Dr.Patrick Orikiriza

BACKGROUND AND OBJECTIVES Children experience high tuberculosis (TB)-related mortality but causes of death among those with presumptive TB are poorly documented. We describe the mortality, likely causes of death, and associated risk factors among vulnerable children admitted with presumptive TB in rural Uganda. METHODS We conducted a prospective study of vulnerable children, defined as <2 years of age, HIV-positive, or severely malnourished, with a clinical suspicion of TB. Children were assessed for TB and followed for 24 weeks. TB classification and likely cause of death were assessed by an expert endpoint review committee, including insight gained from minimally invasive autopsies, when possible. RESULTS Of the 219 children included, 157 (71.7%) were <2 years of age, 72 (32.9%) were HIV-positive, and 184 (84.0%) were severely malnourished. Seventy-one (32.4%) were classified as “likely tuberculosis” (15 confirmed and 56 unconfirmed), and 72 (32.9%) died. The median time to death was 12 days. The most frequent causes of death, ascertained for 59 children (81.9%), including 23 cases with autopsy results, were severe pneumonia excluding confirmed TB (23.7%), hypovolemic shock due to diarrhea (20.3%), cardiac failure (13.6%), severe sepsis (13.6%), and confirmed TB (10.2%). Mortality risk factors were confirmed TB (adjusted hazard ratio [aHR] = 2.84 [95% confidence interval (CI): 1.19–6.77]), being HIV-positive (aHR = 2.45 [95% CI: 1.37–4.38]), and severe clinical state on admission (aHR = 2.45 [95% CI: 1.29–4.66]). CONCLUSIONS Vulnerable children hospitalized with presumptive TB experienced high mortality. A better understanding of the likely causes of death in this group is important to guide empirical management.

Critical illness from tuberculosis (TB) bloodstream infection results in a high case fatality rate for people living with human immunodeficiency virus (HIV). Critical illness can lead to altered pharmacokinetics and suboptimal drug exposures. We enrolled adults living with HIV and hospitalized with sepsis, with and without meningitis, in Mbarara, Uganda that were starting first-line anti-TB therapy. Serum was collected two weeks after enrollment at 1-, 2-, 4-, and 6-h post-dose and drug concentrations quantified by validated LC-MS/MS methods. Non-compartmental analyses were used to determine total drug exposure, and population pharmacokinetic modeling and simulations were performed to determine optimal dosages. Eighty-one participants were enrolled. Forty-nine completed pharmacokinetic testing: 18 (22%) died prior to testing, 13 (16%) were lost to follow-up and one had incomplete testing. Isoniazid had the lowest serum attainment, with only 4.1% achieving a target exposure over 24 h (AUC0–24) of 52 mg·h/L despite appropriate weight-based dosing. Simulations to reach target AUC0–24 found necessary doses of rifampin of 1800 mg, pyrazinamide of 2500–3000 mg, and for isoniazid 900 mg or higher. Given the high case fatality ratio of TB-related critical illness in this population, an early higher dose anti-TB therapy should be trialed.

Abstract Background Chloroquine (CQ) resistance is conferred by mutations in the Plasmodium falciparum CQ resistance transporter (pfcrt). Following CQ withdrawal for anti-malarial treatment, studies across malaria-endemic countries have shown a range of responses. In some areas, CQ sensitive parasites re-emerge, and in others, mutant haplotypes persist. Active surveillance of resistance mutations in clinical parasites is essential to inform treatment regimens; this effort requires fast, reliable, and cost-effective methods that work on a variety of sample types with reagents accessible in malaria-endemic countries. Methods Quantitative PCR followed by High-Resolution Melt (HRM) analysis was performed in a field setting to assess pfcrt mutations in two groups of clinical samples from Southwestern Uganda. Group 1 samples (119 in total) were collected in 2010 as predominantly Giemsa-stained slides; Group 2 samples (125 in total) were collected in 2015 as blood spots on filter paper. The Rotor-Gene Q instrument was utilized to assess the impact of different PCR-HRM reagent mixes and the detection of mixed haplotypes present in the clinical samples. Finally, the prevalence of the wild type (CVMNK) and resistant pfcrt haplotypes (CVIET and SVMNT) was evaluated in this understudied Southwestern region of Uganda. Results The sample source (i.e. Giemsa-stained slides or blood spots) and type of LCGreen-based reagent mixes did not impact the success of PCR-HRM. The detection limit of 10− 5 ng and the ability to identify mixed haplotypes as low as 10 % was similar to other HRM platforms. The CVIET haplotype predominated in the clinical samples (66 %, 162/244); however, there was a large regional variation between the sample groups (94 % CVIET in Group 1 and 44 % CVIET in Group 2). Conclusions The HRM-based method exhibits the flexibility required to conduct reliable assessment of resistance alleles from various sample types generated during the clinical management of malaria. Large regional variations in CQ resistance haplotypes across Southwestern Uganda emphasizes the need for continued local parasite genotype assessment to inform anti-malarial treatment policies.

Background: Non-sputum-based diagnostic approaches are crucial in children at high risk of disseminated tuberculosis (TB) who cannot expectorate sputum. We evaluated the diagnostic accuracy of stool Xpert MTB/RIF and urine AlereLAM tests in this group of children. Methods: Hospitalised children with presumptive TB and either age <2 years, HIV-positive or with severe malnutrition were enrolled in a diagnostic cohort. At enrolment, we attempted to collect two urine, two stool and two respiratory samples. Urine and stool were tested with AlereLAM and Xpert MTB/RIF, respectively. Respiratory samples were tested with Xpert MTB/RIF and mycobacterial culture. Both a microbiological and a composite clinical reference standard were used. Results: The study analysed 219 children; median age 16.4 months, 72 (32.9%) HIV-positive and 184 (84.4%) severely malnourished. 12 (5.5%) and 58 (28.5%) children had confirmed and unconfirmed TB, respectively. Stool and urine were collected in 219 (100%) and 216 (98.6%) children, respectively. Against the microbiological reference standard, the sensitivity and specificity of stool Xpert MTB/RIF was 50.0% (6/12, 95% CI 21.1–78.9%) and 99.1% (198/200, 95% 96.4–99.9%), while that of urine AlereLAM was 50.0% (6/12, 95% 21.1–78.9%) and 74.6% (147/197, 95% 67.9–80.5%), respectively. Against the composite reference standard, sensitivity was reduced to 11.4% (8/70) for stool and 26.2% (17/68) for urine, with no major difference by age group (<2 and ⩾2 years) or HIV status. Conclusions: The Xpert MTB/RIF assay has excellent specificity on stool, but sensitivity is suboptimal. Urine AlereLAM is compromised by poor sensitivity and specificity in children.