High Mortality in Hospitalised Virally Suppressed Adults with Hiv in South Africa

Background: Mortality in PWH has been markedly improved by antiretroviral therapy (ART) but there are few reports describing this in the ~5 million virally suppressed (VS) PWH in South Africa(SA). We describe cause of death(CoD) in adults admitted to hospital with suspected pneumonia in SA. Method(s): We enrolled patients from June 2019-October 2021 at four hospitals and then followed them up for >=1 year. Eligibility included: Age >18 years, >=2 signs/symptoms of pneumonia, < 48 hrs since admission. Medical records were reviewed. All had HIV status ascertained and sputum sent for Xpert Ultra and mycobacterial culture. In PWH CD4 count, viral load (VL) and urine lipoarabinomannan were assessed. For those who died, CoD were ed from medical charts and interview of family. We categorised deaths as early: while admitted or to < 30 days after discharge;or late: >=30 days after discharge. We report mortality and CoD in VSPWH (VL<=50 copies/ml), unsuppressed and HIV uninfected(HUI) adults. Result(s): Of 1999 adults, 54% were PWH;61.2% reported receiving ART of whom 43.1% were VS;55.5% were women. Overall median age of VS was 48 years (IQR: 40-55) at entry;34.3% had comorbidities: hypertension (70.1%, obesity 41.3%, diabetes 28.9%) . Only 11.3% were diagnosed with HIV in the past year, 35.0%, had prior TB. Median CD4 count of VS patients was 289 cells/ mm3 (IQR:133-490) and Hb, 12.5g/dL (IQR:10.5-14.0);53.0% had CRP >100mg/ dL and 69.6% had oxygen saturation < 93% on room air;14.8% had >=1 assay positive for TB;and 42.9% were SARS-CoV-2 positive. Overall 25.4% VSPWH died compared to 31.2% and 22.9% of unsuppressed and HUI, respectively;median ages at death were 49 (IQR:43-59), 38 (IQR: 32-47) and 62 (IQR: 53-69) years respectively. Overall median times to early and late death was 8 (IQR: 4-16) and 104 (IQR: 75-254) days, respectively. The leading CoD in VSPWH were: COVID-19 (22.9%), chronic lung disease(CLD) (17.1%),malignancy (12.9%),sepsis, (12.9%) and TB (8.7%);in HIV unsuppressed, CoD were: advanced HIV and opportunistic infections-(TB,PJP)(55.5%), sepsis(9.6%), COVID-19(8.6%);and in HUI: COVID- 19(43.0%), cardiovascular disease (9.0%), TB(9.0%), malignancy (8.5%). Conclusion(s): Mortality in VSPWH admitted with suspected pneumonia was higher than in HUI and occurred 12 years earlier. The challenge for clinicians is to screen for diseases that disproportionately affect VSPWH and to try to prevent recurrent lung infections thereby increasing their comorbidity-free years and reduce mortality gaps.

Metabolic Biological Markers for Diagnosing and Monitoring the Course of Tuberculosis

The international biomedical community has been currently facing a need to find a simple and most accessible type of analysis that helps to diagnose tuberculosis ( TB) with the maximum reliability even before the onset of clinical manifestations. Tuberculosis results in more deaths than any other pathogen, second only to pneumonia caused by the SARS-CoV-2 virus, but the majority of infected people remain asymptomatic. In addition, it is important to develop methods to distinguish various forms of tuberculosis infection course at early stages and to reliably stratify patients into appropriate groups (persons with a rapidly progressing infection, chronic course, latent infection carriers). Immunometabolism investigates a relationship between bioenergetic pathways and specific functions of immune cells that has recently become increasingly important in scientific research. The host anti-mycobacteria immune response in tuberculosis is regu lated by a number of metabolic networks that can interact both cooperatively and antagonistically, influencing an outcome of the disease. The balance between inflammatory and immune reactions limits the spread of mycobacteria in vivo and protects from developing tuberculosis. Cytokines are essential for host defense, but if uncontrolled, some mediators may contribute to developing disease and pathology. Differences in plasma levels of metabolites between individuals with advanced infection, LTBI and healthy individuals can be detected long before the onset of the major related clinical signs. Changes in amino acid and cortisol level may be detected as early as 12 months before the onset of the disease and become more prominent at verifying clinical diagnosis. Assessing serum level of certain amino acids and their ratios may be used as additional diagnostic markers of active pulmonary TB. Metabolites, including serum fatty acids, amino acids and lipids may contribute to detecting active TB. Metabolic profiles indicate about increased indolamine 2.3-dioxygenase 1 (IDO1) activity, decreased phospholipase activity, increased adenosine metabolite level, and fibrous lesions in active vs. latent infection. TB treatment can be adjusted based on individual patient metabolism and biomarker profiles. Thus, exploring immunometabolism in tuberculosis is necessary for development of new therapeutic strategies.

Enhanced immunogenicity of Mycobacterium bovis BCG through CRISPRi mediated depletion of AftC.

Mycobacterium tuberculosis causes the disease tuberculosis and affects a third of the world's population. The recent COVID-19 pandemic exacerbated the situation with a projected 27% increase in tuberculosis related deaths. M. tuberculosis has an elaborate cell wall consisting of peptidoglycan, arabinogalactan and mycolic acids which shield the bacilli from the toxic bactericidal milieu within phagocytes. Amongst, the numerous glycosyltransferase enzymes involved in mycobacterial cell wall biosynthesis, arabinofuranosyltransferase C (aftC) is responsible for the branching of the arabinan domain in both arabinogalactan and lipoarabinomannan. Using Clustered Regularly Interspaced Short Palindromic Repeats interference (CRISPRi) we have generated aftC knockdowns in Mycobacterium bovis BCG and demonstrated the generation of a truncated, immunogenic lipoarabinomannan within its cell envelope. The aftC depleted BCG mutants were unable to form characteristic mycobacterial pellicular biofilms and elicit a potent immunostimulatory phenotype compared to wild type M. bovis BCG in a THP1 cell line. This study paves the way to further explore novel BCG mutants as promising vaccine boosters in preventing pulmonary tuberculosis.

Utility of urine lipoarabinomannan (LAM) in diagnosing mycobacteria infection among hospitalized HIV-positive patients.

OBJECTIVES: Cross-reactivity with nontuberculous mycobacteria (NTM) species might limit the use of urine lipoarabinomannan (LAM) test to diagnose tuberculosis (TB) in people living with HIV (PLWH). This study aimed to investigate the utility of the LAM test among hospitalized HIV-positive patients. METHODS: This prospective study enrolled HIV-positive inpatients with any TB symptom or seriously ill patients with advanced immunodeficiency. Urine samples were tested using the Alere Determine LAM Ag, and participants were categorized as confirmed TB, confirmed NTM infection, unclassified mycobacteria infection, and no mycobacteria infection based on microbiologic reference standards. RESULTS: A total of 382 participants were included. The prevalence of confirmed TB and NTM infection was 5.24% (20 of 382) and 4.45% (17 of 382), respectively. The sensitivity and specificity of the urine LAM for TB diagnosis were 65.00% (95% confidence interval [CI] 40.78-84.61) and 89.36% (95% CI 85.68-92.36), respectively. The LAM test for NTM yielded a sensitivity of 58.82% (95% CI 32.92-81.56) and specificity of 88.61% (95% CI 84.87-91.70). Notably, the negative predictive values of the urine LAM for TB and NTM were 97.85% (95% CI 95.63-99.13) and 97.85% (95% CI 95.63-99.13), respectively. CONCLUSIONS: Cross-reactivity with NTM cause high false-positive LAM for TB diagnosis in PLWH. The correct identification of mycobacteria species is crucial for deciding treatment strategies.

Towards Accurate Point-of-Care Tests for Tuberculosis in Children.

In childhood tuberculosis (TB), with an estimated 69% of missed cases in children under 5 years of age, the case detection gap is larger than in other age groups, mainly due to its paucibacillary nature and children's difficulties in delivering sputum specimens. Accurate and accessible point-of-care tests (POCTs) are needed to detect TB disease in children and, in turn, reduce TB-related morbidity and mortality in this vulnerable population. In recent years, several POCTs for TB have been developed. These include new tools to improve the detection of TB in respiratory and gastric samples, such as molecular detection of Mycobacterium tuberculosis using loop-mediated isothermal amplification (LAMP) and portable polymerase chain reaction (PCR)-based GeneXpert. In addition, the urine-based detection of lipoarabinomannan (LAM), as well as imaging modalities through point-of-care ultrasonography (POCUS), are currently the POCTs in use. Further to this, artificial intelligence-based interpretation of ultrasound imaging and radiography is now integrated into computer-aided detection products. In the future, portable radiography may become more widely available, and robotics-supported ultrasound imaging is currently being trialed. Finally, novel blood-based tests evaluating the immune response using "omic-"techniques are underway. This approach, including transcriptomics, metabolomic, proteomics, lipidomics and genomics, is still distant from being translated into POCT formats, but the digital development may rapidly enhance innovation in this field. Despite these significant advances, TB-POCT development and implementation remains challenged by the lack of standard ways to access non-sputum-based samples, the need to differentiate TB infection from disease and to gain acceptance for novel testing strategies specific to the conditions and settings of use.