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BacT/ALERT® FN Plus Culture Bottles are used with the BacT/ALERT® Microbial Detection System in qualitative procedures for recovery and detection of anaerobic and facultative anaerobic microorganisms from blood and other normally sterile body fluids.

The proposed resin formulation reagent (BacT/ALERT® FN Plus Culture Bottle) is an improvement upon the cleared charcoal formulation reagent (BacT/ALERT® FN Culture Bottle). The BacT/ALERT® FN Culture Bottles are used with the BacT/ALERT® Microbial Detection Systems in qualitative procedures for recovery and detection of microorganisms from blood.

The predicate BacT/ALERT® FN Culture Bottle contains charcoal in the complex growth medium for its antimicrobial neutralization properties. Charcoal is eliminated in the proposed BacT/ALERT® FN Plus Culture Bottle, and is replaced with two types of adsorbent polymeric beads in the complex growth medium. The proposed BacT/ALERT® FN Plus Culture Bottle (resin) is optimized to increase antimicrobial neutralization properties and to increase the clarity of Gram stains in comparison to the predicate BacT/ALERT® FN Culture Bottle (charcoal) while maintaining the ability to detect and recover microorganisms.

The BacT/ALERT® Microbial Detection System provides both a microbial detection system and a culture medium bottle with suitable nutritional and environmental conditions for microorganisms commonly encountered in blood or other normally sterile body fluid samples (except urine) taken from a patient suspected of having bacteremia/fungemia. An inoculated bottle is placed into the instrument where it is incubated and continuously monitored for the presence of microorganisms that will grow in the BacT/ALERT® bottles.

The BacT/ALERT® Microbial Detection System utilizes a colorimetric sensor and reflected light to monitor the presence and production of carbon dioxide (CO2) that is dissolved in the culture medium. If microorganisms are present in the test sample, carbon dioxide is produced as the microorganisms metabolize the substrates in the culture medium. When growth of the microorganisms produces CO2, the color of the gas-permeable sensor installed in the bottom of each culture bottle changes from blue-areen to vellow. The lighter color results in an increase of reflectance units monitored by the system. Bottle reflectance is monitored and recorded by the instrument every 10 minutes.

This document describes the BacT/ALERT® FN Plus Culture Bottle, a device used for the recovery and detection of anaerobic and facultative anaerobic microorganisms from blood and other normally sterile body fluids. The acceptance criteria and supporting studies are detailed below.

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample Size for Test Set and Data Provenance

• Analytical Studies (Growth Performance, Antimicrobial Neutralization, Interfering Substances, LoD, Precision, Reproducibility): These were "in-house seeded studies" or "seeded studies conducted at three sites."

  • Growth Performance: Varies by organism. For Staphylococcus aureus, 15 bottles with blood, 3 without. For Clostridium septicum, 40 bottles with blood, 5 without.
  • Limit of Detection (LoD): Minimum of 30 replicates per species.
  • Within Laboratory Precision (Repeatability): Minimum of 108 replicates per organism/antimicrobial combination.
  • Reproducibility: Target of 144 replicates per site (3 sites), with actual numbers for each organism varying (e.g., 27 for S. aureus at Site 1, 33 at Site 3). Overall, 693 replicates across 8 organisms for the overall reproducibility study.
  • Delayed Entry: 6 species, target 100 CFU/bottle. Control (89 bottles), 48 hr/2-8°C (65 bottles), 24 hr/20-25°C (62 bottles), 36 hr/20-25°C (62 bottles), 8 hr/35-37°C (72 bottles), 24 hr/35-37°C (80 bottles). Negative Controls (51 bottles).
  • Provenance: "in-house seeded studies" or "seeded studies conducted at three sites," implying laboratory-controlled experiments. The "blood obtained from healthy human volunteers" is noted for some analytical studies. The reproducibility study was conducted at three sites, and the delayed entry study at three sites.

• Clinical Study (Blood Cultures):

  • Sample Size: 2514 anaerobic bottle pairs (from 1080 adult patients).
  • Data Provenance: Multi-center clinical study conducted at three different geographic sites in the U.S. This is prospective clinical data.

• Clinical Study (Sterile Body Fluid Cultures):

  • Sample Size: 339 bottle pairs (from 310 adult patients).
  • Data Provenance: Multi-center clinical study conducted at four different geographic sites in the U.S. and Canada. This is prospective clinical data.

3. Number of Experts and Qualifications for Ground Truth

• Analytical Studies: The document does not specify the number or qualifications of experts for establishing ground truth in the analytical studies. These studies typically rely on standard microbiological techniques (e.g., plating dilutions for CFU counts, subculture and identification for recovery) performed by trained laboratory personnel.

• Clinical Studies (Blood and Sterile Body Fluid Cultures):

  • The classification of clinical isolates (significant, contaminant, or unknown) was based on "determination by the clinical trial sites." The specific number or qualifications of experts (e.g., infectious disease physicians, clinical microbiologists) involved in this determination are not explicitly stated in the provided summary.

4. Adjudication Method for the Test Set

• Analytical Studies: Not explicitly described, but generally, positive findings are confirmed by standard microbiological methods like Gram stain and subculture. For reproducibility, "Percent recovery reflects positive flag by the instrument and . Gram stain/subculture consistent with the seeded organism."

• Clinical Studies (Blood and Sterile Body Fluid Cultures):

  • For clinical studies, a bottle was determined to be a "True Positive" if "the culture was flagged positive by the BacT/ALERT System and resulted in growth of the isolate upon subculture of this bottle."
  • A "pair of bottles was determined to have a positive status if subculture of either the FN Plus or FN bottle was positive." This implies a form of consensus or composite reference standard where detection by either method, confirmed by subculture, counts as a positive case for the pair. However, there isn't a specified 'adjudication panel' or voting method mentioned for resolving discrepancies between the BacT/ALERT system and subculture, or between the FN Plus and FN bottles beyond this composite definition. The "Clinical Determination" (significant, contaminant, unknown) was determined by "the clinical trial sites," suggesting site-specific standard practices rather than a centralized adjudication committee.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

• No, an MRMC comparative effectiveness study was not done. This device is a culture bottle used with an automated microbial detection system, not an AI-assisted diagnostic imaging or interpretation tool where human readers assess cases. Therefore, the concept of "human readers improve with AI vs without AI assistance" is not applicable in this context. The comparison was between two generations of culture bottles (FN Plus vs. FN).

6. Standalone Performance (Algorithm Only without Human-in-the-Loop)

• Yes, standalone performance was done. The BacT/ALERT® Microbial Detection System uses a colorimetric sensor and reflected light to continuously monitor for the presence and production of CO2. The "BacT/ALERT® FN Plus Culture Bottle" is the culture medium, and the "BacT/ALERT® Microbial Detection System" is the instrument that performs the detection. The various analytical studies (LoD, growth performance, precision, reproducibility) evaluate the performance of the bottle and system in detecting microorganisms, which is an automated, algorithm-driven process. Human involvement comes primarily in preparing the samples, loading the bottles, and performing confirmatory subcultures and identification after the instrument flags a positive. The "True Positive" definition states positive flag by the instrument first, then confirmed by subculture.

7. Type of Ground Truth Used

• Analytical Studies:

  • Spiked/Seeded Organisms: Known strains and concentrations of microorganisms were directly introduced into the bottles.
  • Culture/Subculture Confirmation: Positive instrument signals were confirmed by subculture and Gram stain to ensure the detected organism matched the seeded organism.
  • CFU/bottle: Direct quantification of colony-forming units.

• Clinical Studies (Blood and Sterile Body Fluid Cultures):

  • Culture/Subculture Confirmation: The primary ground truth for a positive detection was defined as the "culture was flagged positive by the BacT/ALERT System and resulted in growth of the isolate upon subculture of this bottle." So, it's a combination of the device's automated detection and traditional microbiological culture (subculture).
  • Clinical Determination: For categorizing isolates as significant, contaminant, or unknown, this was based on "determination by the clinical trial sites." This implies a clinical consensus based on patient presentation, other lab results, and standard infection control criteria. It's a form of expert consensus based on clinical context.

8. Sample Size for the Training Set

• The document primarily describes validation studies for the "BacT/ALERT® FN Plus Culture Bottle" in comparison to a predicate device. It details performance characteristics and clinical results. It does not explicitly provide information about a separate "training set" sample size used to develop or train the underlying BacT/ALERT® Microbial Detection System algorithm itself. The existing BacT/ALERT® system algorithm was already established, and the "FN Plus" bottle is an improved reagent formulation. The document mentions, "No changes to software code (in detection software) occurred. ... The structure of the detection algorithm remains unchanged. ... No change was made to the initial value threshold of the BacT/ALERT® FN Plus bottle type knowledge base." This indicates minimal to no re-training of the core algorithm for this specific submission, rather an adaptation to a new bottle type.

9. How the Ground Truth for the Training Set was Established

• As mentioned above, the document does not describe a new training set for the BacT/ALERT® FN Plus bottle explicitly, as the core detection algorithm was largely unchanged from the predicate system. The original BacT/ALERT® Microbial Detection System likely used extensive historical data and various seeded studies to establish its detection algorithms. However, this specific 510(k) summary focuses on the validation of the culture bottle itself.

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BacT/ALERT® FN Culture Bottles are used with the BacT/ALERT Microbial Detection Systems in qualitative procedures for enhanced recovery and detection of anaerobic microorganisms from blood, and other normally sterile body fluids.

The BacT/ALERT FN Plastic Culture Bottle was developed for the same intended use as the current BacT/ALERT FN Glass Culture Bottle, to provide suitable nutritional and environmental conditions for organisms commonly encountered in blood infections and normally sterile body fluids. An inoculated bottle is placed into the BacT/ALERT Microbial Detection Instruments where it is incubated and continuously monitored for the presence of microorganisms that will grow in the BacT/ALERT FN Bottle.

Here's an analysis of the provided text regarding the acceptance criteria and study for the BacT/ALERT FN Culture Bottle:

1. Table of Acceptance Criteria and Reported Device Performance

Note: The document does not explicitly state pre-defined acceptance criteria in terms of specific thresholds for recovery or detection time. Instead, the study's aim was to demonstrate "substantial equivalence" to the predicate device, meaning performance was expected to be comparable or better. The conclusion states equivalence was achieved.

2. Sample Size Used for the Test Set and Data Provenance

• Test Set Sample Size: 9 organisms. The document doesn't specify the number of individual tests or bottles per organism, but mentions "low levels of the 9 microorganisms."
• Data Provenance: Human blood (used for dilution) inoculated into the culture bottles. The origin (country/retrospective/prospective) of the human blood samples is not specified, but the study design ("seeded studies") indicates a controlled, likely prospective, laboratory-based study.

3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications of Experts

This information is not provided in the document. For a microbial growth monitor, the ground truth is typically established by laboratory methods confirming the presence and growth of specific microorganisms, not by human expert interpretation in the same way as, for example, radiology images.

4. Adjudication Method for the Test Set

This information is not applicable/provided in the context of this device. Adjudication methods like 2+1 or 3+1 are used for expert consensus on subjective interpretations (e.g., medical image diagnosis). For a microbial growth monitor, the "ground truth" relies on objective lab measurements (e.g., confirmed microbial growth, identification, and quantification).

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done

No, an MRMC comparative effectiveness study was not done. This type of study is relevant for diagnostic devices where human readers interpret results, and the AI's impact on their performance is evaluated. The BacT/ALERT FN Culture Bottle is a device for detecting microbial growth, not for interpretation by human readers in the same manner.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done

Yes, the study described is essentially a standalone performance study. The device (BacT/ALERT FN Plastic Culture Bottle) was tested directly for its ability to recover and detect microorganisms, and its performance was compared to a predicate device (BacT/ALERT FN Glass Culture Bottle). There's no indication of a human-in-the-loop component in the primary performance evaluation.

7. The Type of Ground Truth Used

The ground truth used was the confirmed presence and growth of specific microorganisms (9 known organisms) inoculated into blood samples at "low levels." This is a laboratory-established ground truth based on microbiology techniques.

8. The Sample Size for the Training Set

This information is not applicable/provided. The BacT/ALERT FN Culture Bottle is a physical culture medium and detection system, not an AI/machine learning algorithm that requires a training set in the conventional sense. The "development" of the device would involve R&D and testing, but not a "training set" of data for algorithmic learning.

9. How the Ground Truth for the Training Set was Established

This information is not applicable/provided for the reasons stated above (not an AI/ML device requiring a training set).

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The BacT/ALERT FN Culture Bottles are used with the BacT/ALERT Microbial Detection Systems in qualitative procedures for enhanced recovery and detection of anaerobic microorganisms from blood and other normally sterile body fluids.

The BacT/ALERT FN Culture Bottle was developed for the same intended use as the current BacT/Alert FAN Anaerobic Culture Bottle, to provide suitable nutritional and environmental conditions for organisms commonly encountered in blood infections and normally sterile body fluids. An inoculated bottle is placed into the BacT/ALERT Microbial Detection Instrument where it is incubated and continously monitored for the presence of microorganisms that will grow in the BacT/ALERT FN Culture Bottle.

Here's an analysis of the provided text to extract the requested information regarding the acceptance criteria and the study that proves the device meets them:

1. Table of acceptance criteria and the reported device performance

2. Sample size used for the test set and the data provenance

• Sample Size: Not explicitly stated, but the study involved "low levels of eleven anaerobic organisms diluted in human blood." The number of samples (bottles) per organism or per blood sample is not provided.
• Data Provenance: The data was generated through "seeded studies" using "human blood." The country of origin is not specified, but the submission is to the FDA in the USA. Given this, it's a prospective study conducted specifically for this submission.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

Not applicable. This device is a diagnostic tool for microbial growth. The "ground truth" for the test set would be the confirmed presence and identity of the seeded anaerobic organisms, which is determined by standard microbiological culture and identification methods, not expert reader consensus.

4. Adjudication method for the test set

Not applicable. As described above, the ground truth for microbial growth detection is based on the inherent biology and laboratory confirmation of the seeded organisms, not expert adjudication of images or diagnoses.

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

Not applicable. This device is a fully automated microbial detection system, not an AI-assisted diagnostic tool that aids human readers.

6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done

Yes, a standalone study was performed. The BacT/ALERT FN Culture Bottle, in conjunction with the BacT/ALERT Microbial Detection Instrument, operates automatically to detect microbial growth. The study compared the performance of this system (BacT/ALERT FN Culture Bottle + Instrument) directly against the predicate device's system (BacT/Alert FAN Anaerobic Culture Bottle + Instrument).

7. The type of ground truth used

The ground truth was established by seeding known anaerobic organisms into human blood at "low levels" and then measuring their recovery and time to detection. This is essentially a controlled laboratory setup where the presence and type of microorganism are known beforehand.

8. The sample size for the training set

Not applicable. This document describes a new iteration of an existing diagnostic culture bottle, not a machine learning algorithm that requires a training set in the conventional sense. The "training" for the device would have been its design and development based on established microbiological principles.

9. How the ground truth for the training set was established

Not applicable. See point 8.

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