First Isolation of Leptospira Borgpetersenii Serovar Hardjobovis in Guanacos (Lama Guanicoe) in South America

Background Leptospirosis is the most widespread zoonotic disease in the world. It is caused by pathogenic spirochetes of the genus Leptospira spp. and is maintained in nature through chronic renal infection of carrier animals, being rodents and other small mammals the main reservoirs. This bacterial genus is highly heterogeneous and divided into three clades (pathogenic, saprophyte and intermediate). Presence of pathogenic strains in wildlife populations is essential to monitor the epidemiological status of this disease worldwide. Methods In this study, we characterize an isolated strain of a Guanaco (Lama guanicoe) using Multiple Locus Variable number tandem repeats Analysis (MLVA) (Variable Number Tandem Repeats-VNTRs: 4, 7, 10, Lb4 and Lb5). To confirm the identity of the isolated strain, partial 16S rRNA sequencing was carried out. Phylogeny was constructed using Neighbor- joining. Results The pathogenic leptospiral strain isolated from Llama guanicoe had the genetic profile identical to L. borgpetersenii serovar Hardjobovis reference strain Sponselee. Conclusions To the best of our knowledge, this is the first isolation and genetic characterization of a pathogenic leptospiral strain in Guanacos in South America.

Detection of Mycobacterium Tuberculosis Multiple Strains in Sputum Samples from Patients with Pulmonary Tuberculosis in South Western Uganda using MIRU-VNTR

Infections with multiple strains of Mycobacterium tuberculosis are now widely recognized as a common occurrence. Identification of patients infected with multiple strains, provides both insight into the disease dynamics and the epidemiology of tuberculosis. Analysis of Mycobacterial Interspersed Repetitive Unit-Variable-Number Tandem Repeats (MIRU-VNTR) has been shown to be highly sensitive in detecting multiple M. tuberculosis strains even in sputum. The goal of this study was to identify cases of multiple M. tuberculosis strain infections among patients with pulmonary tuberculosis in south western Uganda and factors associated with multiple strain infections. Seventy-eight sputum samples were analyzed using the standard 24 loci MIRU-VNTR typing and an exact regression analysis performed using Stata version 14. Five (6.4%) of the 78 patients were infected with multiple strains of M. tuberculosis. All of the patients infected with multiple strains were the newly diagnosed cases while one third of them were co-infected with HIV. These findings point to a critical component of disease dynamics that is most likely being overlooked at the clinical level, emphasizing the need to further study the potential high risk of exposure to these categories of patients at the community level using a larger sample size.

High Prevalence and New Genotype of Coxiella burnetii in Ticks Infesting Camels in Somalia

Coxiella burnetii is the causative agent of Q fever. It can infect animals, humans, and birds, as well as ticks, and it has a worldwide geographical distribution. To better understand the epidemiology of C. burnetii in Somalia, ticks infesting camels were collected from five different regions, including Bari, Nugaal, Mudug, Sool, and Sanaag, between January and March 2018. Collected ticks were tested for C. burnetii and Coxiella-like endosymbiont DNA by using IS1111, icd, and Com1-target PCR assays. Moreover, sequencing of the 16S-rRNA was conducted. Molecular characterization and typing were done by adaA-gene analysis and plasmid-type identification. Further typing was carried out by 14-marker Multi-Locus Variable-Number Tandem Repeats (MLVA/VNTR) analysis. The investigated ticks (n = 237) were identified as Hyalomma spp. (n = 227, 95.8%), Amblyomma spp. (n = 8, 3.4%), and Ripicephalus spp. (n = 2, 0.8%), and 59.1% (140/237) of them were positive for Coxiella spp. While Sanger sequencing and plasmid-type identification revealed a C. burnetii that harbours the QpRS-plasmid, MLVA/VNTR genotyping showed a new genotype which was initially named D21. In conclusion, this is the first report of C. burnetii in ticks in Somalia. The findings denote the possibility that C. burnetii is endemic in Somalia. Further epidemiological studies investigating samples from humans, animals, and ticks within the context of “One Health” are warranted.

Occurrence of DAT1 (VNTR) Polymorphism in Individuals with HIV infection

Background: Antiretroviral treatment (ART) have been reported to make changes in the functioning of dopaminergic neurons by altering the expression of dopamine active transporter (DAT). ART containing efavirenz drug have been related to show the adverse reactions on the central nervous system (CNS). Reported literature indicates the correlation of DAT19/10 genotype with the risk of progression of human immunodeficiency virus (HIV) infection. Objective: To assess the polymorphism in the human gene DAT1 including variable number tandem repeats (VNTR) from individuals having an infection of HIV. Methods: Genotyping was completed by performing a polymerase chain reaction (PCR) in a total of 165 HIV positive patients on ART treatment (34 were HIV-infected patients with hepatotoxicity, 131 HIV-infected patients) and 160 healthy controls without HIV infection. Results: Incidence of DAT19/9, 8/9 genotypes, and allele with 9 repeats were higher in individuals having hepatotoxicity compared to those who do not have hepatotoxicity (5.9 vs. 0.8%, OR = 7.73; 2.9 vs. 0.8%, OR = 3.86; 20.58% vs. 14.12%, OR = 1.56). DAT19/10 genotype was related to severity of hepatotoxicity (OR = 1.86; P = 0.05). Upon comparison of genotype between individuals who do not have hepatotoxicity but having HIV infection and healthy controls without HIV infection, the dispersion of DAT1 10/11, 6/10 genotypes were greater in individuals with HIV infection (1.5% vs. 0.6%, OR = 2.73; 3.1% vs. 1.3%, OR = 2.73). DAT19/10 genotype was related to the people of advanced stage of HIV infection (OR = 2.05, P = 0.04). A higher incidence of DAT19/10 genotype was found in individuals with early stage of HIV infection than healthy controls (26.3 vs. 15.6%, OR = 1.93). In alcohol and tobacco consuming individuals with HIV infection and hepatotoxicity, DAT19/10 genotype has demonstrated hazard in the progression of HIV infection and increasing severity of hepatotoxic condition (OR = 1.40, P = 0.91, OR = 1.50; P = 0.91 and OR = 1.57, P = 0.39; OR = 2.70; P = 0.53). In patients with hepatotoxicity, nevirapine utilization with DAT19/10 genotype had demonstrated an increase in severity of hepatotoxicity (OR = 4.00, P = 0.41). In individuals with HIV infection and hepatotoxicity, alcohol and nevirapine usage along with DAT1 9/10 genotype have indicated a hazard for progression of HIV infection and increase in severity of hepatotoxicity (OR = 1.47, P = 0.85; OR = 1.73; P = 0.32). Conclusion: The genetic polymorphism with DAT19/10 genotype was linked with the progression of HIV infection and in the advancement of HIV-related illnesses.

Genome-wide characterization of human minisatellite VNTRs: population-specific alleles and gene expression differences

Variable Number Tandem Repeats (VNTRs) are tandem repeat (TR) loci that vary in copy number across a population. Using our program, VNTRseek, we analyzed human whole genome sequencing datasets from 2770 individuals in order to detect minisatellite VNTRs, i.e., those with pattern sizes ≥7 bp. We detected 35 638 VNTR loci and classified 5676 as commonly polymorphic (i.e. with non-reference alleles occurring in >5% of the population). Commonly polymorphic VNTR loci were found to be enriched in genomic regions with regulatory function, i.e. transcription start sites and enhancers. Investigation of the commonly polymorphic VNTRs in the context of population ancestry revealed that 1096 loci contained population-specific alleles and that those could be used to classify individuals into super-populations with near-perfect accuracy. Search for quantitative trait loci (eQTLs), among the VNTRs proximal to genes, indicated that in 187 genes expression differences correlated with VNTR genotype. We validated our predictions in several ways, including experimentally, through the identification of predicted alleles in long reads, and by comparisons showing consistency between sequencing platforms. This study is the most comprehensive analysis of minisatellite VNTRs in the human population to date.

Variable number tandem repeats mediate the expression of proximal genes

Variable number tandem repeats (VNTRs) account for significant genetic variation in many organisms. In humans, VNTRs have been implicated in both Mendelian and complex disorders, but are largely ignored by genomic pipelines due to the complexity of genotyping and the computational expense. We describe adVNTR-NN, a method that uses shallow neural networks to genotype a VNTR in 18 seconds on 55X whole genome data, while maintaining high accuracy. We use adVNTR-NN to genotype 10,264 VNTRs in 652 GTEx individuals. Associating VNTR length with gene expression in 46 tissues, we identify 163 “eVNTRs”. Of the 22 eVNTRs in blood where independent data is available, 21 (95%) are replicated in terms of significance and direction of association. 49% of the eVNTR loci show a strong and likely causal impact on the expression of genes and 80% have maximum effect size at least 0.3. The impacted genes are involved in diseases including Alzheimer’s, obesity and familial cancers, highlighting the importance of VNTRs for understanding the genetic basis of complex diseases.

Variable number tandem repeats – Their emerging role in sickness and health

Understanding the mechanisms regulating tissue specific and stimulus inducible regulation is at the heart of understanding human biology and how this translates to wellbeing, the ageing process, and disease progression. Polymorphic DNA variation is superimposed as an extra layer of complexity in such processes which underpin our individuality and are the focus of personalized medicine. This review focuses on the role and action of repetitive DNA, specifically variable number tandem repeats and SINE-VNTR- Alu domains, highlighting their role in modification of gene structure and gene expression in addition to their polymorphic nature being a genetic modifier of disease risk and progression. Although the literature focuses on their role in disease, it illustrates their potential to be major contributors to normal physiological function. To date, these elements have been under-reported in genomic analysis due to the difficulties in their characterization with short read DNA sequencing methods. However, recent advances in long read sequencing methods should resolve these problems allowing for a greater understanding of their contribution to a host of genomic and functional mechanisms underlying physiology and disease.

Molecular characteristics of Brucella melitensis isolates from humans in Qinghai Province, China

Background The prevalence of human brucellosis in Qinghai Province of China has been increasing rapidly, with confirmed cases distributed across 31 counties. However, the epidemiology of brucellosis transmission has not been fully elucidated. To characterize the infecting strains isolated from humans, multiple-locus variable-number tandem repeats analysis (MLVA) and whole-genome single-nucleotide polymorphism (SNP)-based approaches were employed. Methods Strains were isolated from two males blood cultures that were confirmed Brucella melitensis positive following biotyping and MLVA. Genomic DNA was extracted from these two strains, and whole-genome sequencing was performed. Next, SNP-based phylogenetic analysis was performed to compare the two strains to 94 B. melitensis strains (complete genome and draft genome) retrieved from online databases. Results The two Brucella isolates were identified as B. melitensis biovar 3 (QH2019001 and QH2019005) following conventional biotyping and were found to have differences in their variable number tandem repeats (VNTRs) using MLVA-16. Phylogenetic examination assigned the 96 strains to five genotype groups, with QH2019001 and QH2019005 assigned to the same group, but different subgroups. Moreover, the QH2019005 strain was assigned to a new subgenotype, IIj, within genotype II. These findings were then combined to determine the geographic origin of the two Brucella strains. Conclusions Utilizing a whole-genome SNP-based approach enabled differences between the two B. melitensis strains to be more clearly resolved, and facilitated the elucidation of their different evolutionary histories. This approach also revealed that QH2019005 is a member of a new subgenotype (IIj) with an ancient origin in the eastern Mediterranean Sea.