BACTEC FUNGAL MEDIUM

K954923 · Becton Dickinson Diagnostic Instrument Systems · JTA · Nov 21, 1996 · Microbiology

Device Facts

• Record ID: K954923
• Device Name: BACTEC FUNGAL MEDIUM
• Applicant: Becton Dickinson Diagnostic Instrument Systems
• Product Code: JTA · Microbiology
• Decision Date: Nov 21, 1996
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.2560
• Device Class: Class 1

Indications for Use

Qualitative culture and recovery of yeasts and fungi from blood

Device Story

BACTEC Fungal Medium is a specialized growth medium for aerobic detection of yeast and fungi in blood samples (4-10 mL). Used with BACTEC non-radiometric (NR) series instruments; device relies on infrared spectrophotometric measurement of CO2 produced by microbial metabolism. Medium contains enriched brain heart infusion broth, saponin (lysing agent), and ferric ammonium citrate (iron source) to stimulate fungal recovery; dextrose and sucrose concentrations are optimized for yeast. Resin is absent. Healthcare providers use the instrument to monitor vials; detection of CO2 indicates microbial presence. Device benefits patients by providing an optimized environment for fungal recovery compared to standard bacterial culture media.

Clinical Evidence

Multi-center study at four hospitals compared BACTEC Fungal Medium against BACTEC PLUS 26 (n=4886 pairs) and ISOLATOR System (n=4907 pairs). For BACTEC PLUS 26 comparison, 68 fungal isolates were recovered; BACTEC Fungal Medium showed statistically significantly better recovery of all fungi combined and Torulopsis glabrata (p < 0.025). No significant difference in speed of detection. Compared to ISOLATOR, recovery was equivalent for most fungi, though ISOLATOR was superior for Histoplasma capsulatum (p < 0.001). T. glabrata was detected significantly earlier in BACTEC Fungal Medium (p < 0.05).

Technological Characteristics

Growth medium: Enriched brain heart infusion broth with CO2. Lysing agent: Saponin (0.24% w/v). Additives: Ferric ammonium citrate, dextrose, sucrose, m-Inositol, anti-foaming agent, SPS, chloramphenicol, tobramycin. Form factor: Type III soda lime glass vial with rubber closure. Detection principle: Infrared spectrophotometric measurement of CO2 via invasive vial headspace sampling. Incubation: 35°C ± 1.5°C with orbital agitation.

Indications for Use

Indicated for the qualitative culture and recovery of yeasts and fungi from clinical blood specimens (4-10 mL) in patients suspected of having fungal or yeast infections.

Regulatory Classification

Identification

A microbial growth monitor is a device intended for medical purposes that measures the concentration of bacteria suspended in a liquid medium by measuring changes in light scattering properties, optical density, electrical impedance, or by making direct bacterial counts. The device aids in the diagnosis of disease caused by pathogenic microorganisms.

Predicate Devices

• BACTEC® PLUS 26 Culture Vials

Reference Devices

• ISOLATOR™ Microbial Tubes/ISOSTAT® Microbial System

Submission Summary (Full Text)

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K954923

510(k) SUMMARY

NOV 21 1996

SUBMITTED BY: BECTON DICKINSON DIAGNOSTIC INSTRUMENT SYSTEMS
7 LOVETON CIRCLE
SPARKS, MD 21152

CONTACT: Dennis Mertz, Manager Regulatory Affairs
TELEPHONE: [phone]
FAX: [phone]

PREPARED: October 25, 1995

DEVICE NAME: BACTEC® Fungal Medium

PREDICATE DEVICE: BACTEC® PLUS 26 Culture Vials

INTENDED USE: Qualitative culture and recovery of yeasts and fungi from blood

## DEVICE DESCRIPTION:

BACTEC Fungal Medium is a growth medium providing an aerobic environment for the detection of yeast and fungi. It has been designed for blood volumes of four to 10 mL, and is used specifically with BACTEC non-radiometric (NR) series instruments in the monitoring of clinical blood specimens for the presence of yeasts and fungi. BACTEC Fungal medium has a higher weight/volume concentration of dextrose and sucrose than the predicate device to enhance the recovery and CO₂ production of yeast. Saponin was added to the BACTEC Fungal Medium as a lysing agent, and ferric ammonium citrate was added as a source of iron to stimulate recovery of fungi other than yeast. Resin was removed from this medium. Principles for detection of CO₂ produced by microorganisms metabolizing blood culture medium nutrients are identical to the predicate device.

## SUBSTANTIAL EQUIVALENCE:

Table 1 summarizes the similarities and differences between BACTEC® Fungal Medium and BACTEC® PLUS 26 Culture Vials.

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Table 1. Substantial Equivalence of BACTEC® Fungal Medium to BACTEC® PLUS 26 Culture Vials

| | BACTEC®Fungal Medium | BACTEC® PLUS 26 |
| --- | --- | --- |
| Intended use | Qualitative culture and recovery of yeasts and fungi | Qualitative culture and recovery of aerobic microorganisms (mainly bacteria and fungi) |
| Sample type | Blood | Blood |
| Sample volume | 4 - 10 mL | 5 - 10 mL |
| Blood to broth ratio | 1 to 2.5 | 1 to 2.5 |
| Growth medium | Enriched brain heart infusion broth with CO₂ | Enriched soybean-casein digest broth with CO₂ |
| Lysing Agent | Saponin (0.24% w/v) | None |
| Reactive ingredient concentrations | | |
| • Processed water | 25 mL | 25 mL |
| • Brain heart infusion broth | 1.0% w/v | --- |
| • Soybean-casein digest broth | 0.035% w/v | 2.75% w/v |
| • Yeast extract | 0.035% w/v | 0.25% w/v |
| • Dextrose | 0.1% w/v | 0.06% w/v |
| • Sucrose | 0.6% w/v | 0.084% w/v |
| • m-Inositol | 0.05% w/v | --- |
| • Hemin | --- | 0.0005% w/v |
| • Menadione | --- | 0.00005% w/v |
| • Ferric ammonium citrate | 0.0001% w/v | --- |
| • Pyridoxal HCl | --- | 0.001% w/v |
| • Saponin | 0.24% w/v | --- |
| • Anti-foaming agent | 0.01% w/v | --- |
| • SPS | 0.05% w/v | 0.05% w/v |
| • Chloramphenicol | 0.005% w/v | --- |
| • Tobramycin | 0.001% w/v | --- |
| • Nonionic adsorbing resin | --- | 16.0% w/v |
| • Cationic exchange resin | --- | 1.0% w/v |
| Resins | None | Yes (see above) |
| Instrument | BACTEC® NR instruments | BACTEC® NR instruments |
| Growth detection | Infrared spectrophotometric measurement of CO₂ produced by microorganisms metabolizing culture medium nutrients | Infrared spectrophotometric measurement of CO₂ produced by microorganisms metabolizing culture medium nutrients |
| Incubation temperature | 35°C ± 1.5°C | 35°C ± 1.5°C |
| Agitation | Orbital agitation for the first 24 hours recommended | Orbital agitation for the first 24 hours recommended |
| Vial glass | Type III, soda lime | Type III, soda lime |
| Closure | Rubber | Rubber |
| CO₂ Monitoring | Invasive vial headspace sampling | Invasive vial headspace sampling |

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# CLINICAL PERFORMANCE:

A multi-center clinical study comparing BACTEC® Fungal Medium, BACTEC® PLUS 26 blood culture medium, and the ISOLATOR™ Microbial Tubes/ISOSTAT® Microbial System (IS System) was conducted at four university-affiliated hospitals. There were a total of 4886 adequately filled paired vials in the comparison of BACTEC® Fungal Medium to BACTEC® PLUS 26 blood culture medium, and 4907 adequately filled paired vials and tubes in the comparison of BACTEC® Fungal Medium to the IS System. Of the 229 clinically significant isolates recovered in the comparison of BACTEC® Fungal Medium to BACTEC® PLUS 26 blood culture medium, 161 were bacteria and 68 were fungi. Of the 68 fungi, 31 isolates (45.6%) were recovered in both media, 11 (16.2%) were recovered in BACTEC® PLUS 26 blood culture medium only, and 26 (38.2%) were recovered in BACTEC® Fungal Medium only. Recovery of all fungi combined and of *Torulopsis glabrata* was statistically significantly better (p &lt; 0.025) in BACTEC® Fungal Medium. There was no statistically significant difference in the speed of detection of any of the fungi in the two media, nor of all fungi combined.

Of the 218 clinically significant isolates recovered in the comparison of BACTEC® Fungal Medium to the IS System, 125 were bacteria and 93 were fungi. Of the 93 fungi, 42 isolates (45.2%) were recovered in both media, 34 (36.6%) were recovered in the IS System only, and 17 (18.3%) were recovered in BACTEC® Fungal Medium only. Of the 34 isolates recovered only in the IS System, 25 were *Histoplasma capsulatum*; recovery of *H. capsulatum* was statistically significantly better (p &lt; 0.001) in the IS System. Excluding the *H. capsulatum* isolates, 17 fungi were isolated only in BACTEC® Fungal Medium and nine fungi were isolated only in the IS System; this difference is not statistically significant. *T. glabrata* was detected significantly earlier in BACTEC® Fungal Medium (p &lt; 0.05). The difference in speed of detection of all fungi in each of the two media was not significantly significant. Thus, the performance of BACTEC® Fungal Medium in detecting growth of fungi in blood was as good or better than that of BACTEC® PLUS 26 blood culture medium, and, with the exception of *H. capsulatum*, equivalent to that of the IS System.