Interpretationskriterien der Empfindlichkeitsprüfung von Ofloxacin mit dem Agardiffusionstest

Abstract

Regression analyses to determine the correlation of MIC and inhibition zone produced by ofloxacin disks were carried out using 300 freshly isolated cultures of infective organisms (20 strains each from 15 species). It was found in pilot studies that the correlation becomes poorer with increasing disk loads. Disks containing 5 micrograms of ofloxacin were chosen for comparative studies using Mueller-Hinton agar and Kirby-Bauer, as well as DIN-58940 methods. Based on preliminary MIC breakpoints of 1 and 4 mg/l and on calculations from regression equations, the following zone interpretations using the Kirby-Bauer method are recommended: resistant = up to 12 mm, intermediate = 13 to 19 mm, susceptible = 20 mm or more. The respective values for the DIN method are: resistant = up to 14 mm, intermediate = 15 to 21 mm, susceptible = 22 mm or more. The results are similar to those obtained by us in previous studies with norfloxacin, enoxacin and ciprofloxacin.

In vitro Activity of Three Fluoroquinolones against Enterococci and <i>Pseudomonas aeruginosa</i>: Modified Categorization System for Discrepant Broth Dilution and Agar Disk Diffusion Test Results

“…However, there were a relatively large number of category III discrepancies with norfloxacin when fol lowing the interpretive criteria of Shungu et al [17,18] and Wood and Shadomy [22]; with the NCCLS breakpoints [15], the discrepancies were shifted to category V. The criteria of Barry et al [3] resulted in a larger number of category V discrepancies for ciprofloxacin; in contrast, the alterna tive (Bayer) criteria, though reducing cate gory V discrepancies, resulted in two addi tional very major discrepancies. The re sults obtained for ofloxacin revealed that fewer discrepancies, yet at the expense of one category I discrepancy, were encount ered when evaluation was carried out ac cording to the criteria of Fuchs et al [7], as contrasted with those proposed by two other laboratories [9,14]. In the case of P. aeruginosa isolates, norfloxacin again yielded the smallest numbers of discrepancies, although there were two category II discrepancies em ploying the NCCLS criteria [15].…”

“…Cipro floxacin produced additional category V discrepant results; there were two category II discrepancies utilizing the criteria of Barry et al [3]. Ofloxacin yielded more discrepant results, based on the interpre tive criteria of Mandell and Neu [14], The criteria of Grimm [9] permitted circum vention of category I and II discrepancies, noted with the criteria of Fuchs et al [7].…”

Preclinical Assessment of Bacteriophage Therapy against Experimental Acinetobacter baumannii Lung Infection

“…For all experiments, A. baumannii isolate RUH 2037, kindly provided by Alex F. de Vos and Tom van der Poll was used [20,22]. Drug susceptibility profile was determined with disk diffusion method according to DIN (German Institute for Standardization) 58940 guidelines [23] and resistance to more than two classes of antibiotics, including penicillins, cephalosporins, and quinolones was confirmed (Supplementary Materials Table S1, full susceptibility profile is available online [24]). Bacteria were grown from cryopreserved stocks on Columbia agar containing 5% sheep blood (BD, Heidelberg, Germany) and incubated overnight at 37 • C with 5% CO 2 .…”

Interpretation Criteria for Sensitivity Testing of Ceftriaxone in Agar Diffusion Test according to the DIN 58940 Method

“…[4). On the basis of practi cal considerations, it would be reasonable to reduce the disk feeding for ceftriaxone, at least in the ICS or DIN method, as was proposed for cefotaxime [6] and for cefmenoxime [7], Before the inhibitory zone of a new an tibiotic, on the basis of a regression analy sis, can be converted into a sensitivity category, the MIC threshold values (the M IC , mg/l so-called 'breakpoints') must be estab lished. In establishing these breakpoints, consideration must be given above all to the recommended dosage, the application interval, and pharmacokinetic data.…”