scholarly journals Antimicrobial Susceptibility Testing ofHelicobacter pylori in a Large Multicenter Trial: the MACH 2 Study

1999 ◽  
Vol 43 (11) ◽  
pp. 2747-2752 ◽  
Author(s):  
Francis Mégraud ◽  
Norbert Lehn ◽  
Tore Lind ◽  
Ekkehard Bayerdörffer ◽  
Colm O’Morain ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Point Mutations ◽  
Multicenter Trial ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Secondary Resistance ◽  
Agar Dilution ◽  
Resistant Strains ◽  
H Pylori ◽  
The Impact

ABSTRACT Culture and susceptibility testing of Helicobacter pylori strains was performed in a large multinational, multicenter randomized clinical trial. Culture was carried out on gastric biopsy samples obtained from 516 patients at entry and had a sensitivity of 99% when the [13C]urea breath test was used as a reference. Susceptibility testing was performed for clarithromycin and metronidazole on 485 strains by an agar dilution method and the epsilometer test (Etest) and for amoxicillin by an agar dilution method only. Resistance to clarithromycin (>1 μg/ml) was found in 3% of the H. pylori strains, with a perfect correlation between Etest and agar dilution methods. Resistance to metronidazole (>8 μl/ml) was found in 27% of the strains by agar dilution, but there were important discrepancies between it and the Etest method. No resistance to amoxicillin was found. The logarithms of the MICs of the three antibiotics against susceptible strains had a distribution close to normal. The impact of resistance was tested in the four arms of the trial. There were not enough clarithromycin-resistant strains to evaluate the impact of resistance on the cure rate of clarithromycin-based regimens. For metronidazole-resistant strains, the impact noted in the clarithromycin-metronidazole arm was partially overcome when omeprazole was added (76% eradication for resistant strains versus 95% for susceptible strains). Secondary resistance to clarithromycin occurred in strains from 12 of 105 patients (11.4%) after the failure of a clarithromycin-based regimen to effect eradication. The detection of point mutations in clarithromycin-resistant strains was performed by a combination of PCR and restriction fragment length polymorphism. Mutations (A2142G and 2143G) were found in all strains tested except one. This study stresses the importance of performing susceptibility tests in clinical trials in order to explain the results of different treatments.

scholarly journals Antimicrobial Susceptibility of Helicobacter pylori Determined by the E Test Using Tetrazolium Egg Yolk Agar

1998 ◽  
Vol 36 (9) ◽  
pp. 2784-2785 ◽  
Author(s):  
Yanet Valdez ◽  
Billie Velapatiño ◽  
Robert H. Gilman ◽  
Vilma Gutierrez ◽  
Carlos León
Keyword(s):  
Helicobacter Pylori ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Agar Medium ◽  
Egg Yolk ◽  
Blood Agar ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Agar Dilution ◽  
H Pylori

Metronidazole and tetracycline E tests were compared to an agar dilution method for the antimicrobial susceptibility testing ofHelicobacter pylori. Sixteen strains were tested by using tetrazolium egg yolk (TEY) agar. The characteristic E test inhibition ellipse was clearer on TEY agar than on standard blood agar and gave results comparable to those of the agar dilution test. The use of TEY medium is preferable to that of blood agar medium in E test MIC determinations for H. pylori.

scholarly journals High Efficacy of Finafloxacin on Helicobacter pylori Isolates at pH 5.0 Compared with That of Other Fluoroquinolones

2015 ◽  
Vol 59 (12) ◽  
pp. 7629-7636 ◽  
Author(s):  
Jung Won Lee ◽  
Nayoung Kim ◽  
Ryoung Hee Nam ◽  
Jung Mogg Kim ◽  
Jong Youn Park ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Point Mutation ◽  
Point Mutations ◽  
Antimicrobial Efficacy ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Acidic Environment ◽  
Content Type ◽  
H Pylori ◽  
The Impact

ABSTRACTFinafloxacin is a novel fluoroquinolone with improved antimicrobial efficacy, especially in an acidic environment. The efficacy of finafloxacin for the inhibition ofHelicobacter pyloriinfection was compared with the efficacies of levofloxacin and moxifloxacin at neutral and acidic pH. The impacts ofgyrApoint mutation on the efficacy of those three fluoroquinolones were also investigated. A total of 128 clinicalH. pyloristrains were utilized. MICs of levofloxacin, moxifloxacin, and finafloxacin were determined at pH 5.0 and pH 7.0 by the agar dilution method. The impact ofgyrApoint mutations that are responsible for fluoroquinolone resistance was analyzed; the results showed 50 strains with an Asn-87 point mutation, 48 strains with an Asp-91 point mutation, and the remaining 30 strains with nogyrAmutations. The use of finafloxacin led to MIC values at pH 5.0 that were lower than the values seen at pH 7.0 for 112 strains (112/128, 87.5%), and this proportion was higher than that seen with moxifloxacin (21/128, 16.4%,P< 0.001). Finafloxacin also demonstrated a rate of susceptibility (MIC, <1 μg/ml) (37.5%, 48/128) at pH 5.0 that was higher than that seen with moxifloxacin (2.3%, 3/128) (P< 0.001). The trends were similar regardless of which of the Asn-87, Asp-91, and A2143 point mutations were present. In conclusion, the superior antimicrobial efficacy of finafloxacin againstH. pyloriin an acidic environment suggests the possible use of finafloxacin for treatment ofH. pyloriinfection, as has been proposed by its developer, Merlion Pharma.

scholarly journals ANTIBIOGRAM PROFILING OF HELICOBACTER PYLORI STRAINS AND THE EFFICACY OF BRASSICA CAPITATA AGAINST RESISTANT STRAINS ISOLATED FROM THE PATIENTS SUFFERING FROM GASTRODUODENAL DISEASES IN GAUHATI, ASSAM

2018 ◽  
Vol 11 (8) ◽  
pp. 176
Author(s):  
Shweta Mahant ◽  
Valentina Gehlot ◽  
Seema Bhatnagar ◽  
Megha Rikhi ◽  
Asish Kumar Mukhopadhyay ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Alternative Therapy ◽  
Northeast India ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Agar Dilution ◽  
Resistant Strains ◽  
H Pylori ◽  
Drug Resistant Strains

  Objective: Helicobacter pylori resistance toward commonly used antibiotics is increasing leading to the treatment failure; hence, our aim is to determine the antibiogram susceptibility pattern of H. pylori strains isolated from Guwahati, Assam (Northeast India) and also to test the efficacy of the Brassica capitata against the multi and dual drug-resistant strains of North and Northeast India.Methods: Minimum inhibitory concentration of different antibiotics was determined by agar dilution method. Disc diffusion method was used to check the efficacy of B. capitata against clarithromycin (CLR), metronidazole (MTZ), and levofloxacin (LEV)-resistant H. pylori strains.Results: All the H. pylori strains were 100% sensitive to CLR, tetracycline, amoxicillin, and furazolidone. 72.8% of the strains were sensitive toward MTZ and 54.5% were sensitive toward LEV. B. capitata showed good efficacy against the resistant strains of H. pylori of North and Northeast India.Conclusion: Most of the H. pylori strains from Northeast India were sensitive toward the commonly used antibiotics for the treatment regime. B. capitata is effective against H. pylori infection, suggesting its potential as an alternative therapy, and opens the way for further studies on identification of novel antimicrobial targets of B. capitata.

scholarly journals Detection of Clarithromycin-Resistant Helicobacter pylori Strains by a Preferential Homoduplex Formation Assay

2000 ◽  
Vol 38 (1) ◽  
pp. 210-214
Author(s):  
Shin Maeda ◽  
Haruhiko Yoshida ◽  
Hironari Matsunaga ◽  
Keiji Ogura ◽  
Osamu Kawamata ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Point Mutations ◽  
23S Rrna ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Wild Type ◽  
Urease Test ◽  
Agar Dilution ◽  
Type Gene ◽  
H Pylori

ABSTRACT It has been shown that resistance to clarithromycin, a major cause of failure in Helicobacter pylori eradication therapy, is associated with point mutations in the 23S rRNA gene. We sought to apply the preferential homoduplex formation assay (PHFA), a novel technique for the efficient detection of point mutations, to detection of the mutations. PHFA was performed on streptavidin-coated microtiter plates with biotin- and dinitrophenyl-labeled amplicons to detect the wild-type gene or each mutant gene. DNA samples were extracted from gastric juice specimens of 412 patients with H. pylori infection and were applied to the assay. The detection threshold of PHFA was as few as 10 gene copies. The sensitivity of PHFA for the detection of H. pylori infection was higher than those of culture and the rapid urease test. A total of 337 (81.8%) samples had the wild-type gene, 38 (9.2%) had the A2144G mutation, and 37 (9.0%) contained both the wild type and a mutation (A2144G in 30 samples, A2143G in 5 samples, and A2143G plus A2144G in 2 samples). About half the strains isolated from patients with mixed infection were susceptible by the agar dilution method (MIC, <0.1 mg/liter). Therefore, PHFA can detect clarithromycin-resistant H. pylori strains, even in patients with mixed infections with the wild type, that are not detectable by the agar dilution method.

scholarly journals Inaccuracy of the Disk Diffusion Method Compared with the Agar Dilution Method for Susceptibility Testing of Campylobacter spp.

2011 ◽  
Vol 50 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Mirva Lehtopolku ◽  
Pirkko Kotilainen ◽  
Pauli Puukka ◽  
Ulla-Maija Nakari ◽  
Anja Siitonen ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
Agar Dilution ◽  
Campylobacter Spp

scholarly journals In VitroActivity of Fosfomycin against a Collection of Clinical Pseudomonas aeruginosa Isolates from 16 Spanish Hospitals: Establishing the Validity of Standard Broth Microdilution as Susceptibility Testing Method

2013 ◽  
Vol 57 (11) ◽  
pp. 5701-5703 ◽  
Author(s):  
María Díez-Aguilar ◽  
María-Isabel Morosini ◽  
Rosa del Campo ◽  
María García-Castillo ◽  
Javier Zamora ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Susceptibility Testing ◽  
Disk Diffusion ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Broth Microdilution ◽  
Content Type ◽  
Testing Method ◽  
Broth Microdilution Method ◽  
Agar Dilution

ABSTRACTThe broth microdilution method for fosfomycin andPseudomonas aeruginosawas assessed and compared with the approved agar dilution method in 206 genetically unrelatedP. aeruginosaclinical isolates. Essential agreement between the two methods was 84%, and categorical agreement was 89.3%. Additionally, Etest and disk diffusion assays were performed. Results validate broth microdilution as a reliable susceptibility testing method for fosfomycin againstP. aeruginosa. Conversely, unacceptable concordance was established between Etest and disk diffusion results with agar dilution results.

scholarly journals Broth Microdilution and Gradient Diffusion Strips vs. Reference Agar Dilution Method: First Evaluation for Clostridiales Species Antimicrobial Susceptibility Testing

Antibiotics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 975
Author(s):  
Florian Baquer ◽  
Asma Ali Sawan ◽  
Michel Auzou ◽  
Antoine Grillon ◽  
Benoît Jaulhac ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Reference Method ◽  
Antimicrobial Susceptibility Testing ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Broth Microdilution ◽  
Multicenter Studies ◽  
Gradient Diffusion ◽  
Agar Dilution

Antimicrobial susceptibility testing of anaerobes is challenging. Because MIC determination is recommended by both CLSI and EUCAST, commercial broth microdilution and diffusion strip tests have been developed. The reliability of broth microdilution methods has not been assessed yet using the agar dilution reference method. In this work, we evaluated two broth microdilution kits (MICRONAUT-S Anaerobes® MIC and Sensititre Anaerobe MIC®) and one gradient diffusion strip method (Liofilchem®) for antimicrobial susceptibility testing of 47 Clostridiales isolates (Clostridium, Clostridioides and Hungatella species) using the agar dilution method as a reference. The evaluation focused on comparing six antimicrobial molecules available in both microdilution kits. Analytical performances were evaluated according to the Food and Drug Administration (FDA) recommendations. Essential agreements (EA) and categorical agreements (CA) varied greatly according to the molecule and the evaluated method. Vancomycin had values of essential and categorical agreements above 90% for the three methods. The CA fulfilled the FDA criteria for three major molecules in the treatment of Gram-positive anaerobic infections (metronidazole, piperacillin/tazobactam and vancomycin). The highest rate of error was observed for clindamycin. Multicenter studies are needed to further validate these results.

scholarly journals Comparison of Broth Microdilution Method UsingHaemophilus Test Medium and Agar Dilution Method for Susceptibility Testing of Eikenella corrodens

1998 ◽  
Vol 36 (8) ◽  
pp. 2386-2388 ◽  
Author(s):  
Luis Alcalá ◽  
Fernando García-Garrote ◽  
Emilia Cercenado ◽  
Teresa Peláez ◽  
Gema Ramos ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Broth Microdilution ◽  
Test Medium ◽  
Eikenella Corrodens ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Agar Dilution

Susceptibility testing of Eikenella corrodens is usually performed by a Mueller-Hinton sheep blood agar dilution (AD) method. However, this method is impractical for testing only a few strains. We compared AD with the broth microdilution method usingHaemophilus test medium (HTM) in order to determine the susceptibility of 36 clinical isolates of E. corrodens to eight antimicrobial agents. MICs obtained by the HTM method yielded 95.5 and 84% agreement (within 2 and 1 log2 dilutions, respectively) with those obtained by AD. The HTM method with incubation in CO2 for 48 h was highly reproducible and constitutes an easy alternative for antimicrobial susceptibility testing of E. corrodens.

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