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Test Code GENS Bacterial Culture, Aerobic with Antimicrobial Susceptibilities, Varies


Shipping Instructions


Specimen must arrive within 24 hours of collection.



Necessary Information


Specimen source is required; include the specific anatomic source. Indicate whether it is a "surface" or "deep/surgical" specimen. Do not label only as "wound."



Specimen Required


Preferred:

Specimen Type: Closed abscess

Container/Tube: Sterile container

Specimen Volume: Entire collection

Collection Instructions: Aspirate the abscess contents with a syringe.

Specimen Stability Information: Ambient 24 hours (preferred)/Refrigerated 24 hours

 

Acceptable:

Specimen Type: Open abscess, swab, tissue, or fluid

Supplies: Culturette (BBL Culture Swab) (T092)

Sources: Abscess, aspirate, lesion, or wound

Container/Tube: Sterile container or culture transport swab (Dacron or rayon swab with aluminum or plastic shaft with either Stuart or Amies liquid medium)

Collection Instructions: For most open lesions and abscesses, remove superficial flora by decontaminating skin before collecting a specimen from advancing margin or base.

Additional Information:

1. If submitting a specimen from a source contaminated with usual flora, send at refrigerated temperature.

2. Refrigerated specimens are not suitable for isolation of Neisseria species.

Specimen Stability Information: Ambient 24 hours (preferred)/Refrigerated 24 hours


Useful For

Detecting bacteria responsible for infections of sterile body fluids, tissues, or wounds

 

Determining the in vitro antimicrobial susceptibility of potentially pathogenic aerobic bacteria, if appropriate

 

This test is not intended for medicolegal use.

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
COMM Identification Commercial Kit No, (Bill Only) No
RMALD Ident by MALDI-TOF mass spec No, (Bill Only) No
GID Bacteria Identification No, (Bill Only) No
ISAE Aerobe Ident by Sequencing No, (Bill Only) No
REFID Additional Identification Procedure No, (Bill Only) No
SALS Serologic Agglut Method 1 Ident No, (Bill Only) No
EC Serologic Agglut Method 2 Ident No, (Bill Only) No
SHIG Serologic Agglut Method 3 Ident No, (Bill Only) No
STAP Identification Staphylococcus No, (Bill Only) No
STRP Identification Streptococcus No, (Bill Only) No
BLA Beta Lactamase No, (Bill Only) No
MIC Sensitivity, MIC No, (Bill Only) No
SUS Susceptibility No, (Bill Only) No
SIDC Ident Serologic Agglut Method 4 No, (Bill Only) No
PCRID Identification by PCR No, (Bill Only) No

Testing Algorithm

When this test is ordered, the reflex tests may be performed and charged. Antimicrobial agent appropriate to the organism and specimen source will be tested according to Mayo's practice and the laboratory's standard operating procedures.

 

See Special Instructions to review tables that provide a listing of the antimicrobials routinely tested in our laboratory as well as antimicrobials that may be tested upon request. These tables are organized by isolate groups and are not all inclusive. Call 800-533-1710 and ask to speak to the Bacteriology Antimicrobial Susceptibility Testing Laboratory if the organism or antimicrobial of interest are not listed in these tables.

Method Name

Conventional Culture Technique with Minimum Inhibitory Concentration (MIC) by Agar Dilution (if appropriate) 

Reporting Name

Bacterial Culture, Aerobic + Susc

Specimen Type

Varies

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Ambient (preferred) 24 hours
  Refrigerated  24 hours

Reject Due To

Other Specimen >24 hours Dry swab Frozen

Reference Values

No growth or usual flora

 

Identification of probable pathogens

 

Results are reported as minimal inhibitory concentration (MIC) in mcg/mL. Breakpoints (also known as "clinical breakpoints") are used to categorize an organism as susceptible, susceptible-dose dependent, intermediate, resistant, or nonsusceptible according to the Clinical and Laboratory Standards Institute (CLSI) guidelines.

 

In some instances an interpretive category cannot be provided based on available data and the following comment will be included: "There are no established interpretive guidelines for agents reported without interpretations."

 

Susceptible (S):

A category defined by a breakpoint that implies that isolates with an MIC at or below the susceptible breakpoint are inhibited by the usually achievable concentrations of antimicrobial agent when the dosage recommended to treat the site of infection is used, resulting in likely clinical efficacy.

 

Susceptible-Dose Dependent (SDD):

A category defined by a breakpoint that implies that susceptibility of an isolate depends on the dosing regimen that is used in the patient. In order to achieve levels that are likely to be clinically effective against isolates for which the susceptibility testing results are in the SDD category, it is necessary to use a dosing regimen (ie, higher doses, more frequent doses, or both) that results in higher drug exposure than that achieved with the dose that was used to establish the susceptible breakpoint. Consideration should be given to the maximum approved literature-supported dosage regimens, because higher exposure gives the highest probability of adequate coverage of a SDD isolate. The drug label should be consulted for recommended doses and adjustment for organ function.

 

Intermediate (I):

A category defined by a breakpoint that includes isolates with MICs within the intermediate range that approach usually attainable blood and tissue levels and for which response rates may be lower than for susceptible isolates.

Note: The intermediate category implies clinical efficacy in body sites where the drugs are physiologically concentrated or when a higher than normal dosage of a drug can be used. This category also includes a buffer zone, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations, especially for drugs with narrow pharmacotoxicity margins.

 

Resistant (R):

A category defined by a breakpoint that implies that isolates with an MIC at or above the resistant breakpoint are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or that demonstrate MICs that fall in the range in which specific microbial resistance mechanisms are likely, and clinical efficacy of the agent against the isolate has not been reliably shown in treatment studies.

 

Nonsusceptible (NS):

A category used for isolates for which only a susceptible breakpoint is designated because of the absence or rare occurrence of resistant strains. Isolates for which the antimicrobial agent MICs are above the value indicated for the susceptible breakpoint should be reported as nonsusceptible.

Note: An isolate that is interpreted as nonsusceptible does not necessarily mean that the isolate has a resistance mechanism. It is possible that isolates with MICs above the susceptible breakpoint that lack resistance mechanisms may be encountered within the wild-type distribution subsequent to the time the susceptible-only breakpoint was set.

 

Epidemiological Cutoff Value (ECV):

The MIC that separates microbial populations into those with and without acquired resistance (non-wild-type or wild-type, respectively). The ECV defines the highest MIC for the wild type population of isolates. ECVs are based on in vitro data only, using MIC distributions. ECVs are not clinical breakpoints, and the clinical relevance of ECVs for a particular patient has not yet been identified or approved by CLSI or any regulatory agency.

 

When an ECV is reported, the following comment will be included: "This MIC is consistent with the Epidemiological Cutoff Value (ECV) observed in isolates [WITH / WITHOUT] acquired resistance; however, correlation with treatment outcome is unknown."

 

(CLSI. Performance Standards for Antimicrobial Susceptibility Testing. 29th edition. CLSI supplement M100. Wayne, PA: Clinical and Laboratory Standards Institute; 2019)

Day(s) and Time(s) Performed

Monday through Sunday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test uses a standard method. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

87070-Bacterial Culture, Aerobic

87186-Antimicrobial Susceptibility, Aerobic Bacteria, MIC-per organism for routine battery (if appropriate)

87187-Susceptibility per drug and per organism for drugs not in routine battery (if appropriate)

87077-Identification commercial kit (if appropriate)

87077-Ident by MALDI-TOF mass spec (if appropriate)

87077-Bacteria Identification (if appropriate)

87077-Additional Identification procedure (if appropriate)

87077-Identification Staphylococcus (if appropriate)

87077-Identification Streptococcus (if appropriate)

87147 x 1-3-Serologic agglut method 1 ident (if appropriate)

87147-Serologic agglut method 2 ident (if appropriate)

87147 x 4-Serologic agglut method 3 ident (if appropriate)

87147 x 2-6-Serologic Agglut Method 4 Ident (if appropriate)

87153-Aerobe ident by sequencing (if appropriate)

87185-Beta lactamase (if appropriate)

87798-Identification by PCR (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
GENS Bacterial Culture, Aerobic + Susc 634-6

 

Result ID Test Result Name Result LOINC Value
GENS Bacterial Culture, Aerobic + Susc 634-6

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.