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Brucella abortus is an important zoonotic pathogen that infects cattle and buffaloes. In Italy the application of eradication programs combined with vaccination has greatly contributed to reduce the incidence of brucellosis. However, despite the eradication programs brucellosis continue to persist with a high endemicity in some areas of Italy including the province of Caserta. In the present study the genomes of 44 B. abortus strains isolated from different outbreak cases that affected the province of Caserta were sequenced to characterize the genetic diversity of the Brucella strains circulating during the period from 2017 to 2022. The relatedness among these isolates was compared to 52 publicly available genomes of Italian B. abortus isolates. The results highlighted a low genetic diversity in the B. abortus population present in the Caserta area with the persistence of a low number of Brucella lineages and suggests a reduction in circulating lineages in recent years due to eradication programs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The protein MucR from Brucella abortus has been described as a transcriptional regulator of many virulence genes. It is a member of the Ros/MucR family comprising proteins that control the expression of genes important for the successful interaction of α-proteobacteria with their eukaryotic hosts. Despite clear evidence of the role of MucR in repressing virulence genes, no study has been carried out so far demonstrating the direct interaction of this protein with the promoter of its target gene babR encoding a LuxR-like regulator repressing virB genes. In this study, we show for the first time the ability of MucR to bind the promoter of babR in electrophoretic mobility shift assays demonstrating a direct role of MucR in repressing this gene. Furthermore, we demonstrate that MucR can bind the virB gene promoter. Analyses by RT-qPCR showed no significant differences in the expression level of virB genes in Brucella abortus CC092 lacking MucR compared to the wild-type Brucella abortus strain, indicating that MucR binding to the virB promoter has little impact on virB gene expression in B. abortus 2308. The MucR modality to bind the two promoters analyzed supports our previous hypothesis that this is a histone-like protein never found before in Brucella ., Competing Interests: The authors declare no conflict of interest.

Background: Brucellosis is considered the world's most widespread zoonotic infection. It causes abortion and sterility in livestock leading to serious economic losses and has even more serious medical impact in humans, since it can be a trigger to more than 500,000 infections per year worldwide. The aim of this study was to evaluate the role of Haematopinus tuberculatus, a louse that can parasitize several ruminants, as a new host of brucellosis. Louse specimens were collected from seropositive and seronegative water buffaloes and divided in 3 developmental stages: adults, nymphs and nits. All samples were separately screened for Brucella spp. DNA and RNA detection by Real Time PCR. In particular, primers and probes potentially targeting the 16S rRNA and the Brucella Cell Surface 31 kDalton Protein (bcsp31) genes were used for Real Time PCR and buffalo β actin was used as a housekeeping gene to quantify host DNA in the sample. A known amount of B. abortus purified DNA was utilized for standard curve preparation and the target DNA amount was divided by the housekeeping gene amount to obtain a normalized target value. A further molecular characterization was performed for Brucella strain typing and genotyping by the Bruce-ladder, AMOS-PCR and MLVA assays. Data were statistically analysed by ANOVA., Results: Brucella abortus DNA and RNA were detected in all developmental stages of the louse, suggesting the presence of viable bacteria. Data obtained by MLVA characterization support this finding, since the strains present in animals and the relative parasites were not always identical, suggesting bacterial replication. Furthermore, the detection of Brucella DNA and RNA in nits samples demonstrate, for the first time, a trans-ovarial transmission of the bacterium into the louse., Conclusions: These findings identified H. tuberculatus as a new host of brucellosis. Further studies are needed to establish the role of this louse in the epidemiology of the disease, such as vector or reservoir.

Sixty-three Brucella isolates from water buffaloes and cattle slaughtered within the Italian national plan for brucellosis control were characterized by multiple-locus variable-number tandem repeat analysis (MLVA). Genotyping indicated a strong influence of geographic origin on the Brucella abortus biovar distribution in areas where brucellosis is endemic and highlighted the importance of rigorous management procedures aimed at avoiding inter- and intraherd spreading of pathogens.

The objective of this study was to determine if Brucella abortus rough mutant strain RB51 (SRB51) is eliminated in buffalo milk. Thirty Brucella-free female buffaloes were used in this study: ten 4-5 years old were inoculated with the triple of the recommended calfhood dose of SRB51 by subcutaneous route, ten 2-3 years old at the first lactation were previously vaccinated twice as calves with triple the recommended calf dose of RB51, while five 4-5 years old and five 2-3 years old not vaccinated Brucella-free female buffaloes served as controls. Milk samples were taken aseptically on a daily basis for the first 30 days and weekly for the second and third months. The samples were inoculated on selective media for isolation of SRB51 and incubated for 11 days. Moreover, PCR analysis was also performed directly on milk samples. SRB51 was isolated from milk samples only during the first week post-vaccination while RB51 DNA was detected during the first week till the fourth week post-vaccination only in water buffaloes vaccinated as adults. The identification of Brucella RB51 in milk samples, strongly suggests that this Brucella vaccine could be excreted in milk of buffalo cows vaccinated as adults, while our data demonstrate that the vaccine is safe for use in buffaloes vaccinated as calves in which it was not excreted in milk.