BD MAX STAPHSR ASSAY, INSTRUMENT

K132822 · Geneohm Sciences Canada, Inc. (Bd Diagnostics) · NQX · Nov 26, 2013 · Microbiology

Device Facts

• Record ID: K132822
• Device Name: BD MAX STAPHSR ASSAY, INSTRUMENT
• Applicant: Geneohm Sciences Canada, Inc. (Bd Diagnostics)
• Product Code: NQX · Microbiology
• Decision Date: Nov 26, 2013
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.1640
• Device Class: Class 2

Intended Use

The BD MAX™ StaphSR assay performed on the BD MAX™ System is an automated qualitative in vitro diagnostic test for the direct detection and differentiation of Staphylococcus aureus (SA) and methicillin-resistant Staphylococcus aureus (MRSA) DNA from nasal swabs in patients at risk for nasal colonization. The test utilizes realtime polymerase chain reaction (PCR) for the amplification of MRSA/SA DNA and fluorogenic tarqet-specific hybridization probes for the detection of the amplified DNA. The BD MAX™ StaphSR assay is intended to aid in the prevention and control of MRSA and SA infections in healthcare settings. It is not intended to diagnose MRSA or SA infections nor guide or monitor treatment for MRSA/SA infections. A negative result does not preclude nasal colonization. Concomitant cultures are necessary to recover organisms for epidemiological typing or for further susceptibility testing.

Device Story

BD MAX™ StaphSR is an automated, qualitative in vitro diagnostic assay for nasal swab specimens. It detects and differentiates SA and MRSA DNA using real-time PCR. The system automates sample preparation (lysis, DNA extraction/concentration), reagent rehydration, and amplification/detection. It uses fluorogenic target-specific hybridization probes (TaqMan®) to detect specific amplicons: MREJ (FAM channel), mecA/mecC (ROX channel), nuc (VIC channel), and SPC (Cy5.5 channel). Used in clinical laboratories, the system interprets results automatically. Healthcare providers use these results to aid in the prevention and control of MRSA/SA infections in healthcare settings. The device benefits patients by providing rapid identification of colonization status, facilitating infection control measures.

Clinical Evidence

Multi-site prospective study (n=2354 compliant specimens). Compared to direct/enriched culture reference method. MRSA sensitivity 93.1% (95% CI: 88.1-96.1%), specificity 97.5% (95% CI: 96.8-98.1%). SA sensitivity 92.0% (95% CI: 89.7-93.9%), specificity 93.1% (95% CI: 91.8-94.2%). Bench testing included precision, reproducibility, analytical sensitivity (LoD 64-343 CFU/swab), inclusivity, specificity, and interference studies.

Technological Characteristics

Automated real-time PCR assay on BD MAX™ System. Uses disposable microfluidic cartridges, master mixes, and unitized reagent strips. Detection via hydrolysis (TaqMan®) probes in four optical channels (FAM, ROX, VIC, Cy5.5). Targets: MREJ (SCCmec right-extremity junction), mecA/mecC (methicillin resistance), nuc (S. aureus), and SPC (internal control). Automated sample prep includes enzymatic lysis and magnetic bead-based DNA extraction.

Indications for Use

Indicated for direct detection and differentiation of S. aureus (SA) and methicillin-resistant S. aureus (MRSA) DNA from nasal swabs in patients at risk for nasal colonization. Not for diagnosing infections or guiding/monitoring treatment. Negative results do not preclude colonization; concomitant cultures required for typing or susceptibility testing.

Regulatory Classification

Identification

An antimicrobial susceptibility test powder is a device that consists of an antimicrobial drug powder packaged in vials in specified amounts and intended for use in clinical laboratories for determining in vitro susceptibility of bacterial pathogens to these therapeutic agents. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.

Predicate Devices

• BD MAX™ MRSA (K120138)
• BD GeneOhm™ StaphSR Assay (K071026)

Submission Summary (Full Text)

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K132822.

510(k) Summary

November 19, 2013

# BD Diagnostics BD MAX™ StaphSR

Submitted by:

GeneOhm Sciences Canada Inc. (BD Diagnostics) 2555 Boul. Parc-Technologique Quebec (Quebec), Canada G1P 4S5

Contact:

Device:

NOV 2 6 2013

510(k) Number:

Trade Name:

BD MAX™ StaphSR

K132822

Patricia Dionne, Ph.D.

Common Name:

Type of Test:

Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus Qualitative Nucleic Acid Amplification Test from nasal swab specimens

Staphylococcus aureus and Methicillin-resistant

Staphylococcus aureus detection assay

Classification:

Antimicrobial susceptibility test powder Requlation Name:

ll

866.1640 Requiation Number:

Product Code: NQX: OOI

Microbiology (83) Panel:

Predicate Devices: BD MAX™ MRSA and BD GeneOhm™ StaphSR Assay

Predicate 510(k) Numbers: K120138 and K071026

#### Intended Use:

The BD MAX™ StaphSR assay performed on the BD MAX™ System is an automated qualitative in vitro diagnostic test for the direct detection and differentiation of Staphylococcus aureus (SA) and methicillin-resistant Staphylococcus aureus (MRSA) DNA from nasal swabs in patients at risk for nasal colonization. The test utilizes realtime polymerase chain reaction (PCR) for the amplification of MRSA/SA DNA and fluorogenic tarqet-specific hybridization probes for the detection of the amplified DNA. The BD MAX™ StaphSR assay is intended to aid in the prevention and control of MRSA and SA infections in healthcare settings. It is not intended to diagnose MRSA or SA infections nor guide or monitor treatment for MRSA/SA infections. A negative result does

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not preclude nasal colonization. Concomitant cultures are necessary to recover organisms for epidemiological typing or for further susceptibility testing.

#### Indication for Use:

The BD MAX™ StaphSR assay performed on the BD MAX™ System is an automated qualitative in vitro diagnostic test for the direct detection and differentiation of Staphylococcus aureus (SA) and methicillin-resistant Staphylococcus aureus (MRSA) DNA from nasal swabs in patients at risk for nasal colonization. The test utilizes realtime polymerase chain reaction (PCR) for the amplification of MRSA/SA DNA and fluorogenic target-specific hybridization probes for the amplified DNA. The BD MAX™ StaphSR assay is intended to aid in the prevention and control of MRSA and SA infections in healthcare settings. It is not intended to diagnose MRSA or SA infections nor guide or monitor treatment for MRSA/SA infections. A negative result does not preclude nasal colonization. Concomitant cultures are necessary to recover organisms for epidemiological typing or for further susceptibility testing.

#### Special Conditions for Use Statement:

For prescription use

#### Special Instrument Requirements:

The BD MAX™ System

#### Device Description:

The BD MAX™ System and the BD MAX™ StaphSR assay are comprised of an instrument with associated hardware and accessories, disposable microfluidic cartridges, master mixes, unitized reagent strips, extraction reagents, and sample buffer tubes. The instrument automates sample preparation including target lysis, DNA extraction and concentration, reagent rehydration, and target nucleic acid amplification and detection using real-time PCR. The assay includes a Sample Processing Control (SPC) that is present in the Extraction Tube. The SPC monitors DNA extraction steps, thermal cycling steps, reagent integrity and the presence of inhibitory substances. The BD MAX™ System software automatically interprets test results. A test result may be called as [SA NEG MRSA NEG (negative)], [SA POS, MRSA POS (MRSA positive)], [SA POS, MRSA NEG (SA positive)] or [SA UNR, MRSA UNR (Unresolved)] based on the amplification status of the target and of the Sample Processing Control. IND (Indeterminate) or INC (Incomplete) results are due to BD MAX™ System failure.

#### Test Principle:

The BD MAX™ StaphSR assay performed on the BD MAX™ System is an automated in vitro diagnostic test for the direct, qualitative detection and differentiation of the Staphylococcus aureus (SA) and methicillin-resistant Staphylococcus aureus (MRSA) DNA from nasal swabs in patients at risk for nasal colonization.

A nasal specimen is collected and transported to the laboratory using the recommended swab. The swab is placed in a BD MAX™ StaphSR Sample Buffer Tube. The Sample

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Buffer Tube is closed with a septum cap and vortexed. A worklist is created and the Sample Buffer Tube, the BD MAX™ StaphSR unitized reagent strip and the BD MAX™ PCR Cartridge are loaded onto the BD MAX™ System.

Following enzymatic cell lysis, the released nucleic acids are captured on magnetic i beads. The beads, with the bound nucleic acids, are washed using Wash Buffer and the nucleic acids are eluted by heat in Elution Buffer. Eluted DNA is neutralized using Neutralization Buffer and transferred to a Master Mix to rehydrate PCR reagents. After reconstitution, the BD MAX™ System dispenses a fixed volume of PCR-ready solution containing extracted nucleic acids into the BD MAX™ PCR Cartridge. Microvalves in the BD MAX™ PCR Cartridge are sealed by the system prior to initiating PCR to contain the amplification mixture, thus preventing evaporation and contamination.

The amplified DNA targets are detected using hydrolysis (TagMan®) probes labeled at one end with a fluorescent reporter dye (fluorophore) and at the other end with a quencher moiety. Probes labeled with different fluorophores are used to detect a specific amplicon in the SCCmec right-extremity junction (MREJ), the genes for methicillin resistance mecA and mecC, the nuc gene encoding a thermostable nuclease of S. aureus and SPC amplicons in four different optical channels of the BD MAX™ System: MREJ amplicons are detected in the FAM channel, mecA and mecC amplicons are detected in the ROX channel, nuc amplicons are detected in the VIC channel and SPC amplicons are detected in the Cy5.5 channel. When the probes are in their native state, the fluorescence of the fluorophore is quenched due to its proximity to the quencher. However, in the presence of target DNA, the probes hybridize to their complementary sequences and are hydrolyzed by the 5-3' exonuclease activity of the DNA polymerase as it synthesizes the nascent strand along the DNA template. As a result, the fluorophores are separated from the quencher molecules and fluorescence is emitted. The amount of fluorescence detected in the four optical channels used for the BD MAX™ StaphSR assay is directly proportional to the quantity of the corresponding probe that is hydrolyzed. The BD MAX™ System measures these signals at the end of each amplification cycle, and interprets the data to provide a result.

#### Substantial Equivalence:

Table 1 shows the similarities and differences between the BD MAX™ StaphSR assay and the predicate devices.

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| | DEVICE | PREDICATE | |
|-------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| ITEM | BD MAX™ StaphSR<br>(K132822) | BD GeneOhm StaphSR<br>Assay (K071026) | BD MAX MRSA Assay<br>(K120138) |
| Intended Use | The BD MAX™ StaphSR assay<br>performed on the BD MAX ™<br>System is an automated<br>qualitative in vitro diagnostic test<br>for the direct detection and<br>differentiation of Staphylococcus<br>aureus (SA) and methicillin-<br>resistant Staphylococcus aureus<br>(MRSA) DNA from nasal swabs<br>in patients at risk for nasal<br>colonization. The test utilizes<br>real-time polymerase chain<br>reaction (PCR) for the<br>amplification of MRSA/SA DNA<br>and fluorogenic target-specific<br>hybridization probes for the<br>detection of the amplified DNA.<br>The BD MAX™ StaphSR assay<br>is intended to aid in the<br>prevention and control of MRSA<br>and SA infections in healthcare<br>settings. It is not intended to<br>diagnose MRSA or SA infections<br>nor guide or monitor treatment<br>for MRSA/SA infections. A<br>negative result does not<br>preclude nasal colonization.<br>Concomitant cultures are<br>necessary to recover organisms<br>for epidemiological typing or for<br>further susceptibility testing. | The BD GeneOhm™ StaphSR<br>Assay is a qualitative in vitro<br>diagnostic test for the rapid<br>detection of Staphylococcus<br>aureus (SA) and methicillin-<br>resistant Staphylococcus<br>aureus (MRSA) directly from<br>positive blood culture. The<br>assay utilizes polymerase<br>chain reaction (PCR) for the<br>amplification of specific targets<br>and fluorogenic target-specific<br>hybridization probes for the<br>real-time detection of the<br>amplified DNA. The assay is<br>performed on Gram positive<br>cocci, identified by Gram stain,<br>from positive blood cultures.<br>The BD GeneOhm™ StaphSR<br>Assay is not intended to<br>monitor treatment for<br>MRSA/SA infections.<br>Subculturing of positive blood<br>cultures is necessary for<br>further susceptibility testing. | The BD MAX™ MRSA Assay<br>performed on the BD MAX ™<br>System is an automated<br>qualitative in vitro diagnostic<br>test for the direct detection of<br>Methicillin-resistant<br>Staphylococcus aureus (MRSA)<br>DNA from nasal swabs in<br>patients at risk for nasal<br>colonization. The test utilizes<br>real-time polymerase chain<br>reaction (PCR) for the<br>amplification of MRSA DNA and<br>fluorogenic target-specific<br>hybridization probes for the<br>detection of the amplified DNA.<br>The BD MAX™ MRSA Assay is<br>intended to aid in the prevention<br>and control of MRSA infections<br>in healthcare settings. It is not<br>intended to diagnose, guide or<br>monitor MRSA infections. A<br>negative result does not<br>preclude nasal colonization.<br>Concomitant cultures are<br>necessary to recover organisms<br>for epidemiological typing or for<br>further susceptibility testing. |
| Specimen type | Nasal swabs | Positive blood culture | Nasal swabs |
| Assay Format | Amplification: PCR<br>Detection: Fluorogenic target-<br>specific hybridization | Same | Same |
| Mode of Detection<br>for Methicillin<br>Resistance in<br>S.aureus | Presence of SCCmec cassette<br>at orfX junction and mecA or<br>mecC genes | Presence of SCCmec cassette<br>at orfX junction (specific to S.<br>aureus) | Presence of SCCmec cassette<br>at orfX junction (specific to S.<br>aureus) |
| Mode of Detection<br>for SA | Presence of nuc gene specific<br>for SA | Same | Not detected |
| Interpretation of<br>Test Results | Automated (Diagnostic software<br>of BD MAX™ System) | Automated (Diagnostic<br>software of SmartCycler®<br>System) | Automated (Diagnostic software<br>of BD MAX™ System) |
| Analysis Platform | BD MAX™ System | SmartCycler® System | BD MAX™ System |
| PCR Sample<br>Preparation | Automated by the BD MAX TM<br>System | Manual | Automated by the BD MAX TM<br>System |
| Detection Probes | TaqMan® Probe | Molecular Beacon Probe | TaqMan® Probe |
| ITEM | DEVICE | PREDICATE | |
| | BD MAX™ StaphSR<br>(K132822) | BD GeneOhm StaphSR<br>Assay (K071026) | BD MAX MRSA Assay<br>(K120138) |
| Assay Controls | Specimen Processing Control<br>(SPC) | Positive PCR control (DNA<br>from <i>S.aureus</i> ATCC 43300).<br>Negative control (DNA from<br><i>S.epidermidis</i> ATCC 14990).<br>Internal Control | Specimen Processing Control<br>(SPC) |

# Table 1: Substantial Equivalence Information

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# Analytical Performance:

# Precision

Within-laboratory precision was evaluated for the BD MAX™ StaphSR assay at one (1) site. The Precision panel consisted of 4 sample categories near the LoD. Each specimen contained simulated nasal matrix. MRSA and MSSA strains were tested as follows:

- Moderate Positive (MP) MRSA (MREJ Type ii): ≥ 2 and ≤ 5 x LoD .
- Low Positive (LP) MRSA (MREJ Type ii): ≥ 1 and < 2 x LoD .
- Low Positive (LP) MRSA (MREJ Type vii): ≥ 1 and < 2 x LoD .
- Low Positive (LP) MSSA: ≥ 1 and < 2 x LoD .
- High Negative (HN) MRSA (MREJ Type ii): < 1 x LoD .
- High Negative (HN) MSSA: < 1 x LoD .
- True negative (TN): Negative specimens (no target) .

Testing was performed in duplicate, over 12 days, with 2 runs per day, by 2 different technologists. Precision study results for TN, MP, LP, and HN MRSA samples demonstrated 100%, 100%, 97.9%, and 27.1% agreement, respectively. Precision study results for LP and HN MSSA samples demonstrated 100%, and 56.2% agreement, respectively.

# Reproducibility

The reproducibility study was performed using the same sample categories as defined above for the Precision Study.

Samples in each category were tested in triplicate, on 5 distinct days, wherein each day 2 panels were tested by 2 different technologists, at 3 clinical sites using 1 lot of reagents (Site-to-Site). One (1) of these clinical sites participated in an extended study where 2 additional lots of reagents were tested (Lot-to-Lot). Results are shown for each sample category with the data from both MRSA strains pooled and MSSA strains.

For Site-to-Site Reproducibility, the overall percent agreement was 100% for MRSA MP and TN categories; 96.7% and 97.8% for MRSA LP and MSSA LP, respectively; and 36.7% and 30.0% for MRSA HN and MSSA HN, respectively (Table 2).

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| | SITE | | | | | | | | |
|----------|----------------------|-------|----------------------|--------|----------------------|-------|-----------------|-----------------|--|
| Category | Site 1 | | Site 2 | | Site 3 | | Overall Percent | | |
| | Percent<br>Agreement | Count | Percent<br>Agreement | Count | Percent<br>Agreement | Count | | Agreement | |
| HN1 MSSA | 16.7% | 5/30 | 23.3% | 7/30 | 50.0% | 15/30 | 30.0% | (21.5%, 40.1%)2 | |
| HN MRSA | 40.0% | 12/30 | 26.7% | 8/30 | 43.3% | 13/30 | 36.7% | (27.4%, 47.0%) | |
| LP MSSA | 96.7% | 29/30 | 100.0% | 30/30 | 96.7% | 29/30 | 97.8% | (92.3%, 99.4%) | |
| LP MRSA | 95.0% | 57/60 | 98.3% | રુજીકા | 96.7% | 28160 | 96.7% | (92.9%, 98.5%) | |
| MP MRSA | 100.0% | 30/30 | 100.0% | 30/30 | 100.0% | 30/30 | 100.0% | (95.9%, 100.0%) | |
| TN | 100.0% | 30/30 | 100.0% | 30/30 | 100.0% | 30/30 | 100.0% | (95.9%, 100.0%) | |

Table 2. Site-To-Site Reproducibility Study Results Using One Lot of the BD MAX™ StaphSR Assay

1Percent Agreement correlates to the percent of negative results.

2Confidence Interval

For Lot-to-Lot Reproducibility, the overall percent agreement was 100% for MRSA MP and TN; 96.7% for MRSA LP and MSSA LP; 40.0% and 44.4% for MRSA HN and MSSA HN, respectively (Table 3).

Table 3. Lot-To-Lot Reproducibility Study Results using Three Lots of the BD MAX™ StaphSR Assay

| | LOT | | | | | | | | |
|-----------------------|----------------------|-------|----------------------|-------|----------------------|-------|-----------------|-----------------|--|
| Category | Lot 1 | | Lot 2 | | Lot 3 | | Overall Percent | | |
| | Percent<br>Agreement | Count | Percent<br>Agreement | Count | Percent<br>Agreement | Count | Agreement | | |
| HN 1 MSSA | 50.0% | 15/30 | 36.7% | 11/30 | 46.7% | 14/30 | 44.4% | (34.6%, 54.7%)2 | |
| HN MRSA | 43.3% | 13/30 | 43.3% | 13/30 | 33.3% | 10/30 | 40.0% | (30.5%, 50.3%) | |
| LP MSSA | 96.7% | 29/30 | 93.3% | 28/30 | 100.0% | 30/30 | 96.7% | (90.7%, 98.9%) | |
| LP MRSA | 96.7% | 58/60 | 96.7% | 58/60 | 96.7% | 58/60 | 96.7% | (92.9%, 98.5%) | |
| MP MRSA | 100.0% | 30/30 | 100.0% | 30/30 | 100.0% | 30/30 | 100.0% | (95.9%, 100.0%) | |
| TN | 100.0% | 30/30 | 100.0% | 30/30 | 100.0% | 30/30 | 100.0% | (95.9%, 100.0%) | |

1Percent Agreement correlates to the percent of negative results. 2Confidence Interval

Site-to-Site and Lot-to-Lot Reproducibility performance was acceptable for the LP, MP, and TN sample categories. No specific acceptance criteria was defined for the high negative sample category.

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Second Derivative Peak Abscissa (SDPA), an underlying numerical value used to determine a final assay result, was selected as an additional means of assessing assay reproducibility. Overall mean SDPA values with variance components (SD and %CV) are shown in Table 4.

| | | Site-to-Site | | | Lot-to-Lot | | |
|------------------------------------------------------------------------|------|--------------------|---------|---------|--------------------|---------|---------|
| | | HN MRSA | LP MRSA | MP MRSA | HN MRSA | LP MRSA | MP MRSA |
| MREJ1 (MREJ<br>types pooled,<br>FAM Channel) | N | 33 | 174 | 90 | 35 | 174 | 90 |
| | Mean | 33.5 | 31.1 | 30.7 | 33.4 | 31.0 | 30.8 |
| | SD | 0.72 | 1.05 | 0.71 | 0.72 | 0.94 | 0.37 |
| | %CV | 2.2% | 3.4% | 2.3% | 2.2% | 3.0% | 1.2% |
| <i>mecA</i> or <i>mecC</i> 2<br>(MREJ types<br>pooled, ROX<br>Channel) | N | 33 | 174 | 90 | 35 | 174 | 90 |
| | Mean | 35.1 | 31.8 | 31.1 | 35.0 | 31.7 | 31.1 |
| | SD | 1.16 | 1.42 | 0.78 | 1.15 | 1.36 | 0.54 |
| | %CV | 3.3% | 4.5% | 2.5% | 3.3% | 4.3% | 1.7% |
| | | HN MREJ<br>Type ii | HN MSSA | LP MSSA | HN MREJ<br>Type ii | HN MSSA | LP MSSA |
| <i>nuc</i> 3<br>(VIC Channel) | N | 24 | 63 | 88 | 19 | 50 | 87 |
| | Mean | 34.9 | 34.8 | 32.0 | 35.2 | 34.8 | 32.0 |
| | SD | 1.78 | 1.69 | 1.12 | 1.85 | 1.57 | 0.78 |
| | %CV | 5.1% | 4.9% | 3.5% | 5.2% | 4.5% | 2.4% |
| | | HN MREJ<br>Type ii | HN MSSA | TN | HN MREJ<br>Type ii | HN MSSA | TN |
| SPC4<br>(Cy5.5 Channel) | N | 33 | 27 | 90 | 36 | 40 | 90 |
| | Mean | 30.0 | 30.3 | 30.2 | 29.9 | 30.0 | 30.0 |
| | SD | 0.79 | 0.68 | 0.63 | 0.49 | 0.43 | 0.45 |
| | %CV | 2.6% | 2.2% | 2.1% | 1.7% | 1.4% | 1.5% |

| Table 4. Site-to-Site and Lot-to-Lot Reproducibility Study Underlying Numerical SDPA | |
|--------------------------------------------------------------------------------------|--|
| Overall Results | |

'Values shown are those obtained for the MREJ target in the samples that gave a SA POS, MRSA POS result

2Values shown are those obtained for the mech or mec target in the samples that gave a SA POS, MRSA POS result

3Values shown are those obtained for the nuc target in the samples that gave a SA POS, MRSA NEG result 4 Calculated for the Specimen Processing Control of the samples that gave a SA NEG, MRSA NEG result

# Sample Storage

Specimens can be stored at25 ±2°C for a maximum of 48 hours or at 2-8 °C for a maximum of 120 hours (5 days) before testing. In case of repeat testing from the Sample Buffer Tube, the following storage conditions apply:

- within 36 hours of the steps covered in the Specimen Preparation section of the . package insert, when stored at 25 ±2℃ or
- up to 120h (5 days) after the end of the initial run when stored at 2-8°C. .

# Controls

External Control materials are not provided by BD. Various types of External Controls are recommended to allow the user to select the most appropriate for their laboratory quality control program:

- Commercially available control materials [e.g. a reference MRSA strain (ATCC -43300), and Methicillin-susceptible Staphylococcus aureus strain (e.g. ATCC 29213) can be used as positive controls. Staphylococcus epidermidis strain (e.g. ATCC 12228) can be used as negative control.].

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- Previously characterized specimens known to be positive or negative for S. aureus or MRSA.
The assay includes a Sample Processing Control (SPC) that is present in the Extraction Tube. The SPC monitors DNA extraction steps, thermal cycling steps, reagent integrity and the presence of inhibitory substances.

#### Analytical Sensitivity

The analytical sensitivity (Limit of Detection or LoD) for the BD MAX™ StaphSR assay was determined as follows: positive specimens were prepared by soaking swabs in a wide range of MRSA or MSSA bacterial suspensions prepared and quantified from cultures. The tested strains included 11 MRSA strains representing 11 MREJ genotypes (i, ii, iii, iv, v, vi, vii, ix, xiii, xiv and xxi) corresponding to 5 SCCmec types (1, II, III, IV and XI) as well as 2 MSSA strains. The swabs were then eluted in simulated nasal matrix. Each MRSA and MSSA strain was tested in replicates of 24 per concentration by 2 different operators using 3 different production lots of the BD MAX™ StaphSR assay. Analytical sensitivity (LoD), defined as the lowest concentration at which at least 95% of all replicates tested positive, ranged from 64 to 343 CFU/swab (Table 5) for the detection of MRSA strains and from 174 to 211 CFU/swab (Table 6) for the detection of MSSA strains.

| MRSA Strain | MREJ Genotype | SCCmec type | LoD Concentration<br>[CFU/swab (95% CI²)] |
|-------------|---------------|-------------|-------------------------------------------|
| 1 | Type i | I | 84 (49, 142) |
| 2 | Type ii | II | 103 (64, 167) |
| 3 | Type iii | III | 160 (93, 278) |
| 4 | Type iv | III | 68 (42, 109) |
| 5 | Type v | IV | 128 (73, 225) |
| 6 | Type vi | ND³ | 343 (186, 632) |
| 7 | Type vii | II | 219 (110, 439) |
| 8 | Type ix | ND³ | 144 (82, 255) |
| 9 | Type xiii | ND³ | 64 (36, 114) |
| 10 | Type xiv | ND³ | 78 (48, 127) |
| 11 | Type xxi | XI | 112 (64, 197) |

Table 5: Limit of Detection of MRSA Genotypes by the BD MAX™ StaphSR Assay

SCCmec type does not correlate to the MREJ type as these are two different typing methods. CI: Confidence Intervals

ND = not determined

mecc-containing MRSA strains (Also known as mecAuga25; strain)

| | | Table 6: Limit of Detection of MSSA by the | | |
|--|--|--------------------------------------------|--|--|
| | | BD MAX™ StaphSR Assay | | |

| MSSA Strain | LoD Concentration [CFU/swab<br>(95% CI)] |
|-------------|------------------------------------------|
| 1 | 174 (89, 341) |
| 2 | 211 (105, 428) |

1Cl: Confidence Intervals

#### Analytical Inclusivity

An analytical inclusivity study was performed using a variety of MRSA and MSSA strains, taking into account geographic origin, MREJ genotype (wild type and mutant), SCCmec type. Pulsed-Field Gel Electrophoresis (PFGE) type, temporal diversity and susceptibility pattern. Seventy-seven (77) MRSA strains from 27 countries (see Table 7) and 51 MSSA strains from 16 countries were tested in this study, including strains

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from public collections and from well-characterized clinical isolates, including Vancomycin-Resistant Staphylococcus aureus (VRSA) and Vancomycin Intermediate Staphylococcus aureus (VISA) strains.

The BD MAX™ StaphSR assay detected MREJ types i, ii, iii, iv, v, vi, vii, ix, xiii, xiv and xxi when tested at low bacterial load (2-3 x LoD). The BD MAX™ StaphSR assay detected MRSA SCCmec types 1, II, III, IV, V, VI, VII, VIII, VIII and XI as well as MRSA PFGE types USA 100 to 800, 1000 and 1100 at 2-3 x LoD. All MRSA strains displaying additional resistance to vancomycin (VRSA and VISA) were also detected. The BD MAX™ StaphSR assay detected all 51 MSSA strains tested including mecA empty cassette variants.

| Collection | Reference,<br>Number | MREJ<br>Type | SCCmec<br>typing / PFGE<br>type |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------|--------------|---------------------------------|
| ATCC | ATCC BAA-1770 | iii | USA1000 |
| | ATCC BAA-421 | ii | VI |
| | ATCC BAA-38 | i | I |
| | ATCC BAA-41 | ii | II |
| | ATCC BAA-39 | iii | III |
| | ATCC BAA-40 | iv | III |
| | ATCC 43300 | ii | II |
| | ATCC 33592 | iv | III |
| Harmony<br>collection of<br>European<br>epidemic<br>MRSA | 62305 | ii mut36 | IV |
| | 97S99 | ii mut45 | IV |
| | 3717 | iii | III |
| | 9805-01937 | iii mut45 | ND |
| LSPQ | ID-61882 | iii | III / CMRSA-3 |
| | ID-61880 | vii | II / CMRSA-1 |
| NARSA | NRS383 | ii | II / USA200 |
| | NRS385 | ii | IV / USA500 |
| | NRS715 | ii | II/USA600 |
| | NRS386 | ii | IV / USA700 |
| | NRS686 | i | IV/IBERIAN |
| | NRS234 | ii | II |
| | VRS53 | ii | ND |
| | NRS14 | ii | II |
| | NRS44 | ii | II |
| | VRS23 | ii | ND |
| | VRS41,3 | ii | ND |
| | NRS382 | ii | II / USA100 |
| | NRS384 | ii | IV / USA300 |
| | NRS387 | ii | IV / USA800 |
| | NRS484 | ii | IV / USA1100 |
| | NRS645 | ii | IV/IBERIAN |
| | NRS123 | ii mut36 | IV / USA400 |
| NA | NA | ii | II / USA 100 |
| | NA | iii | II / USA 100 |
| | 5599 | ii | II / USA100 |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------<br>Collection | Reference | | SCCmed<br>voing / P<br>type |
| | 7909 | li | IV / USA300 |
| | 7916 | ii | IV / USA300 |
| | 7917 | ii | IV / USA300 |
| | 7921 | li | IV / USA300 |
| | 7922 | li | IV / USA300 |
| | 7913 | ii mut36 | IV / USA400 |
| | NA | ll | IV / USA 800 |
| | 1555 | XXI | ND |
| | MAH 305 | xxi | ND |
| | CCRI-11840 | i | VIII · |
| | JCSC6082 | iii | VII |
| | 92 | xili | ND |
| | 2100 | xiv | ND |
| | CCRI-12480 | li | ND |
| | CCRI-12496 | li | ND |
| | CCRI-12640 ² | li | ND |
| | CCRI-9866 2 | ii mut36 | ND |
| | 48 | iiii | V |
| | 347101 | iii | V |
| | CCRI-12503 | lli | ND |
| | CCRI-12790 | lii | ND |
| | CCRI-12608 | iv | ND |
|…