Antimicrobial Resistance Laboratory Network (ARLN)

What is ARLN?

The Centers for Disease Control and Prevention (CDC) Antibiotic Resistance Laboratory Network (ARLN) is a national initiative that enables state public health labs and state health departments to collaborate with local healthcare facilities and clinical labs to detect, respond to, and contain emerging threats of multidrug resistant organisms (MDROs). CDCs ARLN includes labs in all 50 states, 5 cities (including Washington, DC), and Puerto Rico. This nationwide ARLN network is further divided into 7 regions. The Mid-Atlantic Regional ARLN lab is located in Baltimore, MD and supports the public health laboratories in the District of Columbia (DC) Maryland, Pennsylvania, Delaware, Virginia, West Virginia, North Carolina and South Carolina.

The District of Columbia (DC) received funding to begin building its ARLN program in 2016 and officially kicked-off its implementation in the spring of 2018. DC ARLN has commitment from clinical labs that serve all acute care and some outpatient facilities in DC. Epidemiologists who staff the DC Department of Health (DC Health) Healthcare-Associated Infections (HAI) Program work closely with microbiologists at the DC Department of Forensic Science (DFS) Public Health Lab (PHL) to respond to alerts of new and unusual MDROs that are detected from isolates submitted by clinical labs serving District healthcare facilities. The DC HAI Program then works with infection prevention staff at corresponding healthcare facilities to ensure that appropriate actions are taken to control the spread of these MDROs.
For more information, please send an email to [email protected].

CRE/CRPA Surveillance

Why is DC doing this?

DC PHL is working with Epidemiologists at DC Health and the CDC to enhance detection of carbapenem-resistant Enterobacteriaceae (CRE) and carbapenem-resistant Pseudomonas aeruginosa (CRPA) in the District, track trends in resistance patterns, inform guidelines to interrupt the transmission of these pathogens within different healthcare facility settings, and prevent future threats.
What should clinical/reference labs send to DC PHL each month?

Please send CRE and CRPA isolates to DC PHL that meet the following definitions:
1) Enterobacteriaceae isolates from any specimen source that meet the following criteria:

• Resistant to any carbapenem antibiotic following current CLSI M100 guidelines

Antibiotic	MIC (µg/ml)
doripenem	≥ 4
ertapenem	≥ 2
imipenem	≥ 4
meropenem	≥ 4

• Found to be a carbapenemase-producer via Carba-NP test, Modified Carbapenem Inactivation Method (mCIM), MBL-screen, PCR, or other phenotypic or genotypic carbapenemase test.
NOTE: For Proteus, Providencia, or Morganella sp. resistant to imipenem, please only submit if the isolate is also resistant to another carbapenem antibiotic.

2) Pseudomonas aeruginosa isolates from any specimen source received each month that meet the following criteria:

• Resistant to any carbapenem antibiotic following current CLSI M100 guidelines

Antibiotic	MIC (µg/ml)
doripenem	≥ 8
imipenem	≥ 8
meropenem	≥ 8

• Found to be a carbapenemase-producer via Carba-NP test, mCIM, MBL-screen, PCR, or other phenotypic or genotypic carbapenemase test.

Testing to be performed at DC PHL:
•   Isolate identification will be confirmed using MALDI-TOF MS.
•   Antibiotic susceptibility testing results will be confirmed using manual test methods (Kirby Bauer disc diffusion and/or Etest).
•   Phenotypic detection of carbapenemase production will be carried out using the Modified Carbapenem Inactivation Method (mCIM).
•   Molecular detection of carbapenemase genes (KPC, NDM, VIM, OXA-48, IMP) will be carried out with the Cepheid GeneXpert CarbaR assay.
•   If DC ARLN is unable to fully characterize a CRE/CRPA isolate, or if an unusual resistance mechanism is detected, the isolate will be forwarded to the Mid-Atlantic Regional laboratory for further analysis.

Reporting by DC PHL:
•   Alerts for high priority MDROs will be sent to the submitting laboratory, DC Health and CDC within 2 business days of finalized result.
•   Healthcare facility infection control departments will be notified about DC ARLN alerts by the DC Department of Health Healthcare-Associated Infections Program. For more information, please email [email protected].
Shipping isolates to DC PHL:
•   Submit the CRE/CRPA isolate, antibiotic susceptibility report, test requisition, and chain of custody to the DC PHL during your next scheduled twice-weekly PHL pickup.
•   Send high priority isolates as soon as they’re received by calling 202-481-3937 to schedule a DC PHL courier.
•   High priority isolates include those that are:
o   Positive for following resistance mechanisms: NDM, OXA-48, OXA-48-like, VIM, IMP type resistance
o   Suspected novel resistance
o   Suspected pan resistance
o   Anything else your lab deems noteworthy and has prior approval from [email protected].
For more information, please send an email to [email protected].

Colonization Testing

District healthcare facilities that have received an alert through DC ARLN or who have a concern about an emerging MDRO within their facility may request support from ARLN for colonization screening through the DC Health Healthcare-Associated Infections Program. ARLN can provide screening materials and testing support free of charge. Currently all colonization testing and support for District healthcare facilities is done at the Mid-Atlantic Regional Laboratory.
ALL REQUESTS FOR COLONIZATION SCREENING SUPPORT MUST FIRST BE APPROVED by the DC Health HAI Program. To request support or to obtain more information, please send an email to [email protected].

Targeted Surveillance

DC PHL and DC Health have recruited one clinical lab in the District to serve as a sentinel surveillance site for the detection of carbapenemase-producing Acinetobacter and mcr-1/2. All testing is done at the Mid-Atlantic Regional Lab and results are provided by the Mid-Atlantic Regional Lab to DC Health on a routine basis.
For more information, please send an email to [email protected].

Laboratories Participating in DC ARLN

Nationally, ARLN includes labs in all 50 states, 5 cities (including Washington, DC), and Puerto Rico. This nationwide ARLN network is further divided into 7 regions; the District of Columbia (DC) ARLN is part of the Mid-Atlantic Region, along with Maryland, Pennsylvania, Delaware, Virginia, West Virginia, North Carolina and South Carolina. DC ARLN has commitment from 6 clinical labs, which serve all acute care and some outpatient facilities in DC:
•   Children’s National Medical System
•   George Washington University Hospital
•   Howard University Hospital
•   Johns Hopkins Health System
•   Kaiser Permanente
•   MedStar Health System
•   Quest Diagnostics
•   Veterans Administration
If your clinical or reference lab serves a DC healthcare facility and is interested in joining DC ARLN, please send an email to [email protected].
For more information, please send an email to [email protected].