(265 days)
HardyCHROM ESBL is a selective and differential chromogenic medium which is intended for the qualitative and presumptive detection from stool specimens of: 1) Enterobacteriaceae that are potentially non-susceptible to ceftazidime and cefpodoxime; and 2) Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca.
The test is performed on stool specimens from patients at risk of harboring Enterobacteriaceae that are non-susceptible to 3rd generation cephalosporins or ESBL-producing E. coli, K. pneumoniae and K. oxytoca, and is intended as an aid in the detection, identification of colonization and control of these bacteria in a healthcare setting. HardyCHROM ESBL is not intended to diagnose infection or to guide or monitor treatment for infections. Results can be interpreted after incubation for 18-24 hours. Subculture to non-selective medium is required for confirming identification, susceptibility testing and epidemiological typing.
A lack of growth or the absence of pink, blue or yellow/gold colonies on HardyCHROM ESBL does not preclude the presence of Enterobacteriaceae that are non-susceptible to 3rd generation cephalosporins or ESBL producing organisms.
HardyCHROM™ ESBL is a selective and differential chromogenic medium containing a broad-spectrum beta-lactam intended for detection and isolation of Enterobacteriaceae non-susceptible to 3rd generation cephalosporins. HardyCHROM™ ESBL can also be used as a screening medium for K. pneumoniae, K. oxytoca, and E. coli that produce an extended-spectrum beta-lactamase (ESBL).
The selective components in HardyCHROM™ ESBL are designed to inhibit the growth of yeast, Grampositive bacteria, and Gram-negative bacteria sensitive to broad spectrum beta-lactams (3rd generation cephalosporins). Chromogenic substrates in the medium allow for differentiation of Enterobacteriaceae non-susceptible to 3rd generation cephalosporins or that are ESBL-producing, as bacteria that can grow and utilize the chromogens produce a colored colony. ESBL-producing Klebsiella spp. produce large, dark blue colonies. ESBL-producing Escherichia coli produce colonies that are rose to magenta in color, with darker pink centers. Other Enterobacteriaceae not susceptible to 3rd generation cephalosporins will produce colonies of varying size that are pink, blue, with pink halos, and yellow/gold.
The provided document is a 510(k) Premarket Notification for the HardyCHROM ESBL device. It details the device's indications for use, its comparison to a predicate device, and performance data from various studies.
Here's an analysis of the acceptance criteria and the study proving the device meets them, based on the provided text:
Device: HardyCHROM™ ESBL
Intended Use: Qualitative and presumptive detection from stool specimens of:
- Enterobacteriaceae potentially non-susceptible to ceftazidime and cefpodoxime.
- Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli, Klebsiella pneumoniae, and Klebsiella oxytoca.
1. Table of Acceptance Criteria and Reported Device Performance
The document doesn't explicitly state "acceptance criteria" as a separate, pre-defined set of thresholds. Instead, it presents performance metrics from various studies (clinical, contrived, analytical reactivity, analytical specificity, microbial interference, specimen stability, and reproducibility). The results are presented as the device's performance, implying these values met the internal requirements for substantial equivalence.
Here's a table summarizing key performance metrics observed in the studies:
| Performance Metric Category | Specific Metric | Reported Device Performance | Acceptance Criteria (Implied/Discussed) |
|---|---|---|---|
| Clinical Performance (Prospective) | Detection of 3rd gen. cephalosporin non-susceptible Enterobacteriaceae | Overall Sensitivity: 91.0% (95% CI: 87.8% - 93.4%) | While not explicitly stated as acceptance criteria, these sensitivity and specificity values are presented as evidence of effective performance compared to traditional culture. For a screening device, high sensitivity is often prioritized to minimize false negatives, while reasonable specificity is needed to avoid excessive false positives. The CIs provide an indication of the precision of these estimates. |
| Overall Specificity: 95.2% (95% CI: 94.1% - 96.1%) | |||
| Detection of ESBL-producing K. oxytoca, K. pneumoniae, E. coli | Overall Sensitivity: 97.1% (95% CI: 93.3% - 98.7%) | Similar to above, high sensitivity is crucial for detecting ESBL producers, given their clinical significance. The very high sensitivity (97.1%) and the fact that one site achieved 100% sensitivity for this indication suggest strong performance. Specificity is also important to prevent unnecessary further testing. | |
| Overall Specificity: 87.1% (95% CI: 85.6% - 88.5%) | |||
| Contrived Specimen Performance | PPA (Presumptive Detection of Ref. NS Enterobacteriaceae) | 97.9% (47/48) (95% CI: 89.1% - 99.6%) | The high PPA and NPA (where applicable) for contrived specimens, particularly at LoD (Limit of Detection), indicate the consistent performance of the device under controlled conditions and its ability to detect target organisms even at low concentrations. The recovery rate (LoD) at 10^3 CFU/mL or 10 CFU/plate suggests the device is sensitive enough for clinical utility. |
| NPA (Presumptive Detection of Ref. NS Enterobacteriaceae) | 60.0% (3/5) (95% CI: 23.1% - 88.2%) | (Note: The NPA for presumptive detection of non-susceptible Enterobacteriaceae on contrived specimens is low, likely due to the small sample size (n=5 negative contrived samples) and high variability inherent in such small numbers. This specific metric's low value might be considered acceptable due to the limited sample, the overall positive performance for ESBL, and the requirement for subculture for confirmation.) | |
| PPA (Contrived ESBL-"EC" Pink) | 100% (19/19) (95% CI: 83.1% - 100%) | ||
| NPA (Contrived ESBL-"EC" Pink) | 91.2% (31/34) (95% CI: 77.0% - 97.0%) | ||
| PPA (Contrived ESBL-"KP/KO" Blue) | 100% (26/26) (95% CI: 87.1% - 100%) | ||
| NPA (Contrived ESBL-"KP/KO" Blue) | 92.6% (25/27) (95% CI: 76.6% - 97.9%) | ||
| Recovery Rate (LoD) | 3rd gen. cephalosporin non-susceptible Enterobacteriaceae | No discernable difference in recovery at 10^3 CFU/mL (stool) | The ability to recover target organisms at low concentrations (LoD) is crucial for a screening device. This indicates the device is sufficiently sensitive. |
| ESBL-producing E. coli, K. oxytoca, K. pneumoniae | No discernable difference in recovery at 10 CFU/plate (stool) | ||
| Analytical Reactivity | Recovery of 54 characterized ESBL-producing strains | 100% (54/54) after 24 hours of incubation | 100% recovery indicates the device's ability to detect a broad range of ESBL-producing strains with various genotypes. This is a critical analytical performance metric. |
| Recovery of 21 3rd gen. cephalosporin non-susceptible strains | 100% (21/21) after 24 hours of incubation (71.4% with expected color) | High recovery (100%) for non-susceptible strains is important. The note about 71.4% with expected color indicates that some non-ESBL non-susceptible organisms might not show the typical chromogenic reaction, but are still detected. This aligns with the "presumptive" nature. | |
| Analytical Specificity | Non-growth/non-target color for non-pathogens/susceptible organisms | Majority of non-Enterobacteriaceae did not grow or exhibit target colors. | The device should be specific to the target organisms to minimize false positives and reduce the need for unnecessary follow-up. High specificity (inhibiting non-target growth or showing non-target color) is key for a selective medium. |
| 3rd gen. cephalosporin non-susceptible Enterobacteriaceae (non-ESBL) | 100% (45/45) either no growth or colors other than pink/blue/yellow-gold. | This indicates good specificity in distinguishing ESBL-producing organisms (which are expected to show target colors) from other non-susceptible Enterobacteriaceae, which may not. | |
| Reproducibility | PPA for detection of 3rd gen. cephalosporin non-susceptible Enterobacteriaceae | Overall PPA: 98.2% (95% CI: 95.7% - 99.2%) | High reproducibility across different sites and operators is essential to ensure consistent performance in various clinical settings. PPA and NPA values close to 100% demonstrate this consistency. |
| NPA for detection of 3rd gen. cephalosporin non-susceptible Enterobacteriaceae | Overall NPA: 99.6% (95% CI: 98.0% - 99.9%) | ||
| PPA for detection of ESBL-producing K. oxytoca, K. pneumoniae, E. coli | Overall PPA: 98.1% (95% CI: 95.3% - 99.3%) | ||
| NPA for detection of ESBL-producing K. oxytoca, K. pneumoniae, E. coli | Overall NPA: 83.3% (95% CI: 79.0% - 86.9%) | The lower NPA here is noted. The document explains that false positives included E. cloacae (a non-ESBL producing organism that can still show blue colonies on HardyCHROM ESBL if it’s carbapenem resistant or has other beta-lactamase mechanisms like AmpC). If these are omitted, NPA improves to 99.6%. This indicates that while the device is highly sensitive, interpretation requires confirmation for full specificity. The "presumptive detection" in the Indications for Use allows for this, as subculture is required for confirmation. |
2. Sample Size Used for the Test Set and Data Provenance
Clinical Study (Prospective):
- Sample Size: 1,559 valid clinical stool specimens (out of 1,687 initially tested).
- Data Provenance: Fresh stool specimens collected prospectively at three geographically diverse hospitals. The specific countries are not mentioned, but the context implies US given the FDA submission.
Contrived Specimen Study:
- Sample Size: 50 contrived specimens.
- Data Provenance: Patient specimens inoculated with known resistant organisms (ESBL producing or non-susceptible to third-generation cephalosporins) at the Limit of Detection (LoD).
Reproducibility Study:
- Sample Size:
- For 3rd gen. cephalosporin non-susceptible Enterobacteriaceae: 272 positive samples (N) and 280 negative samples (N) overall across 5 days of testing and 3 sites.
- For ESBL-producing organisms: 216 positive samples (N) and 336 negative samples (N) overall across 5 days of testing and 3 sites.
- Data Provenance: Blinded panels of bacterial suspensions in transport medium. Tested at three different sites.
Analytical Reactivity & Specificity Studies:
- Analytical Reactivity (ESBL): 54 characterized ESBL-producing strains of E. coli, K. pneumoniae, and K. oxytoca.
- Analytical Reactivity (Non-ESBL non-susceptible): 21 strains representative of various Enterobacteriaceae that were non-susceptible to at least one 3rd generation cephalosporin.
- Analytical Specificity: 99 strains (52 Enterobacteriaceae and 47 non-Enterobacteriaceae, including ESBL non-producing and 3rd gen. cephalosporin susceptible species).
- Data Provenance: Internal testing using characterized bacterial strains.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
For the Clinical Study:
- Ground Truth Establishment: "Routine culture, defined as the selective enrichment of microorganisms in Tryptic Soy Broth (TSB) containing either 1ug/mL ceftazidime or 1ug/mL cefotaxime, followed by subculture to MacConkey Agar. Organisms that grew on MacConkey Agar were identified using an FDA-cleared ID system. Confirmation of ESBL production and 3rd generation cephalosporin non-susceptibility was performed using traditional Kirby-Bauer AST following the device manufacturer's instructions. ID of organisms that grew on HardyCHROM™ ESBL was confirmed using an FDA-cleared ID system."
- Number/Qualifications of Experts: The document does not specify the number or qualifications of experts involved in performing the "routine culture" or interpreting the Kirby-Bauer AST and FDA-cleared ID system results. This would typically be performed by trained laboratory personnel (e.g., medical technologists, clinical microbiologists).
For the Reproducibility Study:
- Ground Truth Establishment: Not applicable as it's a test of reproducibility using known positive and negative controls.
- Number/Qualifications of Experts: Readings were performed by 2 independent operators at each of the three sites (total 6 operators). Their specific qualifications beyond "operator" are not detailed.
4. Adjudication Method for the Test Set
For the Clinical Study:
- The ground truth seems to be established by a defined laboratory methodology (selective enrichment, subculture, FDA-cleared ID, Kirby-Bauer AST). There is no explicit mention of expert adjudication of the ground truth in the clinical study beyond the standard laboratory procedures. It's a method-based ground truth comparison.
For the Reproducibility Study:
- Readings were done by "2 independent operators." There is no explicit mention of an adjudication process if their readings differed. However, for a reproducibility study with known controls, discrepancies might lead to re-testing or investigation rather than adjudication of the "truth."
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
- No, a MRMC comparative effectiveness study was not done in the context of comparing human readers with and without AI assistance, as this device is a culture medium, not an AI or imaging diagnostic tool. The performance is compared against a "traditional culture" method.
- The reproducibility study involved multiple readers (operators) across multiple sites, but it was for assessing inter-operator and inter-site variability of the device itself, not a comparative effectiveness study involving AI assistance for human readers.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Yes, in essence, standalone performance was evaluated. The device (HardyCHROM™ ESBL) is a culture medium, and its "standalone" performance is measured by its ability to recover and differentiate target organisms based on colony growth and color from the specimen. Human observation is then used to interpret these results.
- The sensitivity and specificity data presented for the clinical and analytical studies reflect the performance of the medium itself to appropriately grow and present the target organisms, which is then visually interpreted. There is no "algorithm" separate from the biological reaction on the medium.
7. The Type of Ground Truth Used
- Clinical Study: The ground truth for the clinical study was established by conventional microbiological methods, including selective enrichment, subculture, identification using FDA-cleared ID systems, and confirmation of non-susceptibility/ESBL production using traditional Kirby-Bauer Antimicrobial Susceptibility Testing (AST). This is a method-based ground truth derived from established laboratory practices.
- Contrived Specimen Study: The ground truth was based on known resistant organisms (ESBL-producing or non-susceptible) used to inoculate patient specimens. This is a "spiked" study design where the ground truth is precisely controlled.
- Analytical Reactivity/Specificity: The ground truth for these studies was based on characterized bacterial strains with known ESBL production, non-susceptibility, or other relevant characteristics (e.g., non-ESBL, susceptible, non-Enterobacteriaceae).
8. The Sample Size for the Training Set
- The document does not mention a "training set" in the context of machine learning or AI models. This device is a culture medium relying on biological and chemical reactions, not an AI algorithm that requires training data.
- The studies described are primarily for performance validation/verification of the manufactured product (culture medium).
9. How the Ground Truth for the Training Set was Established
- As there is no AI algorithm training set, this question is not applicable to this device.
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Image /page/0/Picture/1 description: The image shows the logo for the Department of Health & Human Services - USA. The logo is a circular seal with the words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. Inside the circle is a stylized image of three human profiles facing to the right, stacked on top of each other.
Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
November 15, 2016
HARDY DIAGNOSTICS ANDRE HSIUNG DIRECTOR TECHNICAL SERVICES 1430 WEST MCCOU LANE SANTA MARIA CA 93455
Re: K160512
Trade/Device Name: HardyCHROM ESBL Regulation Number: 21 CFR 866.1700 Regulation Name: Culture medium for antimicrobial susceptibility tests Regulatory Class: II Product Code: JSO Dated: October 4, 2016 Received: October 11, 2016
Dear Mr. Hsiung:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
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If you desire specific advice for your device on our labeling regulations (21 CFR Parts 801 and 809), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638 2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to
http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.
You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.
Sincerely yours,
Ribhi Shawar -S
For Uwe Scherf, M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known) K160512
Device Name HardyCHROM ESBL
Indications for Use (Describe)
HardyCHROM ESBL is a selective and differential chromogenic medium which is intended for the qualitative and presumptive detection from stool specimens of: 1) Enterobacteriaceae that are potentially non-susceptible to ceftazioine and cefpodoxime; and 2) Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca.
The test is performed on stool specimens at risk of harboring Enterobacteriaceae that are non-susceptible to 3rd generation cephalosporins or ESBL-producing E. coli, K. pneumoniae and K. oxytoca, and is intended as an aid in the detection, identification of colonization and control of these bacteria in a healthcare setting, HardyCHROM ESBL is not intended to diagnose infection or to guide or monitor treatment for infections. Results can be interpreted after incubation for 18-24 hours. Subculture to non-selective medium is required for confirming identification, susceptibility testing and epidemiological typing.
A lack of growth or the absence of pink, blue or yellow/gold colonies on HardyCHROM ESBL does not preclude the presence of Enterobacteriaceae that are non-susceptible to 3rd generation cephalosporins or ESBL producing organisms.
Type of Use (Select one or both, as applicable)
| Prescription Use (Part 21 CFR 801 Subpart D) |
|---|
| Over-The-Counter Use (21 CFR 801 Subpart C) |
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Appendix D - 510(k) Summary
I. SUBMITTER
Andre Hsiung Director of Technical Services Hardy Diagnostics 1430 W. McCoy Lane Santa Maria, Ca. 93455 Phone: 805-346-2766 x5706 E-mail: HsiungA@hardydiagnostics.com
II. DEVICE
Name of Device: HardyCHROM™ ESBL Classification Name: Culture medium for anti-microbial susceptibility tests Regulatory Class: II Product Code: JSO
III. PREDICATE DEVICE
Bio Rad VRESelect, K122187
IV. DEVICE DESCRIPTION
According to Centers for Disease Control and Prevention (CDC), Extended Spectrum Beta Lactamases (ESBLs) refer to a variety of enzymes which confer resistance to third generation cephalosporins and monobactams. ESBLs are widespread among Enterobacteriaceae and have no effect on carbapenems or cephamycins. ESBLs are distinguished from AmpC type beta lactamases by their susceptibility to beta lactamase inhibitors such as clavulanic acid.
HardyCHROM™ ESBL is a selective and differential chromogenic medium containing a broad-spectrum beta-lactam intended for detection and isolation of Enterobacteriaceae non-susceptible to 3rd generation cephalosporins. HardyCHROM™ ESBL can also be used as a screening medium for K. pneumoniae, K. oxytoca, and E. coli that produce an extended-spectrum beta-lactamase (ESBL).
The selective components in HardyCHROM™ ESBL are designed to inhibit the growth of yeast, Grampositive bacteria, and Gram-negative bacteria sensitive to broad spectrum beta-lactams (3" generation cephalosporins). Chromogenic substrates in the medium allow for differentiation of Enterobacteriaceae non-susceptible to 3rd generation cephalosporins or that are ESBL-producing, as bacteria that can grow and utilize the chromogens produce a colored colony. ESBL-producing Klebsiella spp. produce large, dark blue colonies. ESBL-producing Escherichia coli produce colonies that are rose to magenta in color, with darker pink centers. Other Enterobacteriaceae not susceptible to 3rd generation cephalosporins will produce colonies of varying size that are pink, blue, with pink halos, and yellow/gold.
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V. INDICATIONS FOR USE
HardyCHROM™ ESBL is a selective and differential chromogenic medium which is intended for the qualitative and presumptive detection from stool specimens of: 1) Enterobacteriaceae that are potentially non-susceptible to ceftazidime and cefpodoxime; and 2) Extended-spectrum beta-lactamase (ESBL)producing Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca.
The test is performed on stool specimens from patients at risk of harboring Enterobacteriaceae that are non-susceptible to 3th generation cephalosporins or ESBL-producing E. coli, K. pneumoniae and K. oxytoca, and is intended as an aid in the detection, identification of colonization and control of these bacteria in a healthcare setting. HardyCHROM™ ESBL is not intended to diagnose infection or to guide or monitor treatment for infections. Results can be interpreted after incubation for 18-24 hours. Subculture to non-selective medium is required for confirming identification, antimicrobial susceptibility testing and epidemiological typing.
A lack of growth or the absence of pink, blue or yellow/gold colonies on HardyCHROM™ ESBL does not preclude the presence of Enterobacteriaceae that are non-susceptible to 3tt generation cephalosporins or ESBL producing organisms.
NOTE: The Indications for Use statement for HardyCHROM™ ESBL is not identical to the predicate device; however, the differences do not alter the intended use of the device nor do they affect the safety and effectiveness of the device relative to the predicate. Both the subject and predicate devices have the same intended use for screening of stool samples by selective and differential culture for microorganisms that are non-susceptible to antimicrobial agents.
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VI. COMPARISON OF TECHNOLOGICAL CHARACTERISTICS WITH THE PREDICATE DEVICE
| Attribute | Device | Comparator | SubstantiallyEquivalent? |
|---|---|---|---|
| Name | HardyCHROM™ ESBL agar | Bio Rad VRESelect | |
| 510(k) Details | Product Code JSO21 CFR 866.1700"Culture medium for anti-microbialsusceptibility tests"Class IIPanel 83 Microbiology | Product Code JSO21 CFR 866.1700"Culture medium for anti-microbialsusceptibility tests"Class IIPanel 83 Microbiology | Yes |
| Intended Use | HardyCHROM™ ESBL is a selective anddifferential chromogenic medium which isintended for the qualitative and presumptivedetection from stool specimens of: 1)Enterobacteriaceae that are potentially non-susceptible to ceftazidime and cefpodoxime;and 2) Extended-spectrum beta-lactamase(ESBL)-producing Escherichia coli ,Klebsiella pneumoniae and Klebsiellaoxytoca .The test is performed on stool specimens frompatients at risk of harboringEnterobacteriaceae that are non-susceptible to3rd generation cephalosporins or ESBL-producing E. coli, K. pneumoniae and K.oxytoca , and is intended as an aid in thedetection, identification of colonization andcontrol of these bacteria in a healthcaresetting. HardyCHROM™ ESBL is notintended to diagnose infection or to guide ormonitor treatment for infections. Results canbe interpreted after incubation for 18-24hours. Subculture to non-selective medium isrequired for confirming identification,antimicrobial susceptibility testing andepidemiological typing.A lack of growth or the absence of pink, blueor yellow/gold colonies on HardyCHROM™ESBL does not preclude the presence ofEnterobacteriaceae that are non-susceptible to3rd generation cephalosporins or ESBLproducing organisms. | VRESelect™ is a selective anddifferential chromogenic medium,containing 8 µg/mL of vancomycin, forthe qualitative detection ofgastrointestinal colonization ofvancomycin resistant Enterococcusfaecium (VREfm) and vancomycinresistant Enterococcus faecalis (VREfs)and to aid in the prevention and controlof vancomycin-resistant Enterococcus(VRE) in healthcare settings. The test isperformed on rectal swabs or fecalspecimens from patients to be screenedfor VRE colonization. VRESelect™ isnot intended to diagnose VRE infectionnor to guide or monitor treatment ofinfection. Results can be interpreted after24 to 28 hours incubation. Subculture tonon-selective media (e.g., trypticase soyagar with 5% sheep blood) is needed forsusceptibility testing and epidemiologicaltyping. | Yes |
| Methodology | Enzymatic - Chromogenic | Enzymatic - Chromogenic | Yes |
| Inoculation | Direct | Direct | Yes |
| Sample Type | Fecal Specimen | Rectal Swab or Fecal Specimen | Yes |
| Interpretation | Manual, Visual | Manual, Visual | Yes |
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VII. PERFORMANCE DATA
Performance of HardyCHROM™ ESBL was evaluated at three geographically diverse hospitals with fresh stool specimens. The recovery of ESBL-producing K. oxytoca, and E. coli on HardyCHROM™ ESBL was compared to routine culture, defined as the selective enrichment of microorganisms in Tryptic Soy Broth (TSB) containing either 1ug/mL ceftazidime or 1ug/mL cefotaxime, followed by subculture to MacConkey Agar. Organisms that grew on MacConkey Agar were identified using an FDA-cleared ID system. Quality control was performed in parallel every day of testing. Results from days of QC failure were excluded from the analysis. Confirmation of ESBL production and 3tt generation cephalosporin non-susceptibility was performed using traditional Kirby-Bauer AST following the device manufacturer's instructions. ID of organisms that grew on HardyCHROM™ ESBL was confirmed using an FDA-cleared ID system. A total of 1,687 samples were tested against routine culture, 128 specimens did not meet enrollment criteria, and were therefore excluded from the analysis. Of the remaining 1.559 valid samples tested, a total of 166 isolates were recovered on HardyCHROM™ ESBL as ESBL-producing with concordant results obtained on traditional culture and confirmed by AST and ID. A total of 373 isolates were recovered on HardyCHROM™ ESBL as non-susceptible to 300 generation cephalosporins with concordant results obtained on traditional culture and confirmed by AST and ID. Product performance with prospectively collected clinical samples is summarized below:
HardyCHROM™ ESBL for use in confirming the presence of 3th generation cephalosporin nonsusceptible Enterobacteriaceae vs. confirmation of 3th generation cephalosporin non-susceptible Enterobacteriaceae from traditional culture
| Site | TP | FP | FN | TN | % Sensitivity | 95% CI | % Specificity | 95% CI | ||
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 85 | 15 | 9 | 526 | 90.4 | 82.8 | 94.9 | 97.2 | 95.5 | 98.3 |
| 2 | 71 | 25 | 6 | 678 | 92.2 | 84.0 | 96.4 | 96.4 | 94.8 | 97.6 |
| 3 | 217 | 53 | 22 | 638 | 90.8 | 86.5 | 93.8 | 92.3 | 90.1 | 94.1 |
| Overall | 373 | 93 | 37 | 1842 | 91.0 | 87.8 | 93.4 | 95.2 | 94.1 | 96.1 |
Confirmed Non Susceptible 18 hr1
The same performance was observed at 18 and 24 hours
HardyCHROM™ ESBL used to screen for ESBL-producing K. oxytoca, K. pneumoniae, and E. codi vs. confirmation of ESBL-resistance from traditional culture
| Site | TP | FP | FN | TN | % Sensitivity | 95% CI | 95% CI | % Specificity | 95% CI | 95% CI |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 26 | 67 | 1 | 456 | 96.3 | 81.7 | 99.3 | 87.2 | 84.1 | 89.8 |
| 2 | 25 | 65 | 0 | 564 | 100.0 | 86.7 | 100.0 | 89.7 | 87.0 | 91.8 |
| 3 | 115 | 148 | 4 | 471 | 96.6 | 91.7 | 98.7 | 76.1 | 72.6 | 79.3 |
| Overall | 166 | 280 | 5 | 1894 | 97.1 | 93.3 | 98.7 | 87.1 | 85.6 | 88.5 |
Morphology vs. Confirmed ESBL 18 hr1
1The same performance was observed at 18 and 24 hours
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To supplement testing of prospectively collected clinical specimens, a total of 50 contrived specimens were also evaluated. Patient specimens were inoculated with known resistant (ESBL producing or nonsusceptible to third generation cephalosporin) organisms at LoD and tested against routine culture. Results are summarized below.
| Performance Metric | Overall(n=53) |
|---|---|
| PPA | 47/4897.9%(89.1% - 99.6%) |
| NPA | 3/560.0%(23.1% - 88.2%) |
| Contrived Specimen Morphology vs. Ref. NS 18 hr |
|---|
1 The same performance was observed at 18 hr and 24 hr
Contrived Specimen Morphology vs. ESBL Ref 18 hr
| PerformanceMetric | "EC"Pink | "KP/KO"Blue |
|---|---|---|
| PPA | 19/19100%(83.1% - 100%) | 26/26100%(87.1% - 100%) |
| NPA | 31/3491.2%(77.0% - 97.0%) | 25/2792.6%(76.6% - 97.9%) |
The same performance was observed at 18 hr and 24 hr
RECOVERY RATE
HardyCHROM™ ESBL was evaluated to determine the recovery (limit of detection (LoD)) of 3th generation cephalosporin non-susceptible Enterobacteriaceae in specimen matrix. One isolate of five representative genera of Enterobacteriaceae with ceftazidime MIC's varying between 1μg/mL and >32ug/mL and cefotaxime MICs varying between 1ug/mL and >16ug/mL were evaluated for recovery on HardyCHROM™ ESBL. Sheep Blood Agar (BAP) plates were used to determine the concentration of organisms present in each dilution. At 10°CFU/mL, there was no discernable difference in recovery. Variable recovery was seen at lower concentrations.
In addition, HardyCHROM™ ESBL was also evaluated to determine the recovery of ESBL-producing E. coli, K. oxytoca, and K. pneumoniae in stool specimen matrix. Two strains of each species with varying ceftazidime MIC values and different ß-lactamase genotype were evaluated for recovery on HardyCHROM™ ESBL. Sheep Blood Agar (BAP) plates were used to determine the concentration of organisms present in each dilution. At 103 CFU/mL of stool (10 CFU/plate when using a 10μL inoculating loop), there was no discernable difference in recovery. Variable recovery was seen at lower concentrations.
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ANALYTICAL REACTIVITY
Internal testing was performed using 54 characterized ESBL-producing strains of E. coli, K. pneumoniae and K. oxvtoca with confirmed ESBL phenotype that were associated with various ß-lactamase genotypes. The strains were tested using a clean suspension in the absence of stool matrix. HardyCHROM™ ESBL was able to recover 54 of 54 (100%) of the ESBL-producing strains after 24 hours of incubation. Some strains containing enzymes such as CTX-M-116 and CTX-M-130 are more susceptible to the selective agent in the medium and were recovered on HardyCHROMI™ ESBL at an inoculum of 100 CFU/plate; all other strains were recovered from an inoculum of 10 CFU/plate.
| Species | n | Mechanism |
|---|---|---|
| E. coli | 24 | TEM (6, 12, 19, 21, 29, 210, 214, 215), CTX-M (1, 2, 3, 8, 14, 15, 24, 27, 28, 40, 55, 75, 79, 116, 125, 130), TEM-OSBL |
| K. pneumoniae | 26 | SHV (2, 11, 14, 18, 31, 55, 83, 89, 90, 108, 120, 133, 173, 178, 179, 180, 182), TEM (4, 11, 129), CTX-M (12, 14, 15, 22, 38, 40, 64, 74, 124), VEB-1 , SHV-OSBL , TEM-OSBL |
| K. oxytoca | 4 | TEM (, 52), CTX-M (22, 30, 75), SHV (7, 12), DHA-1 |
Summary of Analytical Sensitivity Testing
Note: 53/54 strains (98.1%) were also non-susceptible to at least one 3th generation cephalosporin and produced results on HardyCHROM™ ESBL that were consistent with this phenotype
In addition, 21 strains representative of Citrobacter, Escherichia, Hafnia, Klebsiella Morganella, Proteus, Providencia, Raoultella, Serratia, and Shigella that were non-susceptible to at least one 3th generation cephalosporin. Organisms showed a range of MICs to each antibiotic: CAZ (2 µg/mL to >32 µg/mL), CTX (0.38 µg/mL to >16 µg/mL), and CPD disk zone sizes (6-27 mm). The strains were tested using a clean suspension containing an inoculum of approximately 10 CFU/plate HardyCHROM™ ESBL was able to recover 21 of 21 (100%) of the 3tt generation cephalosporin nonsusceptible strains after 24 hours of incubation, although only 15 of 21 (71.4%) showed Pink, Blue, or Yellow/Gold color development. Non-susceptible isolates of Cronobacter. Salmonella, and Yersinia were not evaluated.
ANALYTICAL SPECIFICITY
To determine the potential for cross-reactivity on HardyCHROM™ ESBL, internal testing was conducted with ESBL non-producing and 3th generation cephalosporin susceptible species as well as non-Enterobacteriaceae. A total of 99 strains were tested by plating 10μL of a 108 CFU/mL suspension of each organism on HardyCHROM™ ESBL. Included in the study were 52 strains of Enterobacteriaceae and 47 non-Enterobacteriaceae. The majority of non-Enterobacteriaceae species did not grow on HardyCHROM™ ESBL medium and none exhibited pink, blue or yellow/gold colonies. Of the Enterobacteriaceae, 45/45 (100%) of those that were 3th generation cephalosporin non-susceptible either did not grow on HardyCHROM™ ESBL or produced colony colors other than pink, blue or yellow/gold. Four strains (1 each of C. braakii. C. freundii, E. cloacae and Y. kristensenii) that were non-susceptible to cefpodoxime were not recovered on HardyCHROMIM ESBL. Three carbapenem resistant and 3th generation cephalosporin non-susceptible strains (E. coli (1) and K. pneumoniae (2)) produced pink or blue colonies, as expected (1 of these strains was ESBL negative; 2 were ESBL non-determinable).
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Because non-ESBL producing organisms that are carbapenem resistant or which exhibit other betalactamase resistance mechanisms such as AmpC may produce pink, blue or yellow/gold colonies on HardyCHROM™ ESBL, it is important to subculture such colonies for identification and antimicrobial susceptibility testing to confirm the ESBL-producing phenotype.
MICROBIAL INTERFERENCE
A study was conducted using known concentrations of ESBL-producing K. oxytoca, and E. coli with 10 non-target organisms that grow, but which exhibit non-target colors on HardyCHROM™ ESBL. Suspensions of non-ESBL organisms were prepared at a concentration of at least 10° CFU/mL and mixed with suspensions of ESBL strains at the detection limit concentration (102 CFU/mL). HardyCHROM™ ESBL recovered all target organisms used in the presence of high concentrations of non-target organisms, although the number of colonies of E. coli recovered was reduced in the presence of high concentrations of A. baumanni and colonies of K. pneumoniae appeared unusually small in the presence of Pseudomonas fluorescens.
| Non-target organisms used in mixed-infection study |
|---|
| Geotrichum guilliermondii |
| Geotrichum candidum |
| Aspergillus brasiliensis |
| Penicillium rubens |
| Penicillium chrysogenum |
| Pediococcus acidilactici |
| Provicencia stuartii |
| Acinetobacter baumannii |
| Pseudomonas fluorescens |
| Stenotrophomonas maltophilia |
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INTERFERENCE STUDY
Commonly used or encountered transport devices and endogenous substances that may be present in stool samples were evaluated for potential interference with the growth or chromogenic reaction of target organisms on HardyCHROM™ ESBL. The devices and substances tested are listed in the table below. No interference was observed with any substance at the highest clinically relevant concentration in ESBL-negative specimen matrix.
Summary of Interference Study
| Category | Substance | Concentrationof Substance1 | Category | Substance | Concentrationof Substance1 |
|---|---|---|---|---|---|
| Antifungal | Nystop (Nystatin) | 5% | GI Medication | Rolaids (Mg(OH)2) | 5% |
| Antifungal | Lotrimin (Clotrimazole) | 5% | GI Medication | Milk of Magnesia(Mg(OH)2) | 5% |
| Antifungal | Lotrimin Ultra(ButenafineHydrochloride) | 5% | GI Medication | Dulcolax (Sodiumpicosulfate solution) | 5% |
| Antifungal | Lamisil (TerbinafineHydrochloride 1%) | 5% | GI Medication | Immodium AD(Loperamide) | 5% |
| Antiseptic | Bactine (BenzalkoniumChloride) | 1% | Lubricant | Mineral oil | 10% |
| Antiseptic | Ethanol | 1% | Lubricant | Petroleum jelly | 10% |
| Biologic | Whole blood | 5% | Lubricant | Fleet (Glycerin) | 10% |
| Contraceptive | Nonoxynol-9 | 5% | Lubricant | KY Jelly | 10% |
| GI Medication | Pepto-Bismol (BismuthSubsalicylate) | 5% | Other | C&S TransportMedium | 75% |
| GI Medication | Prilosec OTC(Omeprazole) | 5% | Other | Physiological Saline | 10% |
| GI Medication | Alka-Seltzer (Sodiumcarbonate/potassiumcarbonate) | 5% | Other | Tween80(Polysorbate80) | 10% |
| GI Medication | Mylanta (Al(OH)3) | 5% | TopicalMedication | Preparation H(Hemorrhoid Cream) | 10% |
| GI Medication | Tums (CaCO3) | 5% | TopicalMedication | Cortizone 10(Hydrocortizone) | 10% |
1 v/v or w/v as appropriate
SPECIMEN STABILITY
The stability of spiked raw stool and in stool preserved in C&S Medium (modified Cary Blair formula) was verified. Stool specimens were inoculated near LoD with ESBL-producing and 3th generation cephalosporin non-susceptible Enterobacteriaceae species (ie. E. coli, K. oxytoca, K. pneumoniae, E. cloacae, and P. mirabilis) and held at both room temperature (23-24°C) and 2-8°C. Specimens were subcultured to HardyCHROM™ ESBL at 0 hours, 1 hours, 4 hours, 8 hours, 12 hours, and 24 hours, 48 hours, 72 hours, 96 hours, 120 hours, 144 hours, and 168 hours.
Acceptable results were defined as recovery of organism with no appreciable decrease in colony counts (<1 logio decrease from baseline). Target organisms were stable in raw, unpreserved, stool for up to 4 hours at 23-24°C and 7 days at refrigerated temperature (2-8°C). Target organisms preserved in C&S Medium (modified Cary Blair formula) were stable for 24 hours at 23-24°Cand 7 days at refrigerated temperature.
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REPRODUCIBILITY
Prior to the start of the prospective clinical study, each site tested blinded panels of bacterial suspensions in transport medium on five separate days to evaluate the reproducibility of HardyCHROM™ ESBL. Each panel included duplicate suspensions of 5 3td generation cephalosporin non-susceptible strains of Enterobacteriaceae (E. coli (2), Enterobacter cloacae (1), Klebsiella pneumoniae (1), and Klebsiella oxytoca (1) at 10° CFU/mL) and 5 susceptible strains of bacteria (1 each of E. coli, Staphylococcus aureus, Staphylococcus epidermidis, Shigella flexneri and Shigella sonnei at 10° CFU/mL). Each day of testing, a 10μL loop of each bacterial suspension was used to inoculate a plate of HardyCHROMI™ ESBL culture medium, which was then incubated for 24 hours at 35°C prior to being read by 2 independent operators (10 strains x 2 replicates x 5 days x 2 operators x 3 sites = 600 results). With regards to detection of 3" generation cephalosporin non-susceptible Enterobacteriaceae, the overall PPA for all three sites was 98.2% (95.7% - 99.2%) and the overall NPA was 99.6% (98.0% - 99.9%). With regards to ESBL-producing E. coli, K. oxytoca, and K. pneumoniae, the overall PPA for all three sites was 98.1% (95.3% - 99.3%) and the overall NPA was 83.3% (79.0% - 86.9%).
| Results of the Reproducibility Study at 24 hours for detection of 3rd generation cephalosporin non- |
|---|
| susceptible producing organisms. |
| Positive Percent Agreement | Negative Percent Agreement | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| N | HCPositive | PPA% | low95% | high95% | N | HCNegative | NPA% | low95% | high95% | |
| Day 1 | 60 | 59 | 98.3 | 91.1 | 99.7 | 60 | 59 | 98.3 | 91.1 | 99.7 |
| Day 2 | 60 | 60 | 100.0 | 94.0 | 100.0 | 60 | 60 | 100.0 | 94.0 | 100.0 |
| Day 3 | 52 1 | 50 | 96.2 | 87.0 | 98.9 | 60 | 60 | 100.0 | 94.0 | 100.0 |
| Day 4 | 40 2 | 40 | 100.0 | 91.2 | 100.0 | 40 | 40 2 | 100.0 | 91.2 | 100.0 |
| Day 5 | 60 | 58 | 96.7 | 88.6 | 99.1 | 60 | 60 | 100.0 | 94.0 | 100.0 |
| Overall | 272 | 267 | 98.2 | 95.7 | 99.2 | 280 | 279 | 99.6 | 98.0 | 99.9 |
Expected colony colors: Pink, Blue or Yellow/Gold
1 8 samples at Site 1 (4 from each operator) were excluded due to an error in preparation
2 20 positive and 20 negative samples excluded from analysis due to control failure at Site 3
| Results of the Reproducibility Study at 24 hours for detection of ESBL-producing organisms | |||||||
|---|---|---|---|---|---|---|---|
| -------------------------------------------------------------------------------------------- | -- | -- | -- | -- | -- | -- | -- |
| Positive Percent Agreement | Negative Percent Agreement | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| N | HCPositive | PPA% | low95% | high95% | N | HCNegative | NPA% | low95% | high95% | |
| Day 1 | 48 | 48 | 100.0 | 92.6 | 100.0 | 72 | 60 | 83.3 | 73.1 | 90.2 |
| Day 2 | 48 | 48 | 100.0 | 92.6 | 100.0 | 72 | 60 | 83.3 | 73.1 | 90.2 |
| Day 3 | 401 | 38 | 95.0 | 73.5 | 98.6 | 72 | 60 | 83.3 | 73.1 | 90.2 |
| Day 4 | 322 | 32 | 100.0 | 89.3 | 100.0 | 48 | 402 | 83.3 | 70.4 | 91.3 |
| Day 5 | 48 | 46 | 95.8 | 86.0 | 98.9 | 72 | 60 | 83.3 | 73.1 | 90.2 |
| Overall | 216 | 212 | 98.1 | 95.3 | 99.3 | 336 | 280 | 83.3 | 79.0 | 86.9 |
Expected colony colors: E. coli: Pink; K. pneumoniae/K. oxytoca: Blue
8 samples at Site 1 (4 from each operator) were excluded due to an error in preparation
2 16 positive and 24 negative samples excluded from analysis due to control failure at Site 3
Note: Samples that contained E. cloacae and which exhibited blue colonies on HardyCHROM™ ESBL were considered "false possive" for ESBL-producing E. coli and K. pneumoniae/K. oxytoca. If these samples are omitted from the analysis, negative agreement was 279/280 (99.6%).
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VIII. CONCLUSIONS
Since the predicate device was cleared based in part on the results of clinical studies, and since the comparison of bench testing to clinical outcomes is still not well understood for this type of device, clinical testing was required to support substantial equivalence. The non-clinical data support the safety of the device and the device verification and validation demonstrate that the HardyCHROM™ ESBL device should perform as intended in the specified use conditions. The analytical and clinical data demonstrate that the HardyCHROM™ ESBL device is substantially equivalent to the predicate device.
§ 866.1700 Culture medium for antimicrobial susceptibility tests.
(a)
Identification. A culture medium for antimicrobial susceptibility tests is a device intended for medical purposes that consists of any medium capable of supporting the growth of many of the bacterial pathogens that are subject to antimicrobial susceptibility tests. The medium should be free of components known to be antagonistic to the common agents for which susceptibility tests are performed in the treatment of disease.(b)
Classification. Class II (performance standards).