Brucella Melitensis Research Articles

Characteristics and outcomes of pediatric brucellosis cases collected from a tertiary academic hospital in Saudi Arabia

Brucellosis is a zoonotic disease caused by Brucella spp., affecting different body systems and leading to multiple complications. Although brucellosis is prevalent in several regions, including Saudi Arabia, limited research has focused on childhood brucellosis. This study aimed to characterize the features and outcomes of brucellosis in pediatric patients. We conducted a retrospective descriptive study involving children (<18 years) with confirmed brucellosis (diagnosed through culture, serology, or both) who received antibiotic therapy. Subjects were stratified into two groups based on age: younger (≤8 years) and older (>8 years). We assessed treatment outcomes, including clinical cure, mortality, and hospital length of stay. A total of 20 patients were included, with 52.3% in the younger group and 47.7% in the older group. The majority were male (65%), with a mean age of 8.9 years, and 45% required hospitalization. Out of all the patients, only 6 (30%) reported consuming dairy products. Serologically, the baseline median antibody titers for Brucella melitensis and Brucella abortus were 1:1280 and 1:640, respectively. In the younger group, half reported arthralgia and presented with fever. While white blood cell elevation was not significant, C-reactive protein, erythrocyte sedimentation rate, and liver enzymes were elevated at baseline. The administered regimen varied, but about half of the patients received at least three antibiotics. All patients experienced clinical cures, and there were no deaths. This study highlights the characteristics of pediatric brucellosis in a country where the disease is endemic and provides evidence of positive prognosis associated with appropriate antibiotic therapy.

Multiple Brucella melitensis lineages are driving the human brucellosis epidemic in Shaanxi Province, China: evidence from whole genome sequencing-based analysis

IntroductionHuman brucellosis is a severe public concern in Shaanxi Province, China, and investigating the epidemiological relationship and transmission pattern of B. melitensis is necessary to devise control strategies.MethodsIn this study, a conventional bio-typing approach and whole genome sequencing of single-nucleotide polymorphisms (SNPs) were employed to identify 189 strains.ResultsBased on the conventional bio-typing, 189 Brucella strains were identified as B. melitensis, of which 14 were in bv. 1, 145 were in bv. 3, and 30 were variant, and the Brucella strains were distributed in all ten cities in Shaanxi Province. SNP analysis was used to identify genetic variation in 189 B. melitensis genomes, and maximum-likelihood was used to generate a phylogeny that identified two clades (A and B) and 19 sequence types (STs). The two clades were highly diverse and exclusively of Eastern Mediterranean origin. Clade B contained 18 STs (2-19), with most isolates originating from a broad swath, implying that multiple B. melitensis lineages circulated in Shaanxi. The 19 STs were composed of 3 to 46 strains isolated from different counties and years, suggesting that multiple cross-county brucellosis outbreak events are driven by multiple B. melitensis lineages. Global phylogenetic analysis revealed that clade A was close to GTIIb, and clade B was placed in the GTIIh lineage, expanding the known diversity of B. melitensis from China.ConclusionThe human brucellosis epidemic in Shaanxi is driven by multiple indigenous circulating B. melitensis lineages, the knowledge of which will contribute to devising a control strategy and providing the foundation for a comprehensive regional phylogeny of this important zoonotic pathogen.

Whole-genome sequencing-based analysis of Brucella species isolated from ruminants in various regions of Türki̇ye

BackgroundBrucellosis, a zoonotic disease in Türkiye, which has significant direct and indirect impacts on the healthcare system and livestock. This study, which aimed to investigate the differences among Brucella spp. isolates originating from different regions of Türkiye, for implications for public health and veterinary medicine.MethodTwenty-one isolates from ruminants and two isolates from humans obtained from various regions of Türkiye were utilized in the study. The isolates were identified and biotyped using traditional microbiological procedures, and whole-genome sequencing (WGS) was performed. This was followed by single nucleotide polymorphism (SNP)--based phylogenetic analysis and WGS-based analysis of virulence and resistance genes. Additionally, phenotypic antimicrobial resistance and phage susceptibilities were determined. The obtained data were then compared for concordance, ensuring the validity and reliability of the results.ResultsOur study, employing culture methods, polymerase chain reaction (PCR), and WGS analyses, identified 11 Brucella melitensis (bv 3 (n = 9), one each bv 1 and bv 2) and 12 B. abortus (bv 3 (n = 11), bv 9 (n = 1)) isolates All B. abortus isolates were of bovine origin, while the B. melitensis isolates were from sheep (n = 7), goat (n = 1), ram (n = 1), and humans (n = 2). In the whole-genome SNP-based phylogenetic tree, all B. melitensis strains were found to be of the IIb subtype of genotype II associated with the Eastern Mediterranean lineage. Ten different genotypes were identified in the SNP analysis of the isolates, with a maximum SNP difference of 278 and a minimum SNP difference of 4 among these genotypes. According to the WGS-SNP-based phylogenetic tree of B. abortus isolates, they were grouped in clade C1. In the SNP analysis, where ten different genotypes were identified, the SNP difference among these genotypes was a maximum of 316 and a minimum of 6.In the in silico MLST analysis performed with WGS data, B. melitensis isolates were identified as ST8 and ST102 genotypes, while B. abortus isolates were identified as ST2 and ST3 genotypes. The dominant genotypes were ST8 for B. melitensis and ST2 for B. abortus, respectively. Virulence gene analysis conducted based on WGS data of the 23 B. abortus and B. melitensis isolates revealed 43 virulence gene-associated regions in all strains, irrespective of species, host, or isolation year. Although classical resistance-related genes were not detected by WGS-based antimicrobial resistance gene analysis, phenotypic resistance analysis revealed resistance to azithromycin, rifampin, and trimethoprim/sulfamethoxazole in B. abortus and B. melitensis isolates.ConclusionBoth B. melitensis and B. abortus were circulating species in animals and human. The dominant genotypes were ST8 for B. melitensis and ST2 for B. abortus, respectively. All B. melitensis strains were found to be of the IIb subtype of genotype II associated with the Eastern Mediterranean lineage, while B. abortus isolates, they were grouped in clade C1. Further, a comprehensive study with a sufficient number of isolates covering all regions of Türkiye would provide more accurate information about the current epidemiological situation in the country.

Molecular prevalence, phylogenetic analysis, and PCR-based detection of Brucella melitensis in humans and cattle in Southern Khyber Pakhtunkhwa, Pakistan

Brucellosis is a bacterial disease due to Brucella melitensis, considered a zoonotic agent affecting humans and animals, especially in areas with high disease occurrence, south Khyber Pakhtunkhwa, Pakistan. This work was designed to evaluate the molecular rate of B. melitensis in humans and cattle species and also to perform a phylogenetic analysis between both species. A cross-sectional survey involving 800 participants, including 600 cattle and 200 human participants, underwent blood sample collection with conventional PCR and IS711 locus PCR amplification and Sanger sequencing. The findings detected Brucella melitensis in 37 of the 800 samples, with a molecular prevalence of 3.1 % in cattle and 9 % in humans. The molecular trees play a role in zoonotic transmission and point to the necessity of a further unified approach toward the management of brucellosis in both humans and animals. This is further backed by the use of 95 % C.I for the prevalence rates making the results statistically robust. This research shows that using the IS711 insertion sequence is an efficient and selective method for identifying Brucella species.

Novel dual-pathogen multi-epitope mRNA vaccine development for Brucella melitensis and Mycobacterium tuberculosis in silico approach.

Brucellosis and Tuberculosis, both of which are contagious diseases, have presented significant challenges to global public health security in recent years. Delayed treatment can exacerbate the conditions, jeopardizing patient lives. Currently, no vaccine has been approved to prevent these two diseases simultaneously. In contrast to traditional vaccines, mRNA vaccines offer advantages such as high efficacy, rapid development, and low cost, and their applications are gradually expanding. This study aims to develop multi-epitope mRNA vaccines argeting Brucella melitensis and Mycobacterium tuberculosis H37Rv (L4 strain) utilizing immunoinformatics approaches. The proteins Omp25, Omp31, MPT70, and MPT83 from the specified bacteria were selected to identify the predominant T- and B-cell epitopes for immunological analysis. Following a comprehensive evaluation, a vaccine was developed using helper T lymphocyte epitopes, cytotoxic T lymphocyte epitopes, linear B-cell epitopes, and conformational B-cell epitopes. It has been demonstrated that multi-epitope mRNA vaccines exhibit increased antigenicity, non-allergenicity, solubility, and high stability. The findings from molecular docking and molecular dynamics simulation revealed a robust and enduring binding affinity between multi-epitope peptides mRNA vaccines and TLR4. Ultimately, Subsequently, following the optimization of the nucleotide sequence, the codon adaptation index was calculated to be 1.0, along with an average GC content of 54.01%. This indicates that the multi-epitope mRNA vaccines exhibit potential for efficient expression within the Escherichia coli(E. coli) host. Analysis through immune modeling indicates that following administration of the vaccine, there may be variation in immunecell populations associated with both innate and adaptive immune reactions. These types encompass helper T lymphocytes (HTL), cytotoxic T lymphocytes (CTL), regulatory T lymphocytes, natural killer cells, dendritic cells and various immune cell subsets. In summary, the results suggest that the newly created multi-epitope mRNA vaccine exhibits favorable attributes, offering novel insights and a conceptual foundation for potential progress in vaccine development.

Detection of Brucella militensis in the Serum of Patients Suspected of Brucellosis by the Omp31 Gene Amplification, Compared to the Serological Diagnostic Tests

Background and Objectives: Brucellosis is one of the most common infectious diseases with a global spread. It has a high prevalence in Iran. This study aims to diagnose brucellosis caused by Brucella melitensis in the serum of patients by the amplification of omp31 gene, compared to the serological tests. Methods: Blood samples were collected from 200 people suspected of brucellosis. The samples were evaluated by serological tests including Rose Bengal test, Wright test, Coombs-Wright test, gel agglutination test, and 2-mercaptoethanol (2ME) test. DNA extraction was done by the phenol/chloroform extraction method. Molecular detection with polymerase chain reaction (PCR) method was done using the specific primers of the Omp31 gene. Data were analyzed in SPSS software, version 23 using the analysis of variance. Results: Of 200 patients, 122 were female and 78 were male with a mean age of 45.17±17.43 years. The results of PCR test for the omp31 gene were positive in 14.5% of cases, which was consistent with the results of serological tests (13.8%). The sensitivity of Wright, Coombs-Wright, 2ME, and gel agglutination tests, compared to PCR, was 89.7, 75.9, 55.2 and 55.2%, respectively. Most of the affected people were housekeepers (41.5%) and urban residents (75.5%). Muscle pain (68%) and leg pain (62.3%) were the most common symptoms. Consumption of non-pasteurized dairy products was the highest risk factor (17%). Conclusion: The diagnosis of brucellosis by the omp31 gene amplification has higher sensitivity and accuracy compared to the serological tests. Considering the importance of rapid and timely diagnosis of brucellosis to control its clinical complications, the molecular diagnosis method is recommended as a diagnostic method.

Seroprevalence of brucellosis among cows and sheep in Assiut province: A pilot study

Brucellosis is a common neglected zoonotic disease with a global geographic distribution that endangers human health and animal production. However, there is a scarcity of studies focusing on brucellosis in neglected regions such as Assiut governorate in Egypt. Therefore, the objective of this study was to investigate the prevalence of antibodies reactive to Brucella sp. in sheep and cows, as well as the associated risk factors, in Assiut governorate. A total of 184 sheep and 166 cows were included in the study, and their serum samples were subjected to screening using the Rose-Bengal plate test, followed by confirmation through the serum tube agglutination test. The overall seroprevalence of Brucella antibodies in sheep of 8.2% (15/184), while in cows, the seroprevalence was 1.2% (2/166). Among sheep, the seropositivity for Brucella abortus was 4.3% (8/184), whereas for Brucella melitensis, it was 6% (11/184). In cows, one cow displayed seropositivity for Brucella abortus, while the other exhibited mixed infection with both Brucella abortus and Brucella melitensis. Moreover, animals originating from villages bordering Sohag governorate demonstrated a higher risk of contracting brucellosis while other risk factors did not impact the occurrence of brucellosis. In conclusion, this study provides compelling evidence of the endemic nature of brucellosis in the investigated areas, with a particularly high prevalence observed in sheep. Both cows and sheep are susceptible to infection by either Brucella abortus or Brucella melitensis. To gain a comprehensive understanding of the epidemiological factors associated with infection, it is imperative to conduct large-scale surveys that incorporate molecular isolation of various Brucella species to facilitate the development of appropriate prevention strategies.

Development of a colloidal gold immunochromatographic test strip for detecting the smooth Brucella

SummaryBrucellosis, caused by Gram-negative Brucella, spreads in human and animal populations through contact with infected animals and products. Developing a rapid and sensitive detection technology for pathogen is crucial to reduce the risk of this disease transmitting between animal populations and to humans. We produced a monoclonal antibody LPS-6B5, which shows high affinity to LPS and limited cross-reactivity with other bacteria. Based on LPS-6B5, a colloidal gold immunochromatographic assay (GICA) was developed which demonstrates high sensitivity and specificity in detecting cultured B. melitensis, B. abortus and B. suis. The Gold Immunochromatographic Assay (GICA) strips exhibited the most sensitive detection limits, with a value of 7.8125 × 105 CFU/mL for Brucella melitensis, surpassing the sensitivity levels observed for Brucella abortus and Brucella suis. It is also suitable for clinical and field samples, providing a cost-effective and user-friendly alternative to traditional methods.

Antimicrobial Susceptibility Testing and Molecular Genotyping of Brucella melitensis Isolates at the Human Animal Interface in Upper Egypt and Egyptian Boundaries

Antimicrobial Susceptibility Testing and Molecular Genotyping of Brucella melitensis Isolates at the Human Animal Interface in Upper Egypt and Egyptian Boundaries

Bioinformatics analysis of the antigenic epitopes of L7/L12 protein in the B- and T-cells active against Brucella melitensis

Abstract The objective is to analyse the physicochemical properties, spatial structure and protein–protein interactions (PPIs) of L7/L12 protein using bioinformatics methods and predict their B- and T-cell epitopes to lay a theoretical foundation for developing a novel multiepitope vaccine (MEV). The National Center for Biotechnology Information (NCBI) database was searched for the amino acid sequences of L7/L12 from Brucella melitensis. In addition, the online softwares, ProtParam and ProtScale, were used to predict the physicochemical properties: NetPhos3.1 and CD-search to predict the phosphorylation sites and conserved domains; SOMPA and SWISS-MODEL to predict the secondary and tertiary structures; the STRING database to analyse the PPIs; and the IEDB, ABCpred, SVMTrip and SYFPEITHI databases to predict the B- and T-cell epitopes. L7/L12 was docked to Toll-like receptor 4 (TLR4), B-cell receptor (BCR), Major histocompatibility complex I-T cell receptor (MHC I-TCR) and MHC II-TCR complexes, respectively, and the binding ability of L7/L12 to the targeted receptors was tested. L7/L12, consisting of 124 amino acids, was determined to be a stable, intracellular, hydrophilic protein containing 6 phosphorylation sites and ribosomal protein-related conserved domains. α-helices accounted for 70.16 %, β-turns for 2.42 %, extended strands for 8.87 % and irregular coils for 18.55 % of the secondary structure. The PPIs indicated that L7/L12 was involved in the constitution of ribosomes and regulating the accuracy of the translation process. Three B-cells, two cytotoxic T lymphocytes and three helper T lymphocyte epitopes were finally screened by comparing multiple databases. L7/L12 binds to TLR4, BCR, MHC I-TCR and MHC II-TCR complexes and forms stable hydrogen bonds, respectively. L7/L12, which governs the translation curate of proteins, possesses several potentially advantageous epitopes, laying a theoretical foundation for designing MEVs.

A Review On Human Brucellosis: An Important Occupational Hazard

Human brucellosis is a re-emerging and neglected zoonotic disease caused by Brucella spp., with Brucella melitensis being the principal cause worldwide. Despite the disease's prevalence, serological surveillance is not routinely practiced, even in countries where Brucella is endemic. Although eradication efforts have been successful in many developed and developing countries, brucellosis continues to pose a significant health risk to both animals and humans. Transmission to humans occurs by direct or indirect contact with infected animals or their products. Veterinary professionals, especially those conducting per-vaginal examinations without proper protective gear, and animal handlers are particularly vulnerable to infection. The pathogenesis of brucellosis is complex, involving bacterial invasion of host cells, immune evasion, and the potential for chronic infection. In humans, brucellosis often becomes chronic, but in acute cases, it presents as undulant fever with nonspecific symptoms. To reduce morbidity and mortality, early diagnosis and timely antibiotic treatment are most important. For diagnosis of Brucella spp. reliable, rapid, sensitive, specific, easy-to-perform, and automated detection systems are urgently required. Currently, there is no safe and effective vaccine available for humans. Prevention relies on controlling the disease in domestic livestock, primarily through mass vaccination, effective heat treatment of dairy products, and hygienic precautions to minimize occupational exposure. Treatment requires prolonged antibiotic therapy with a combination of drugs. To control human brucellosis, awareness programs, safe livestock practices, and timely diagnosis are essential

The Protection of Astragalus Polysaccharide in BALB/C Mice during Brucella melitensis M5 Infection

ABSTRACT Introduction Brucellosis is an important zoonosis worldwide, affecting humans and animals. There are no specific medicines available to treat brucellosis. Astragalus polysaccharide (APS) is derived from Astragalus membranaceus and exhibits impressive bioactivity, including anti-aging, anti-tumor, and immunomodulatory functions. Methods Mice were intraperitoneally inoculated with Brucella melitensis M5 and then treated with APS intraperitoneally injection daily for 7 d. Results Compared to the M5-infected group, the lower bacteria loads in the APS-treated groups were proved, especially at the acute stage of infection. APS treatment relieved splenomegaly, excess expressions of several pro-inflammatory cytokines (including CXCL1, IFN-γ, IL-1β, IL-2, IL-12p70, and TNF-α). The raised level of IL-4 was observed in APS-treated mice. APS contributed to raising the ratio of M1 macrophage and reducing the ratio of M2 macrophage in the blood. Discussion The present study provides some evidence on the potential application of APS in controlling and treating brucellosis and should be further explored.

Genome-wide analysis of Brucella melitensis growth in spleen of infected mice allows rational selection of new vaccine candidates.

Live attenuated vaccines (LAVs) whose virulence would be controlled at the tissue level could be a crucial tool to effectively fight intracellular bacterial pathogens, because they would optimize the induction of protective immune memory while avoiding the long-term persistence of vaccine strains in the host. Rational development of these new LAVs implies developing an exhaustive map of the bacterial virulence genes according to the host organs implicated. We report here the use of transposon sequencing to compare the bacterial genes involved in the multiplication of Brucella melitensis, a major causative agent of brucellosis, in the lungs and spleens of C57BL/6 infected mice. We found 257 and 135 genes predicted to be essential for B. melitensis multiplication in the spleen and lung, respectively, with 87 genes common to both organs. We selected genes whose deletion is predicted to produce moderate or severe attenuation in the spleen, the main known reservoir of Brucella, and compared deletion mutants for these genes for their ability to protect mice against challenge with a virulent strain of B. melitensis. The protective efficacy of a deletion mutant for the plsC gene, implicated in phospholipid biosynthesis, is similar to that of the reference Rev.1 vaccine but with a shorter persistence in the spleen. Our results demonstrate that B. melitensis faces different selective pressures depending on the organ and underscore the effectiveness of functional genome mapping for the design of new safer LAV candidates.

Analysis of the Brucella melitensis epidemic in Xinjiang: genotyping, polymorphism, antibiotic resistance and tracing

Brucella spp. are facultative intracellular pathogens that cause zoonosis- brucellosis worldwide. There has been a trend of the re-emergence of brucellosis worldwide in recent years. The epidemic situation of brucellosis is serious in Xinjiang. To analyze the epidemic situation of Brucella spp. in Xinjiang among humans and animals, this study identified 144 Brucella isolates from Xinjiang using classical identification and 16 S rRNA sequencing. MLVA, drug resistance testing, and wgSNP detection were also performed. At the same time, analysis was conducted based on the published data of Brucella isolates worldwide. The results showed that the dominant species was B. melitensis biovar 3, which belonged to GT42 (MLVA-8 typing) and the East Mediterranean lineage. The correlation among isolates was high both in humans or animals. The isolates in Xinjiang exhibited higher polymorphism compared to other locations in China, with polymorphism increasing each year since 2010. No amikacin/kanamycin-resistant strains were detected, but six rifampicin-intermediate isolates were identified without rpoB gene variation. The NJ tree of the wgSNP results indicated that there were three main complexes of the B. melitensis epidemic in Xinjiang. Based on the results of this study, the prevention and control of brucellosis in Xinjiang should focus on B. melitensis, particularly strains belonging to B. melitensis bv.3 GT42 (MLVA-8 typing) and East Mediterranean lineage. Additionally, the rifampicin- and trimethoprim-sulfamethoxazole- resistance of isolates in Xinjiang should be closely monitored to avoid compromising the therapeutic efficacy and causing greater losses. These results provide essential data for the prevention and control of brucellosis in Xinjiang and China. Although the isolates from Xinjiang have significant characteristics among Chinese isolates and can reflect the epidemiological situation of brucellosis in China to some extent, this study cannot represent the characteristics of isolates from other regions.

Meta-genomic next-generation sequencing in the diagnosis of brucellosis: Five cases from a non-endemic area.

Metagenomic next-generation sequencing (mNGS) in diagnosis of human brucellosis is comparatively unexplored. This report details five human brucellosis cases diagnosed using mNGS based on Illumina sequencing platform, comprising three females and two males, four with epidemiological exposure. In cases 1 and 2, plasma mNGS results showed one positive and one negative for Brucella melitensis, and subsequent blood cultures were both positive. Cases 3, 4 and 5 involved spinal brucellosis, some with paravertebral abscesses. mNGS from infectious tissue samples successfully detected Brucella, with read counts ranging between 30 and 1314, yet cultures were negative in cases 4 and 5. Following antibiotic and surgical treatments, all patients showed clinical improvement. This report shows mNGS testing enhances the detection sensitivity of brucellosis diagnosis.

Molecular detection of Brucella melitensis in sheep from district Budgam, Jammu and Kashmir

Farmers reported abortions and stillbirths in 600 sheep including 471 pregnant ewes. A complete investigation including physical examination of livestock, postmortem examination of stillbirths, serological examination of ewes and molecular study of abomasal contents, peritoneal fluid, liver and kidney tissue collected from still born lambs was done to ascertain the cause of mortality at Disease Investigation Laboratory, Nowshera, Srinagar. Also, on spot heat fixed tissue smears were prepared for Gram’s staining and accordingly observed for presence of organism. Extraction of bacterial genomic DNA from samples from still born lambs was performed and obtained DNA extracts were checked by agarose gel electrophoresis and stored at -20°C till further use. The PCR conducted on the abomasal, peritoneal contents and liver and kidney tissues revealed 731 bp band after the gel electrophoresis, confirming Brucella melitensis as cause of stillbirths in the flock. The investigation revealed that Brucella melitensis was cause of stillbirths and abortions in sheep flocks.

Draft genome sequences of Brucella melitensis from human and animal sources in India.

We present the draft genome sequences of 23 Brucella melitensis isolates derived from human and animal sources across India with genome size predominantly at 3.207 M and uniform GC content (57.24%) across isolates. The accession numbers and detailed sequencing data enhance the utility of this resource for further genomic studies.

An 8000 years old genome reveals the Neolithic origin of the zoonosis Brucella melitensis

Brucella melitensis is a major livestock bacterial pathogen and zoonosis, causing disease and infection-related abortions in small ruminants and humans. A considerable burden to animal-based economies today, the presence of Brucella in Neolithic pastoral communities has been hypothesised but we lack direct genomic evidence thus far. We report a 3.45X B. melitensis genome preserved in an ~8000 year old sheep specimen from Menteşe Höyük, Northwest Türkiye, demonstrating that the pathogen had evolved and was circulating in Neolithic livestock. The genome is basal with respect to all known B. melitensis and allows the calibration of the B. melitensis speciation time from the primarily cattle-infecting B. abortus to approximately 9800 years Before Present (BP), coinciding with a period of consolidation and dispersal of livestock economies. We use the basal genome to timestamp evolutionary events in B. melitensis, including pseudogenization events linked to erythritol response, the supposed determinant of the pathogen’s placental tropism in goats and sheep. Our data suggest that the development of herd management and multi-species livestock economies in the 11th–9th millennium BP drove speciation and host adaptation of this zoonotic pathogen.

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.

Human brucellosis and associated risk factors in the Middle East region: A comprehensive systematic review, meta-analysis, and meta-regression

IntroductionHuman brucellosis, caused by the bacteria Brucella, is a significant infectious disease globally, also known as Mediterranean fever or Malta fever. MethodsThis meta-analysis and systematic review focuses on the prevalence rate, risk factors, and diagnostic methods of human brucellosis in Middle Eastern countries, where the disease remains a significant public health issue. The analysis included 92 studies conducted between 1993 and 2024, following specified inclusion and exclusion criteria among symptomatic patients across these countries. The prevalence rate was calculated by dividing positive samples by total samples. The I2 index and Chi-squared test assessed study heterogeneity. Significant heterogeneity occurred when I2 exceeded 50 %. ResultsThe highest prevalence rate was observed in Oman, Lebanon, and Kuwait countries, emphasizing a notable burden of Brucella infection in these regions. Risk factors associated with human brucellosis were identified, with unpasteurized dairy consumption and close animal contact being predominant. Various professions such as farmers, dairy factory workers, and agriculture workers showed higher prevalence rate. Gender analysis indicated a prevalence rate of 18.02 % (95 % CI: 11.55–25.51 %) in males and 13.61 % (95 % CI: 10.8–16.68 %) in females, with no significant difference in hospitalization rates. The prevalence rate of Brucella spp. was varied across detection methods, with immunocapture agglutination assay (Brucellacapt) showing the highest estimated prevalence rate of (44.04 %, 95 % CI: 27.71–61.04), followed by PCR (39.84 %, 95 % CI: 20.14–61.39) and culture (29.22 %, 95 % CI: 17.89–42.03). Among Brucella species, Brucella melitensis (B. melitensis) and Brucella abortus (B. abortus) were the highest prevalence rate. Although statistically insignificant, the meta-analysis also revealed an upward trend in prevalence rate from 1993 to 2024, (P value = 0.277). DiscussionThis comprehensive review emphasizes the need for tailored strategies to control brucellosis in the Middle East, highlighting the importance of timely diagnosis, public awareness, and effective treatment protocols. These findings provide valuable insights for policymakers and healthcare professionals working to mitigate the impact of this disease in the region.