Implementation of Xpert MTB/Rif Assay in Buhera District ... ... MTB/RIF. Xpert MTB/Rif is a TB-specific,

  • View
    0

  • Download
    0

Embed Size (px)

Text of Implementation of Xpert MTB/Rif Assay in Buhera District ... ... MTB/RIF. Xpert MTB/Rif is a...

  • Implementation of Xpert MTB/Rif Assay in Buhera District, Zimbabwe: Lessons Learned

    Milton Chemhuru*, Marve Duka MDŦ, Kassi Joseph Bernardin Nanan-n’zeth MDŦ, Sandrina Simons MD#, Steven Van Den Broucke MDŦ, Emmanuel Fajardo@ and Helen Bygrave,MDδ

    Contents Introduction .................................................................................. 1

    Laboratory implementation ............................................................. 4

    Clinical Implementation .................................................................. 4

    Outcomes of parallel phase implementation .................................... 10

    Workload .................................................................................... 18

    Cost ........................................................................................... 19

    Conclusions ................................................................................. 20

    Introduction

    Zimbabwe is ranked 17th of the 22 high-burden TB countries in the world1. In 2010, the country reported 47,557 cases of tuberculosis with a case notification rate of 633 cases per 100 000 population for all TB cases. 43% of TB cases are notified as smear negative and the HIV co- infection rate is reported as 80%2.

    *Provincial Medical Director, Manicaland Province, Zimbabwe Ŧ MSF Medical Doctor # MSF MedCo Zimbabwe @ Mobile Implementing Officer – Laboratory, SAMU δ Mobile Implementing Officer –HIV, SAMU

    1 http://www.usaid.gov/our_work/global_health/id/tuberculosis/countries/africa/zimbabwe.pdf: Accessed 13/12/11

    2https://extranet.who.int/sree/Reports?op=Replet&name=/WHO_HQ_Reports/G2/PROD/EXT/TBCountryProfil e&ISO2=ZW&outtype=html : Accessed 13/12/11

    http://www.usaid.gov/our_work/global_health/id/tuberculosis/countries/africa/zimbabwe.pdf https://extranet.who.int/sree/Reports?op=Replet&name=/WHO_HQ_Reports/G2/PROD/EXT/TBCountryProfile&ISO2=ZW&outtype=html https://extranet.who.int/sree/Reports?op=Replet&name=/WHO_HQ_Reports/G2/PROD/EXT/TBCountryProfile&ISO2=ZW&outtype=html

  • The burden of HIV in the country is also high at 13.7%3 in the general population with TB being reported as the most frequent cause of death among persons living with HIV/AIDS.

    In addition to the high co-infection rates, drug resistant TB is also emerging as an increasing problem. The drug resistance survey performed in 1994 showed a prevalence of

  • TB or MDR-TB. Sensitivity of a single Xpert MTB/RIF test in smear- negative/culture-positive patients was 72.5%, increasing to 90.2% when three samples were tested.

    MSF- Belgium in collaboration with MoH has been supporting TB/HIV activities since 2004 in Buhera district, Manicaland, an eastern Zimbabwean province bordering with Mozambique. The district has an estimated population of 238.293 people. There are 30 health facilities in the district, which includes 3 hospitals, 26 government or council clinics/health centers and 1 private mining clinic. Weekly outreach for HIV/TB care to 22 clinics (including BBH) is performed by MSF mobile teams. To date 18.048 patients have been started on ART in Buhera, with 13.603 patients remaining on ART follow-up.

    Murambinda Mission Hospital (MMH) and Birchenough Bridge Hospital (BBH), where Xpert MTB Rif machines have been installed, are rural district hospitals. The laboratories in both hospitals are equipped with a fluorescence microscope for auramine staining. This is more sensitive than the light optical microscope for Ziehl-Neelsen staining. Both settings have been equipped with air-conditioning in order to maintain the temperature at levels below 30oC necessary for optimum instrument operation. Although studies indicate that sample preparation does not require handling under a biosafety cabinet, both laboratories utilise this safety measure.

    MSF-Belgium in Zimbabwe is one of seven MSF project sites to implement Xpert MTB/Rif during 2011. All sites implemented an initial parallel phase combining conventional smear microscopy alongside Xpert MTB/Rif. In Zimbabwe this parallel phase was implemented in Murambinda Mission Hospital (MMH, May – August 2011) and Birchenough Bridge Hospital (BBH, April – August 2011.

    The objectives of implementing Xpert /MTB Rif in this parallel phase were:

    • to assess the operational challenges of implementing the Xpert MTB/Rif in a rural district laboratory setting.

    • to observe the additional diagnostic value of the tool at rural district level compared to sputum smear microscopy, in particular in the diagnosis of smear negative TB in co-infected patients.

  • Laboratory implementation

    The installation of the Xpert MTB/Rif was performed by staff from PointeCare Company - Harare in presence of the complete staff in both laboratories . The installation was complete in 1 day. The first machine (BBH) was installed in presence of a Senior Laboratory Scientist of Mutare provincial hospital.

    Prior to installation the following logistical requirements were fulfilled at both sites:

    • Air conditioning: Xpert MTB/Rif is designed for indoor use only. Operating temperature should be between 15-30 degrees, meaning that a Functioning air conditioner is required in most African settings.

    • The machine should not be placed directly under an air vent or in direct sunlight

    • Stable electricity supply: power interruptions can lead to instrument damage and incomplete testing. It is therefore mandatory to have a uninterruptable power supply (UPS) for operation of Xpert MTB/Rif

    • Storage of cartridges: The single use cartridges are bulky and require substantial storage space. This needs to be planned for.

    • Waste management: Disposal of cartridges is similar to that of other biological waste. i.e sterilisation (autoclave) and appropriate chemical waste incineration.

    • Training: laboratory staff can be trained in a one day training provided by the local supplier. Follow up of implementation is however essential to ensure SOPs are followed accurately

    Clinical Implementation

    Figure 1 demonstrates the clinical algorithm followed during the initial parallel phase. Samples were collected from ALL TB suspect patients, regardless of HIV status. Current WHO recommendations suggest that Xpert MTB/Rif should be used as first test only in co-infected patients or those suspected of DRTB. However there is argument that in high burden HIV/TB settings Xpert MTB/Rif should be made available to all patients; especially in setting with MDR TB patients. This is a crucial

  • question to be analysed further in terms of direct patient benefit versus presumed additional costs related to Xpert MTB/Rif use.

    Validation studies for Xpert MTB/RIF have only demonstrated accuracy in testing sputum specimens, the project focused mainly on sputa, but did not deny extra-pulmonary specimens as having an additional benefit for doctors to diagnose EPTB cases clinically. Children were also included provided they were able to produce sputum. A TB suspect as defined by NTP was any patient who presents with cough of more than 2 weeks, fever more than 3 weeks, night sweat more than 3 weeks, weight loss more than 5% of body weight, chest pain more than 2 weeks or having a close TB contact.

  • Figure 1: Algorithm for diagnosis of (DR-) TB during the parallel testing period

    Each TB-suspect was requested to submit 2 sputum specimens: 1 for the conventional smear plus Xpert MTB/Rif and a second for conventional smear alone. PITC was offered (if status unknown) and an empirical antibiotic trial with amoxicillin for 1 week was started for patients seen at health centre level. If Xpert MTB/Rif detected M.

    CXR suggestive

    of TB

    PTB Suspect*

    Negative result

    Positive result with NO Rif- resistance

    - Ensure TB IC measures in place - Start treatment for drug- sensitive TB

    - Clinical reassessment for other causes - Give 2° empiric antibiotic course with erythromycin/azithromycin - CXR

    - Offer HIV testing and counseling - 2 quality sputum specimens for microscopy and one used for GeneXpert - Give 1° empiric course with amoxicillin

    Positive result with Rif-resistance

    - Ensure TB IC measures in place - Start treatment for drug-sensitive TB

    One additional quality sputum for repeat of Xpert MTB/RIF assay

    Positive result with Rif-

    resistance

    - Clinical reassessment and rule out other causes - Refer to Doctor for further decision

    Follow right side of this algorithm

    PTB still suspected, CXR not suggestive

    - Repeat Xpert and send for culture and DST If second Xpert shows rif resistance commence empirical DRTB treatment If second Xpert sensitive to rifampicin commence first line TB treatment

    Positive result with

    NO Rif- resistance

    Negative results

    DANGER SIGNS:

    Resp rate > 30/min and fever > 39° and/or pulse > 120/min and or unable to walk→ REFER FOR HOSPITALISATION

    * Suspect = cough > 2 w or, fever >3 w or, night sweats or, weight loss > 5% or, chest pains or TB- contact in the family

  • tuberculosis and the strain was not rifampicin resistant, then nurses initiated CAT I or CAT II TB treatment and registered the patient based on smear result. If Xpert MTB/Rif detected M. tu