scholarly journals Comparative Analysis of Gradient Diffusion and Disk Diffusion with Agar Dilution for Susceptibility Testing of Elizabethkingia anophelis

Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 450
Author(s):  
Chien-Tung Chiu ◽  
Chung-Hsu Lai ◽  
Yi-Han Huang ◽  
Chih-Hui Yang ◽  
Jiun-Nong Lin
Keyword(s):  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
Gradient Diffusion ◽  
Minimum Requirements ◽  
Agar Dilution

Elizabethkingia anophelis has recently emerged as a cause of life-threatening infections. This study compared the results of antimicrobial susceptibility testing (AST) conducted for E. anophelis through different methods. E. anophelis isolates collected between January 2005 and June 2019 were examined for their susceptibility to 14 antimicrobial agents by using disk diffusion, gradient diffusion (Etest; (bioMérieux S.A., Marcy l’Etoile, France), and agar dilution methods. The agar dilution method was the reference assay. According to the agar dilution method, the isolates exhibited the highest susceptibility to minocycline (100%), doxycycline (97.6%), rifampin (95.2%), and levofloxacin (78.6%). A very major error rate of >1.5% was observed for nine antibiotics tested using the disk diffusion method. The overall categorical agreement rate between the disk diffusion and agar dilution methods was 74.8%, and ceftazidime, minocycline, levofloxacin, and rifampin met the minimum requirements for discrepancy and agreement rates. The Etest method tended to produce lower log2 minimum inhibitory concentrations for the antibiotics, except for trimethoprim–sulfamethoxazole and rifampin; the method resulted in very major errors for nine antibiotics. The overall essential and categorical agreement rates between the Etest and agar dilution methods were 67.3% and 76.1%, respectively. The Etest method demonstrated acceptable discrepancy and agreement rates for ceftazidime, minocycline, doxycycline, levofloxacin, and rifampin. AST results obtained through the disk diffusion and Etest methods for multiple antibiotics differed significantly from those obtained using the agar dilution method. These two assays should not be a routine alternative for AST for E. anophelis.

scholarly journals Comparison of methods for the determination of antimicrobial resistance in Campylobacter spp. human and the food chain isolates

2008 ◽  
Vol 52 (No. 4) ◽  
pp. 169-174
Author(s):  
M. Holasova ◽  
R. Karpiskova ◽  
S. Karpiskova ◽  
V. Babak ◽  
J. Schlegelova
Keyword(s):  
Nalidixic Acid ◽  
Antimicrobial Agents ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Study Results ◽  
Agar Dilution

With a microdilution method, using the commercial diagnostic test Sensititre Susceptibility Plates for Campylobacter MIC (Trek Diagnostic Systems, Cleveland, OH, USA), disk diffusion and agar dilution method, resistance to six antimicrobial agents were examined in a reference strain <i>Campylobacter jejuni</i> ATCC 33560 and 73 thermo-tolerant isolates of <i>Campylobacter</i> spp. For the microdilution method and all tested antimicrobial agents, our determined values of microbiological breakpoints of resistant strains were suggested as the minimum inhibitory concentration (MIC<sub>R</sub>) for ciprofloxacin &ge; 0.5, erythromycin &ge; 4, gentamicin &ge; 4, nalidixic acid &ge; 32 and tetracycline &ge; 4 &mu;g/ml. On the basis of our study results, strains resistant to clindamycin were MIC<sub>R</sub> &ge; 2 &mu;g/ml for the dilution methods and a zone diameter R ≤ 16 mm for the disk diffusion method. Comparison of the results of the resistance examination, a microdilution method and disk diffusion method with the reference agar dilution method, showed that all compared methods yielded identical results with the exception of the resistance determination in erythromycin and nalidixic acid. The errors were mostly the result of the interpretation criteria for MIC<sub>R</sub> of agar dilution method and different conditions of cultivation used. However, the compared methods, provide results comparable with the reference method having greater convenience of measurement.

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 Molecular identification and antimicrobial resistance profiles of Campylobacter strains of poultry origin in India with special emphasis on fluoroquinolone resistance

2015 ◽  
Vol 1 (1) ◽  
pp. 1-8
Author(s):  
SM Lutful Kabir ◽  
Masahiro Asakura ◽  
Sachi Shiramaru ◽  
Amit Pal ◽  
Atsushi Hinenoya ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Quinolone Resistance ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Slight Variation ◽  
Gyra Gene ◽  
Disk Diffusion Method ◽  
Agar Dilution

The current study aimed to identify the selected number of Campylobacter strains of poultry origin in India that were isolated in the Laboratory of International Prevention of Epidemics, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Japan to the species level with the aid of cdtA/B/C gene-based multiplex PCR assays as well as to investigate their antimicrobial resistance profiles. C. jejuni (4 strains) and C. coli (16 strains) were identified. The poultry isolates identified were subjected to susceptibility testing with the aid of disk diffusion method using 12 antimicrobial agents. Again, the resistant and intermediate isolates confirmed by the disk diffusion method were subjected to determination of minimum inhibitory concentration by agar dilution method. To elucidate the mechanism of quinolone resistance, a total number of 20 quinolone resistant strains were subjected to sequence determination and analysis of the gyrA gene in the quinolone-resistance determining region. The results of the disk diffusion method were consistent with the results of the agar dilution method with slight variation in case of ampicillin, levofloxacin, ofloxacin and fosfomycin. All C. jejuni and C. coli strains had the Thr 86 to Ile substitution in gyrA. Results of this study support the emergence of resistance of C. jejuni and C. coli strains of poultry origin in India to a variety of antimicrobials especially fluoroquinolones.Asian J. Med. Biol. Res. June 2015, 1(1): 1-8

scholarly journals Antibiotic Susceptibility Profile of Clostridium Difficile Bacteria Isolated from Older Residents of a Nursing Home in Iran

Salmand ◽  
2021 ◽  
Vol 15 (4) ◽  
pp. 496-505
Author(s):  
Ahmad Ghasemi ◽  
◽  
Ashraf Mohabati Mobarez ◽  
Ehsan Mostafavi ◽  
◽  
...  
Keyword(s):  
Nursing Home ◽  
Clostridium Difficile ◽  
Antibiotic Susceptibility ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
Nosocomial Diarrhea ◽  
Agar Dilution

Objectives: Clostridium difficile (C. diff) is a gram-positive anaerobic bacterium knwon as the most common cause of nosocomial diarrhea in nursing homes. The antibiotic susceptibility profile is the basic way for successful treatment due to antimicrobial resistance. This present study aims to assess the antibiotic susceptibility profile of C. diff isolated from older residents of a nursing home in Tehran, Iran. Methods & Materials: Forty-two isolates of C. diff were used in this study collected from 289 residents of Kahrizak Nursing Home. Antibiotic susceptibility testing was conducted by using disk-diffusion method, agar dilution method, and Epsilometer test (E-test). Results: All C. diff strains were susceptible to Metronidazole, Vancomycin, Rifampicin, Linezolid and Tigecycline. By using the disk-diffusion method, the highest rate of resistance was related to Clindamycin (100%), Levofloxacin (96.2%), Imipenem (81%), Azithromycin (61%) and Erythromycin (54.8%). All C. diff strains were susceptible to Metronidazole under E-test. Furthermore, 100% and 59.5% of strains were susceptible to Vancomycin and Erythromycin, respectively under agar dilution test. Conclusion: C. diff strains are sensitive to Vancomycin and Metronidazole. These two antibiotics can be used to treat C. diff infections in older adults. The disk diffusion method can be used as a screening test to determine antibiotic resistance.

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.

scholarly journals In Vitro Antimicrobial Susceptibility Testing of Helicobacter felis, H. bizzozeronii, and H. salomonis

2005 ◽  
Vol 49 (7) ◽  
pp. 2997-3000 ◽  
Author(s):  
K. Van den Bulck ◽  
A. Decostere ◽  
I. Gruntar ◽  
M. Baele ◽  
B. Krt ◽  
...  
Keyword(s):  
Antimicrobial Agent ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Acquired Resistance ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Helicobacter Felis ◽  
Agar Dilution

ABSTRACT The susceptibilities of Helicobacter felis (15 strains), H. bizzozeronii (7 strains), and H. salomonis (3 strains) to 10 antimicrobial agents were investigated by determination of the MIC using the agar dilution method. No consistent differences were noticed between the different Helicobacter species, which were all highly susceptible to ampicillin, clarithromycin, tetracycline, tylosin, enrofloxacin, gentamicin, and neomycin, as demonstrated by low MICs. Higher MICs were obtained for lincomycin (up to 8 μg/ml) and spectinomycin (up to 4 μg/ml). Two H. felis strains showed a MIC of 16 μg/ml for metronidazole, suggesting acquired resistance to this antimicrobial agent.

scholarly journals Detection of Plasmid-Mediated Colistin Resistant mcr-1 Gene in Escherichia coli Isolated from Infected Chicken Livers in Nepal

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2060
Author(s):  
Sayara Bista ◽  
Upendra Thapa Shrestha ◽  
Binod Dhungel ◽  
Pragya Koirala ◽  
Tulsi Ram Gompo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Conventional Polymerase Chain Reaction ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Human Pathogens ◽  
Colistin Resistance ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Agar Dilution

Background: Plasmid-mediated resistance to the colistin in poultry is considered as an emerging problem worldwide. While poultry constitutes the major industry in Nepal, there is a paucity of evidence on colistin resistance in Escherichia coli isolates causing natural infections in poultry. This study aimed to explore the prevalence of plasmid-mediated colistin resistance gene, mcr-1 in E. coli isolated from liver samples of dead poultry suspected of E. coli infections. Methods: A total of two hundred and seventy liver samples (227 broilers and 43 layers) from dead poultry suspected of colibacillosis were collected from post-mortem in the Central Veterinary Laboratory (CVL), Kathmandu, between 1 February and 31 July 2019. The specimens were processed to isolate and identify E. coli; an antimicrobial susceptibility test (AST) using disk diffusion method was performed with 12 different antibiotics: Amikacin (30 µg), ampicillin (10 µg), ciprofloxacin (5 µg), chloramphenicol (30 µg), cefoxitin (30 µg), ceftazidime (30 µg), ceftriaxone (30 µg), cotrimoxazole (25 µg), gentamicin (10 µg), imipenem (10 µg), levofloxacin (5 µg) and tetracycline (30 µg). Colistin resistance was determined by agar dilution method and colistin-resistant strains were further screened for plasmid-mediated mcr-1 gene, using conventional polymerase chain reaction (PCR). Results: Out of 270 liver samples, 53.3% (144/270) showed growth of E. coli. The highest number (54%; 109/202) of E. coli isolates was obtained in the liver samples from poultry birds (of both types) aged less than forty days. In AST, 95.1% (137/144) and 82.6% (119/144) of E. coli isolates were resistant against tetracycline and ciprofloxacin, respectively, while 13.2% (19/144) and 25.7% (37/144) isolates were resistant to cefoxitin and imipenem, respectively. In the same assay, 76.4% (110/144) E. coli isolates were multi-drug resistant (MDR). The phenotypic prevalence of colistin resistance was 28.5% (41/144). In the PCR assay, 43.9% (18/41) of colistin-resistant isolates were screened positive for plasmid-mediated mcr-1. Conclusion: The high prevalence of mcr-1 in colistin-resistant E. coli isolates in our study is a cause of concern for the probable coming emergence of colistin resistance in human pathogens, due to horizontal transfer of resistant genes from poultry to human isolates.

scholarly journals COLISTIN RESISTANCE IN CARBAPENEM-RESISTANT KLEBSIELLA PNEUMONIAE STRAINS

2017 ◽  
Vol 10 (9) ◽  
pp. 70
Author(s):  
Beena Hosdurg Bhaskar ◽  
Shalini Shenoy Mulki ◽  
Sangeeta Joshi ◽  
Ranjeeta Adhikari ◽  
Bhavana Malavalli Venkatesh
Keyword(s):  
Antibiotic Susceptibility ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Ethylenediaminetetraacetic Acid ◽  
Diffusion Method ◽  
Resistance Pattern ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Antibiotic Susceptibility Testing ◽  
Carbapenem Resistant

Objective: There is an increasing use of colistin consequent to increase in the infections caused by carbapenem-resistant Klebsiella pneumoniae.The present study was conducted to determine the minimum inhibitory concentration (MIC) of colistin and the resistance pattern of colistin in carbapenem-resistant K. pneumoniae (CRKP) strains in our intensive care unit (ICU).Methods: Antibiotic susceptibility testing for other antimicrobial agents was done by Kirby-Bauer disk diffusion method. MIC of colistin was determined by agar dilution method. The results of antibiotic susceptibility testing were interpreted as per Clinical Laboratory Standard Institute guidelines 2016 and MIC of colistin were interpreted as per European Committee on Antimicrobial susceptibility testing. The carbapenem resistance was phenotypically detected by modified hodge test and imipenem/imipenem ethylenediaminetetraacetic acid disk method.Results: Out of 518 K. pneumoniae, 329 were resistant to carbapenems, and 91 isolates showed resistance to colistin. The MIC of colistin ranged between 4 and >512 ug/ml and MIC90 was 16 ug/L and MIC50 was 4 ug/ml. A majority of the colistin-resistant isolates were found in multidisciplinary ICU (85/91).Conclusion: The emergence of colistin-resistant strains is a major problem due to limited treatment options for infections caused by CRKP carbapenemase producing K. pneumoniae. Colistin should not be used alone, combination therapy should be preferred.

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