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

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-1ß, 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-1ß, IL-17A, and IFN-α.

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.