(42 days)
Use of BBL® Cefdinir Sensi-Discs® for in vitro agar diffusion susceptibility testing is indicated when there is a need to determine the susceptibility of bacteria to Cefdinir. Cefdinir has been shown to be active against most strains of microorganisms listed below, as described in the Parke-Davis package insert for this antimicrobic.
Active In Vitro and In Clinical Infections Against:
Aerobic Gram-Positive Microorganisms
Staphylococcus aureus (including ß-lactamase producing strains, but excluding methicillin-resistant staphylococci) Streptococcus pneumoniae (penicillin-susceptible strains only) Streptococcus pvogenes
Aerobic Gram-Neqative Microorganisms
Haemophilus influenzae (including ß-lactamase producing strains) Haemophilus parainfluenzae (including ß-lactamase producing strains) Moraxella catarrhalis (including ß-lactamase producing strains)
Active In Vitro Only Against:
Aerobic Gram-Positive Microorganisms Staphylococcus epidermidis (methicillin-susceptible strains only) Streptococcus agalactiae Viridans group streptococci Aerobic Gram Negative Microorganisms Citrobacter diversus Escherichia coli Klebsiella pneumoniae Proteus mirabilis
Antimicrobial Susceptibility Test Discs are used for semi-quantitative in vitro susceptibility testing by standardized agar diffusion test procedures. Cefdinir Sensi-Discs® are intended for use in determining the susceptibility to Cefdinir of a wide range of bacteria, as described under Indications For Use below. Zone sizes used for interpretation of tests, including control organism limits, were determined by the antimicrobic manufacturer, Parke-Davis, a Division of Warner-Lambert Co., and received FDA approval under NDA Nos. 50-739 and 50-749.
Cefdinir Susceptibility Test Discs are prepared by impregnating high quality paper with accurately determined amounts of Cefdinir supplied by the manufacturer. Parke-Davis. Each Cefdinir disc is clearly marked on both sides with the agent and content. Cefdinir discs are furnished in cartridges of 50 discs each. Cefdinir 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-A6 (1/97) and M100-S8 (1/98).
Discs containing a wide variety of antimicrobial agents are applied to the surface of Mueller Hinton Agar plates [or Haemophilus Test Medium Agar for Haemophilus influenzae or Mueller Hinton Agar with 5% Sheep Blood for Streptococcus 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-A6 ("Performance Standards for Antimicrobial Disk Susceptibility Tests - Sixth Edition, Approved Standard", 1/97) and of NCCLS Document M100-S8 ("Performance Standards for Antimicrobial Susceptibility Testing", Eighth Informational Supplement, 1/98).
Here's an analysis of the provided text regarding the acceptance criteria and study for the Cefdinir, 5 µg, Sensi-Discs:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Category | Acceptance Criteria (Implicit) | Reported Device Performance (Summary) |
|---|---|---|
| Performance Standard | Conformity to NCCLS standards | Demonstrated conformant performance based on interpretation of zone sizes against NCCLS M2-A6 and M100-S8. |
| Zone Size Interpretation | Comparison to established ranges | Zone sizes are compared with established zone size ranges for individual antimicrobial agents to determine susceptibility. |
| Control Organism Limits | Within defined limits | Control organism limits determined by antimicrobic manufacturer (Parke-Davis) and received FDA approval. |
Note: The document itself does not explicitly list numerical acceptance criteria in a pass/fail format. Instead, it refers to industry-standardized procedures and interpretation guidelines. The "reported device performance" is essentially that the device functions according to these standards, allowing for accurate interpretation.
2. Sample size used for the test set and the data provenance
- Test Set Sample Size: Not explicitly stated. The document refers to "pure cultures of clinical isolates" but does not give a number.
- Data Provenance: The document does not explicitly state the country of origin or if the data was retrospective or prospective. It refers to "clinical isolates," suggesting real-world samples.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Number of Experts: Not explicitly stated.
- Qualifications of Experts: The ground truth for interpreting zone sizes and control organism limits was "determined by the antimicrobic manufacturer, Parke-Davis, a Division of Warner-Lambert Co., and received FDA approval" and by reference to "National Committee for Clinical Laboratory Standards (NCCLS) Document M2-A6" and "NCCLS Document M100-S8." This implies that the standards themselves, developed by expert committees and validated by regulatory bodies, serve as the "ground truth establishment." There is no mention of individual experts reviewing the test set results.
4. Adjudication method for the test set
- Adjudication Method: Not applicable in the traditional sense of human consensus for individual test results. The device's performance is adjudicated against pre-established, standardized criteria (NCCLS documents and manufacturer-defined zone sizes/control limits). Interpretation of results involves comparing measured zone sizes to these established standards.
5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
- MRMC Study: No. This device is an antimicrobial susceptibility test disc, a consumable used in a laboratory procedure. It does not involve AI or human "readers" in the context of image interpretation or diagnostic scanning for which MRMC studies are typically performed.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Standalone Performance: Not applicable in the context of an algorithm. The device itself is a physical disc. Its "standalone performance" is its ability to produce a measurable zone of inhibition when used according to standardized laboratory procedures. The interpretation of this zone into "susceptible," "intermediate," or "resistant" is a manual human step, guided by the NCCLS standards. There is no automated algorithm performing this interpretation described.
7. The type of ground truth used
- Type of Ground Truth: The primary ground truth is expert consensus/standardization as defined by the National Committee for Clinical Laboratory Standards (NCCLS) documents (M2-A6 and M100-S8) and manufacturer-established (Parke-Davis) zone size interpretation guidelines and control organism limits, which received FDA approval. This is essentially a standardized, accepted reference for what constitutes "susceptible," "intermediate," or "resistant."
8. The sample size for the training set
- Training Set Sample Size: Not applicable. This is not a machine learning or AI device that requires a "training set." The performance is based on chemical properties and standardized biological reactions, not statistical model training.
9. How the ground truth for the training set was established
- Ground Truth for Training Set: Not applicable, as there is no training set for this type of device. The "ground truth" for the interpretation of the disc's results is established through the rigorous standardization process of the NCCLS and validation by the manufacturer and FDA.
§ 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).