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.

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 Study of antibiotic resistance profiling of Staphylococcus aureus isolated from clinical specimens of the patients attending a tertiary teaching hospital from Chhattisgarh

2017 ◽  
Vol 5 (11) ◽  
pp. 4808
Author(s):  
Archana Bhimrao Wankhade ◽  
Sanjibkumar Panda ◽  
Riddhi Hathiwala ◽  
Yogendra Keche
Keyword(s):  
Staphylococcus Aureus ◽  
Multidrug Resistance ◽  
Antibiotic Susceptibility ◽  
Susceptibility Testing ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Resistance Pattern ◽  
Antibiotic Susceptibility Testing ◽  
Microbiological Methods ◽  
Tertiary Teaching

Background: Staphylococcus aureus is a pathogen causing wide spectrum of infections. It has tendency for the development of multidrug resistance thereby exposing the selection of appropriate treatment. Therefore, the present study was undertaken to find out the antibiotic susceptibility pattern of Staphylococcus aureus isolated from various clinical samples in teaching tertiary hospital.Methods: Total 85 Staphylococcus aureus was isolated from clinical samples (pus, urine, sputum and blood) tested. Identification of Staphylococcus aureus was done by standard conventional microbiological methods. Antibiotic susceptibility testing was done by using disk diffusion method as per CLSI guidelines.Results: Staphylococcus aureus was isolated maximum from pus samples followed by urine samples. Antibiotic susceptibility testing showed highest resistance against Penicillin (69%) and Erythromycin (51%) followed by Cotrimoxazole (50%) & Nitrofurantoin (50%). All the strains were sensitive to Vancomycin. Amongst the urine isolates all were sensitive to Norfloxacin. These percentages of sensitivities are characteristically higher in our study than the previous studies in the literature. In addition, out of 85 Staphylococcus aureus isolates, 26 isolates showed sensitivity   to all antibiotics.Conclusions: From the present study we conclude that though the Staphylococcus aureus is usually having multidrug resistance pattern. So regular antimicrobial susceptibility surveillance is essential for area‐wise monitoring of the resistance patterns. This will be beneficial to preserve the effectiveness of antibiotics and for better patient management.

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

Current Fluoroquinolone Susceptibility Criteria for Salmonella Needs Re-evaluation

2012 ◽  
Vol 10 (1) ◽  
pp. 66-71 ◽  
Author(s):  
D Acharya ◽  
S Malla ◽  
DR Bhatta ◽  
N Adhikari ◽  
SP Dumre
Keyword(s):  
Nalidixic Acid ◽  
Enteric Fever ◽  
Susceptibility Testing ◽  
Break Point ◽  
Resistance Rate ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disc Diffusion ◽  
Zone Diameter

Background Disc diffusion technique is the routine susceptibility testing procedure for isolates of enteric fever, the most common clinical diagnosis among febrile patients in Nepal. Objective To evaluated the current fluoroquinolones (FQs) susceptibility criteria and nalidixic acid screening test in Salmonella enterica serovar Typhi and Paratyphi A. Methods S. Typhi and Paratyphi A strains isolated from 443 suspected enteric fever patients visiting National Public Health Laboratory (NPHL) during April through October 2008 were analyzed. All isolates were confirmed by standard microbiological procedures including serotyping. Antibiotic susceptibility testing was performed by using Kirby Bauer disc diffusion method and Clinical and Laboratory Standards Institute (CLSI) approved interpretive criteria. Agar dilution method was used to determine Minimum Inhibitory Concentration (MIC) of ciprofloxacin, ofloxacin and nalidixic acid. Result Out of 41 Salmonella isolates, 80.49% were nalidixic acid resistant, with S. Paratyphi A showing higher resistance rate (88.23%) compared to S. Typhi (75%). The difference in both MIC and zone diameter in nalidixic acid susceptible and nalidixic acid resistant isolates was found to be significant (P < 0.001) and decreased susceptibility to FQs was strongly correlated (sensitivity and specificity of 100%) with resistance to nalidixic acid. Regression analysis of MIC against zone diameter based on the current CLSI recommended guidelines suggests that accommodation of current susceptible and resistant MIC requires increase in the zone diameter of ciprofloxacin and ofloxacin. Conclusion Before using these drugs for management of enteric fever, appropriate identification of Salmonella isolates with reduced susceptibility to FQs is essential to limit the possible treatment failure and development of highly resistant strains. The current FQs susceptibility break point criteria for Salmonella need re-evaluation. KATHMANDU UNIVERSITY MEDICAL JOURNAL  VOL.10 | NO. 1 | ISSUE 37 | JAN - MAR 2012 | 24-29DOI: http://dx.doi.org/10.3126/kumj.v10i1.6909

scholarly journals Novel Antibiotic Susceptibility Tests by the ATP-Bioluminescence Method Using Filamentous Cell Treatment

1998 ◽  
Vol 42 (6) ◽  
pp. 1406-1411 ◽  
Author(s):  
Noriaki Hattori ◽  
Moto-O Nakajima ◽  
Koji O’Hara ◽  
Tetsuo Sawai
Keyword(s):  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Test Model ◽  
The Novel ◽  
Gram Negative ◽  
Atp Bioluminescence ◽  
Filamentous Cell ◽  
Bioluminescence Method

ABSTRACT Antimicrobial susceptibility testing by the ATP-bioluminescence method has been noted for its speed; it provides susceptibility results within 2 to 5 h. However, several disagreements between the ATP method and standard methodology have been reported. The present paper describes a novel ATP method in a 3.5-h test which overcomes these deficiencies through the elimination of false-resistance discrepancies in tests on gram-negative bacteria with β-lactam agents. In our test model using Pseudomonas aeruginosa and piperacillin, it was shown that ATP in filamentous cells accounted for the false resistance. We found that 0.5% 2-amino-2-methyl-1,3-propanediol (AMPD) extracted ATP from the filamentous cells without affecting normal cells and that 0.3 U of adenosine phosphate deaminase (APDase)/ml simultaneously digested the extracted ATP. We used the mixture of these reagents for the pretreatment of cells in a procedure we named filamentous cell treatment, prior to ATP measurements. This novel ATP method with the filamentous cell treatment eliminated false-resistance discrepancies in tests on P. aeruginosa with β-lactam agents, including piperacillin, cefoperazone, aztreonam, imipenem-cilastatin, ceftazidime, and cefsulodin. Furthermore, this novel methodology produced results which agreed with those of the standard microdilution method in other tests on gram-negative and gram-positive bacteria, including P. aeruginosa, Escherichia coli,Staphylococcus aureus, and Enterococcus faecalis, for non-β-lactam agents, such as fosfomycin, ofloxacin, minocycline, and aminoglycosides. MICs obtained by the novel ATP method were also in agreement with those obtained by the agar dilution method of susceptibility testing. From these results, it was shown that the novel ATP method could be used successfully to test the activities of antimicrobial agents with the elimination of the previously reported discrepancies.

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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