Trends in extrapulmonary TB cases at three teaching hospitals in Ghana, 2008-2017

The Burden of Bacteriologically Negative TB Diagnosis: A Four-Year Review of Tuberculosis Cases at a Tertiary Facility

Aim

We aimed to investigate the demographic and clinical factors associated with TB mortality in patients managed at a tertiary TB referral center.

Methods

We conducted a retrospective review of the medical records of 1,933 TB patients seen between January 2017 and December 2020 at the Korle-Bu Teaching Hospital (KBTH) Chest Department in Accra, Ghana. TB mortality was defined as any TB patient who died for any reason during the course of treatment. Multivariable logistic regression was used to estimate adjusted odds ratios with 95% confidence intervals for factors associated with TB mortality.

Results

A total of 1,933 patients with TB were registered at the chest clinic over the study period. Males accounted for 1,227 (63.5%), and majority of participants were between 24 and 64 years old. Pulmonary TB (PTB) and extrapulmonary TB (EPTB) cases accounted for 51% and 48.4% of the total TB cases, respectively. A significant proportion (69%) of the patients managed for TB had no bacteriological confirmation of the disease. About 34% of tested TB patients were HIV positive. Mortality among patients was 33.6%. In a multivariable regression model, patients with HIV positive status had over 3-fold increased risk of mortality, compared to those with HIV negative status. TB patients diagnosed empirically had an increased risk of death compared to those with a confirmed diagnosis.

Conclusion

The proportion of clinically diagnosed TB was high among the patients seen at the chest clinic. Mortality was high among the patients with HIV/TB coinfection as well as in patients with empirical TB diagnosis.

Utility of anti-Mycobacterium tuberculosis antibody (ab905) for detection of mycobacterial antigens in formalin-fixed paraffin-embedded tissues from clinically and histologically suggestive extrapulmonary tuberculosis cases

Background

The detection of acid-fast bacilli in extrapulmonary tissue samples is challenging due to its paucibacillary nature. The present study assessed the utility of immunohistochemistry (IHC) using anti-Mycobacterium tuberculosis antibody (ab905) for detecting the presence of mycobacterial antigens in archived formalin-fixed paraffin-embedded (FFPE) tissues.

Methods

FFPE tissues [surgical biopsies (n = 32) and post-mortem tissues (n = 8)] from clinically and histologically suggestive extrapulmonary tuberculosis (EPTB) cases at the Korle Bu Teaching Hospital, Accra, Ghana from 2015 to 2020 were stained with IHC (anti-Mycobacterium tuberculosis antibody) and Ziehl-Neelsen (ZN) stain. The staining outcomes of IHC and ZN were compared, and their sensitivity and specificity determined against histopathology as reference standard.

Results

Lymph nodes were about 40% (16/40) of the samples analyzed. IHC stained positive in 43.8% (7/16) biopsies and 87.5% (4/5) post-mortem samples ranging from 43.8% (7/16) in lymph nodes to 80% (4/5) in gastrointestinal organs. The overall sensitivity for IHC was 52.50% (95% CI: 36.13%-68.49%) and 0% (95% CI: 0.00%-8.81%) for ZN. Specificity was 72.50% (95% CI: 56.11%-85.40%) and 75% (95% CI: 58.80-87.31%) for IHC and ZN respectively.

Conclusions

IHC using anti-Mycobacterium tuberculosis antibody (ab905) can detect mycobacterial antigens in diverse range of paucibacillary extrapulmonary tissue sections. It is potentially a useful tool for the diagnosis of EPTB in FFPE tissues in a routine pathology laboratory.

Genetic diversity and drug resistance profiles of Mycobacterium tuberculosis complex isolates from patients with extrapulmonary tuberculosis in Ghana and their associated host immune responses

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Pleural TB and TB lymphadenitis are the most common forms of extrapulmonary TB in Ghana.

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M. tb sub-lineage Cameroon is associated with decreased serum IL-1β, IL-17A, and IFN-α.

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A significant association was observed between age and M. tb complex lineages.

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Generally, M. bovis contributes minimally to human extrapulmonary TB in Ghana.

Objectives

This study sought to determine the genetic diversity and drug resistance profiles of Mycobacterium tuberculosis complex (MTBC) isolates from extrapulmonary tuberculosis (EPTB) patients in Ghana, and their associated immune responses.

Methods

Spoligotyping was performed on 102 MTBC isolates from EPTB patients. Lineages/sub-lineages were assigned by comparing spoligotyping patterns primarily with the SITVIT2 database and subsequently with the TB-Lineage online tool for unknown isolates in SITVIT2. Drug susceptibility testing was performed using MGIT (BD BACTEC 960), Lowenstein-Jensen media (indirect proportion method), and GenoType MTBDRplus/MTBDRsl assays. Differential cytokine levels in the serum of 20 EPTB patients infected with MTBC lineage 4 were determined using the Luminex multiplex immunoassay.

Results

Around 95% (97/102) of isolates were Mycobacterium tuberculosis, predominantly lineage 4 (95%; 92/97). Of the lineage 4 isolates, the majority were sub-lineage Cameroon (37%, 34/92). Prevalence was significantly higher in the 15–34 years age group among EPTB patients infected with lineage 4 strains (p = 0.024). Fifteen isolates were resistant to at least one anti-TB drug tested. Decreased levels of IL-1β, IL-17A, and IFN-α were observed in individuals infected with Cameroon sub-lineages compared with other lineage 4 sub-lineages.

Conclusions

Our study confirms Cameroon (SIT61) as the most common spoligotype causing human EPTB in Ghana, and that it is associated with decreased serum IL-1β, IL-17A, and IFN-α.