scholarly journals Use of the National Committee for Clinical Laboratory Standards Guidelines for Disk Diffusion Susceptibility Testing in New York State Laboratories

2000 ◽  
Vol 38 (9) ◽  
pp. 3341-3348 ◽  
Author(s):  
Julia A. Kiehlbauch ◽  
George E. Hannett ◽  
Max Salfinger ◽  
Wendy Archinal ◽  
Catherine Monserrat ◽  
...  

Accurate antimicrobial susceptibility testing is vital for patient care and surveillance of emerging antimicrobial resistance. The National Committee for Clinical Laboratory Standards (NCCLS) outlines generally agreed upon guidelines for reliable and reproducible results. In January 1997 we surveyed 320 laboratories participating in the New York State Clinical Evaluation Program for General Bacteriology proficiency testing. Our survey addressed compliance with NCCLS susceptibility testing guidelines for bacterial species designated a problem (Staphylococcus aureus and Enterococcusspecies) or fastidious (Streptococcus pneumoniae,Haemophilus influenzae, and Neisseria gonorrhoeae) organism. Specifically, we assessed compliance with guidelines for inoculum preparation, medium choice, number of disks per plate, and incubation conditions for disk diffusion tests. We also included length of incubation for S. aureus andEnterococcus species. We found overall compliance with the five characteristics listed above in 80 of 153 responding laboratories (50.6%) for S. aureus and 72 of 151 (47.7%) laboratories for Enterococcus species. The most common problem was an incubation time shortened to less than 24 h. Overall compliance with the first four characteristics was reported by 92 of 221 (41.6%) laboratories for S. pneumoniae, 49 of 163 (30.1%) laboratories for H. influenzae, and 11 of 77 (14.3%) laboratories for N. gonorrhoeae. Laboratories varied from NCCLS guidelines by placing an excess number of disks per plate. Laboratories also reported using alternative media forEnterococcus species, N. gonorrhoeae, andH. influenzae. This study demonstrates a need for education among clinical laboratories to increase compliance with NCCLS guidelines.

1996 ◽  
Vol 8 (3) ◽  
pp. 337-344 ◽  
Author(s):  
Thomas R. Shryock ◽  
Donald W. White ◽  
J. Mitchell Staples ◽  
Carolyn S. Werner

Tilmicosin is a novel macrolide antibiotic developed for exclusive use in veterinary medicine. The first tilmicosin-containing product was approved to treat bovine respiratory disease associated with pasteurellae. The development of antimicrobial susceptibility testing guidelines for tilmicosin was predicated on the relationship of clinical efficacy studies that demonstrated a favorable therapeutic outcome, on pharmacokinetic data, and on in vitro test data, as recommended by the National Committee for Clinical Laboratory Standards (NCCLS). The NCCLS-approved breakpoints for the MIC dilution testing are resistant ‡ 32 g/ml, intermediate 16 g/ml, and susceptible £ 8 g/ml. The zone of inhibition interpretive criteria for disk diffusion testing with a 15- g disk are resistant £ 10 mm, intermediate 11–13 mm, and susceptible ‡ 14 mm.


1999 ◽  
Vol 123 (7) ◽  
pp. 622-625
Author(s):  
Natalie Williams-Bouyer ◽  
Barbara S. Reisner ◽  
Carla E. Woodmansee ◽  
Pamela S. Falk ◽  
C. Glen Mayhall

Abstract Objective.—To compare the ability of the Vitek GPS-TB card with disk diffusion testing for determining the susceptibility of enterococci to vancomycin. Design.—Vitek susceptibility testing was performed using the GPS-TB card and software version R05.03. Disk diffusion susceptibility testing was performed according to National Committee for Clinical Laboratory Standards guidelines. When discrepancies occurred between the interpretation of Vitek and disk diffusion, both tests were repeated and the epsilometer test (E test) and agar screen containing 6 μg/mL vancomycin were performed. Results.—Of 415 isolates tested, 313 were susceptible to vancomycin and 97 were resistant to vancomycin by both test methods. Two isolates were intermediate by Vitek and resistant by disk diffusion, 2 were intermediate by Vitek and susceptible by disk diffusion, and 1 was susceptible by Vitek and intermediate by disk diffusion. All but 1 of these latter 5 isolates (intermediate by Vitek and susceptible by disk diffusion) were available for retesting. On repeat testing, the 2 isolates that were intermediate by Vitek and resistant by disk diffusion were resistant by both methods, the 1 isolate that was intermediate by Vitek and susceptible by disk diffusion was susceptible by both methods, and the isolate that was susceptible by Vitek and intermediate by disk diffusion was also susceptible by both methods. These results were confirmed by E test and agar screen. Conclusion.—We found the results of the GPS-TB card compared well with disk diffusion. However, isolates with intermediate results by Vitek should be retested using another method, such as the E test.


2000 ◽  
Vol 38 (1) ◽  
pp. 453-455
Author(s):  
Brant A. Odland ◽  
Meredith E. Erwin ◽  
Ronald N. Jones

ABSTRACT This multicenter study proposes antimicrobial susceptibility (MIC and disk diffusion methods) quality control (QC) parameters for seven compounds utilized in veterinary health. Alexomycin, apramycin, tiamulin, tilmicosin, and tylosin were tested by broth microdilution against various National Committee for Clinical Laboratory Standards (NCCLS)-recommended QC organisms ( Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, Streptococcus pneumoniae ATCC 49619, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853). In addition, disk diffusion zone diameter QC limits were determined for apramycin, enrofloxacin, and premafloxacin by using E. coli ATCC 25922, P. aeruginosa ATCC 27853, and S. aureus ATCC 25923. The results from five or six participating laboratories produced ≥99.0% of MICs and ≥95.0% of the zone diameters within suggested guidelines. The NCCLS Subcommittee for Veterinary Antimicrobial Susceptibility Testing has recently approved these ranges for publication in the next M31 document.


2005 ◽  
Vol 49 (1) ◽  
pp. 82-87 ◽  
Author(s):  
Ruben Avendaño-Herrera ◽  
Rute Irgang ◽  
Soledad Núñez ◽  
Jesús L. Romalde ◽  
Alicia E. Toranzo

ABSTRACT In the present study, Anacker and Ordal agar, marine agar (MA), and Flexibacter maritimus medium (FMM) were compared with the dilute versions of Mueller-Hinton agar (DMHA) medium recommended by the National Committee for Clinical Laboratory Standards (NCCLS) for their use in disk diffusion tests with Tenacibaculum maritimum strains and to calculate the MICs of five drugs by the Etest method. Preliminary growth tests performed with 32 strains of this pathogen on each medium revealed that all strains failed to grow on DMHA, while the remaining media supported good growth of all isolates. In the susceptibility tests, which were carried out with the other three media, all strains were resistant to oxolinic acid and were highly susceptible to amoxicillin and trimethoprim-sulfamethoxazole, showing a good correspondence with the Etest values, which ranged from 0.064 to 0.75 and 0.006 to 1.5 μg/ml, respectively. Enrofloxacin and oxytetracycline produced significantly smaller inhibition zones and MICs on MA than on the other media assayed. However, fast, clear, and well-defined zones of inhibition were displayed for all strains at 24 h of incubation only on FMM by both the disk diffusion assay and Etest. In addition, FMM prepared with commercial sea salts instead of seawater was also suitable for bacterial isolation as well as for susceptibility testing. On the basis of these results, the use of FMM to determine the in vitro susceptibility of T. maritimum and its inclusion in a future revision of the NCCLS M42 report are recommended.


2003 ◽  
Vol 47 (5) ◽  
pp. 1647-1651 ◽  
Author(s):  
Madonna J. Matar ◽  
Luis Ostrosky-Zeichner ◽  
Victor L. Paetznick ◽  
Jose R. Rodriguez ◽  
Enuo Chen ◽  
...  

ABSTRACT The activities of fluconazole and voriconazole against isolates of Candida spp. (n = 400) were tested by the E-test, disk diffusion, and the National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 broth microdilution-based reference methods. More than 96% of isolates found to be susceptible to fluconazole by the reference method were identified as susceptible by the agar-based methods. Lesser degrees of correlation with the reference method were seen for isolates identified as resistant by the agar-based methods. Interpretive categories are not available for voriconazole, but results qualitatively similar to those for fluconazole were seen. The agar-based E-test and disk diffusion methods are reliable alternatives to the NCCLS M27-A2 reference microdilution method for isolates that test susceptible to fluconazole.


1998 ◽  
Vol 36 (1) ◽  
pp. 302-304 ◽  
Author(s):  
E. Kent Korgenski ◽  
Judy A. Daly

The BIOMIC System (Giles Scientific, New York, N.Y.) includes software and a video-assisted plate reader that functions with a personal computer to automate, speed read, and interpret standard antibiotic disk diffusion test plates. The video reader helps standardize endpoints, speeds quantitative measurements by 40 to 90%, and reduces fatigue and transcription and interpretation errors (H. Wei-Fang, Am. Clin. Lab. 13:28–29, 1994). Organisms tested were isolated from patient specimens collected at Primary Children’s Medical Center and included rapidly growing gram-positive and gram-negative strains that fulfill the National Committee for Clinical Laboratory Standards guidelines for disk diffusion susceptibility testing. A comparison of the plate reader-determined zones and visually measured zones for 3,339 organism-antimicrobial agent combinations was performed. The results demonstrated 0.1% (4 of 3,339) false-susceptible reads and 0.2% (6 of 3,339) false-resistant reads by the video reader compared with visual reads. Minor discrepancies (4.7% [156 of 3339]), resulting in category interpretation changes of intermediate to resistant or susceptible or changes of resistant or susceptible to intermediate, were also encountered. Of the discrepant results, 80.8% (139 of 172) resulted from a 3-mm or less zone diameter difference between the two different techniques. We conclude that the video-assisted plate reader is a reliable system for determining interpretative categories from zone diameters of standard antibiotic disk diffusion test plates.


2002 ◽  
Vol 36 (10) ◽  
pp. 1505-1511 ◽  
Author(s):  
Steven L Clause ◽  
Robert A Hamilton

BACKGROUND: Since the early 1970s, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC) has been tasked with the formulation of national guidelines for the management of hypertension. These were significantly changed in 1993 with publication of JNC-5. JNC-6 kept many basic treatment recommendations (i.e., initiation of therapy with a thiazide diuretic or β-blocker), partly in response to the low adoption rate of the treatment recommendations of JNC-5. OBJECTIVE: To describe single-drug outpatient therapy of hypertension and temporally correlate these therapies with the publication of JNC-5 and JNC-6. METHODS: The electronic records of randomly selected New York State Medicaid recipients without hospitalization who had a diagnosis of hypertension and who were receiving only 1 antihypertensive medication were analyzed for 1994, 1997, and 1999. This analysis identified the medications selected for monotherapy of hypertension and compared these therapies with JNC recommendations. The analysis was correlated to patient comorbidities to further account for provider selection of a non—first-line agent. RESULTS: In 1994, angiotensin-converting enzyme (ACE) inhibitors and calcium-channel blockers accounted for 69% of therapies, with 67.5% of these patients having no JNC-recognized individualizing consideration for their use. In 1999, the combined use of ACE inhibitors and calcium-channel blockers accounted for over 65% of all single-drug therapy; 60% of these patients had no individualizing considerations. Also, in 1999, 47.7% of all patients appeared to be receiving antihypertensive therapies that are not compliant with JNC recommendations. CONCLUSIONS: Single-drug therapy of hypertension in a nonhospitalized New York state Medicaid population from 1994 through 1999 did not closely follow JNC recommendations for the single-agent treatment of hypertension.


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