Test Catalog

Test Id : GENS

Bacterial Culture, Aerobic with Antimicrobial Susceptibilities, Varies

Useful For
Suggests clinical disorders or settings where the test may be helpful

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
Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial 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
REFID Additional Identification Procedure No, (Bill Only) No
STAP Identification Staphylococcus No, (Bill Only) No
STRP Identification Streptococcus 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
SIDC Ident Serologic Agglut Method 4 No, (Bill Only) No
ISAE Aerobe Ident by Sequencing No, (Bill Only) No
PCRID Identification by PCR No, (Bill Only) No
TISSR Tissue Processing No, (Bill Only) No
BLA Beta Lactamase No, (Bill Only) No
MIC Susceptibility, MIC No, (Bill Only) No
SUS Susceptibility No, (Bill Only) No
HPCR1 H pylori + Clarithro Resistance PCR No, (Bill Only) No
MARP1 mecA PCR (Bill Only) No, (Bill Only) No

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, the reflex tests may be performed at an additional charge. Antimicrobial agents appropriate to the organism and specimen source will be tested according to Mayo Clinic's practice and the laboratory's standard operating procedures.

 

The following tables provide a listing of the antimicrobials routinely tested in the 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.

-Aerobic Gram-Negative Bacilli Antimicrobials

-Additional Gram-Negative Bacteria Antimicrobials

-Staphylococcus, Enterococcus, Bacillus, and Related Genera Antimicrobials

-Additional Gram-Positive Bacteria Antimicrobials

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test

Conventional Culture Technique with Minimal Inhibitory Concentration (MIC) (Agar Dilution or Broth Microdilution or Gradient Diffusion) or Disk Diffusion (if appropriate)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Bacterial Culture, Aerobic + Susc

Aliases
Lists additional common names for a test, as an aid in searching

Aerobic Bacteria Culture

Aerobic Culture

Bacteria Aerobic Culture (CSF)

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, the reflex tests may be performed at an additional charge. Antimicrobial agents appropriate to the organism and specimen source will be tested according to Mayo Clinic's practice and the laboratory's standard operating procedures.

 

The following tables provide a listing of the antimicrobials routinely tested in the 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.

-Aerobic Gram-Negative Bacilli Antimicrobials

-Additional Gram-Negative Bacteria Antimicrobials

-Staphylococcus, Enterococcus, Bacillus, and Related Genera Antimicrobials

-Additional Gram-Positive Bacteria Antimicrobials

Specimen Type
Describes the specimen type validated for testing

Varies

Shipping Instructions

Specimen must arrive within 24 hours of collection. Ship ambient or refrigerated. Frozen specimens will be rejected.

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."

ORDER QUESTIONS AND ANSWERS

Question ID Description Answers
Q00M0027 Specimen Source

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Preferred:

Specimen Type: Closed abscess; deep tissue or fluid

Container/Tube: Sterile container

Specimen Volume: Entire collection

Collection Instructions: Aspirate the abscess contents/fluid with a syringe or excise a portion of tissue.

 

Acceptable:

Specimen Type: Open abscess, superficial lesion/wound, swab, tissue, or fluid

Supplies:

-Culturette (BBL Culture Swab) (T092)

-BD E-Swab (T853)

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

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.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Forms

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

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.5 mL or 0.5 x 0.2 x 0.2-cm sized piece of tissue

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Dry swab Reject

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

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

Useful For
Suggests clinical disorders or settings where the test may be helpful

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.

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, the reflex tests may be performed at an additional charge. Antimicrobial agents appropriate to the organism and specimen source will be tested according to Mayo Clinic's practice and the laboratory's standard operating procedures.

 

The following tables provide a listing of the antimicrobials routinely tested in the 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.

-Aerobic Gram-Negative Bacilli Antimicrobials

-Additional Gram-Negative Bacteria Antimicrobials

-Staphylococcus, Enterococcus, Bacillus, and Related Genera Antimicrobials

-Additional Gram-Positive Bacteria Antimicrobials

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Sterile Body Fluids and Normally Sterile Tissues:

In response to infection, fluid may accumulate in any body cavity.

 

Wound, Abscess, Exudates:

Skin and soft tissue infections can occur as a result of a break in the skin surface, or they can occur as complications of surgery, trauma, human, animal, or insect bites or diseases that interrupt a mucosal or skin surface. Specimen collection is of utmost importance for these specimen types. For most open lesions and abscesses, remove the superficial flora by decontaminating the skin before collecting a specimen from the advancing margin or base. A closed abscess is the specimen site of choice. Aspirate the abscess contents with a syringe.

 

The specific anatomic site is required to establish possible contaminating flora in the area of specimen collection for appropriate reporting of culture results. For this reason, specimens should be labeled as to the specific anatomic source and to distinguish between “surface" and “deep/surgical" specimens. Do not label only as “wound."

 

Antimicrobial susceptibility testing should be performed on pure culture isolates of pathogenic (or potentially pathogenic in special situations) bacteria grown from specimens that have been appropriately collected so as not to confuse clinically significant isolates with normal flora.

 

Antimicrobial susceptibility testing determines the minimal inhibitory concentration (MIC) value of selected antimicrobial agents against isolated potentially pathogenic bacteria. The MIC is the lowest antimicrobial concentration (of a series of increasing concentrations) that inhibits growth of the bacterium. Agar dilution MIC testing is performed by testing for growth of bacteria on agar plates containing varying concentrations of antimicrobial agents.

 

For each organism-antimicrobial agent combination, the Clinical and Laboratory Standards Institute and/or the European Committee on Antimicrobial Susceptibility Testing provides interpretive criteria for determining whether the MIC should be interpreted as susceptible, susceptible dose dependent, intermediate, nonsusceptible, resistant, or epidemiological cutoff value.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

No growth or usual flora

 

Identification of probable pathogens

 

Susceptibility 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 breakpoint setting organizations, either the Clinical and Laboratory Standards Institute (CLSI) or the European Committee on Antimicrobial Susceptibility Testing (EUCAST), as applicable.

 

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."

 

Clinical and Laboratory Standards Institute (CLSI) Interpretive Category Definitions:

Susceptible:

A category defined by a breakpoint that implies that isolates with an MIC at or below or a zone diameter at or above 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:

A category defined by a breakpoint that implies that susceptibility of an isolate depends on the dosing regimen that is used in the patient. To achieve levels that are likely to be clinically effective against isolates for which the susceptibility testing results (either MICs or zone diameters) are in the susceptible-dose dependent (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 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:

A category defined by a breakpoint that includes isolates with MICs or zone diameters within the intermediate range that approach usually attainable blood and tissue levels and/or 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:

A category defined by a breakpoint that implies that isolates with an MIC at or above or a zone diameter at or below the resistant breakpoint are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or that demonstrate MICs or zone diameters 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:

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 or the zone diameters are below 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 after the time the susceptible-only breakpoint was set.

 

Epidemiological Cutoff Value:

The MIC that separates microbial populations into those with and without phenotypically detectable resistance (non-wild-type or wild-type, respectively). The epidemiological cutoff value (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, an interpretive category is not assigned, and 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."

-Wild-type (WT)-an interpretive category defined by an ECV that describes the microbial population with no phenotypically detectable mechanisms of resistance or reduced susceptibility for an antimicrobial agent being evaluated.

-Non-wild-type (NWT)-an interpretive category defined by an ECV that describes the microbial population with phenotypically detectable mechanisms of resistance or reduced susceptibility for the antimicrobial agent being evaluated.

Note: MIC values for which ECV’s are defined are not to be interpreted or reported as susceptible, intermediate, or resistant but rather as WT or NWT. The ECV’s should not be used as clinical breakpoints.(Clinical and Laboratory Standards Institute [CLSI]: Performance Standards for Antimicrobial Susceptibility Testing. 31st ed. CLSI supplement M100. CLSI; 2021:4-6 and 268-269)

 

European Committee on Antimicrobial Susceptibility Testing (EUCAST) Interpretive Category Definitions:

S-Susceptible, standard dosing regimen: A microorganism is categorized as "Susceptible, standard dosing regimen", when there is a high likelihood of therapeutic success using a standard dosing regimen of the agent

 

I-Susceptible, increased exposure*: A microorganism is categorized as "Susceptible, Increased exposure*" when there is a high likelihood of therapeutic success because exposure to the agent is increased by adjusting the dosing regimen or by its concentration at the site of infection.

 

R-Resistant: A microorganism is categorized as "Resistant" when there is a high likelihood of therapeutic failure even when there is increased exposure.*

 

*Exposure is a function of how the mode of administration, dose, dosing interval, infusion time, as well as distribution and excretion of the antimicrobial agent will influence the infecting organism at the site of infection.(The European Committee on Antimicrobial Susceptibility Testing. Breakpoint tables for interpretation of MICs and zone diameters. Version 11.0, 2021. Available at www.eucast.org)

Interpretation
Provides information to assist in interpretation of the test results

Any microorganism is considered significant and is reported when the anatomical source is considered sterile and no resident flora is expected. For specimens contaminated with the usual bacterial flora, bacteria that are potentially pathogenic are identified.

 

A "susceptible" category result and a low minimum inhibitory concentration value indicate in vitro susceptibility of the organism to the antimicrobial tested.

 

Refer to the Reference Values section for interpretation of various antimicrobial susceptibility interpretive categories (ie, susceptible, susceptible-dose dependent, intermediate, nonsusceptible, resistant, or epidemiological cutoff value).

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

When antimicrobial susceptibilities are performed, in vitro susceptibility does not guarantee clinical response. Therefore, the decision to treat with a particular agent should not be based solely on the antimicrobial susceptibility testing result.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Forbes BA, Sahm DF, Weissfeld AS, eds: Bailey and Scott's Diagnostic Microbiology. 12th ed. Mosby; 2007:chap 55, 56, 58, 60, 61

2. Miller JM, Binnicker JM, Campbell S, et al: A guide to utilization of the microbiology laboratory for diagnosis of infectious diseases: 2018 Update by the Infectious Diseases Society of America and the American Society for Microbiology. Clin Infect Dis. 2018 Aug 31;67(6):e1-e94. doi: 10.1093/cid/ciy381

3. Procop GW, Church DL, Hall GS, eds, et al: Introduction to Microbiology Part II: Guidelines for the collection, transport, processing, analysis, and reporting of cultures from specific specimen sources. In: Koneman's Color Atlas and Textbook of Diagnostic Microbiology. 7th ed. Wolters Kluwer Health; 2017:66-110

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Description
Describes how the test is performed and provides a method-specific reference

Specimens are cultured to enriched and/or selective media appropriate to the anatomic location and the scope of microorganisms expected. Cultures are incubated for 3 to 5 days depending on the specimen source. Pathogens or possible pathogens are identified using one or a combination of the following techniques: commercial identification strips or panels, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, conventional biochemical tests, carbon source utilization, real-time polymerase chain reaction (PCR), and nucleic acid sequencing of the 16S ribosomal RNA (rRNA) gene. "Usual flora" is reported as such (as appropriate to the specimen).( Leber AL, ed: Clinical Microbiology Procedures Handbook. Vol 1. 4th ed. ASM Press; 2016:sections 3.5, 3.7, 3.9, 3.10, 3.13)

 

When antimicrobial susceptibility testing is performed, an agar dilution method is used for routine testing. The agar dilution method employs the use of antimicrobial agents incorporated in agar plates. The antimicrobial is added to agar in various concentrations depending upon levels attainable in serum, urine, or both. A standardized suspension of the organism is applied to the agar plates, which are incubated for a minimum of 16 to 18 hours at 35 degrees C. Complete inhibition of all but 1 colony or a very fine residual haze represents the end point.(Clinical and Laboratory Standards Institute [CLSI]: Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically. 11th ed. CLSI standard M07. CLSI; 2018)

 

Daptomycin and tigecycline are tested by agar gradient diffusion.(Clinical and Laboratory Standards Institute [CLSI]: Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically. 11th ed. CLSI standard M07; CLSI; 2018; package insert: Etest Biomerieux;15203E-EN-2016/07. Available at: www.biomerieux.com/techlib)

 

Colistin is tested by the CLSI-approved Colistin agar test for Enterobacterales and Pseudomonas aeruginosa.(Clinical and Laboratory Standards Institute [CLSI]: Performance Standards for Antimicrobial Susceptibility Testing. 31st ed. CLSI supplement M100. CLSI; 2021:142-147)

 

Cefiderocol is tested by disk diffusion.(Clinical and Laboratory Standards Institute [CLSI]: Performance Standards for Antimicrobial Disk Susceptibility Tests. 13th ed. CLSI standard M02. CLSI; 2018)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

5 to 14 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

2 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

87070-Bacterial Culture, Aerobic

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)

87150-Identification by PCR (if appropriate)

87176-Tissue Processing (if appropriate)

87185-Beta lactamase (if appropriate)

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

87181-Susceptibility per drug and per organism for drugs not in routine battery (if appropriate)

87150-H pylori + Clarithro Resistance PCR (if appropriate)

87150-mec A PCR (if appropriate)

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
GENS Bacterial Culture, Aerobic + Susc 634-6
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
GENS Bacterial Culture, Aerobic + Susc 634-6

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports