scholarly journals Comparison of antimicrobial susceptibilities of Corynebacterium species by broth microdilution and disk diffusion methods.

1996 ◽  
Vol 40 (4) ◽  
pp. 930-933 ◽  
Author(s):  
K Weiss ◽  
M Laverdière ◽  
R Rivest
Keyword(s):  
Clinical Laboratory ◽  
High Rate ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
National Committee ◽  
Broth Microdilution ◽  
Disk Diffusion Method ◽  
Corynebacterium Species ◽  
Broth Microdilution Method

Corynebacterium species are increasingly being implicated in foreign-body infections and in immunocompromised-host infections. However, there are no specific recommendations on the method or the criteria to use in order to determine the in vitro activities of the antibiotics commonly used to treat Corynebacterium infections. The first aim of our study was to compare the susceptibilities of various species of Corynebacterium to vancomycin, erythromycin, and penicillin by using a broth microdilution method and a disk diffusion method. Second, the activity of penicillin against our isolates was assessed by using the interpretative criteria recommended by the National Committee for Clinical Laboratory Standards for the determination of the susceptibility of streptococci and Listeria monocytogenes to penicillin. Overall, 100% of the isolates were susceptible to vancomycin, while considerable variations in the activities of erythromycin and penicillin were noted for the different species tested, including the non-Corynebacterium jeikeium species. A good correlation in the susceptibilities of vancomycin and erythromycin between the disk diffusion and the microdilution methods was observed. However, a 5% rate of major or very major errors was detected with the Listeria criteria, while a high rate of minor errors (18%) was noted when the streptococcus criteria were used. Our findings indicate considerable variations in the activities of erythromycin and penicillin against the various species of Corynebacterium. Because of the absence of definite recommendations, important discrepancies were observed between the methods and the interpretations of the penicillin activity.

scholarly journals Evaluation of Disk Diffusion Method for Determining Posaconazole Susceptibility of Filamentous Fungi: Comparison with CLSI Broth Microdilution Method

2006 ◽  
Vol 50 (3) ◽  
pp. 1108-1111 ◽  
Author(s):  
E. López-Oviedo ◽  
A. I. Aller ◽  
C. Martín ◽  
C. Castro ◽  
M. Ramirez ◽  
...  
Keyword(s):  
Filamentous Fungi ◽  
Clinical Laboratory ◽  
Culture Media ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Broth Microdilution Method

ABSTRACT The disk diffusion method was evaluated for determining posaconazole susceptibility against 78 strains of molds using two culture media in comparison with the CLSI (Clinical Laboratory Standards Institute) broth microdilution method (M38-A). A significant correlation between disk diffusion and microdilution methods was observed with both culture media.

scholarly journals In Vitro Activities of the New Antifungal Triazole SCH 56592 against Common and Emerging Yeast Pathogens

2000 ◽  
Vol 44 (1) ◽  
pp. 226-229 ◽  
Author(s):  
Francesco Barchiesi ◽  
Daniela Arzeni ◽  
Annette W. Fothergill ◽  
Luigi Falconi Di Francesco ◽  
Francesca Caselli ◽  
...  
Keyword(s):  
Clinical Laboratory ◽  
Clinical Development ◽  
National Committee ◽  
In Vitro Activity ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Vitro Data ◽  
In Vitro Data

ABSTRACT A broth microdilution method performed in accordance with the National Committee for Clinical Laboratory Standards guidelines was used to compare the in vitro activity of the new antifungal triazole SCH 56592 (SCH) to that of fluconazole (FLC), itraconazole (ITC), and ketoconazole (KETO) against 257 clinical yeast isolates. They included 220 isolates belonging to 12 different species of Candida, 15 isolates each of Cryptococcus neoformans andSaccharomyces cerevisiae, and seven isolates ofRhodotorula rubra. The MICs of SCH at which 50% (MIC50) and 90% (MIC90) of the isolates were inhibited were 0.06 and 2.0 μg/ml, respectively. In general, SCH was considerably more active than FLC (MIC50 and MIC90 of 1.0 and 64 μg/ml, respectively) and slightly more active than either ITC (MIC50 and MIC90 of 0.25 and 2.0 μg/ml, respectively) and KETO (MIC50 and MIC90 of 0.125 and 4.0 μg/ml, respectively). Our in vitro data suggest that SCH has significant potential for clinical development.

scholarly journals Categorizing susceptibility of clinical isolates of Candida auris to amphotericin B, caspofungin, and fluconazole utilizing the CLSI M44-A2 disk diffusion method

2021 ◽  
Author(s):  
Natalie S. Nunnally ◽  
Tajah Damm ◽  
Shawn R. Lockhart ◽  
Elizabeth L. Berkow
Keyword(s):  
Amphotericin B ◽  
Accurate Method ◽  
Clinical Isolates ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Candida Auris ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Broth Microdilution Method

We evaluated the CLSI M44ed3E disk diffusion method in comparison with the CLSI M27ed4 broth microdilution method for caspofungin and fluconazole and the Etest method for amphotericin B to categorize susceptibility of 347 clinical isolates of Candida auris. Utilizing the zone diameter cutoffs established here we observed the overall categorial agreement between the two methods. For caspofungin, concordant results were observed for 98% of isolates with <1% very major and 1% major errors. For fluconazole, concordant results were observed for 91% of isolates with 1% very major and 8% major errors. For amphotericin B, concordant results were observed for 74% of isolates with <1% very major errors and 25% major errors. The disk diffusion approach provides an accurate method for determining the susceptibility of C. auris for caspofungin and fluconazole, and for identification of at least 75% of amphotericin B-susceptible isolates.

scholarly journals In Vitro Activity of the New Triazole Voriconazole (UK-109,496) against Opportunistic Filamentous and Dimorphic Fungi and Common and Emerging Yeast Pathogens

1998 ◽  
Vol 36 (1) ◽  
pp. 198-202 ◽  
Author(s):  
Ana Espinel-Ingroff
Keyword(s):  
Amphotericin B ◽  
Clinical Laboratory ◽  
Wide Spectrum ◽  
Sporothrix Schenckii ◽  
National Committee ◽  
Broth Microdilution ◽  
Pseudallescheria Boydii ◽  
Broth Microdilution Method ◽  
Better Than

The in vitro antifungal activity of a new triazole derivative, voriconazole, was compared with those of itraconazole and amphotericin B against 67 isolates of Aspergillus flavus,Aspergillus fumigatus, Bipolaris spp.,Fusarium oxysporum, Fusarium solani,Pseudallescheria boydii, Rhizopus arrhizus,Blastomyces dermatitidis, Histoplasma capsulatum, and Sporothrix schenckii. The in vitro activities of voriconazole were also compared with those of amphotericin B, fluconazole, and itraconazole against 189 isolates of emerging and common yeast pathogens of Blastoschizomyces capitatus, Candida (13 species), Cryptococcus neoformans, Hansenula anomala, Rhodotorula rubra, Saccharomyces cerevisiae, Sporobolomyces salmonicolor, and Trichosporon beigelii. MICs were determined according to a procedure under evaluation by the National Committee for Clinical Laboratory Standards (NCCLS) for broth microdilution testing of filamentous fungi and by the NCCLS M27-A broth microdilution method for yeasts. The in vitro activities of voriconazole were similar to or better than those of itraconazole and amphotericin B against Aspergillus spp.,Fusarium spp., and P. boydii as well as againstB. dermatitidis and H. capsulatum. The activities of voriconazole were also comparable to or better than those of amphotericin B, fluconazole, and itraconazole against most species of yeasts tested. Exceptions were certain isolates of R. rubra and S. salmonicolor. These results suggest that voriconazole has a wide spectrum of activity in vitro; its effectiveness in the treatment of human mycoses is under evaluation in clinical trials.

scholarly journals Antibiotic susceptibility of campylobacter isolates from sewage and poultry abattoir drain water

1995 ◽  
Vol 115 (3) ◽  
pp. 475-483 ◽  
Author(s):  
P. M. F. J. Koenraad ◽  
W. F. Jacobs-Reitsma ◽  
T. Van Der Laan ◽  
R. R. Beumer ◽  
F. M. Rombouts
Keyword(s):  
Nalidixic Acid ◽  
Clinical Laboratory ◽  
Quinolone Resistance ◽  
Diffusion Method ◽  
National Committee ◽  
Meat Processing ◽  
Disk Diffusion Method ◽  
Sources Of Infection ◽  
Sewage Purification

SummaryIn this study, thein vitrosusceptibility of 209 campylobacter strains to the quinolones nalidixic acid, flumequine, ciprofloxacin, enrofloxacin, and to ampicillin, tetracycline and erythromycin was tested by the disk diffusion method. The strains were isolated from poultry abattoir effluent (DWA) and two sewage purification plants (SPA and SPB). Sewage purification plant SPA received mixed sewage, including that from a poultry abattoir, whereas SPB did not receive sewage from any meat-processing industry. The quinolone resistance of the DWA isolates ranged from 28% for enrofloxacin to 50% for nalidixic acid. The strains isolated from the sewage purification plants were more susceptible to the quinolones with a range of 11–18% quinolone resistance for SPB isolates to 17–33% quinolone resistance for SPA isolates. The susceptibility criteria as recommended by National Committee Clinical Laboratory Standards (USA) cannot readily be employed for campylobacter isolates. This investigation shows that the resistance of campylobacter bacteria is highest in the plant receiving sewage from a poultry slaughterhouse. Monitoring of antibiotic resistance of aquaticCampylobacterspp. is important, as surface waters are recognized as possible sources of infection.

scholarly journals Comparison of Agar Diffusion Methodologies for Antimicrobial Susceptibility Testing of Pseudomonas aeruginosa Isolates from Cystic Fibrosis Patients

2000 ◽  
Vol 38 (5) ◽  
pp. 1818-1822 ◽  
Author(s):  
Jane L. Burns ◽  
Lisa Saiman ◽  
Susan Whittier ◽  
Davise Larone ◽  
Jay Krzewinski ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Susceptibility Testing ◽  
Correlation Coefficients ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Disk Diffusion Method ◽  
Agar Diffusion ◽  
Broth Microdilution Method

Pseudomonas aeruginosa is the most common pathogen infecting the lungs of patients with cystic fibrosis (CF). Improved antimicrobial chemotherapy has significantly increased the life expectancy of these patients. However, accurate susceptibility testing of P. aeruginosa isolates from CF sputum may be difficult because the organisms are often mucoid and slow growing. This study of 597 CF isolates of P. aeruginosa examined the correlation of disk diffusion and Etest (AB BIODISK, Solna, Sweden) results with a reference broth microdilution method. The rates of interpretive errors for 12 commonly used antipseudomonal antimicrobials were determined. The disk diffusion method correlated well (zone diameter versus MIC) for all of the agents tested. However, for mucoid isolates, correlation coefficients (r values) for piperacillin, piperacillin-tazobactam, and meropenem were <0.80. The Etest correlation with reference broth microdilution results (MIC versus MIC) was acceptable for all of the agents tested, for both mucoid and nonmucoid isolates. Category interpretation errors were similar for the disk diffusion and Etest methods with 0.4 and 0.1%, respectively, very major errors (false susceptibility) and 1.1 and 2.2% major errors (false resistance). Overall, both agar diffusion methods appear to be broadly acceptable for routine clinical use in susceptibility testing of CF isolates of P. aeruginosa.

scholarly journals Use of an Oxacillin Disk Screening Test for Detection of Penicillin- and Ceftriaxone-Resistant Pneumococci

1999 ◽  
Vol 37 (4) ◽  
pp. 1178-1181 ◽  
Author(s):  
Louise P. Jetté ◽  
Christian Sinave
Keyword(s):  
Antimicrobial Agents ◽  
Clinical Laboratory ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
National Committee ◽  
Zone Of Inhibition ◽  
Diffusion Test ◽  
Disk Diffusion Method ◽  
Disk Diffusion Test ◽  
Intermediate Resistance

In a context of worldwide emergence of resistance amongStreptococcus pneumoniae strains, early detection of strains with decreased susceptibility to β-lactam antibiotics is important for clinicians. If the 1-μg oxacillin disk diffusion test is used as described by the National Committee for Clinical Laboratory Standards, no interpretation is available for strains showing zone sizes of ≤19 mm, and there is presently no disk diffusion test available for screening cephalosporin resistance. The zones obtained by the diffusion method by using the 1-μg oxacillin disk were compared with penicillin MICs for 1,116 clinical strains and with ceftriaxone MICs for 695 of these strains. Among the 342 strains with growth up to the 1-μg oxacillin disk margin, none were susceptible (MIC, ≤0.06 μg/ml), 62 had intermediate resistance (MIC, 0.12 to 1.0 μg/ml), and 280 were resistant (MIC, ≥2.0 μg/ml) to penicillin. For ceftriaxone, among 98 strains with no zone of inhibition in response to oxacillin, 68 had intermediate resistance (MIC, 1.0 μg/ml), and 22 were resistant (MIC, ≥2.0 μg/ml). To optimize the use of the disk diffusion method, we propose that the absence of a zone of inhibition around the 1-μg oxacillin disk be regarded as an indicator of nonsusceptibility to penicillin and ceftriaxone and recommend that such strains be reported as nonsusceptible to these antimicrobial agents, pending the results of a MIC quantitation method.

scholarly journals Evaluation of the Revised Ceftaroline Disk Diffusion Breakpoints When Testing a Challenge Collection of Methicillin-ResistantStaphylococcus aureusIsolates

2018 ◽  
Vol 56 (12) ◽  
Author(s):  
Helio S. Sader ◽  
Paul R. Rhomberg ◽  
Timothy B. Doyle ◽  
Robert K. Flamm ◽  
Rodrigo E. Mendes
Keyword(s):  
Error Rates ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Wild Type ◽  
Disk Diffusion Method ◽  
Content Type ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Mueller Hinton Agar

ABSTRACTWe assessed ceftaroline disk diffusion breakpoints forStaphylococcus aureuswhen applying revised Clinical and Laboratory Standards Institute (CLSI) ceftaroline MIC breakpoints. Disk-MIC correlation was evaluated by testing a challenge collection (n= 158) of methicillin-resistantS. aureus(MRSA) isolates composed of 106 randomly selected isolates plus 52 isolates with decreased susceptibility to ceftaroline (MIC, 1 to 16 μg/ml). Disk diffusion was performed with 30-μg disks and Mueller-Hinton agar from 2 manufacturers each. Revised CLSI susceptible (S)/susceptible dose-dependent (SDD)/resistant (R) MIC breakpoints of ≤1/2 to 4/≥8 μg/ml were applied. The disk breakpoints that provided the lowest error rates were CLSI S/R breakpoints of ≥25 mm/≤19 mm, with no very major (VM) or major (Ma) errors and with minor (Mi) error rates of 0.0% for ≥2 doubling dilutions above the I or SDD (≥I + 2), 22.1% for I or SDD plus or minus 1 doubling dilution (I ± 1), and 2.3% for ≤2 doubling dilutions below the I or SDD ≤I − 2 (overall Mi error rate, 16.5%). No mutation in the penicillin-binding protein 2a (PBP2a) was observed in 5 of 15 isolates with a ceftaroline MIC of 2 μg/ml; 3 of 11 isolates with a ceftaroline MIC of 1 μg/ml exhibited mutations in the penicillin-binding domain (PBD; 1 isolate) or in the non-PBD (2 isolates). All isolates except 1, with a ceftaroline MIC of ≥4 μg/ml, showed ≥1 mutation in the PBD and/or non-PBD. In summary, results from the disk diffusion method showed a good correlation with those from the reference broth microdilution method. Our results also showed that the ceftaroline MIC distribution of isolates with no mutations in the PBP2a goes up to 4 μg/ml, and reference broth microdilution and disk diffusion methods do not properly separate wild-type from non-wild-type isolates.

scholarly journals In vitro activity of glycopeptides against clinical isolates of Entercocci from a tertiary care hospital

2016 ◽  
Vol 12 (1) ◽  
Author(s):  
Muhammad Tahir Majeed Tahir Majeed ◽  
Mateen Izhar
Keyword(s):  
Clinical Laboratory ◽  
Tertiary Care ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Medical Institute ◽  
National Committee ◽  
Care Hospital ◽  
Glycopeptide Antibiotics ◽  
Disk Diffusion Method

Objective: The objective of this study was to establish the prevalence of glycopeptide (vancomycin and teicoplanin) resistance among clinical isolates of enterococci in Shaikh Zayed Hospital, Lahore, and comparison of antimicrobial sensitivities of vancomycin and teicoplanin among these isolates. Design: A comparative analytical study. Place of study: This study was conducted in the Department of Microbiology, Federal Postgraduate Medical Institute, Shaikh Zayed Hospital, Lahore. Materials and methods: 60 (Sixty) enterococci isolates were collected from clinical specimens received in the laboratory. Identification of these bacteria was done utilizing standard laboratory operating procedures. Their sensitivity to glycopeptide antibiotics was tested by disk diffusion method in accordance with the National Committee for Clinical Laboratory Standards (NCCLS) guidelines. Results: Results show that all enterococci were sensitive to teicoplanin. However, among these isolates 1.7% resistance to vancomycin was detected. Conclusion: The results indicate that resistance to glycopeptide antibiotics in the test organisms is low in our hospital. The presence of vancomycin resistance in 1.7% clinical enterococcal isolates necessitates strict surveillance of these organisms, institution of effective infection control policies and judicious use of antibiotics.

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