Browsing by Author "Sonda, Tolbert"

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Complete genome sequence of Brucella abortus isolated from a human blood culture sample in Tanzania
(American society for microbiology, 2024-01-30) Mbwambo, Gershom; Zwetselaar, Marco; Sonda, Tolbert; Lukambagire, AbdulHamid; Njau, Judith; Wadugu, Boaz; Ignass, Ignass; Amani, Nelson; Hugho, Ephrasia; Rubach, Matthew; Sakasaka, Philoteus; Oisso, Rose; Mkenda, Nestory; Shirima, Gabriel; Ashford, Roland; Haydon, Daniel; Maro, Venance; Kazwala, Rudovick; Kumburu, Happiness; Mmbaga, Blandina; Halliday, Jo E.
Brucella abortus causes infections in humans and livestock. Bacterial isolates are challenging to obtain, and very little is known about the genomic epidemiology of this species in Africa. Here, we report the complete genome sequence of a Brucella abortus isolate cultured from a febrile human in northern Tanzania
Genomic characterization of methicillin-resistant Staphylococcus aureus isolated from patients attending regional referral hospitals in Tanzania
(BioMed Central, 2024-08-14) Geofrey, Mujungu; Sauli, Elingarami; Kanje, Livin; Beti, Melkiory; Shayo, Mariana; Kuchaka, Davis; Zwetselaar, Marco; Wadugu, Boaz; Mmbaga, Blandina; Mkumbaye, Sixbert; Kumburu, Happiness; Sonda, Tolbert
Background Methicillin-resistant Staphylococcus aureus (MRSA) colonization increases the risk of subsequent infection by MRSA strain complex interlinking between hospital and community-acquired MRSA which increases the chance of drug resistance and severity of the disease. Objective Genomic characterization of Staphylococcus aures strains isolated from patients attending regional referral hospitals in Tanzania. Methodology A laboratory-based cross-sectional study using short read-based sequencing technology, (Nextseq550,Illumina, Inc. San diego, California, USA). The samples used were collected from patients attending selected regional referral hospitals in Tanzania under the SeqAfrica project. Sequences were analyzed using tools available in the center for genomic and epidemiology server, and visualization of the phylogenetic tree was performed in ITOL 6.0. SPSS 28.0 was used for statistical analysis. Results Among 103 sequences of S. aureus, 48.5% (50/103) carry the mecA gene for MRSA. High proportions of MRSA were observed among participants aged between 18 and 34 years (52.4%), in females (54.3%), and among outpatients (60.5%). The majority of observed MRSA carried plasmids rep5a (92.0%), rep16 (90.0%), rep7c (90.0%), rep15 (82.0%), rep19 (80.0%) and rep10 (72.0%). Among all plasmids observed rep5a, rep16, rep20, and repUS70 carried the blaZ gene, rep10 carried the erm(C) gene and rep7a carried the tet(K) gene. MLST and phylogeny analysis reveal high diversity among MRSA. Six different clones were observed circulating at selected regional hospitals and MRSA with ST8 was dominant. Conclusion The study reveals a significant presence of MRSA in Staphylococcus aureus strains from Tanzanian regional hospitals, with nearly half carrying the mecA gene. MRSA is notably prevalent among young adults, females, and outpatients, showing high genetic diversity and dominance of ST8. Various plasmids carrying resistance genes indicate a complex resistance profile, highlighting the need for targeted interventions to manage MRSA infections in Tanzania.
Plasmid characterization in bacterial isolates of public health relevance in a tertiary healthcare facility in Kilimanjaro region, Tanzania
(Elsevier, 2022-09) Sengeruan, Lameck; Zwetselaar, Marco; Kumburu, Happiness; Aarestrup, Frank; Kreppel, Katharina; Sauli, Elingarami; Sonda, Tolbert
Objectives Plasmids are infectious double stranded DNA molecules that are found within bacteria. Horizontal gene transfer promotes successful spread of different types of plasmids within or among bacteria species, making their detection an important task for guiding clinical treatment. We used whole genome sequenced data to determine the prevalence of plasmid replicon types in clinical bacterial isolates, the presence of resistance and virulence genes in plasmid replicon types, and the relationship between resistance and virulence genes within each plasmid replicon. Methods All bacterial sequences were de novo assembled using Unicycler before extraction of plasmids. Assembly graphs were submitted to Gplas+plasflow for plasmid contigs prediction. The predicted plasmid contigs were validated using PlasmidFinder. Results A total of 159 (56.2%) out of 283 bacterial isolates were found to carry plasmid replicons, with Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus being the most prevalent plasmid carriers. A total of 26 (86.7%) multiple-replicon types were found to carry both resistance and virulence genes compared to 4 (13.3%) single plasmid replicons. No statistically significant correlation was found between the number of antibiotic resistance and virulence genes in multiple-replicon types (r = - 0.14, P > 0.05). Conclusion Our findings show a relatively high proportion of plasmid replicon-carrying isolates suggesting selection pressure due to antibiotic use in the hospital. Co-occurrence of antibiotic resistance and virulence genes in clinical isolates is a public health problem warranting attention.
Prevalence and associated risk factors for Kaposi’s sarcoma among HIV-positive patients in a referral hospital in Northern Tanzania: a retrospective hospital-based study
(BMC, 2018-12-17) Semango, George; Charles, Renard; Swai, Consolata; Mremi, Alex; Amsi, Patrick; Sonda, Tolbert; Shao, Elichilia; Mavura, Daudi; Joosten, Leo; Sauli, Elingarami; Nyindo, Mramba
Background Kaposi’s sarcoma (KS) is a multifocal angioproliferative tumor involving blood and lymphatic vessels, caused by Human Herpes Virus-8 (HHV-8). KS is an important AIDS-defining tumor with high prevalence in Sub-Saharan Africa, including Tanzania which has high HIV and HHV-8 sero-prevalence. It is critically important to monitor the prevalence of AIDS-defining tumors, such as KS, in the age of HIV/AIDS. We studied the prevalence of KS and associated risk factors among HIV-positive patients at Kilimanjaro Christian Medical Centre (KCMC), a referral hospital in northern Tanzania, over the period from January 2012 to December 2015. Methods This was a retrospective hospital-based cross-sectional study to determine the prevalence of KS among HIV/AIDS patients between 2012 and 2015. The study included 1100 HIV patients’ data which were collected at the Infectious Disease Clinic (IDC) from patients’ files. Stata version 13 (StataCorp LP, Texas 77,845 USA) was used for all statistical analyses. The prevalence of KS was calculated across levels of a number of categorical variables. Logistic regression was performed to determine relative risk of KS for all characteristics. We included all variables with p-values ≤10% in the multivariate analysis, including ART use, as this is considered to have an influence on KS. In the multivariate analysis, statistical significance was established based on a two-tailed p-value ≤5%. All patients’ notes were kept confidential as per the Helsinki declaration. Results Our results revealed a 4.6% prevalence of KS at KCMC hospital, between January 2012 and December 2015, 51(4.6%) patients were diagnosed with KS out of 1100 HIV-positive patients. The study further revealed that KS in HIV patients was most associated with low CD4 cell count (less than or equal to 200 cells/μl). Moreover, women were more likely than men to diagnosed with KS, with higher odds significantly associated with KS (OR 0.42, p < 0.009). Increased age, above 35 years, among the HIV seropositive patients was significantly associated with KS (OR 25.67, p < 0.007). HIV patients who were none smokers were more likely to suffer from KS compared to HIV smokers (OR 0.41, p < 0.010). Conclusion KS remains a common malignant vascular tumor commonly associated with HIV/AIDS in Tanzania. Our study highlights the need for continued efforts to combat HIV, as well as associated diseases such as KS. Continued availability of ART (Anti-Retroviral Therapy) to HIV/AIDS patients, and test reagents for CD4 cell count and viral load determination are important measures to alleviate the suffering of these patients. Furthermore, studies to gather more evidence on ART resistance are highly needed to guide treatment choices.