Genotyping of culture-positive TB isolates can provide valuable information to state TB programs with regard to TB epidemiology within local populations, TB transmission, multi-jurisdictional clustering, and identification of false-positive specimens. This information can assist in defining program priorities for surveillance, case management, and education and training at state and local levels.
In 1996, the Maryland Center for Tuberculosis Control and Prevention (CTBCP) initiated genotyping of culture-positive TB patients, with a goal that every resident with culture-positive TB would have an isolate genotyped. In 2009 and 2010, the goal was reached and 100% of all Maryland TB culture-positive isolates were genotyped. How this goal was accomplished, and how other states can meet this same goal, is demonstrated below.
Success is dependent upon fostering good, sustainable working relationships among the State Mycobacteriology Laboratory, CTBCP, and private sector hospitals and laboratories. The guiding principle of these relationships was a commitment to improve the public health of all Maryland residents who have contracted TB, through testing, diagnosis, and treatment. Maryland maintains and fosters these relationships through frequent communication both by telephone and fax with all partners, including private providers, hospital laboratories, public laboratories, and county health department staff.
The State Genotyping Coordinator is based within the CTBCP. The State Genotyping Coordinator maintains the database with all the genotyping test results, clusters, and pertinent patient information. The State Mycobacteriology Laboratory has identified a coordinator, who maintains the isolates on all genotyped patients and collects isolates from private laboratories on Maryland residents. Each coordinator has his or her specific roles and tools to use, and these individuals work closely together.
The State Laboratory Coordinator prepares and sends isolates to the reference genotyping laboratory in Michigan monthly, and provides a list of outgoing isolates to the State Genotyping Coordinator. The State Genotyping Coordinator enters the names and other pertinent data into the local genotyping database. Both coordinators have access to TB GIMS. Genotyping reports are received by both the laboratory and program coordinators, and results entered into the local database. The genotyping coordinator then assumes primary responsibility for contacting and consulting with local health departments regarding potential links within clusters. Any suspicions of or questions arising from possible multi-jurisdictional clusters are referred to the CTBCP program chief. Suspected laboratory contaminations are referred by the program genotyping coordinator to both the local health department and the CTBCP program chief for follow-up.
Genotyping begins with the CTBCP surveillance staff generating a list of all culture-positive TB cases for the current year. The list is updated monthly and sent to both the Genotyping Coordinator and the Mycobacteriology Laboratory Coordinator. This list contains the patient’s name, county of residence, and date of culture identification, and indicates if the culture was identified as TB at the state or other laboratory.
Other laboratories include private hospitals, commercial or university laboratories, and other public laboratories in other states. The genotyping and laboratory coordinators regularly discuss which isolates have not been received from other laboratories, and determine who will take responsibility for requesting individual isolates from which laboratories to be sent to the State Mycobacteriology Laboratory.
For those isolates not already received at the State Laboratory, the Genotyping Coordinator contacts the local health department(s) to obtain a copy of the laboratory report form for the patient’s TB positive culture. This form provides the name of the laboratory that processed the specimen, the patient’s name and date of birth, the healthcare provider or center that requested the test, the laboratory accession number for the specimen, and the date the specimen was processed.
Several tools have been developed to request specimens from other laboratories. The first tool is a directory that contains the names and contact information of all private and public laboratories that have processed Maryland TB case specimens, the name of each laboratory supervisor or contact person, and their direct telephone and fax numbers. The directory is amended as new laboratories, hospitals, or other institutions are identified that collect or process specimens for Maryland TB cases.
The second tool is a standardized isolate requisition form used for requesting isolates from other laboratories. It contains the patient’s name and date of birth, specimen type and date of specimen collection, and laboratory accession number to help identify the correct specimen needed from the laboratory. The request form also contains space for the laboratory name, address, contact person and their numbers. Lastly the form has the State Mycobacteriology Laboratory Chief’s name, and mailing address for shipping purposes.
For example, when a positive TB isolate needs to be retrieved from a private laboratory, a coordinator calls the facility contact person directly. Once the location of the specimen is confirmed, a requisition form is faxed to the contact person so that the isolate is shipped to the Maryland State Mycobacteriology Laboratory.
Sometimes the private laboratory is unaware that the patient is a Maryland resident, or may have sent the isolate to another laboratory instead. The time spent building relationships with the specific contact personnel working in outside laboratories ultimately saves time and avoids confusion. These relationships have proven very helpful when false-positive results are suspected. Regular contact makes communication much easier.
Tracking down positive TB cultures processed in other laboratories across the United States is a time-consuming process. Since 1996, isolates have been obtained from more than 75 laboratories. In October 2008, Maryland regulators eased the TB isolate tracking process by changing Maryland state regulations.
This third tool, the revised Maryland code (COMAR) 10.06.01.03 C, states that a positive TB culture from a Maryland resident must automatically be sent to the Maryland State Mycobacteriology Laboratory for testing and processing. This regulation has decreased the number of requests made to larger laboratories, but smaller ones still need reminding.
In 2010, only 93 (57%) isolates from 162 culture positive cases were processed in the State Mycobacteriology Laboratory. The other 69 specimens were processed at private Maryland hospitals, out-of-state hospitals, and commercial or out-of-state laboratories. Using the system described enabled the Maryland State Mycobacteriology Laboratory to retrieve all 162 isolates for genotyping.
The success of Maryland’s Genotyping Program is a direct result of 17 years spent fostering strong, collaborative working relationships with local health departments, public and private laboratories, and hospitals nationwide. The development and implementation of a protocol that provides routine access to a surveillance list of culture-positive cases, the laboratory directory, an isolate request form, and the 2008 regulations has provided tools that Maryland has relied on for continued success in the genotyping program.
The national TB GIMS program is another communication resource that provides names and contact information from other public laboratories. The utility of TB GIMS will ensure continued success for Maryland’s Genotyping Program in the future.
—Submitted by Heather Rutz, MCRP, MHS and Rachel A. VadenMaryland Department of Health and Mental HygieneCDC - SEOIB Updates - TB Notes 4, 2011 - TB