Expanded Carbapenemase Testināāg āāāāāSāāāāāāāāāāāervices Frequently Asked Questions (āFAQ) February 1st, 2023 Updatāāeāā
ā
- Whaāt types of samples should we send?ā
- The following carbapenem-resistant organisms may be submitted to the California Department of Public Health, Microbial Diseases Laboratory (MDL) for further testing.āāāāā
-
āāāāCarbapenem-resistant Enterobacterales(CRE):
Submit carbapenem-resistant
Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, and
Enterobacter spp. that are resistant to imipenem, meropenem, doripenem, or ertapenem by standard antimicrobial susceptibility testing (AST) methods (i.e., minimum inhibitory concentrations (MIC) of ā„ 4 Āµg/mL for doripenem, imipenem or meropenem, or ā„2 Āµg/mL for ertapenem).āāā
āāā
-
Carbapenem-resistant
Pseudomonas aeruginosa(CRPA):
Submit carbapenem-resistant
P. aeruginosa isolates that are resistant to imipenem, meropenem, or doripenem by standard AST methods (i.e., MIC of ā„ 8 Āµg/mL)
and nonsusceptible (i.e., intermediate or resistant MIC ā„ 16Āµg/ml) to cefepime or ceftazidime.āāā
-
Pan-nonsusceptible Carbapenem-resistant
Acinetobacter baumannii(CRAB), CRE,and CRPA:
A pan-nonsusceptible (pan-NS) isolate is defined as an isolate nonsusceptible to all drugs tested to date. Routinely submit all pan nonsusceptible CRE (regardless of species), CRPA, and CRAB to MDL for surveillance purposes. These isolates will be tested at āthe MDL or an Antibiotic Resistance Laboratory Network (ARLN) Regional Laboratory.āāā
-
Other CRE not listed in (1.a):
At this time, the CDPH Healthcare-Associated Infections (HAI) Program will provide approval on a case-by-case basis for testing of āother CRE, including
Providencia,
Proteus,
Morganella,
Citrobacter, and
Serratia spp. Please contact the HAI Program at
HAIprogram@cdph.ca.gov āprior to submission. If approved, these isolates will be tested at the MDL or the āāāAntibiotic Resistance Laboratory Network (AR Lab Network)ā. CRE isolates not listed in (1.a.) that are submitted without prior approval will not be tested.āāāā
- CRAB isolates
(excluding pan-nonsusceptible) may be submitted directly to the ARLN Regional Laboratory for testing as a part of their targeted surveillance program with coordination of the HAI program and MDL.ā
ā
āāāāāāSubmit CRAB isolates that are resistant to imipenem, meropenem, or doripenem by standard susceptibility testing methods (i.e., MIC of >=8 Ī¼g/mL). The āARLN Regional Laboratoryāā will perform bacterial identification confirmation, AST, and PCR testing to detect carbapenemase genes for CRAB isolates. Agar slants and shipping materials can be provided to submitting clinical laboratories at no charge. Detailed information for submittal criteria, forms, and shipping instructions can be found at: ā āARLN Lab Network Test Menuāā.
Please contact the HAI program at HAIprogram@cdph.ca.govā at āand MDL Bacterial Diseases Section (BDS) at āMDLBDS@cdph.ca.govāā for any assistance. āāāāā
āāā
- If your institution uses nonstandard AST method, we will review the provided AST results and perform testing on a case-by-case basis.āāā
- āāIsolates from patients being investigated as part of a cluster or outbreak, or containing novel resistance mechanisms, may be referred for Whole Genome Sequencing (WGS) by the CDPH HAI Program. Approval is required by the HAI Program and the MDL Molecular Characterization Unit (MCU) prior to submission. Contact the HAI Program at HAIprogram@cdph.ca.gov and MDL MCU at
MDL.Submissions@CDPH.ca.govā prior to submitting isolates for submittal instructions.
- All isolates āmust be identified to at least the genus level by the submitter.
- Mixed cultures received by MDL will not be tested.āā
- āHow should samples be sent in for the laboratory testing?āā
- āāāāSubmit isolates to the MDL Bacterial Diseases Section (BDS) for modified Carbapenem Inactivation Method (mCIM) for detection of carbapenemase production, polymerase chain reaction (PCR) for detection of carbapenemase genes, SensititreTM AST, and routine submittal of pan-NS isolates for surveillance purposes.
- āUse the MDL barcode submittal form: āMDL General Electronic Submission Form. This barcode submittal form can be found at: MDL Submission Instructions and Formsā.
- āāāāUnder the Select Test Requisition field, select the
Antimicrobial Susceptibility Testing-AST form.
- Please ātype in the relevant information into the form. Information written in by hand is not coded into the barcode.
- Provide identification (ID), AST results, and any available phenotypic and molecular carbapenmase testing results. Attach printouts from ID and AST systems to the submittal form.
- Type in the full name of
the healthcare facility of origin on the submittal form under āSubmitting Facility.āā
- Type in the test(s) requested:
- āPhenotypic (mCIM), Molecular (carbapenemase gene detection by PCR), or multiple tests (please specify).
- Sensititre
TM AST testing is currently not available by submitter request. This test is performed on selected isolates āfor surveillance purposes (please see #7 for details).ā
- āSubculture isolates onto a non-selective nutrient agar slant (e.g. Tryptic Soy Agar) with a screw-top cap and ship at ambient temperature or refrigerated (cold pack). Frozen cultures in trypticase soy broth (TSB) with 15% glycerol may also be submitted on dry ice. Ship isolates as soon as possible to ensure viability and to avoid loss of antimicrobial resistance mechanisms. Please see
MDL Service and Test Catalogā for details.ā
ā
- āFor WGS, contact MDL MCU for consultation an dthe appopiate submittal form by emailing at MDL.Submissions@CDPH.ca.gov. Consultation and approval is required prior to submission. Submital forms and shipping instructions will be provided after approval. ā
- What is the shipping address?
āCalifornia Deparment of Public Health
Microbial Diseases Laboratory
ATTN: Bacterial Diseases Section
850 Marina Bay Parkwayā
Specimen Receiving, Room B-106
Richmond, CA 94804ā
- Who ācan submit isolates for testing?āāāā
Isolates will be accepted from California Local Public Health Laboratories āonly. Isolates āāwill not be accepted directly from hospitals or other healthcare facilities unless approved by the MDL and CDPH HAI Program, and applicable Local Public Health Laboratories.āāā
āāā
- āIf I already have molecular testing results for carbapenemase gene detection, can I still submit my sample?āāāā
āYes.ā CRE and CRPA isolates that have tested
negative for known carbapenemase genes by a validated molecular test method can be submitted to MDL for mCIM testing. CRE or CRPA isolates that have tested negative for known carbapenemase genes but are carbapenemase positive by a phenotypic test may indicate a novel or unusual carbapenemase; such isolates may be forwarded to the ARLN Regional Lab for additional characterization. Molecular testing of these isolates will not be repeated at MDL.
- Can isolates be submitted for real-time PCR testing for carbapenemase gene detectionāāā
āāYes.ā CRE and CRPA isolates determined to be carbapenemase-producers by a phenotypic test may be submitted to MDL for carbapenemase gene testing by real-time PCR, if that has not already been performed.
- Do I need to submit isolates for the SensititreTM AST?āāā
āNo.ā CRE, CRPA and CRAB isolates will be selected for confirmatory SensititreTM AST for surveillance purposes based on the priorities detailed below:āāā
āā
- āāāāāāāāāPan-Resistant and pan-NS CRE, CRPA and CRAB
- āNon-KPC CRE isolates that are positive for
blaNDM,
blaOXA-48-like,
blaVIM, and
blaIMP by real-time PCRāāāā
- āāāCRPA isolates that are positive for carbapenemase production or/and carbapenemase gene (
blaKPC,
blaNDM,
blaIMP,
blaVIM and blaOXA-48-like)āā
- Other isolates that are associated with outbreaks and requested by HAI epidemiologists
- Can
Enterobacterales be submitted for Expanded AST (ExAST) for hard-to-treat infections?āāāā
āāYes.ā With approval from the HAI Program and MDL, ExAST on CRE isolates that are highly resistant (ānon-susceptible to all beta-lactamsā) or possess metallo-beta-lactamase genes (NDM, VIM, IMP) for clinical-decision making purposes is available directly through the ARLN Regional Lab. Detāailed information for submittal criteria, forms, and shipping instructions can be found here: ARLN Lab Test Menu.ā
Contact the HAI Program at
HAIProgram@cdph.ca.govāā and MDL BDS at
MDLBDS@cdph.ca.govā prior to submitting isolates. Submitting isolates to MDL may result in delays in testing.
- Can duplicate isolates be submitted for testing?
āNo.ā Isolates from specimens collected within a 30-day timeframe that are from the same patient, and are the same species, specimen source, and AST profile are considered duplicates. However, if there is a special need to test the duplicate isolates, please contact the HAI Program at āāHAIProgram@cdph.ca.govāāā for approval prior to submission.
- Can isolates be submitted for WGS only?
āYes.ā Prior approval is required by the HAI Program and MDL prior to submission. Please contact the HAI Program at
HAIProgram@cdph.ca.govā, and MCU/MDL at
MDL.Submissions@CDPH.ca.govā to get approval to submit isolates for WGS. Once the submission has been approved, the submittal form and shipping instructions will be provided.
ā ā
- What is the turn-around-time (TAT) for testing?
ā
āTurn-around time (TAT) is based on day of receipt and is dependent on the test requested. Additional reflex testing will extend the TAT by the times indicated for the add-on method(s).
āā
- āReal-time PCR testing: 7 business days
- āāmCIMā testing: 14 business days
- SensititreTM AST (surveillance testing only): 14 business days
- Whole Genome Sequencing: 21 calendar days
- Results of ExAST for isolates forwarded to the ARLN Regional Lab will be available within 3 business days from time of receipt for CRE, CRPA and CRAB.āāā