Molecular characterization of zoonotic Brucella species isolated from animal and human samples in Iran

Molecular epidemiology of brucellosis in Asia: insights from genotyping analyses

Brucellosis infects humans and animals worldwide but is particularly prevalent in Asia. In many Asian countries, molecular diagnostic tools for accurate molecular diagnostics and molecular epidemiology are lacking. Nonetheless, some countries have conducted in-depth molecular epidemiological studies. The objective of this study was to reveal the genetic relationships, geographic origins, and distributions of Brucella strains across Asia for two primary species, B. abortus and B. melitensis. For this, we systematically searched genotyping data from published studies on the molecular epidemiology of Brucella species for both humans and livestock in Asia. We used data from multilocus sequence typing (MLST), multiple-locus variable-number tandem repeat analysis (MLVA), and whole genome sequencing analysis of Brucella strains. We also analyzed the MLVA genotypes of 129 B. abortus isolates and 242 B. melitensis isolates with known origins in Asia from an online MLVA database using MLVA-11 data in minimum spanning trees and MLVA-16 data in neighbor-joining trees. We found that the B. melitensis East Mediterranean lineage is predominant across the continent, with only a small number of samples from the Africa and Americas lineages, and none from the West Mediterranean lineage. The "abortus C" genotype was the most common group of B. abortus in Asia, with limited genetic variation for this species. Several studies also reported that Near Eastern countries frequently encounter human brucellosis cases of B. abortus from genotypes 42 and 43. Our study highlights the inconsistent collection of genetic data for Brucella species across Asia and a need for more extensive sampling in most countries. Finally, a consistent nomenclature is necessary to define various groupings of strains within a lineage (i.e., clade) so uniform terminology should denote particular genetic groups that are understood by all researchers.

Bovine Brucellosis: First Comprehensive Evaluation from Hamedan, an Endemic Area in Iran

Brucellosis is an infectious zoonotic disease. The disease is one of the major concerns in developing societies due to its great importance for public health and economic losses in the animal industry. The principal target of the study was to detect the prevalence of brucellosis and associated risk factors in cattle from Hamedan (western Iran) using different laboratory techniques. In 2020, blood samples from 900 cattle were obtained to detect brucellosis prevalence in the region. After screening by the modified Rose Bengal plate test, the positive samples were reevaluated using the Wright standard tube agglutination test (SAT), 2-Mercaptoethanol (2-ME), and Enzyme-linked immunosorbent assay. Serology-positive samples were confirmed by culturing bacteria from the lymph nodes and detecting Brucella DNA using specific primers, the BCSP31 target gene, and the IS711 locus. Brucellosis was detected in 1.88% (17/900, 95% CI 1-2.76%) of animals. The high prevalence of brucellosis was observed in female animals (2.77%, p = 0.947), 2-4 years old animals (2.88%, p = 0.994), Holsteins (5.69%, p = 0.989), farm animals (6.49%, p = 0.999), and animals with a history of vaccination against brucellosis (3.04%, p = 0.915). In addition, there was no positive sample in October and December, and also the highest prevalence rate was found in September (5.33%, p = 0.970). There was no statistically significant relationship between the variables and the rate of brucellosis. There were similar results between the different applied laboratory methods. The minimum and maximum levels of titer in the SAT method were + 2/80 and + 2/320, respectively. The rates for 2-ME were + 2/40 and + 4/160. Out of 17 positive samples, 2 were confirmed for B. melitensis and 15 for B. abortus. Notably, no sample showed co-infection of both B. abortus and B. melitensis. This study represents the first comprehensive evaluation of cattle brucellosis in Hamedan. Through molecular evaluation, the presence of Brucella spp. was identified in the seropositive samples. Among the cattle samples, the primary species isolated and confirmed was B. abortus. This finding shed light on the prevalence and distribution of Brucella species in the region, providing crucial insights for future disease management and control efforts. Considering the specificity of the used genes to detect bacteria, molecular biology can be a safe and rapid technique for diagnosing brucellosis, especially in cases without conclusive results. Regular screening of animals and culling seropositive animals are highly recommended; these affect the control of disease at the herd level.

Clinical characterization of brucellosis in children from non-pastoral areas: a report of five cases

BACKGROUND

Brucellosis is a global public health concern and occurs mainly in young adults and the elderly, with children having a lower incidence, thus often leading to delayed treatment. This study aimed to describe the epidemiologic features and clinical characteristics of brucellosis in children.

METHODS

In this retrospective study, the clinical data of five children diagnosed with brucellosis in Anhui Provincial Children's Hospital between January 1, 2021 and December 30, 2022 were analyzed.

RESULTS

All five cases were from non-pastoral areas, among which three have a history of livestock exposure and originated from the countryside. All patients had medium-high grade fever, mostly accompanied by night sweats and malaise, and three had joint pains. Laboratory tests showed that their white blood cell count was normal or mildly raised, with lymphocytes as the predominant cell population. Four patients had anemia, four had aspartate aminotransferase and alanine aminotransferase abnormality, and two had elevated ferritin levels. All blood samples were positive for Brucella culture, one of which had positive bone marrow culture, and all had positive serology test results. All patients were treated with rifampicin, in combination with sulfamethoxazole or doxycycline for 6 weeks following diagnosis. Four children had a good prognosis, but one child had recurrent joint pain.

CONCLUSIONS

The epidemiologic history of children from non-pastoral areas with brucellosis is often unclear; clinical manifestations and laboratory tests lack specificity; and they are easily delayed diagnosis. Clinicians should remain vigilant regarding the possibility of this disease in children with fever of unknown origin. The epidemiological history should be investigated in detail to improve the diagnostic ability of brucellosis. We recommend emphasizing serological testing. Children with brucellosis who receive timely diagnosis and standardized treatment can expect a favorable prognosis.

Molecular epidemiology of Brucella abortus isolated from the environment in Ningxia Hui autonomous region, China

Brucellosis is among the key zoonotic infectious diseases in China, and The Ningxia Hui Autonomous Region represents a major endemic area, and it is one of the main causes of poverty in the region due to illness. In Ningxia, there is substantial research on Brucella melitensis, studies on the molecular epidemiology of Brucella abortus are notably scarce. Consequently, this study aims to undertake pathogenic isolation and molecular epidemiological research on Brucella abortus isolated from the environment in Ningxia, providing insights and evidence to advance the prevention and control measures for brucellosis in the region. Building on traditional pathogenic detection methods, this research employs whole-genome sequencing(WGS) techniques and bioinformatics software to conduct a phylogenetic comparison of Ningxia strains and strains of Brucella abortus from various geographical origins. The results indicate that four Brucella abortus strains are classified as biovar 3 and MLST type ST2. It is shown that the local strains were closer phylogenetic relationships with strains from Asian and European countries. The presence of Brucella abortus in certain environmental sectors of Ningxia indicates a risk of transmission from the environment to animals and subsequently to humans. In conclusion, the Brucella abortus exists in some farming environments in Ningxia, and exists for a long time. Therefore, it is necessary to strengthen the monitoring of the disinfection effect of the farming environment to provide a basis for the forward movement of the gate of brucellosis prevention and control.

Molecular typing methods to characterize Brucella spp. from animals: A review

Brucellosis is an infectious disease of animals that can infect humans. The disease causes significant economic losses and threatens human health. A timely and accurate disease diagnosis plays a vital role in the identification of brucellosis. In addition to traditional diagnostic methods, molecular methods allow diagnosis and typing of the causative agent of brucellosis. This review will discuss various methods, such as Bruce-ladder, Suiladder, high-resolution melt analysis, restriction fragment length polymorphism, multilocus sequence typing, multilocus variable-number tandem repeat analysis, and whole-genome sequencing single-nucleotide polymorphism, for the molecular typing of Brucella and discuss their advantages and disadvantages.

A study of rural populations' knowledge, attitude, and practice about brucellosis: a descriptive, cross-sectional, multicenter study

OBJECTIVE

Brucellosis is a highly contagious disease which is transmitted from animals to humans. One of the populations at high risk of infection is those living in rural areas. The present study was conducted to investigate rural populations' knowledge, attitude, and practice about brucellosis in Iran. The study used a descriptive, cross-sectional design to assess 300 individuals who were living in rural areas. The subjects were selected using convenience sampling from six villages located in the south of Iran. The data gathered were analyzed using Analysis of variance (ANOVA), and Pearson correlation coefficient in SPSS version 23.

RESULTS

From the 300 individuals who were enrolled in this study, 189 were male and 111 were female. The mean age of the participants was 48.27 ± 4.28 years. The mean scores of the study population's knowledge, attitude, and practice about brucellosis were found to be low. A significant direct correlation was found between the subjects' knowledge, attitude, and practice regarding brucellosis.

Molecular epidemiological characteristics of Brucella in Guizhou Province, China, from 2009 to 2021

Introduction

Brucellosis was made statutorily notifiable in 1955, in China, while in Guizhou Province, the pathogen of human brucellosis was isolated for the first time in 2011. However, currently, the brucellosis epidemic is becoming more and more severe in Guizhou Province. The type distribution and genetic characteristics of Brucella in Guizhou Province, as well as its evolutionary relationship with domestic and foreign strains, are still unclear.

Methods

MLST, MLVA, and rpoB typing techniques were used for the molecular epidemiological study of the 83 Brucella isolates in Guizhou province.

Results

Among the 83 Brucella strains, MLST identified three ST genotypes, of which ST39 is a newly reported type in China. MLVA-16 generated 49 genotypes, and MLVA-11 generated 5 known genotypes and 2 unreported genotypes. Six genotypes were identified by rpoB technology.

Discussion

MLVA has a high resolution, but differences at the Bruce 04 and 16 loci cannot exclude associations between epidemics, and combining MLST and rpoB typing methods for epidemiologic tracing can avoid erroneous judgments. Moreover, through the combined analysis of the three typing techniques, the possible origin of the new Brucella can be reasonably inferred, which is also conducive to promoting the subsequent research of the novel Brucella.

Whole-genome sequencing for genetic diversity analysis of Iranian Brucella spp. isolated from humans and livestock

Brucellosis is one of the most common zoonoses in the Middle East. It is causing economic losses to the livestock industry and has a great public health concern. Little is known about the genetic diversity and distribution of brucellae in Iran. Therefore, forty Brucella spp. strains (B. abortus and B. melitensis) isolated from animals and humans were analyzed by whole genome sequencing (WGS) technology using single nucleotide polymorphism (SNP) analysis and core genome multilocus sequence typing (cgMLST). Brucella isolates were obtained from lymph nodes (cows and camels), milk (cows, camels and sheep), and aborted foetus samples (sheep and goats), as well as cerebrospinal fluid and blood of humans. The isolates were originating from thirteen provinces of Iran and isolated between 2015 and 2020. According to in-silico MLST, ST8 and ST2 were the most frequent sequence types in B. melitensis and B. abortus, respectively. Based on phylogeographic reconstruction using cgSNP analysis, the investigated Iranian B. melitensis strains belonged to the American and Mediterranean lineages of the B. melitensis phylogeny. Furthermore, cgSNP analysis revealed a similarity between Iranian B. abortus isolates and strains from Iraq and Egypt. Therefore, the origin of the Iranian strains can be suggested to be strains from neighboring and Middle East countries. Moreover, cgMLST analysis showed that the Iranian B. melitensis strains were closely relative to strains recovered from sheep and humans in Iraq, Afghanistan, Syria, Turkmenistan, and Pakistan. In the current panel of strains, cgMLST and cgSNP analysis provided an appropriate and accurate tool for effective traceback analyses for Brucella spp. from Iran. The results of cgSNP and cgMLST helped to understand the geographic distribution and interspecies transmission of Iranian strains and highlight the importance of specific brucellosis control measures in Iran with regard to the One-Health approach.