QUALITY CONTROL: AST, ID TESTS, MEDIA, AND STAINS

By: Josephine San Pedro, MPH, SM (ASCP)

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OUTLINE

Quality Control of:• Antibiotic Disks• Vitek AST Cards• ID Reagents and Disks• Commercial Microbial ID Systems• Gram Stain• Media

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QC OF ANTIBIOTIC DISKSOrganism ATCC # AST QCE. coli 25922 Routine QC of Gram-neg. disksS. aureus 25923 Routine QC of Gram-pos. disksP. aeruginosa 27853 Pseudomonas disks, Carbapenems disksE. coli 35218 β-lactam/β-lactamase inhibitor combination

disksS. aureus 29213 β-lactamase + (CLSI TABLE 3D)E. faecalis 29212S. pneumoniae 49619 QC of S. pneumo. disksK. pneumoniae 700603 ESBL + (CLSI TABLE 3A)S. aureus 43300 Ox/Fox resistant (mecA+) (CLSI TABLE 3E)S. Aureus BAA-976 D-zone – (CLSI TABLE 3G)S. aureus BAA-977 D-zone + (CLSI TABLE 3G)

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QC OF ANTIBIOTIC DISKS (2)

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QC OF ANTIBIOTIC DISKS (3)

QC frequency:

QC each new lot # or new shipment of antibiotic disks as soon as received then daily/weekly thereafter

Daily QC: 20-day or 30-day or 3 x 5-day plan

Convert to weekly QC(for in-use cartridges)

Passed

Label all boxes of antibiotics“QC Passed”

Record all QC Results, include lot #, expiry date, date received (for new lot/shipment)

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QC OF VITEK AST CARDS

QC Organism ATCC # Vitek Panel QC for

S. aureus 29213 GP All drugs except HLAR & ICR

E. faecalis 29212 GP All drugs including HLAR (SYN-S)except Fox, Gent, OX, SXT, RIF, ICR,

E. faecalis 51299 GP HLAR (SYN-R)

S. aureus BAA-1026 GP Cefoxitin screen +

S. aureus BAA-976 GP ICR -

S. aureus BAA-977 GP ICR+

E. coli 25922 GN All drugs, ESBL-

E. coli 35218 GN AMP, AMP-SULBACTAM, PIP-TAZO

P. aeruginosa 27853 GN All anti-pseudomonas drugs

K. pneumoniae 700603 GN ESBL+

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QC OF VITEK AST CARDS (2)

QC frequency:

QC each new lot # or new shipment of antibiotic disks as soon as received then daily/weekly thereafter

Daily QC: 20-day or 30-day or 3 x 5-day plan

Convert to weekly QC(for in-use lot)

Passed

Label all Vitek cards boxes “QC Passed”

Record all QC Results, include lot #, expiry date, date received (for new lot/shipment)

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QC OF ID REAGENTS AND DISKS

Oxidase, indole, bile solubility, catalase, coagulaseBacitracin disk, Optochin disk, XV factor disks, Novobiocin disk, PYR kit, Strep grouping kit, S. pneumo kit,…• Perform QC on each new batch or lot/shipment• QC needs to be done on each time of use for tests

that are performed less frequently than once per month

• Label reagent/kit: “QC Passed”

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• Label container of prepared reagent properly• Store in appropriate condition (RT, 2-8oC, brown

bottle, etc.)• Store reagents and kits according to manufacturer’s

directions• From the refrigerator, allow reagent to equilibrate at

room temperature before use• Label reagents with new expiry date if opening the

container or reconstitution changes the expiration date. Refer to manufacturer product insert

QC OF ID REAGENTS AND DISKS (2)

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QC OF COMMERCIAL MICROBIAL ID SYSTEMS

Any ID system with 2 or more substrates: e.g., API, VITEK/PHOENIX ID cards• Comprehensive QC – check each lot # or shipment

for positive and negative reactivity of each reagent or substrate

• Streamlined QC

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QC OF COMMERCIAL MICROBIAL ID SYSTEMS (2)

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QC OF COMMERCIAL MICROBIAL ID SYSTEMS (3)

CLSI M50-A: Quality Control for Commercial Microbial Identification Systems; Approved Guideline

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QC OF GRAM STAIN REAGENTS• Perform QC on each new batch/lot and at least

weekly thereafter • E. coli and S. aureus in NSS/broth (slightly turbid) • Label slides: Gram QC, date prepared• Place one drop each on a slide. Allow to dry• Heat fix. Store smears in a box• maybe stored at room temperature for at least 3

months

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• Label container properly Reagent name and concentration Date prepared Expiry date Storage (room temperature) Date in-use Label: “QC Passed”

QC OF GRAM STAIN REAGENTS (2)

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QC OF CULTURE MEDIA

• QC each batch of media prepared sterility testing – one plate per batch use control organisms to test ability to support

growth and ability to produce appropriate biochemical reactions

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QC OF CULTURE MEDIA (2)

Clinical Microbiology Procedures Handbook, 2nd ed. Vol. 3 Chapter 14: QA & QC

QC of Culture Media (3)

• Label prepared media with media name, date prepared and expiry date

• Store plated media in bags to avoid dehydration

• Store tubed media with caps tightened• Label bags of media: “QC Passed”

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Thank you