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BACKGROUND: Drug-resistant tuberculosis (DR-TB) poses a major global challenge to public health and therapeutics. It is an emerging global concern associated with increased morbidity and mortality mostly seen in the low- and middle-income countries. Molecular techniques are highly sensitive and offer timely and accurate results for TB drug resistance testing, thereby positively influencing patient management plan. METHODS: The study was carried out at the National Tuberculosis Reference Laboratory (NTRL) in Kenya in the period between January and October 2022. A total of 243 Mycobacterium tuberculosis (M.tb) clinical isolates were included in the study. These isolates comprised of 50 isolates with mutations in rpoB, 51 isolates with katG mutations, 51 isolates with mutations in inhA, and 91 M.tb isolates lacking mutations in these genes based on Genotype MTBDRplus results. DNA from the isolates was extracted using the FluoroLyse extraction kit. Real-time polymerase chain reaction targeting the rpoB, InhA, and katG genes was performed using the FluoroType MTBDR amplification mix. Isolates with discordant results between Genotype MTBDRplus and FluoroCycler® MTBDR assays underwent targeted sequencing for the respective genes, then, sequences were analyzed for mutations using Geneious version 11.0 software. RESULTS: The sensitivity of the Fluorocycler XT MTBDR assay for the detection of mutations that confer drug resistance was 86% (95% confidence interval [CI] 73.0-94.0) for rpoB, 96% (95% CI 87-100) for katG and 92% (95% CI 81-98) for inhA. The assay's specificity was 97% (95% CI 93-99) for rpoB, 98% (95% CI 96-100) for katG, and 97% (95% CI 93-99) for inhA. CONCLUSION: The diagnostic accuracy of FluoroType MTBDR for the detection of mutations conferring resistance to rifampicin and isoniazid was high compared with that of Genotype MTBDRplus and demonstrates its suitability as a replacement assay for Genotype MTBDRplus.

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BACKGROUND: Though persons of African descent have one of the widest genetic variability, genetic polymorphisms of drug-metabolising enzymes such as N-Acetyltransferase-2 (NAT2) are understudied. This study aimed to identify prevalent NAT2 single nucleotide polymorphisms (SNPs) and infer their potential effects on enzyme function among Kenyan volunteers with tuberculosis (TB) infection. Genotypic distribution at each SNP and non-random association of alleles were evaluated by testing for Hardy-Weinberg Equilibrium (HWE) and Linkage Disequilibrium (LD). METHODS: We isolated genomic DNA from cryopreserved Peripheral Blood Mononuclear Cells of 79 volunteers. We amplified the protein-coding region of the NAT2 gene by polymerase chain reaction (PCR) and sequenced PCR products using the Sanger sequencing method. Sequencing reads were mapped and aligned to the NAT2 reference using the Geneious software (Auckland, New Zealand). Statistical analyses were performed using RStudio version 4.3.2 (2023.09.1 + 494). RESULTS: The most frequent haplotype was the wild type NAT2*4 (37%). Five genetic variants: 282C > T (NAT2*13), 341 T > C (NAT2*5), 803A > G (NAT2*12), 590G > A (NAT2*6) and 481C > T (NAT2*11) were observed with allele frequencies of 29%, 18%, 6%, 6%, and 4% respectively. According to the bimodal distribution of acetylation activity, the predicted phenotype was 76% rapid (mainly consisting of the wildtype NAT2*4 and the NAT2*13A variant). A higher proportion of rapid acetylators were female, 72% vs 28% male (p = 0.022, odds ratio [OR] 3.48, 95% confidence interval [CI] 1.21 to 10.48). All variants were in HWE. NAT2 341 T > C was in strong complete LD with the 590G > A variant (D' = 1.0, r2 = - 0.39) but not complete LD with the 282C > T variant (D' = 0.94, r2 = - 0.54). CONCLUSION: The rapid acetylation haplotypes predominated. Despite the LD observed, none of the SNPs could be termed tag SNP. This study adds to the genetic characterisation data of African populations at NAT2, which may be useful for developing relevant pharmacogenomic tools for TB therapy. To support optimised, pharmacogenomics-guided TB therapy, we recommend genotype-phenotype studies, including studies designed to explore gender-associated differences.

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The increasing prevalence of human immunodeficiency virus (HIV) drug resistance mutations (HIVDRM) in untreated seropositive persons has consequences for future treatment options. This is extremely important in key populations such as female sex workers (FSWs), where the prevalence of pretreatment drug resistance (PDR) and associated risk factors are unknown. In this study, we analyzed PDR and associated risk factors in recently diagnosed and treatment-naive FSWs in Nairobi, Kenya. In this cross-sectional study, we used 64 HIV-seropositive plasma samples collected from FSWs between November 2020 and April 2021. To identify HIVDRM, the pol gene was amplified and genotyped using sanger sequencing. The effects of age, tropism, CD4+ T cell count, subtype, and location on HIVDRM counts were examined using Poisson regression. Overall, the prevalence of PDR was 35.9% (95% CI: 24.3-48.9), which was strongly influenced by K103N and M184V mutations, which confer resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs) and nucleoside reverse transcriptase inhibitors (NRTI), respectively. Subtype A1 was predominant followed by subtype D with a notable increase in inter-subtype recombinants. We found statistically significant evidence that age was inversely related to HIVDRM. A FSW who is 1 year older had 12% less HIVDRM (incidence rate ratios [IRR]: 0.88; 95% CI: 0.82-0.95; P < .001), after adjusting for CD4+ T cell count, subtype, location, and tropism. Similarly, an increase in CD4+ T cell count by 1 unit, was associated with 0.4% fewer HIVDRM (IRR: 0.996; 95% CI: 0.994-0.998; P = .001), while controlling for the other variables. HIV-1 tropism was not associated with HIVDRM counts. In conclusion, our findings show a high prevalence of NNRTIs. Lower CD4+ T cell counts and younger age were significant risk factors that influenced HIVDRM loads. This finding underscores the relevance of targeted interventions and the importance of continuing to focus on FSWs as a way of addressing the HIV epidemic.

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We report the draft genome sequences and annotation of Enterococcus faecium, Enterococcus gallinarum, and Lactococcus lactis isolates that were recovered from a mastitis-infected camel in Isiolo County, Kenya. Collectively, these data provide an invaluable repository for data mining to support the development of a potential multicomponent mastitis subunit vaccine.

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Human immunodeficiency virus (HIV) infection affects around 37 million people worldwide, and in Kenya, key populations especially female sex workers (FSW), are thought to play a substantial role in the wider, mostly heterosexual HIV-1 transmission structure. Notably, HIV tropism has been found to correlate with HIV-1 transmission and disease progression in HIV-infected patients. In this study, recently infected FSWs from Nairobi, Kenya, were assessed for HIV tropism and the factors related to it. We used a cross-sectional study design to analyze 76 HIV-1 positive plasma samples obtained from FSWs enrolled in sex worker outreach program clinics in Nairobi between November 2020 and April 2021. The effects of clinical, demographic, and viral genetic characteristics were determined using multivariable logistic regression. HIV-1 subtype A1 accounted for 89.5% of all cases, with a prevalence of CXCR4-tropic viruses of 26.3%. WebPSSMR5X4 and Geno2Pheno [G2P:10-15% false positive rate] showed high concordance of 88%. Subjects infected with CXCR4-tropic viruses had statistically significant lower baseline CD4+T-cell counts than those infected with CCR5-tropic viruses (P = .044). Using multivariable logistic regression and adjusting for potential confounders, we found that net charge, the amino acid at position 22 of the V3 loop, and the geographic location of the subject were associated with tropism. A unit increase in V3 loop's net-charge increased the odds of a virus being CXCR4-tropic by 2.4 times (OR = 2.40, 95%CI = 1.35-5.00, P = .007). Second, amino acid threonine at position 22 of V3 loop increased the odds of a strain being X4 by 55.7 times compared to the alanine which occurred in CCR5-tropic strains (OR = 55.7, 95%CI = 4.04-84.1, P < .003). The Kawangware sex worker outreach program clinic was associated with CXCR4-tropic strains (P = .034), but there was there was no evidence of a distinct CXCR4-tropic transmission cluster. In conclusion, this study revealed a high concordance of WebPSSMR5X4 and Geno2Pheno in predicting HIV tropism. The most striking finding was that amino acid position 22 of the V3 loop is linked to tropism in HIV-1 subtype A1. Additional studies with a large dataset are warranted to confirm our findings.

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