Test Catalog

Test ID: ZMMLS    
Antimicrobial Susceptibility, Aerobic Bacteria, Varies

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.


All aerobically growing bacteria submitted will automatically have susceptibility testing performed and billed as appropriate. 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.


If appropriate, testing for mecA will be performed by polymerase chain reaction (PCR) under MARP1 / mecA, Molecular Detection, PCR (Bill Only). Indications for mecA testing include inadequate growth by phenotypic antimicrobial susceptibility testing, lack of current organism breakpoints for oxacillin or cefoxitin, and assessment of discrepancies between cefoxitin and oxacillin phenotypic testing results.


In the event that an isolate of Helicobacter pylori does not grow from a client sample or does not grow for susceptibility testing, reflex testing for HPCR1 / Helicobacter pylori with Clarithromycin Resistance Prediction, Molecular Detection, PCR (Bill Only) may be added.


The following tables provide a listing of the antimicrobials routinely tested 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


For test utilization options, see Helicobacter pylori Diagnostic Algorithm in Special Instructions.

Specimen Type Describes the specimen type validated for testing


Ordering Guidance

Mayo Clinic Laboratories will not perform susceptibility testing on select agents (eg, Bacillus anthracis, Brucella species, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis, and Yersinia pestis). Consult with your state health department or the CDC regarding antimicrobial susceptibility testing of such isolates.

Shipping Instructions

1. See Infectious Specimen Shipping Guidelines in Special Instructions.

2. Place specimen in a large infectious container and label as an etiologic agent/infectious substance.

Necessary Information

Organism identification and specimen source are required.

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

Supplies: Infectious Container, Large (T146)

Container/Tube: Agar slant or other appropriate media

Specimen Volume: Organism in pure culture

Collection Instructions:

1. Perform isolation of infecting bacteria.

2. Organism must be in pure culture, actively growing. Do not submit mixed cultures.

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


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

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

Agar plate 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 TypeTemperatureTimeSpecial Container
VariesAmbient (preferred)