Browsing by Author "Mwesigwa, Alex"

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    Assessment of different genotyping markers and algorithms for distinguishing Plasmodium falciparum recrudescence from reinfection in Uganda
    (Research Square, 2025-02-05) Mwesigwa, Alex; Golumbeanu, Monica; Jones, Sam; Cantoreggi, Sara L.; Musinguzi, Benson; Nankabirwa, Joaniter I.; Bikaitwoha, Everd Maniple; Kalyango, Joan N; Karamagi, Charles; Plucinski, Mateusz; Nsobya, Samuel L.; Nsanzabana, Christian; Byakika-Kibwika, Pauline
    Antimalarial therapeutic efficacy studies are vital for monitoring the efficacy of antimalarial drugs in malaria-endemic regions. The WHO recommends genotyping of polymorphic markers including msp-1, msp-2, and glurp to aid distinguishing recrudescences from reinfections. Recently, WHO proposed replacing glurp with microsatellites (Poly-α, PfPK2, TA1). However, suitable combinations with msp-1 and msp-2 have not been systematically assessed. Additionally, the performance of different algorithms for classifying recrudescence is unclear. This study investigated various microsatellites alongside msp-1 and msp-2 for molecular correction and compared genotyping algorithms across three malaria-endemic areas in Uganda. Microsatellites 313, Poly-α, and 383 exhibited the highest diversity, while PfPK2 and Poly-α revealed elevated multiplicities of infection across all sites. The 3/3 match-counting algorithm classified fewer recrudescences than the ≥ 2/3, and Bayesian algorithms at both ≥ 0.7 and ≥ 0.8 probability cutoffs. The msp-1/msp-2/2490 combination identified more recrudescences using the ≥ 2/3 and 3/3 algorithms in the artemether-lumefantrine (AL) treatment arm, while msp-1/msp-2/glurp combination identified more cases of recrudescence using the ≥ 2/3 in the dihydroartemisinin-piperaquine (DP) arm. Microsatellites PfPK2 and Poly-α, potentially sensitive to detecting minority clones, are promising replacements for glurp. Discrepancies in recrudescence classification between match-counting and Bayesian algorithms highlight the need for standardized PCR correction practices.
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    Distribution and antifungal susceptibility profile of oropharyngeal Candida species isolated from people living with HIV in the era of universal test and treat policy in Uganda
    (Sage Publishing, 2024-04-30) Musinguzi, Benson; Turyamuhika, Laban; Mwesigwa, Alex; Nalumaga, Pauline Petra; Kabajulizi, Immaculate; Njovu, Israel Kiiza; Mwebesa, Edson; Luggya, Tonny; Ocheng, Francis; Kateete, David Patrick; Itabangi, Herbert; Mboowa, Gerald; Sande, Obondo James; Achan, Beatrice
    Despite the increased frequency of oropharyngeal candidiasis among people living with human immunodeficiency virus (HIV), its management is no longer effective due to empirical treatment and emergence of antifungal resistance (AFR). This study sought to investigate the prevalence of oropharyngeal candidiasis and assess the antifungal susceptibility profile of oropharyngeal Candida species isolated from people living with human immunodeficiency virus. Additionally, we evaluated the correlation between oropharyngeal candidiasis and CD4 T cell as well as viral load counts. A descriptive cross-sectional study was carried out from April to October 2023 in which 384 people living with HIV underwent clinical examination for oral lesions. Oropharyngeal swabs were collected and cultured on Sabouraud Dextrose agar to isolate Candida species which were identified using the matrix assisted laser desorption ionization time of flight mass spectrometry. Additionally, the antifungal susceptibility profile of Candida isolates to six antifungal drugs was determined using VITEK® (Marcy-l’Étoile, France) compact system. Data on viral load were retrieved from records, and CD4 T cell count test was performed using Becton Dickinson Biosciences fluorescent antibody cell sorter presto. The prevalence of oropharyngeal candidiasis was 7.6%. Oropharyngeal candidiasis was significantly associated with low CD4 T cell count and high viral load. A total of 35 isolates were obtained out of which Candida albicans comprised of 20 (57.1%) while C. tropicalis and C. glabrata comprised 4 (11.4%) each. C. parapsilosis, C. dubliniensis and C. krusei accounted for 2 (5.7%) each. Additionally, 7 (20%) isolates were resistant to fluconazole, 1 (2.9%) to flucytocine and 0.2 (5.7%) isolates were intermediate to caspofungin. However, specific specie isolates like C. albicans showed 20% (4/20), C. glabrata 50% (2/4) and C. krusei 50% (1/2) resistance to fluconazole. Additionally, C. krusei showed 50% resistance to flucytosine. The prevalence of oropharyngeal candidiasis (OPC) among people living with HIV was low, and there was a significant association between OPC and CD4 T cell count as well as viral load. C. albicans was the most frequently isolated oropharyngeal Candida species. C. glabrata and C. krusei exhibited the highest AFR among the non-albicans Candida species. The highest resistance was demonstrated to fluconazole.
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    Distribution of Candida species isolated from people living with human immunodeficiency virus with oropharyngeal and oral candidiasis in Africa in the era of universal test and treat policy: a systematic review and meta‑analysis
    (Springer Nature, 2024-11-27) Musinguzi, Benson; Obuku, Ekwaro A.; Mwesigwa, Alex; Migisha, Richard; Kinengyere, Alison Annet; Ndagire, Regina; Baguma, Andrew; Okek, Erick Jacob; Olum, Ronald; Itabangi, Herbert; Mboowa, Gerald; Sande, Obondo James; Achan, Beatrice
    Background: The introduction of antiretroviral therapy (ART) and the implementation of the human immunodeficiency virus (HIV) universal test and treat (UTT) policy have led to a decline in the incidence of opportunistic infections. However, oropharyngeal and oral candidiasis remain prevalent and continue to pose challenges among people living with human immunodeficiency virus (PLHIV) in Africa, indicating the need for a better understanding of the distribution of Candida species responsible for these infections. This systematic review and meta-analysis aimed to determine the distribution of Candida species isolated from PLHIV with oropharyngeal and oral candidiasis in Africa in the era of UTT policy. Methods: The review followed the preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines. A comprehensive search was conducted to identify eligible studies to be included in the meta-analysis and analysed using a random effects model in STATA version 17. The risk of bias was assessed using the Joanna Briggs Institute quality assessment tool. Results: Fourteen studies with 4281 participants were included in the review. Overall, 2095 Candida isolates were reported, 78.7% (1650/2095) of which were C. albicans, 19.6% (410/2095), non-albicans Candida (NAC), and 1.7% (35/2095) could not be identified to the Candida specific species level. The most prevalent NAC species were C. glabrata (26.3%), followed by C. tropicalis (24.9%), C. krusei (15.6%), C. parapsilosis (11%), and C. dubliniensis (6.3%). The pooled prevalence of oropharyngeal and oral candidiasis was 48% (95% CI 34–62%). The prevalence of oropharyngeal candidiasis was higher in the pre-UTT era, at 56% (95% CI 40–72%, p < 0.001), than in the post-UTT era, at 34% (95% CI 10–67%, p < 0.001). The risk of bias assessment revealed that 71.4% (10/14) of the included studies had a low risk of bias and that 28.6% (4/14) had a moderate risk of bias. Conclusions: While C. albicans remain, the predominant species causing oropharyngeal and oral candidiasis among PLHIV in Africa, NAC species also contribute significantly to the infection burden. Despite ART and UTT policies, oropharyngeal candidiasis remains prevalent, emphasizing the need for targeted interventions.
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    Extracellular hydrolytic enzyme activities and biofilm formation in Candida species isolated from people living with human immunodeficiency virus with oropharyngeal candidiasis at HIV/AIDS clinics in Uganda
    (Elsevier, 2024-12-14) Musinguzi, Benson; Akampurira, Andrew; Derick, Hope; Turyamuhika, Laban; Mwesigwa, Alex; Mwebesa, Edson; Mwesigye, Vicent; Kabajulizi, Immaculate; Sekulima, Tahalu; Ocheng, Francis; Itabangi, Herbert; Mboowa, Gerald; Sande, Obondo James; Achan, Beatrice
    Background: Commensal oral Candida species can become opportunistic and transition to pathogenic causes of oropharyngeal candidiasis (OPC) in individuals with impaired immunity through ecological cues and the expression of extracellular hydrolytic enzyme activities and biofilm formation. Objective: We evaluated phospholipase, proteinase, hemolysin, esterase, and coagulase enzymatic activities and biofilm formation in Candida species isolated from people living with human immunodeficiency virus (PLHIV) with OPC. Methods: Thirty-five Candida isolates from PLHIV with OPC were retrieved from a sample repository and evaluated for phospholipase activity using the egg yolk agar method, proteinase activity using the bovine serum albumin agar method, hemolysin activity using the blood agar plate method, esterase activity using the Tween 80 opacity test medium method, coagulase activity using the classical tube method, and biofilm formation using the microtiter plate assay method in vitro. Results: A total of 35 Candida isolates obtained from PLHIV with OPC were included in this study, and phospholipase and proteinase activities were detected in 33/35 (94.3 %) and 31/35 (88.6 %) Candida isolates, respectively. Up to 25/35 (71.4 %) of the Candida isolates exhibited biofilm formation, whereas esterase activity was demonstrated in 23/35 (65.7 %) of the Candida isolates. Fewer isolates (21/35, 60 %) produced hemolysin, and coagulase production was the least common virulence activity detected in 18/35 (51.4 %) of the Candida isolates. Conclusion: Phospholipase and proteinase activities were the strongest in oropharyngeal Candida species.
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    Plasmodium falciparum genetic diversity and multiplicity of infection among asymptomatic and symptomatic malaria-infected individuals in Uganda
    (Springer Nature, 2024-11-14) Mwesigwa, Alex; Ocan, Moses; Cummings, Bryan; Musinguzi, Benson; Kiyaga, Shahid; Kiwuwa, Steven M.; Okoboi, Stephen; Castelnuovo, Barbara; Bikaitwoha, Everd Maniple; Kalyango, Joan N.; Karamagi, Charles; Nankabirwa, Joaniter I.; Nsobya, Samuel L.; Byakika-Kibwika, Pauline
    Background: Plasmodium falciparum (P. falciparum) remains a significant public health challenge globally, especially in sub-Saharan Africa (SSA), where it accounts for 99% of all malaria infections. The outcomes of P. falciparum infection vary, ranging from asymptomatic to severe, and are associated with factors such as host immunity, parasite genetic diversity, and multiplicity of infection (MOI). Using seven neutral microsatellite markers, the current study investigated P. falciparum genetic diversity and MOI in both asymptomatic and symptomatic malaria individuals in Uganda. Methods: This cross-sectional study analyzed 225 P. falciparum isolates from both asymptomatic and symptomatic malaria patients, ranging in age from 6 months to ≥ 18 years. P. falciparum genetic diversity, MOI, and multi-locus linkage disequilibrium (LD) were assessed through genotyping of seven neutral microsatellite markers: Poly-α, TA1, TA109, PfPK2, 2490, C2M34–313, and C3M69–383. Genetic data analysis was performed using appropriate genetic analysis software. Results: P. falciparum infections exhibited high genetic diversity in both asymptomatic and symptomatic individuals. The mean expected heterozygosity (He) ranged from 0.79 in symptomatic uncomplicated malaria cases to 0.81 in asymptomatic individuals. There was no significant difference (p = 0.33) in MOI between individuals with asymptomatic and symptomatic infections, with the mean MOI ranging from 1.92 in symptomatic complicated cases to 2.10 in asymptomatic individuals. Polyclonal infections were prevalent, varying from 58.5% in symptomatic complicated malaria to 63% in symptomatic uncomplicated malaria cases. A significant linkage disequilibrium (LD) was observed between asymptomatic and symptomatic uncomplicated/complicated infections (p < 0.01). Genetic differentiation was low, with FST values ranging from 0.0034 to 0.0105 among P. falciparum parasite populations in asymptomatic and symptomatic uncomplicated/complicated infections. Conclusion: There is a high level of P. falciparum genetic diversity and MOI among both symptomatic and asymptomatic individuals in Uganda. Asymptomatic carriers harbor a diverse range of parasites, which poses challenges for malaria control and necessitates targeted interventions to develop effective strategies.
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    Plasmodium falciparum genetic diversity and multiplicity of infection based on msp-1, msp-2, glurp and microsatellite genetic markers in sub-Saharan Africa: a systematic review and meta-analysis
    (Springer Nature, 2024-04-08) Mwesigwa, Alex; Ocan, Moses; Musinguzi, Benson; Nante, Rachel Wangi; Nankabirwa, Joaniter I.; Kiwuwa, Steven M.; Kinengyere, Alison Annet; Castelnuovo, Barbara; Karamagi, Charles; Obuku, Ekwaro A.; Nsobya, Samuel L.; Mbulaiteye, Sam M.; Byakika-Kibwika, Pauline
    In sub-Saharan Africa (SSA), Plasmodium falciparum causes most of the malaria cases. Despite its crucial roles in disease severity and drug resistance, comprehensive data on Plasmodium falciparum genetic diversity and multiplicity of infection (MOI) are sparse in SSA. This study summarizes available information on genetic diversity and MOI, focusing on key markers (msp-1, msp-2, glurp, and microsatellites). The systematic review aimed to evaluate their influence on malaria transmission dynamics and offer insights for enhancing malaria control measures in SSA. The review was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Two reviewers conducted article screening, assessed the risk of bias (RoB), and performed data abstraction. Meta-analysis was performed using the random-effects model in STATA version 17. The review included 52 articles: 39 cross-sectional studies and 13 Randomized Controlled Trial (RCT)/cohort studies, involving 11,640 genotyped parasite isolates from 23 SSA countries. The overall pooled mean expected heterozygosity was 0.65 (95% CI: 0.51–0.78). Regionally, values varied: East (0.58), Central (0.84), Southern (0.74), and West Africa (0.69). Overall pooled allele frequencies of msp-1 alleles K1, MAD20, and RO33 were 61%, 44%, and 40%, respectively, while msp-2 I/C 3D7 and FC27 alleles were 61% and 55%. Central Africa reported higher frequencies (K1: 74%, MAD20: 51%, RO33: 48%) than East Africa (K1: 46%, MAD20: 42%, RO33: 31%). For msp-2, East Africa had 60% and 55% for I/C 3D7 and FC27 alleles, while West Africa had 62% and 50%, respectively. The pooled allele frequency for glurp was 66%. The overall pooled mean MOI was 2.09 (95% CI: 1.88–2.30), with regional variations: East (2.05), Central (2.37), Southern (2.16), and West Africa (1.96). The overall prevalence of polyclonal Plasmodium falciparum infections was 63% (95% CI: 56–70), with regional prevalences as follows: East (62%), West (61%), Central (65%), and South Africa (71%)
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    Temporal changes in Plasmodium falciparum genetic diversity and multiplicity of infection across three areas of varying malaria transmission intensities in Uganda
    (Springer Nature, 2023-12-30) Mwesigwa, Alex; Kiwuwa, Steven M.; Musinguzi, Benson; Kawalya, Hakiim; Katumba, James Davis; Baguma, Andrew; Mutuku, Irene M.; Adebayo, Ismail Abiola; Nsobya, Samuel L.; Byakika‑Kibwika, Pauline; Kalyango, Joan N.; Karamagi, Charles; Nankabirwa, Joaniter I.
    Background: Malaria is a significant public health challenge in Uganda, with Plasmodium falciparum (P. falciparum) responsible for most of malaria infections. The high genetic diversity and multiplicity of infection (MOI) associated with P. falciparum complicate treatment and prevention efforts. This study investigated temporal changes in P. falciparum genetic diversity and MOI across three sites with varying malaria transmission intensities. Understanding these changes is essential for informing effective malaria control strategies for the different malaria transmission settings. Methods: A total of 220 P. falciparum-positive dried blood spot (DBS) filter paper samples from participants in a study conducted during 2011–2012 and 2015–2016 were analyzed. Genotyping utilized seven polymorphic markers: Poly-α, TA1, TA109, PfPK2, 2490, C2M34–313, and C3M69–383. Genetic diversity metrics, including the number of alleles and expected heterozygosity, were calculated using GENALEX and ARLEQUIN software. MOI was assessed by counting distinct genotypes. Multi-locus linkage disequilibrium (LD) and genetic differentiation were evaluated using the standardized index of association (IAS) and Wright’s fixation index (FST), respectively. Statistical comparisons weremade using the Kruskal–Wallis test, and temporal trends were analyzed using the Jonckheere–Terpstra test, with statistical significance set at p < 0.05. Results: Of the 220 samples, 180 were successfully amplified. The majority of participants were males (50.6%) and children aged 5–11 years (46.7%). Genetic diversity remained high, with mean expected heterozygosity (He) showing a slight decrease over time (range: 0.73–0.82). Polyclonal infections exceeded 50% at all sites, and mean MOI ranged from 1.7 to 2.2, with a significant reduction in Tororo (from 2.2 to 2.0, p = 0.03). Linkage disequilibrium showed a slight increase, with Kanungu exhibiting the lowest IA S in 2011–2012 (0.0085) and Jinja the highest (0.0239) in 2015–2016. Overall genetic differentiation remained low, with slight increases in pairwise FST values over time, notably between Jinja and Tororo (from 0.0145 to 0.0353).