpoints. Overall, 72.5% of the isolates were susceptible to C-T by rBMD. Etest and disk diffusion demonstrated acceptable performance, whereas MTS yielded a greater than acceptable percentage of minor errors. Categorical agreement was 96.8% for Etest, 87.0% for MTS, and 92.9% for disk diffusion. No very major errors were observed by any test, and no major errors (ME) were observed by Etest or disk diffusion. Two ME (0.9% of susceptible isolates) were observed by MTS. The incidence of minor errors was 3.2%, 12.3%, and 7.1% for Etest, MTS, and disk diffusion, respectively. Essential agreement (EA) for Etest was excellent, at 97.7%, whereas the MICs obtained by MTS tended to be 1 to 2 dilutions higher than those obtained by rBMD, with an EA of 87.0%.

scholarly journals Activity of Daptomycin against Recent North American Isolates of Streptococcus pneumoniae

2003 ◽  
Vol 47 (9) ◽  
pp. 2974-2977 ◽  
Author(s):  
M. I. Restrepo ◽  
J. A. Velez ◽  
M. L. McElmeel ◽  
C. G. Whitney ◽  
J. H. Jorgensen
Keyword(s):  
Streptococcus Pneumoniae ◽  
North American ◽  
Broth Microdilution ◽  
Test Strips ◽  
Sheep Blood ◽  
Microdilution Method ◽  
Mueller Hinton ◽  
Broth Microdilution Method

ABSTRACT Daptomycin MICs at which 50% of isolates were inhibited (MIC50s) and MIC90s determined by the NCCLS broth microdilution method were both 0.25 μg/ml (range, 0.06 to 2 μg/ml) for 350 pneumococcal isolates. MICs determined by E test strips on commercially prepared Mueller-Hinton sheep blood agars with different calcium contents were 2 to 3 dilutions higher than those determined by strips that contained daptomycin plus calcium. Daptomycin zone diameters varied little on the same media.

scholarly journals High-throughput, multiplex microfluidic test strip for the determination of antibiotic susceptibility in uropathogenic E. coli with smartphone detection

2021 ◽  
Author(s):  
Sarah H Needs ◽  
Zara Rafaque ◽  
Wajiha Imtiaz ◽  
Partha Ray ◽  
Simon Andrews ◽  
...  
Keyword(s):  
High Throughput ◽  
Gold Standard ◽  
Antibiotic Susceptibility ◽  
Cost Effective ◽  
Test Strip ◽  
Broth Microdilution ◽  
Test Strips ◽  
E Coli ◽  
Broth Microdilution Method ◽  
Tract Infections

Antibiotic resistance in urinary tract infections is a major global challenge and improved cost-effective and high throughput antibiotic susceptibility tests (AST) are urgently needed to inform correct antibiotic selection. We evaluated a high throughput microfluidic test strip for AST and minimum inhibitory concentration (MIC) determination in 20 urinary pathogenic E. coli (UPEC) isolates using six commonly prescribed or therapeutically beneficial antibiotics. The microfluidic MIC performs broth microdilution in 1 microliter volume capillaries, 100 X smaller than standard broth microdilution. Each test strip contains 10 parallel capillaries which are dipped into a single well of a 96 well plate, significantly increasing throughput over a microtitre plate. When tested with clinical UPEC isolates at standardised inoculum density, these devices gave 100% essential agreement (+/- 1 doubling dilution of antibiotic) to the gold standard microplate broth microdilution method described by CLSI. Although for some antibiotic/isolate combinations an earlier endpoint readout reduced accuracy, MIC test strips read at a 6h endpoint still gave 69 to 100 % essential agreement depending on the antibiotic. Growth could be detected significantly earlier than 6h, but with a trade-off between speed vs accuracy. These high-throughput, multiplexed test strips could be used to increase throughput and give faster results than microplates while retaining the core broth microdilution methodology of gold standard techniques for AST and MIC determination.

scholarly journals Klebsiella pneumoniae and Colistin Susceptibility Testing: Performance Evaluation for Broth Microdilution, Agar Dilution and Minimum Inhibitory Concentration Test Strips and Impact of the “Skipped Well” Phenomenon

Diagnostics ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2352
Author(s):  
Rita Elias ◽  
José Melo-Cristino ◽  
Luís Lito ◽  
Margarida Pinto ◽  
Luísa Gonçalves ◽  
...  
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Klebsiella Pneumoniae ◽  
Susceptibility Testing ◽  
Inhibitory Concentration ◽  
Quantitative Description ◽  
Reference Method ◽  
Broth Microdilution ◽  
Test Strips ◽  
Agar Dilution ◽  
The Impact

The emergence of multidrug resistant Gram-negative pathogens, particularly carbapenemase producers, has forced clinicians to use last line antibiotics, such as colistin. Since colistin susceptibility testing presents several challenges, this study aimed at evaluating the performance of two alternative susceptibility methods for Klebsiella pneumoniae, namely, agar dilution (AD) and MIC test strips (MTS). These approaches were compared with the reference method, broth microdilution (BMD), and provide a quantitative description for the “skipped well” (SW) phenomenon. Colistin susceptibility was evaluated by BMD and AD in parallel and triplicate, using 141 K. pneumoniae clinical isolates while MTS performance was evaluated only for a subset (n = 121). Minimum inhibitory concentration analysis revealed that a substantial part (n = 26/141; 18.4%) of the initial isolates was deemed undetermined by BMD due to the following: discordance between replicates (1.4%); presence of multiple SWs (7.8%); and the combination of both events (9.2%). Both AD and MTS revealed a high number of false-susceptible strains (“very major errors”), 37.5% and 68.8%, respectively. However, AD agreement indices were reasonably high (EA = 71.3% and CA = 94.8%). For MTS these indices were lower, in particular EA (EA = 41.7% and CA = 89.6), but the approach enabled the detection of distinct sub-populations for four isolates. In conclusion, this study provides the most comprehensive study on the performance of AD and MTS for colistin susceptibility testing in K. pneumoniae, highlighting its limitations, and stressing the importance of sample size and composition. Further, this study highlights the impact of the SW phenomenon associated with the BMD method for K. pneumoniae.

Wundinfektionen durch methicillinresistente Staphylococcus spp. (MRS) bei Kleintieren und Pferden: klinische Bedeutung, Therapie und Prophylaxe

2008 ◽  
Vol 36 (S 01) ◽  
pp. S5-S10
Author(s):  
B. Walther ◽  
A. Lübke-Becker ◽  
L. H. Wieler
Keyword(s):  
Klinische Relevanz ◽  
Klinische Bedeutung ◽  
Staphylococcus Spp

Zusammenfassung:In den vergangenen Jahrzehnten erlangten verschiedene Populationen von Staphylococcus sp. multiple Resistenzen durch die Akkumulation vielfältiger Resistenzdeterminanten. Heutzutage besitzen Infektionen durch methicillinresistente Staphylococcus sp. (MRS) weltweit sowohl in der Humanmedizin als auch in zunehmendem Maße in Veterinärmedizin große klinische Relevanz. Seit den frühen siebziger Jahren sind MRS-Infektionen bei Tieren bekannt. In den letzten Jahren kam es jedoch zu einem deutlichen Anstieg derartiger Berichte. Insbesondere bei Kleintieren und Pferden treten Infektionen durch MRS auf, und zwar vorrangig in Zusammenhang mit nosokomialen Wundinfektionen. Die eindeutige Diagnose einer Infektion mit MRS bereitet zwar heute keine Probleme mehr, doch sind einige wesentliche Punkte zu beachten, weshalb nur erfahrene Diagnostiker mit dieser Thematik beauftragt werden sollten. Die Therapie erfolgt nach Auswertung des Antibiogramms (unabhängig vom Antibiogramm sind alle β-Lactame als resistent einzustufen) und wenn möglich lokal. Auch die Frage nach dem Zoonosecharakter animaler MRS und den damit verbunden Problembereichen (Hygienemanagement, Haftungsfragen, Sorgfaltspflichten, Einsatz humaner Reservewirkstoffe) tritt zunehmend in den Fokus der öffentlichen Wahrnehmung.

Wundinfektionen durch methicillinresistente Staphylococcus spp. (MRS) bei Kleintieren und Pferden: klinische Bedeutung, Therapie und Prophylaxe

2008 ◽  
Vol 36 (S 01) ◽  
pp. S05-S10
Author(s):  
A. Lübke-Becker ◽  
L. Wieler ◽  
B. Walther
Keyword(s):  
Klinische Relevanz ◽  
Klinische Bedeutung ◽  
Staphylococcus Spp

ZusammenfassungIn den vergangenen Jahrzehnten erlangten verschiedene Populationen von Staphylococcus sp. multiple Resistenzen durch die Akkumulation vielfältiger Resistenzdeterminanten. Heutzutage besitzen Infektionen durch methicillinresistente Staphylococcus sp. (MRS) weltweit sowohl in der Humanmedizin als auch in zunehmendem Maße in Veterinärmedizin große klinische Relevanz. Seitden frühen siebziger Jahren sind MRS-Infektionen bei Tieren bekannt.Inden letzten Jahren kam es jedoch zu einem deutlichen Anstieg derartiger Berichte. Insbesondere bei Kleintieren und Pferden treten Infektionen durch MRSauf,und zwar vorrangig in Zusammenhang mit nosokomialen Wundinfektionen. Die eindeutige Diagnose einer Infektion mit MRS bereitet zwar heute keine Probleme mehr,doch sind einige wesentliche Punkte zu beachten, weshalb nur erfahrene Diagnostiker mit dieser Thematik beauftragt werden sollten. Die Therapie erfolgt nach Auswertung des Antibiogramms (unabhängigvom Antibiogramm sindalle β-Lactame als resistent einzustufen) und wenn möglich lokal. Auch die Frage nach dem ZoonosecharakteranimalerMRS undden damit verbunden Problembereichen (Hygienemanagement, Haftungsfragen, Sorgfaltspflichten, Einsatz humaner Reservewirkstoffe) tritt zunehmend in den Fokus der öffentlichen Wahrnehmung.

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