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Test Code HELIS Helicobacter pylori Culture with Antimicrobial Susceptibilities

Useful For

Recovery of Helicobacter pylori from gastric specimens for antimicrobial susceptibility testing of the organism (amoxicillin, ciprofloxacin, clarithromycin, metronidazole and tetracycline are routinely tested)

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
GID Bacteria Identification No, (Bill Only) No
TISSR Tissue Processing No, (BIll Only) No
MIC Sensitivity, MIC No, (Bill Only) No
SUS Susceptibility No, (Bill Only) No
ISAE Aerobe Ident by Sequencing No, (Bill Only) No

Testing Algorithm

When this test is ordered, the reflex tests may be performed and charged.

 

When Helicobacter pylori is isolated, identification will be confirmed and susceptibility testing performed. The routine susceptibility panel includes amoxicillin, ciprofloxacin, clarithromycin, metronidazole, and tetracycline.

 

See Helicobacter pylori Diagnostic Algorithm in Special Instructions

Reporting Name

Helicobacter pylori Culture + Susc

Specimen Type

Varies


Shipping Instructions


Specimen must be received in laboratory within 48 hours of collection.



Necessary Information


Specimen source is required; include the specific anatomic source.



Specimen Required


Preferred:

Specimen Type: Gastric biopsy

Container/Tube: Sterile container

Specimen Volume: Entire collection

Collection Instructions: Acquire biopsied tissue; moisten with sterile saline.

 

Acceptable:

Specimen Type: Gastric brushings or gastric aspirate

Container/Tube: Sterile container

Specimen Volume: Entire collection


Specimen Minimum Volume

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

Specimen Stability Information

Specimen Type Temperature Time
Varies Refrigerated 48 hours

Reject Due To

Hemolysis

NA

Lipemia

NA

Icterus

NA

Other

>48 hours; biopsy submitted in fluid other than sterile saline

Clinical Information

Helicobacter pylori is a spiral-shaped gram-negative bacterium that may cause chronic gastritis, peptic ulcer disease, or gastric neoplasia. In adults of industrialized countries, an estimated 0.5% of the susceptible population becomes infected each year, although the incidence has been decreasing over time. The organism may asymptomatically colonize humans. In suspected H pylori-associated disease, the noninvasive stool antigen or urea breath test is recommended. If patients fail to respond to treatment and antimicrobial resistance is suspected, gastric biopsy, gastric brushings, or gastric aspirate may be cultured to attempt to recover the organism for antimicrobial susceptibility testing to assess for resistance.

Multidrug regimens are required to attain successful cure of H pylori infection. Antimicrobial resistance in H pylori is increasing. Disease caused by H pylori resistant to clarithromycin or metronidazole is associated with a greater incidence of treatment failure than disease caused by a susceptible strain.

 

The Clinical and Laboratory Standards Institute (CLSI) recommends agar dilution for H pylori antimicrobial susceptibility testing. Amoxicillin, ciprofloxacin, clarithromycin, metronidazole and tetracycline are routinely tested. The only antimicrobial for which interpretive breakpoints have been defined by the CLSI is clarithromycin.

Reference Values

No growth after 7 days

Susceptibility results are reported as minimum inhibitory concentration (MIC) in mcg/mL and as susceptible, intermediate, or resistant 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):

The "susceptible" category implies that isolates 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.

Intermediate (I)

The "intermediate" category includes isolates with antimicrobial agent minimum inhibitory concentrations (MICs) 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)

The "resistant" category implies that the isolates are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or that demonstrate MIC that fall in the range where specific microbial resistance mechanisms are likely, and clinical efficacy of the agent against the isolate has not been reliably shown in treatment studies.

(Clinical and Laboratory Standards Institute: Performance Standards for Antimicrobial Susceptibility Testing. 26th Informational Supplement. CLSI document M100S. Wayne, PA, 2016)

Interpretation

A positive result provides definitive evidence of the presence of Helicobacter pylori.

 

Organisms may be detected in asymptomatic (colonized) individuals.

 

False-negative culture results may occur since the organism may die between biopsy collection and laboratory culture.

Cautions

Culture-negative results may occur due to the fastidious nature of the organism. Delays in specimen transportation will decrease recovery of the organism. Culture should be set up as soon as possible following specimen collection. Antimicrobial therapy may render the culture negative.

 

Due to Helicobacter pylori's fastidious nature and slow-growth, it may take 7 days to recover the organism and up to an additional 21 days to perform antimicrobial susceptibility testing.

 

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. The only antimicrobial for which interpretive breakpoints have been defined by the Clinical and Laboratory Standards Institute is clarithromycin.

Day(s) and Time(s) Performed

Monday through Sunday; Continuously

Analytic Time

7 days

Specimen Retention Time

7 days

Performing Laboratory

Mayo Medical 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

87081-Helicobacter pylori culture

87077-Bacteria identification (if appropriate)

87153-Aerobe Ident by Sequencing (if appropriate)

87176-Tissue processing (if appropriate)

87181-Susceptibility (if appropriate)

87186-Sensitivity, MIC (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HELIS Helicobacter pylori Culture + Susc 587-6

 

Result ID Test Result Name Result LOINC Value
HELIS Helicobacter pylori Culture + Susc 587-6

Method Description

The selective Helicobacter pylori media used for isolation has a Brucella agar base with added vancomycin, trimethoprim, polymyxin B, and vitamin K1. Fresh medium and high humidity are essential for organism recovery. Plates are incubated at 35° C in a microaerophilic atmosphere.(Lawson AJ: Chapter 57, Helicobacter. In Manual of Clinical Microbiology. 11th edition. Edited by J Jorgensen. ASM Press. Washington DC, 2015, pp 1013-1027)

 

The agar dilution method is used for susceptibility testing. The antimicrobial is added to agar in various concentrations depending upon levels attainable in serum. A standardized suspension of the organism is applied to the agar plates that are incubated for 72 hours at 35° C. Complete inhibition of all but 1 colony or a very fine residual haze represents the endpoint.(CLSI. Methods for Antimicrobial Dilution and Disk Susceptibility Testing of Infrequently Isolated or Fastidious Bacteria. Third edition. CLSI document M45. Wayne, PA: Clinical and Laboratory Standards Institute; 2015)

Method Name

Conventional Culture Techniques

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

Microbiology Test Request Form (T244) (http://www.mayomedicallaboratories.com/it-mmfiles/microbiology_test_request_form.pdf)

Gastroenterology and Hepatology Test Request Form (T728) (http://www.mayomedicallaboratories.com/it-mmfiles/gastroenterology-and-hepatology-test-request.pdf)