DETERRENCES OF RAPID LABORATORY DIAGNOSIS OF TUBERCULOSIS IN RESOURCE-LIMITED TUBERCULOSIS ENDEMIC AREAS: SPUTUM CHARACTERISTICS OR TECHNIQUES?

1
DETERRENCES OF RAPID LABORATORY DIAGNOSIS OF
TUBERCULOSIS IN RESOURCE-LIMITED TUBERCULOSIS
ENDEMIC AREAS SPUTUM CHARACTERISTICS OR
TECHNIQUES?
MAKERERE
UNIVERSITY

• BY
• EKUKA GODFREY
• BBLT (Mak)

2
Introduction

• Globally, the disease remains a public health
  threat accounting for over 10 million new
  infections that is (5.8 million men, 3.2 million
  women and 1.0 million children(World Health
  Organization, 2018)).
• As of 2018, the disease was assessed against HIV
  status and WHO results revealed that it caused an
  estimated 1.3 million (13) deaths with 1.0
  million being among HIV negative people and 0.3
  million among HIV positive
• Tuberculosis(TB) is a devastating infectious
  disease. Its eradication is still a challenge
  given the limitations of the current
  diagnostic technologies and capacities in the
  developing world

3
Introduction.

• Collection of epidemiological data and care of
  patients are hindered by lack of access to
  appropriate laboratory diagnostic equipment
• Specimen characteristics and time to culture have
  long been assumed to be important predictors for
  the performance characteristics of microbiologic
  tests, particularly those used to diagnose lower
  respiratory-tract infections
• Unfortunately, the amount and quality of evidence
  on how sputum characteristics(appearance, volume,
  transport time and host HIV status) affects the
  performance of TB diagnostic tests is still
  scanty

4
Objectives of the Study

• General Objective
• To determine how sample characteristics impacts
  on the recovery of Mycobacteria species and
  technique for rapid detection.
• Specific Objectives
• Identify how sputum characteristics affect the
  recovery of MTB species.
• Determine the time to detection of MTB using the
  various available techniques

5
Material and Methods

• Sputum was collected from 73 patients and tested
  with GeneXpert MTB/RIFTM, microscopy, Glycerated
  and pyruvated Lowenstein Jensen media and
  Mycobacterium growth indicator tube (MGIT).
• Positive cultures were confirmed using lateral
  flow device Capillia NeoTM, M. bovis and Line
  probe assay.
• Data was entered in Microsoft excel (Office
  program 2019) and analyzed using R-Studio version
  3.5.2 for windows.
• Descriptive statistics were used for categorical
  data to determine demographic-based prevalence
• Kaplan-Meier survival estimates of sample
  characteristic, comparison of the recovery and
  identification tests were analyzed

6
Results

• The results showed that there is higher TB
  prevalence among male 63 (55-71, p0.0016), age
  group 20-40 years 52 (44-61, p0.6183), primary
  education 61 (52-69, p0.1273) and HIV negative
  66 (57-73, p0.0002).
• The mean detection time for MGIT was 18 days
  (8-32), LJG 42 days (30-58) and LJP 38 days
  (28-52). MGIT recovery rate was 93.2
  (82.7-97.8), LJP 84.7 (72.5-92.4) and LJG 83.1
  (70.6-91.2).
• Sensitivity of Gene Xpert and Capillia NeoTM
  based on Culture was 98.3 (89.7-99.9), LPA test
  89.8 (78.5-95.8), Microscopy 59.3 (45.8-71.7)
  and LFD M. bovis 26 (20.9-45.8).

7
Results 1..Sputum characteristics
Variable Category Positive Frequency () Total Frequency ()
Appearance Bloody 4(2.8) 5(3.45)
Appearance Mucoid 21(14.5) 21(14.5)
Appearance Mucopurulent 20(13.8) 25 (17.25)
Appearance Mucosalivary 39(26.8) 43 (29.56)
Appearance Purulent 25(17.2) 25(17.25)
Appearance Salivary 23(15.9) 26 (17.97)
Volume (mL) 0.5-2.5 8(5.5) 9 (6.19)
Volume (mL) 2.6-5.0 69(47.5) 74(50.95)
Volume (mL) 5.1-10.0 46(31.7) 49 (33.14)
Volume (mL) 10.1-15.0 7(4.8) 11(7.56)
Volume (mL) 15.1-20.0 2(1.4) 2 (1.40)
Duration of transport (Days) lt3 64(44.1) 74 (50.95)
Duration of transport (Days) 3-7 55(37.9) 58(40.6)
Duration of transport (Days) gt7 13(8.9) 13 (8.90)
Host HIV Status Negative 95(65.5) 102(70.33)
Host HIV Status Positive 30(20.6) 36 (24.24)
Host HIV Status Unknown 7(4.8) 7 (4.80)
8
Sputum appearance and time to detection

• The appearance, was significantly associated with
  time to detection of Mycobacterium tuberculosis
  complex using MGIT culture (Plt0.05)

9
HIV status of patient and time to detection

• MGIT culture has a shorter time for MTB recovery
  but may miss it from mucopurulent and HIV
  positive samples after 42 days of incubation.

10
Results 2.Diagnostic Techniques
Diagnostic Test Number positive Number Negative Gold Standard (Culture ) Sensitivity (95 CI), P-Value
FM 43 30 73 58.9 (46.7-70.1) 0.160
GX 72 1 73 98.6 (91.5-99.9) 0.000
LG 59 14 73 80.8(69.5-88.8) 0.000
LP 56 17 73 76.7 (65.0-85.5) 0.000
MG 68 5 73 93.1 (84.1-97.5) 0.000
LB 19 54 73 26.0 (16.8-37.8) 0.009
LM 72 1 73 98.6 (91.5-99.9) 0.000
HN 54 19 73 73.9 (62.1-83.2) 0.000
11
Conclusion

• MGIT technique has shorter time to detection of
  mycobacteria, however after the conventional 42
  days of incubation, 42 of mucopurulent samples
  and 32 of HIV would be reported as negative.
• Gene Xpert is the best identification test for
  the detection of MTBC from clinical specimen with
  shorter turnaround time compared to Culture
  followed by LFD Capillia NeoTM.
• We recommend studies for MGIT culture durations
  extension to recover Mycobacteria from
  Mucopurulent and HIV patients.

12
Acknowledgement

• Dr. Clovice Kankya, Dr. Adrian Muwonge Dr. Olea
  Popelka, Angela Varnum and James Muleme for the
  guidance and financial support
• Special thanks go to Dr. Samuel Majalija
• Mubende District Administration
• Mubende R R Hospital Director and staff
• NTLP staff
• NTRL staff