scholarly journals Stenotrophomonas maltophilia endogenous endophthalmitis: clinical presentation, sensitivity spectrum and management

2009 ◽  
Vol 58 (6) ◽  
pp. 837-838 ◽  
Author(s):  
T. Das ◽  
H. S. Deshmukh ◽  
A. Mathai ◽  
Ashok Kumar Reddy
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Susceptibility Testing ◽  
Clinical Presentation ◽  
Diffusion Method ◽  
Endogenous Endophthalmitis ◽  
Antibiotic Susceptibility Testing ◽  
Disc Diffusion ◽  
Antibiotic Regimen ◽  
Nosocomial Pathogen ◽  
Disc Diffusion Method

Stenotrophomonas maltophilia is gaining importance as a community-acquired pathogen, after becoming firmly established as a nosocomial pathogen. Here we report a case of endogenous endophthalmitis due to S. maltophilia. Antibiotic-susceptibility testing of the isolate was performed by the Kirby–Bauer disc diffusion method. The organism was resistant to aminoglycosides, imipenem, ticarcillin and cotrimoxazole and was sensitive to ceftazidime and chloramphenicol. The patient was successfully treated with a sensitivity-based intravitreal antibiotic regimen.

scholarly journals Russia-made Mueller–Hinton agar: compliance with contemporary requirements

2019 ◽  
Vol 9 (2) ◽  
pp. 409-416
Author(s):  
L. V. Domotenko ◽  
I. S. Kosilova ◽  
A. P. Shepelin
Keyword(s):  
Quality Control ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Diffusion Method ◽  
Disc Diffusion ◽  
Disc Diffusion Method ◽  
Nutrient Media ◽  
Mueller Hinton ◽  
Mueller Hinton Agar

At present, a rise of antimicrobial resistance requires that susceptibility of infectious agents to antimicrobial agents could be accurately evaluated as related errors may lead to selecting improper therapeutics provoking spread of drug resistance. Pathogen sensitivity to antimicrobial agents is commonly determined by a disc diffusion method. A quality of nutrient medium used in assays plays a crucial role influencing final results. In Russia, it turned out that regulatory documents such as the nationwide guidelines and clinical recommendations outlining methodology for antimicrobial susceptibility testing underlay availability in domestic market few nutrient media, including Mueller–Hinton Agar, AGV medium etc. exhibiting sometimes unsatisfactory quality. To harmonize such methodology with international requirements, theStateResearchCenterfor Applied Microbiology and Biotechnology has developed a technology and promoted manufacture of Russia-made Mueller–Hinton agar satisfying requirements of EUCAST documents, clinical guidelines, and ISO/TS 16782:2016. The main objective of this study was to compare quality of new agar product with five similar foreign media while examining 11 test strains by disc diffusion method. As a result, some of nutrient media available to the Russian market turned out to be off-standard: not all of them satisfy to the EUCAST requirements and clinical guidelines since diameter distribution for growth inhibition recommended by EUCAST for quality control does not fit into permissible range. Moreover, susceptibility of P. aeruginosa ATCC 27853 to aminoglycosides, fluoroquinolones, Meropenem, as well as S. aureus ATSS 25923 and E. faecalis ATCC 29212 to tigecycline was assessed with certain mistakes. The data obtained by us were analyzed in accordance to the new document ISO/TS 16782:2016 “Clinical laboratory testing — criterion for acceptable lots of dehydrated Mueller–Hinton agar and broth for antimicrobial susceptibility testing”, not approved yet In Russia. To determine potential reason for deviation of data from reference range, we measured concentration of bivalent metals in all nutrient media examined by atomic emission spectrometry with inductively coupled plasma. We determined new patterns affecting reliability of results on microbial antibiotic susceptibility. A need to check intralaboratory quality control of nutrient media was emphasized.  

scholarly journals Interpreting Susceptibility Testing of Carbapenem Against Pseudomonas aeruginosa

2016 ◽  
Vol 4 (1) ◽  
pp. 1-8
Author(s):  
Maite Micaelo ◽  
Florence Brossier ◽  
Nicolas Brechot ◽  
Charles Edouard Luyt ◽  
Qin Lu ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Diffusion Method ◽  
Disc Diffusion ◽  
Limited Data ◽  
Disc Diffusion Method ◽  
New Guidelines

Objectives: Carbapenems are among the most powerful anti pseudomonal agents. Since meropenem and doripenem were marketed, there are limited data regarding drug susceptibility testing by routine methods (disc diffusion and Etest) for them. The aim of our study was to compare in vitro activity of the imipenem, meropenem and doripenem against Pseudomonas aeruginosa. Methods: Three hundred and eleven P. aeruginosa strains isolated from respiratory specimens in 170 patients who developed ventilator-associated pneumonia in two intensive care units were collected over a period of 31 months. The susceptibility of all of these isolates to imipenem, meropenem and doripenem were determined by Etest and disc diffusion method. Results: Considering either all of the isolates or only the first isolates recovered per patient (311 and 170 respectively) the susceptibility rate for doripenem was higher than that for meropenem and imipenem. When MICs determined by Etest were converted into interpretative categories (S, I, R) using French (CA-SFM) guidelines, agreement was poor, especially for meropenem and doripenem. The percent of agreement with the disc diffusion method were 90.6% and 89.7% for imipenem, 80.5% and 82.6% for meropenem and 80.5% and 73.3% for doripenem, for the first isolates and all of the isolates, respectively. Errors were mostly minor errors, and the rate of errors was as high as 17.7% and 16.1% for meropenem and 17.7% and 25.7% for doripenem for the first isolates and all of the isolates, respectively Conclusion: The accuracy of disc diffusion using CA-SFM guidelines appears unsatisfactory for all the three carbapenems justifying the adaptation of new guidelines for P. aeruginosa and carbapenems

Categorization of temocillin susceptibility using the disc diffusion method: Susceptible, Intermediate, Resistant or Undetermined?

2020 ◽  
Author(s):  
Amandine HENRY ◽  
Anthony Michaud ◽  
Nicolas Degand ◽  
Emmanuelle Bille ◽  
Damien Fournier ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Inhibition Zone ◽  
Generation Cephalosporin ◽  
Diffusion Method ◽  
Disc Diffusion ◽  
Disc Diffusion Method ◽  
Beta Lactamases ◽  
Inhibition Zone Diameter ◽  
Zone Diameter ◽  
Extended Spectrum Beta Lactamases

Abstract Background: Since the pandemic of ESBL (extended-spectrum beta-lactamases) and the emergence of carbapenemase-producing Enterobacterales there is a renewed interest in temocillin. However, as the molecule was little used, except in Belgium and UK, there are few guidelines for its antibiotic susceptibility testing (AST). We aim to assess the accuracy of the disc diffusion method (DDM) for temocillin susceptibility testing. Methods: Eight hundred eighty-eight Enterobacterales clinical strains of which 61.7% were resistant to 3 rd generation cephalosporin (3GC-R) were included. AST was performed using DDM in comparison to gradient strip tests (GST) and interpreted using the diameter breakpoint of 20mm and MIC breakpoint of 8 mg/L for DDM and GST as recommended by EUCAST-CASFM recommandations. Results: At breakpoint of 8mg/L, temocillin rates of susceptibility were 76.9%, 95.6% and 67.7% for overall, 3GC-S and 3GC-R strains respectively. Ninety-four (10.6%) discrepancies were noticed including 68 (72.3%) major errors and 26 (27.6%) very major errors. Sixty-eight (72.3%) of all errors correspond to inhibition diameters comprised between 17 and 23 mm. The presence of colonies within the inhibition diameter was noticed for 32 (5.3%) strains susceptible to temocillin. Conclusions: DDM lacks accuracy for strains displaying borderline inhibition zone diameter. We suggest applying the concept of area of technical uncertainty (ATU) for standard DDM. The strains displaying a diameter within the ATU should be tested by another method. The significance of colonies within the inhibition zone diameter should be explored.

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