(89 days)
Not Found
No
The device is a culture medium that relies on a chemical color change reaction to indicate the presence of bacteria. There is no mention of any computational analysis, algorithms, or learning processes.
No
This device is a diagnostic tool used to detect Group B Streptococcus (GBS) and is not intended for treatment or alleviation of a disease.
Yes
The device is intended for the detection of Group B Streptococcus (GBS) from anovaginal specimens and is used as an aid in the qualitative determination of GBS colonization in pregnant women. This direct clinical application for determining the presence of a specific pathogen indicates its role as a diagnostic device.
No
The device is a selective and differential culture medium (broth) used for detecting bacteria, which is a physical reagent, not software.
Yes, this device is an IVD (In Vitro Diagnostic).
Here's why:
- Intended Use: The intended use clearly states it's for the "detection of Group B Streptococus (GBS) from anovaginal specimens collected from pregnant women" and is used as an "aid in the qualitative determination of GBS colonization in pregnant women." This indicates it's used to test a specimen taken from the human body to provide information about a physiological state (GBS colonization).
- Device Description: It describes a "selective and differential medium" used to identify the presence of GBS based on a color change reaction. This is a common characteristic of IVD devices used in microbiology.
- Performance Studies: The document details performance studies comparing the device to a reference method (LIM Broth routine culture) and provides metrics like sensitivity and specificity. This type of evaluation is required for IVD devices to demonstrate their accuracy and reliability.
- Predicate Device: A predicate device (LIM Broth) is listed, which is a common practice when seeking regulatory clearance for a new IVD device.
All of these factors strongly indicate that the Strep B Carrot Broth™ Kit is an In Vitro Diagnostic device.
N/A
Intended Use / Indications for Use
Strep B Carrot Broth™ Kit is a selective and differential medium which is intended for the detection of Group B Streptococus (GBS) from anovaginal specimens collected from pregnant women. The medium is used as an aid in the qualitative determination of GBS colonization in pregnant women. The color change reaction from white to orange is representative of a positive result for presence of GBS. The medium requires 24 hours of incubation but positive results can be interpreted and reported as early as 16 hours. Due to the properties of Strep B Carrot Broth™ Kit, non-hemolytic GBS cannot be detected by the medium's color change and require subculture for identification. Any presumptive negative indicated by lack of color change at the end of the incubation period must be subcultured to a non-selective medium (e.g., Tryptic Soy Agar with 5% Sheep Blood) to confirm absence of GBS. Subculture must also be performed to recover isolates for conducting susceptibility testing as recommended for penicillin-allergic women.
Product codes (comma separated list FDA assigned to the subject device)
POZ
Device Description
Approximately 10-35% of women are asymptomatic carriers of group B streptococci (GBS) in the genital and gastrointestinal tracts. Group B Streptococi (GBS) remains a leading cause of serious illness and death in newborn populations and, therefore, the detection of Group B Streptococci in the vaginal-anorectal area is critical to the prevention of neonatal GBS disease. The Centers for Disease Control and Prevention (CDC) recommends the screening of all pregnant women for vaginal and rectal Group B Streptococci colonization between 35 and 37 weeks of gestation using an enrichment broth followed by subculture.
Strep B Carrot Broth™ is a selective and differential medium with selective components designed to enrich for Group B Streptococci. The production of a light orange, or red-orange pigment is a unique characteristic of β-hemolytic GBS due to reaction with substrates such as starch, and folate pathway inhibitors. GBS detection by color with Strep B Carrot Broth™ is only possible with ß-hemolytic Group B Streptococci colonies, which provides evidence of a direct genetic linkage between pigment production in this media and hemolysin production. Non-hemolytic GBS can be recovered Strep B Carrot Broth™ upon subculture to 5% sheep blood agar plates.
Mentions image processing
Not Found
Mentions AI, DNN, or ML
Not Found
Input Imaging Modality
Not Found
Anatomical Site
anovaginal specimens (vaginal and rectal)
Indicated Patient Age Range
pregnant women
Intended User / Care Setting
Not Found
Description of the training set, sample size, data source, and annotation protocol
Not Found
Description of the test set, sample size, data source, and annotation protocol
Performance Data: Performance of Strep B Carrot Broth™ was evaluated at four geographically diverse hospitals with routine GBS specimen in the form of an anovaginal swab. The detection of Group B Streptocci by orange color development in Strep B Carrot Broth™ Kit was compared to routine culture, defined as the selective enrichment of specimen in LIM Broth, followed by subculture to Blood Agar and confirmed by biochemical testing. Additionally, the recovery of Group B Streptococi from Strep B Carrot Broth™ that been subsequently subcultured to Blood Agar was also compared to LIM broth routine culture. Organisms that grew on Blood Agar were confirmed to be Group B Streptococci using gram-stain, catalase test, and latex agglutination.
Sample Size: A total of 884 specimens were tested against routine culture, 113 specimens did not meet enrollment criteria, and were therefore excluded from the analysis. Of the remaining 771 valid samples tested.
Annotation Protocol: All discrepant isolates were frozen in CryoSavers™ with Brucella Broth and returned to Hardy Diagnostics for testing. The identity of each isolate was confirmed (β Group B Streptococci, NH Group B Streptococci, or non-Group B Streptococci). Once the identity was confirmed, positive organisms (β Group B Streptococci or NH Group B Streptococi) were tested at LoD (10 CFU/mL) in donated negative-vaginal rectal matrix for their recovery from the LIM reference method, color development in Carrot Broth™ Kit, and recovery from the Carrot Broth™ Kit to Blood Agar System.
Summary of Performance Studies (study type, sample size, AUC, MRMC, standalone performance, key results)
Study Type: Clinical performance study comparing Strep B Carrot Broth™ Kit with a LIM reference method. Evaluation of analytical reactivity, analytical specificity, microbial interference, and incubation time.
Sample Size:
- Clinical Study: 771 valid samples
- Analytical Reactivity: 54 ATCC reference and clinical Group B Streptococci strains
- Analytical Specificity: 78 non-target organisms
- Microbial Interference: Target organisms at LoD with non-target organisms at high concentration (1.5 x 10^6 CFU/mL)
- Incubation Study: 9 beta-hemolytic strains of GBS and 1 non-hemolytic strain of GBS at LoD
Key Results:
- Clinical Performance (Color Reaction vs. LIM Reference Method):
- Overall Sensitivity: 87.73% (95% CI: 81.8-91.9)
- Overall Specificity: 98.83% (95% CI: 97.6-99.4)
- When considering non-hemolytic GBS as negatives, sensitivity and specificity for β-hemolytic GBS: 90.4% (141/156) [95% Cl: 84.7-94.1] and 98.5% (606/615) [95% Cl: 97.2-99.2], respectively.
- Clinical Performance (Color Reaction + Subculture vs. LIM Reference Method):
- Overall Sensitivity: 98.8% (95% CI: 95.6-99.7)
- Overall Specificity: 97.9% (95% CI: 96.4-98.7)
- Analytical Reactivity: Strep B Carrot Broth™ was able to recover both S. agalactiae ATCC 12386 and S. agalactiae ATCC 12403 at a LoD of 10^4 CFU/mL. All beta-hemolytic GBS strains produced the expected orange color. Non-hemolytic strains did not produce color but were recovered upon subculture.
- Analytical Specificity: All 78 non-target organisms tested produced a negative color reaction. 48/78 (61.5%) were recoverable upon subculture.
- Microbial Interference: Strep B Carrot Broth™ produced the expected color reaction and allowed recovery of GBS in the presence of high concentrations of all but one non-target organism (E. faecalis ATCC 29212). S. agalactiae ATCC 12386 produced the expected color reaction when E. faecalis ATCC 29212 was 10^4 CFU/mL or lower. S. agalactiae ATCC 13813 (non-hemolytic) was recovered upon subculture when E. faecalis ATCC 29212 was 10^4 CFU/mL or lower.
- Incubation Study: All hemolytic organisms consistently produced an orange color by 12 hours. All organisms, including the non-hemolytic strain, were recovered upon subculture at 12 hours. Recommended incubation range: 16-24 hours.
- Specimen Stability: GBS strains were recovered and produced orange coloration from certain transport swabs (Healthlink Liquid Amies Stuart's liquid, Amies Gel, Stuart's Gel at 2-8°C for up to 96 hours; TransPRO™ Liquid Amies at 2-8°C for up to 120 hours). Recovery declined after 24 hours at room temperature storage for all transport systems.
- Reproducibility: Agreement of >95% with known test results. Strains in panel produced expected color results >95% of the time at 24 hours. All non-hemolytic GBS isolates (100%) were recovered upon subculture.
Key Metrics (Sensitivity, Specificity, PPV, NPV, etc.)
Overall Sensitivity (Color Reaction vs. LIM Reference Method): 87.73% (95% CI: 81.8-91.9)
Overall Specificity (Color Reaction vs. LIM Reference Method): 98.83% (95% CI: 97.6-99.4)
Overall Sensitivity (Color Reaction + Subculture vs. LIM Reference Method): 98.8% (95% CI: 95.6-99.7)
Overall Specificity (Color Reaction + Subculture vs. LIM Reference Method): 97.9% (95% CI: 96.4-98.7)
Predicate Device(s): If the device was cleared using the 510(k) pathway, identify the Predicate Device(s) K/DEN number used to claim substantial equivalence and list them here in a comma separated list exactly as they appear in the text. List the primary predicate first in the list.
LIM Broth, K871447
Reference Device(s): Identify the Reference Device(s) K/DEN number and list them here in a comma separated list exactly as they appear in the text.
Not Found
Predetermined Change Control Plan (PCCP) - All Relevant Information for the subject device only (e.g. presence / absence, what scope was granted / cleared under the PCCP, any restrictions, etc).
Not Found
§ 866.2360 Selective culture medium.
(a)
Identification. A selective culture medium is a device that consists primarily of liquid or solid biological materials intended for medical purposes to cultivate and identify certain pathogenic microorganisms. The device contains one or more components that suppress the growth of certain microorganisms while either promoting or not affecting the growth of other microorganisms. The device aids in the diagnosis of disease caused by pathogenic microorganisms and also provides epidemiological information on these diseases.(b)
Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 866.9.
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Image /page/0/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a circular seal with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. Inside the circle is a stylized image of a caduceus, a symbol often associated with healthcare, featuring a staff with a serpent entwined around it.
Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
May 16, 2017
HARDY DIAGNOSTICS RIANNA MALHERBE LEAD PERFORMANCE STUDIES MICROBIOLOGIST 1430 WEST MCCOY LANE SANTA MARIA CA 93455
Re: K170481
Trade/Device Name: Strep B Carrot Broth Kit Regulation Number: 21 CFR 866.2360 Regulation Name: Selective culture medium Regulatory Class: I Product Code: POZ Dated: January 20, 2017 Received: February 16, 2017
Dear Ms. Malherbe:
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 (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
1
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/Resourcesfor You/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
2
Indications for Use
510(k) Number (if known) K170481
Device Name Strep B Carrot Broth™ Kit
Indications for Use (Describe)
Strep B Carrot Broth™ Kit is a selective and differential medium which is intended for the detection of Group B Streptococus (GBS) from anovaginal specimens collected from pregnant women. The medium is used as an aid in the qualitative determination of GBS colonization in pregnant women. The color change reaction from white to orange is representative of a positive result for presence of GBS. The medium requires 24 hours of incubation but positive results can be interpreted and reported as early as 16 hours. Due to the properties of Strep B Carrot Broth™ Kit, non-hemolytic GBS cannot be detected by the medium's color change and require subculture for identification. Any presumptive negative indicated by lack of color change at the end of the incubation period must be subcultured to a non-selective medium (e.g., Tryptic Sov Agar with 5% Sheep Blood) to confirm absence of GBS. Subculture must also be performed to recover isolates for conducting susceptibility testing as recommended for penicillin-allergic women.
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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3
Appendix D - 510(k) Summary
I. SUBMITTER
Rianna Malherbe Lead Performance Studies Microbiologist Hardy Diagnostics 1430 W. McCoy Lane Santa Maria, CA 93455 Phone: 805-346-2766 x 5714 E-mail: MalherbeR@hardydiagnostics.com
II. DEVICE
Name of Device: Strep B Carrot Broth™ Kit Classification Name: Selective Culture Medium Regulatory Class: I Product Code: PQZ
III. PREDICATE DEVICE
LIM Broth, K871447
IV. DEVICE DESCRIPTION
Approximately 10-35% of women are asymptomatic carriers of group B streptococci (GBS) in the genital and gastrointestinal tracts. Group B Streptococi (GBS) remains a leading cause of serious illness and death in newborn populations and, therefore, the detection of Group B Streptococci in the vaginal-anorectal area is critical to the prevention of neonatal GBS disease. The Centers for Disease Control and Prevention (CDC) recommends the screening of all pregnant women for vaginal and rectal Group B Streptococci colonization between 35 and 37 weeks of gestation using an enrichment broth followed by subculture.
Strep B Carrot Broth™ is a selective and differential medium with selective components designed to enrich for Group B Streptococci. The production of a light orange, or red-orange pigment is a unique characteristic of β-hemolytic GBS due to reaction with substrates such as starch, and folate pathway inhibitors. GBS detection by color with Strep B Carrot Broth™ is only possible with ß-hemolytic Group B Streptococci colonies, which provides evidence of a direct genetic linkage between pigment production in this media and hemolysin production. Non-hemolytic GBS can be recovered Strep B Carrot Broth™ upon subculture to 5% sheep blood agar plates.
V. INDICATIONS FOR USE
Strep B Carrot Broth™ Kit is a selective and differential medium which is intended for the detection of Group B Streptoccus (GBS) from anovaginal specimens collected from pregnant women. The medium is used as an aid in the qualitative determination of GBS colonization in pregnant women. The color change reaction from white to orange is representative of a positive result for presence of GBS. The medium requires 24 hours of incubation but positive results can be interpreted and reported as early as 16 hours. Due to the properties of Strep B Carrot Broth™ Kit, non-hemolytic GBS cannot be detected by the medium's color change and require subculture for identification. Any presumptive negative indicated by lack of color change at the incubation period must be subcultured to a non-selective medium (e.g., Tryptic Soy Agar with 5% Sheep Blood) to confirm absence of GBS. Subculture must also be performed to recover isolates for conducting susceptibility testing as recommended for penicillin-allergic women.
4
| Attribute | Device | Comparator | Substantially
Equivalent? |
|----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------|
| Name | Strep B Carrot Broth™ Kit | LIM Broth | |
| 510(k) Details | 510(k) number K170481
Product Code PQZ
21 CFR 866.2360
"Culture media, selective and differential"
Class I
Panel 83 Microbiology | 510(k) number K871447
Product Code JSD
21 CFR 866.2360
"Culture Media, Selective Broth"
Class I
Panel 83 Microbiology | Yes |
| Intended Use | Strep B Carrot Broth™ Kit is a selective and
differential medium which is intended for the
detection of Group B Streptococcus (GBS) from
anovaginal specimens collected from pregnant
women. The medium is used as an aid in the
qualitative determination of GBS colonization
in pregnant women. The color change reaction
from white to orange is representative of a
positive result for presence of GBS. The
medium requires 24 hours of incubation but
positive results can be interpreted and
reported as early as 16 hours. Due to the
properties of Strep B Carrot Broth™ Kit, non-
hemolytic GBS cannot be detected by the
medium's color change and require subculture
for identification. Any presumptive negative
indicated by lack of color change at the end of
the incubation period must be subcultured to
a non-selective medium (e.g., Tryptic Soy Agar
with 5% Sheep Blood) to confirm absence of
GBS. Subculture must also be performed to
recover isolates for conducting susceptibility
testing as recommended for penicillin-allergic
women. | Remel Todd Hewitt Broth w/ CNA (Lim
Broth) is a liquid medium recommended for
use in qualitative procedures for the
isolation of Group B Streptococcus (GBS)
from clinical specimens containing mixed
bacterial flora. | Yes |
| Methodology | Enrichment Broth, Chromogenic | Enrichment Broth | Yes |
| Inoculation | Direct | Direct | Yes |
| Sample Type | Vaginal/rectal swab | Vaginal/rectal swab | Yes |
| Interpretation | Manual/visual and subculture negatives | Manual/visual and subculture | Yes |
vi. COMPARISON OF TECHNOLOGICAL CHARACTERISTICS WITH THE PREDICATE DEVICE
5
VII. PERFORMANCE DATA
Performance of Strep B Carrot Broth™ was evaluated at four geographically diverse hospitals with routine GBS specimen in the form of an anovaginal swab. The detection of Group B Streptocci by orange color development in Strep B Carrot Broth™ Kit was compared to routine culture, defined as the selective enrichment of specimen in LIM Broth, followed by subculture to Blood Agar and confirmed by biochemical testing. Additionally, the recovery of Group B Streptococi from Strep B Carrot Broth™ that been subsequently subcultured to Blood Agar was also compared to LIM broth routine culture. Organisms that grew on Blood Agar were confirmed to be Group B Streptococci using gram-stain, catalase test, and latex agglutination.
A total of 884 specimens were tested against routine culture, 113 specimens did not meet enrollment criteria, and were therefore excluded from the analysis. Of the remaining 771 valid samples tested, a total of 143 specimens were positive for Group B Streptococi by orange color development in Strep B Carrot Broth™ after 24 hours of incubation at 35-37ºC with concordant results obtained from the LIM reference method. Those results are shown in Table 1.
All discrepant isolates were frozen in CryoSavers™ with Brucella Broth and returned to Hardy Diagnostics for testing. The identity of each isolate was confirmed (β Group B Streptococci, NH Group B Streptococci, or non-Group B Streptococci). Once the identity was confirmed, positive organisms (β Group B Streptococci or NH Group B Streptococi) were tested at LoD (10° CFU/mL) in donated negative-vaginal rectal matrix for their recovery from the LIM reference method, color development in Carrot Broth™ Kit, and recovery from the Carrot Broth™ Kit to Blood Agar System.
| Site | TP | FP1 | FN2 | TN | Sensitivity | 95% CI | Specificity | 95% CI | ||
|---|---|---|---|---|---|---|---|---|---|---|
| CCP | 47 | 1 | 4 | 141 | 92.2 | 81.5 | 96.9 | 99.3 | 96.1 | 99.9 |
| NY | 34 | 3 | 9 | 137 | 79.1 | 64.8 | 88.6 | 97.9 | 93.9 | 99.3 |
| CC | 26 | 0 | 2 | 83 | 92.9 | 77.4 | 98.0 | 100.0 | 95.6 | 100.0 |
| MCW | 36 | 3 | 5 | 240 | 87.8 | 74.5 | 94.7 | 98.8 | 96.4 | 99.6 |
| Overall | 143 | 7 | 20 | 601 | 87.73 | 81.8 | 91.9 | 98.83 | 97.6 | 99.4 |
Table 1. LIM Reference Method vs. Strep B Carrot Broth™ Kit Color reaction
There were 7 False Positives observed. All isolates were re-tested and confirmed at Hardy Diagnostics using the discrepant analysis protocol described above. Three isolates were originally negative by LIM reference method, showed a positive color reaction in Carrot Broth, but no ß-hemolytic colonies were recovered upon subculture to Blood Agar. Of these three, both Blood Agar plates from one sample (from LIM and CB subcultured plates) were swarmed with Proteus and no β-hemolytic colonies could be isolated for confirmation. No ß-hemolytic colonies were recovered from the frozen samples of the other two isolates, and therefore could not be confirmed. The remaining four discrepant isolates were confirmed to be ß Group B Streptococci.
² There were 20 False Negatives observed. All isolates were re-tested and confirmed at Hardy Diagnostics using the discrepant analysis protocol described above. Fourteen of the β Group B Streptococi isolates recovered from LIM, but originally gave a negative Carrot Broth color reaction, were confirmed as β Group B Streptococi and subsequently confirmed to have a positive Strep B Carrot Broth™ Kit color reaction at LoD. Two isolates were identified as a very weak β Group B Streptococi and did not produce the expected color reaction in Strep B Carrot Broth™ Kit. Four isolates were confirmed as non-hemolytic Group B Streptococci with a negative color reaction in Strep B Carrot Broth™.
3 considering that non-hemolytic GBS cannot be detected by the medium's color change and require subculture for identification, there were seven specimens that were found to be non-hemolytic upon subculture and identification by the reference method. If these specimens are included as negatives, then the overall sensitivity and specificity values observed when comparing the recovery of β-hemolytic GBS by the LIM reference method to the Strep B Carrot Broth™ Kit color reaction were 90.4% (141/156) [95% Cl: 84.7-94.1] and 98.5% (606/615) [95% Cl: 97.2-99.2], respectively.
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When comparing the number of Group B Streptococi positive specimens recovered by the LIM reference method to the number identified by Strep B Carrot Broth™ color change in conjunction with the subculture of presumptive negatives to the Blood Agar, an additional 18 specimens showed concordant positive results for a total of 161 true positive results. The Lim reference method included the identification of both ß-hemolytic GBS from samples by culture. Those results are shown in Table 2.
| Site | TP | FP1 | FN2 | TN | Sensitivity | 95% CI | Specificity | 95% CI | ||
|---|---|---|---|---|---|---|---|---|---|---|
| CCP | 50 | 1 | 1 | 141 | 98.0 | 89.7 | 99.7 | 99.3 | 96.1 | 99.9 |
| NY | 43 | 7 | 0 | 133 | 100.0 | 91.8 | 100.0 | 95.0 | 90.0 | 97.6 |
| CC | 28 | 0 | 0 | 83 | 100.0 | 87.9 | 100.0 | 100.0 | 95.6 | 100.0 |
| MCW | 40 | 5 | 1 | 238 | 97.6 | 87.4 | 99.6 | 97.9 | 95.3 | 99.1 |
| Overall | 161 | 13 | 2 | 595 | 98.8 | 95.6 | 99.7 | 97.9 | 96.4 | 98.7 |
Table 2. LIM Reference Method vs. Strep B Carrot Broth™ Kit (color), plus Subculture of Presumptive Negatives to Blood Agar with Biochemical Testing
' There were thirteen False Positives observed. All isolates were re-tested and confirmed at Hardy Diagnostics using the discrepant analysis protocol described above. All isolates recovered from the Strep B Carrot Broth to Blood Agar system were confirmed to be ß Group B Streptococci.
2 There were two False Negatives observed. Both isolates were re-tested and confirmed at Hardy Diagnostics using the discrepant analysis protocol described above. Both of the ß Group B Streptococi isolates recovered from LIM were confirmed as β Group B Streptococci.
RECOVERY RATE
To determine the recovery (Limit of Detection (LoD)) of Strep B Carrot Broth™, the media was challenged with two beta-hemolytic ATCC strains of Group B Streptococi at 10-fold decreasing concentrations and evaluated for color change. The lowest concentration at which a positive reaction was seen, indicated by an orange color, was determined to be the LoD. The determined by testing Strep B Carrot Broth™ with 20 replicate dilutions of the determined LoD concentrations. Strep B Carrot Broth™ was able to recover both S. agalactiae ATCC 12386 and S. agalactiae ATCC 12403 at a LoD of 10' CFU/mL of the fluid from a flocked anovaginal swab specimen (30 CFU/tube when using a 30μL inoculum). Variable recovery was seen at lower concentrations. Blood Agar plates were used to determine the concentration of organisms present in each dilution.
ANALYTICAL REACTIVITY
Fifty-four ATCC reference and clinical Group B Streptococci strains representing seven of the nine known serotypes were recovered in Strep B Carrot Broth™ when inoculated at the limit of detection concentration of 10° CFU/mL. The GBS serotypes included in this study were serotypes la, Ib, III, IV, V, and VI. Four strains that were nontypable against the nine known serotypes were also included. All the beta-hemolytic strains of Group B Streptococi produced the expected orange color in Strep B Carrot Broth™. The non-hemolytic strains showed no orange color in Strep B Carrot Broth™ but were successfully recovered upon subculture to Blood Agar.
ANALYTICAL SPECIFICITY
Seventy-eight non-target organisms that are phylogenetically-related to Group B Streptococci or potentially encountered in an anovaginal swab were tested in Strep B Carrot Broth™ at a concentration of 10° CFU/mL. All
7
organisms tested are listed in Table 3 below. After 24 hours of incubation, all Carrot Broth tubes were evaluated for color reaction. In order to determine if Strep B Carrot Broth™ supported the growth of non-target organisms in the absence of a color reaction, all negative tubes were subcultured to an appropriate medium for the non-target organism. All organisms tested produced a negative color reaction in Strep B Carrot Broth™ and 48/78 (61.5%) of the organisms were recoverable when subcultured after enrichment.
| Organism | Organism | Organism |
|---|---|---|
| Acinetobacter baumannii | Enterococcus durans | Proteus mirabilis |
| Aeromonas hydrophila | Enterococcus faecalis | Providencia alcalifaciens |
| Aspergillus brasiliensis | Enterococcus faecium | Pseudomonas aeruginosa |
| Bacillus cereus | Enterococcus flavescens | Pseudomonas fluorescens |
| Bacillus subtilis | Enterococcus hirae | Saccharomyces cerevisiae |
| Bacteroides fragilis | Enterococcus raffinosus | Salmonella enterica (typhii) |
| Bifidobacterium breve | Enterococcus saccharolyticus | Salmonella enterica arizonae |
| Campylobacter coli | Escherichia coli | Serratia marcescens |
| Campylobacter jejuni | Gardnerella vaginalis | Shigella boydii |
| Candida albicans | Geotrichum candidum | Shigella flexneri |
| Candida glabrata | Hafnia alvei | Shigella sonnei |
| Candida parapsilosis | Klebsiella oxytoca | Staphylococcus aureus |
| Candida tropicalis | Klebsiella pneumoniae | Staphylococcus epidermidis |
| Citrobacter brakkii | Lactobacillus acidophilus | Staphylococcus saprophyticus |
| Citrobacter freundii | Lactobacillus gasseri | Stenotroph. maltophilia |
| Citrobacter koseri | Lactobacillus leichmannii | Streptococcus mutans |
| Clostridium difficile | Lactococcus lactis | Streptococcus anginosus |
| Clostridium novyi | Legionella pneumophila | Streptococcus bovis |
| Clostridium perfringens | Listeria monocytogenes | Streptococcus dysgalactiae |
| Clostridium sporogenes | Micrococcus luteus | Streptococcus mitis |
| Corynebacterium jekeium | Moraxella catarrhalis | Streptococcus pneumoniae |
| Enterobacter aerogenes | Morganella morganii | Streptococcus pyogenes |
| Enterobacter cloacae | Neisseria gonorrhoeae | Streptococcus salivarius |
| Enterococcus casseliflavus | Pediococcus acidilacti | Streptococcus uberis |
| Enterococcus cecorum | Peptostreptococcus anaerobius | Vibrio parahaemolyticus |
| Enterococcus dispar | Plesiomonas shigelloides | Yersinia enterocolitica |
Table 3. List of non-target organisms tested in Analytical Specificity
MICROBIAL INTERFERENCE
Strep B Carrot Broth™ was challenged to determine if target organisms at low concentration could be recovered in the presence of non-target organisms at a high concentration. All organisms that were recovered upon subculture from Strep B Carrot Broth™ in the Analytical Specificity study were used in this Microbial Interference study. Nontarget organisms at a high concentration (1.5 x 10° CFU/mL) were mixed with each target organism at the LoD and
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inoculated into Strep B Carrot Broth™. If the target organism was not recovered, the concentration of the nontarget organism was lowered 10-fold until the target organism was recovered.
Strep B Carrot Broth™ was able to produce the expected color reaction with target organisms and allowed the recovery of both GBS strains in the presence of high concentrations (1.5 x 10° CFU/mL) of all but one of the nontarget organisms used in this study. The only organism found to affect recovery of Group B Streptococci was E. faecalis ATCC 29212. S. agalactiae ATCC 12386 produced the expected color reaction when the concentration of E. faecalis ATCC 29212 was 10 CFU/mL or lower. S. agalactiae ATCC 13813, a non-hemolytic strain, was recovered upon subculture when the concentration of E. faecalis ATCC 29212 was 10° CFU/mL or lower.
INTERFERENCE
Commonly used or encountered endogenous and exogenous substances that may be present in anovaginal swabs were evaluated for potential interference of growth or chromogenic reaction in Strep B Carrot Broth™. The substances tested are listed in the table below. No interference was observed with any substance at the highest clinically relevant concentration in the GBS-negative specimen matrix.
| Interfering Substances | |||||||
|---|---|---|---|---|---|---|---|
| Category | Substance/Supplier | Concentration in | |||||
| Sample Matrix* | |||||||
| Anti-diarrheal | Pepto-Bismol® (Bismuth subsalicylate solution) | 1% v/v | |||||
| Medication | Imodium A-D® (Loperamide HCl) | 2% w/v | |||||
| Body Oil | Neutrogena Body Oil | 2% v/v | |||||
| Body Powder | Gold Bond Body Powder | 1% w/v | |||||
| Contraceptive Gel | Options Gynol II® (Nonoxynol-9) | 0.59% w/v | |||||
| Enema Solution | Physiological saline | 0.25% v/v | |||||
| Lubricating Gel | K-Y® Jelly | 0.57% w/v | |||||
| Milk of Magnesia | 1.78% v/v | ||||||
| Oral Laxative | Dulcolax® (Sodium picosulfate solution) | 1% w/v | |||||
| Polysorbate 80 | Tween®80 | 10% v/v | |||||
| Rectal Laxative | Fleet® Glycerin Suppositories | 10% v/v | |||||
| Topical Hemorrhoid | |||||||
| Ointment | Preparation-H® | 0.26% w/v | |||||
| Vaginal Anti-Itch | |||||||
| Medication | Vagisil® Cream | 0.41% w/v | |||||
| Vaginal Anti-Fungal | Monistat® (Miconazole nitrate) | 0.29% w/v | |||||
| Medication | Lotrimin® (Clotrimazole) | 0.29% w/v | |||||
| Endogenous Substances | |||||||
| Human Amniotic Fluid | Medfusion | 2% v/v | |||||
| Human Feces | Central Coast Pathology | 2% v/v | |||||
| Human Meconium | LEE Biosolutions | 2% v/v | |||||
| Human Urine | Central Coast Pathology | 2% v/v | |||||
| Human Whole Blood | In-house | 2% v/v | |||||
| Mucin | Sigma, M2378 | 0.05% w/v |
'Specific amounts of substance added to anovaginal specimen matrix calculated using C.V-=C.V2 with the assumption that 1g=1mL.
INCUBATION STUDY
In order to determine a recommended incubation time range, the performance of Strep B Carrot Broth™ was evaluated using nine beta-hemolytic strains of GBS and one non-hemolytic strain of GBS at the LoD from 12 to 24
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hours at 35°C. The enrichment broth was subcultured to a Tryptic Soy Agar plate with 5% sheep blood every two hours to confirm the presence of GBS. All hemolytic organisms tested produced some kind of orange color reaction by 12 hours. All organisms, including the non-hemolytic strain tested, were recovered upon subculture of Strep B Carrot Broth™ at 12 hours. The incubation range for Strep B Carrot Broth™ was set from 16-24 hours.
SPECIMEN STABILITY
Various types of specimen transport swabs were evaluated to determine the acceptable storage conditions required to recover GBS from Strep B Carrot Broth™. Swabs were spiked with Group B Streptococci and a contrived matrix consisting of organisms commonly found in vaginal flora, kept at both room temperature and refrigerated conditions, and were inoculated to Carrot Broth at 0, 24, 48, 72, 96, and 120 hours. Eight different GBS strains were used in this study and were spiked into the contrived matrix near LoD. The contrived matrix containing nontarget organisms consisted of E. faecalis, E. coli, C. albicans, and L. acidophilus. TransPRO™ swabs with Liquid Amies (flocked swab liquid-based transport system) and four types of Healthlink transport systems: Sponge-based Liquid Amies and Liquid Stuart's, and Gel-based: Amies Gel and Stuart's Gel were used in this study.
Strep B Carrot Broth™ was able to recover 8/8 (100%) of GBS strains and produce orange coloration from Healthlink swabs in Liquid Amies Stuart's liquid, Amies Gel, and Stuart's Gel when stored at 2-8°C for up to 96 hours. 100% of GBS strains also produced the expected orange color reaction from the flocked swab TransPRO™ Liquid Amies stored at 2-8°C for up to 120 hours. All transport systems tested saw a decline in recovery of GBS after 24 hours of room temperature storage.
REPRODUCIBILITY
Prior to initiating the study, a panel of 12 blinded isolates provided by Hardy Diagnostics was tested at three distinct study sites in triplicate on five work days to demonstrate reproducibility and to document proficiency in the performance of the test. Agreement of >95% with known test results was required before proceeding with the study. The testing was done with at least one operator and two readers, blinded to each other's results, per site. Strains in the reproducibility panel produced the expected color results with Strep B Carrot Broth™ > 95% of the time at 24 hours. All non-hemolytic GBS isolates tested (100%) were recovered upon subculture to TSA with 5% Sheep's Blood.
CONCLUSIONS
The clinical and performance studies summarized above demonstrate the substantial equivalence of Strep B Carrot Broth™ Kit to the predicate device.