(35 days)
Antimicrobial Susceptibility Test Discs are used for semi-quantitative in vitro susceptibility testing by standardized agar diffusion test procedures. Sparfloxacin Sensi-Discs® are intended for use in determining the susceptibility to Sparfloxacin of a wide range of bacteria, including Staphylococcus aureus, Streptococcus pneumoniae (penicillin-susceptible strains), Enterobacter cloacae, Haemophilus influenzae, Haemophilus parainfluenzae, Klebsiella pneumoniae, Moraxella catarrhalis, Chlamydia pneumoniae, and Mycoplasma pneumoniae. Zone sizes used for interpretation of tests, including control organism limits, were determined by the antimicrobic manufacturer, Rhone Poulenc Rorer Pharmaceuticals, Inc., and received FDA approval under NDA No. 20-677.
Use of BBL® Sparfloxacin Sensi-Discs® for in vitro agar diffusion susceptibility testing is indicated when there is a need to determine the susceptibility of bacteria to Sparfloxacin. Sparfloxacin has been shown to be active against most strains of microorganisms listed below, both in vitro and in clinical infections, as described in the Rhone Poulenc Rorer Pharmaceuticals, Inc., package insert for this antimicrobic.
Sparfloxacin Susceptibility Test Discs are prepared by impregnating high quality paper with accurately determined amounts of Sparfloxacin supplied by the manufacturer, Rhone Poulenc Rorer Pharmaceuticals, Inc., Collegeville, Pennsylvania. Each Sparfloxacin disc is clearly marked on both sides with the agent and content. Sparfloxacin discs are furnished in cartridges of 50 discs each. Sparfloxacin cartridges are packed as either a single cartridge in a single box, or in a package containing ten cartridges.
Agar diffusion methods employing dried filter paper discs impregnated with specific concentrations of antimicrobial agents were developed in the 1940's. In order to eliminate or minimize variability in the testing, Bauer et al. developed a standardized procedure in which Mueller Hinton Agar was selected as the test medium.
Various regulatory agencies and standards-writing organizations subsequently published standardized reference procedures based on the Bauer-Kirby method. Among the earliest and most widely accepted of these standardized procedures were those published by the U.S. Food and Drug Administration (FDA) and the World Health Organization (WHO). The procedure was adopted as a consensus standard by the National Committee for Clinical Laboratory Standards (NCCLS) and is periodically updated. The latest NCCLS documents are M2-A5 (12/93) and M100-S6 (12/95).
Discs containing a wide variety of antimicrobial agents are applied to the surface of Mueller Hinton Agar plates [or Haemophilus Test Medium Agar for H. influenzae or Mueller Hinton Agar with 5% Sheep Blood for S. pneumoniae] inoculated with pure cultures of clinical isolates. Following incubation, the plates are examined and the zones of inhibition surrounding the discs are measured and compared with established zone size ranges for individual antimicrobial agents in order to determine the agent(s) most suitable for use in antimicrobial therapy. The determination as to whether the organism in question is susceptible (S), intermediate (I), or resistant (R) to an antimicrobial agent is made by comparing zone sizes to those found in the respective organism tables of National Committee for Clinical Laboratory Standards (NCCLS) Document M2-A5 ("Performance Standards for Antimicrobial Disk Susceptibility tests - Fifth Edition, Approved Standard", 12/93) and of NCCLS Document M100-S6 ("Performance Standards for Antimicrobial Susceptibility Testing", Sixth Informational Supplement, 12/95).
This document describes the BBL® Sparfloxacin Sensi-Discs® for antimicrobial susceptibility testing. The data provided focuses on the clinical effectiveness of Sparfloxacin itself, rather than the performance of the Sensi-Discs® as a diagnostic device. The Sensi-Discs® are intended to determine the susceptibility of bacteria to Sparfloxacin using standardized agar diffusion tests.
Here's an analysis of the provided information regarding acceptance criteria and supporting studies, contextualized for the device (Sparfloxacin Sensi-Discs®) where possible, and acknowledging that much of the performance data relates to the drug Sparfloxacin:
1. Table of Acceptance Criteria and Reported Device Performance
For the Sparfloxacin Sensi-Discs®, the acceptance criteria are not explicitly detailed in terms of a device-specific performance study with metrics like accuracy, sensitivity, or specificity against a reference method. Instead, the performance is tied to zone size interpretation and quality control ranges provided by the drug manufacturer (Rhone Poulenc Rorer Pharmaceuticals) and standardized by NCCLS.
| Acceptance Criteria (from NCCLS guidelines, applied to disc test) | Reported Device Performance (Implicit via compliance with NCCLS) |
|---|---|
| For aerobic microorganisms (other than Haemophilus influenzae): | |
| Zone Diameter ≥19 mm for Susceptible (S) | Implied to meet these interpretive standards through product design and quality control, as per NCCLS M2-A5. The device's function is to produce these zones. |
| Zone Diameter 16-18 mm for Intermediate (I) | |
| Zone Diameter ≤15 mm for Resistant (R) | |
| For Haemophilus influenzae and Haemophilus parainfluenzae: | |
| Zone Diameter ≥19 mm for Susceptible (S) | Implied to meet these interpretive standards as above. "The current absence of data on resistant strains precludes defining any category other than 'Susceptible.'" |
| Quality Control Ranges (Zone Diameter for Disc Diffusion): | |
| Escherichia coli ATCC 25922: 30-38 mm | The device is expected to produce zone diameters within this range for quality control organisms. |
| Staphylococcus aureus ATCC 25923: 27-33 mm | The device is expected to produce zone diameters within this range for quality control organisms. |
| MIC Interpretive Standards (Sparfloxacin drug performance, not disc diameter directly): | |
| ≤1 µg/mL for Susceptible (S) (for aerobic microorganisms other than Haemophilus influenzae) | The drug (Sparfloxacin) exhibits these MIC values against various organisms. The discs are calibrated to reflect this. |
| 2 µg/mL for Intermediate (I) | |
| ≥4 µg/mL for Resistant (R) | |
§ 866.1620 Antimicrobial susceptibility test disc.
(a)
Identification. An antimicrobial susceptibility test disc is a device that consists of antimicrobic-impregnated paper discs used to measure by a disc-agar diffusion technique or a disc-broth elution technique the in vitro susceptibility of most clinically important bacterial pathogens to antimicrobial agents. In the disc-agar diffusion technique, bacterial susceptibility is ascertained by directly measuring the magnitude of a zone of bacterial inhibition around the disc on an agar surface. The disc-broth elution technique is associated with an automated rapid susceptibility test system and employs a fluid medium in which susceptibility is ascertained by photometrically measuring changes in bacterial growth resulting when antimicrobial material is eluted from the disc into the fluid medium. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.(b)
Classification. Class II (performance standards).