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Veterinary Medicine and Science Jul 2022Abortions cause tremendous economic losses in food-producing animals and may lead to food insecurity.
BACKGROUND
Abortions cause tremendous economic losses in food-producing animals and may lead to food insecurity.
OBJECTIVES
This study aimed to characterize Brucella spp. and other abortigenic pathogens from aborted tissues of cattle.
METHODS
For cattle, aborted tissues (n = 19) were cultured, and Brucella spp. were detected using the genus-specific 16S-23S ribosomal DNA interspacer region (ITS) assay and speciated using Brucella abortus, Brucella melitensis, Brucella ovis, and Brucella suis (AMOS) and Bruce-ladder PCR assays. Brucella negative samples were screened using the eight abortigenic pathogens PCR panel. Samples from an abortion outbreak that occurred within a goat tribe were included in this investigation. Sera of females (n = 8) and males (n = 2) were analyzed using the Rose Bengal Test (RBT) and indirect enzyme-linked immunosorbent assay (i-ELISA), while vaginal swabs (n = 3) and aborted tissues (n = 1) were cultured and characterized.
RESULTS
The ITS-PCR detected Brucella DNA in cultures from two aborted tissues of cattle (10.5%, [2/19]), which were identified as B. melitensis (n = 1), and B. abortus (n = 1) using AMOS and Bruce-ladder PCR assays. Campylobacter fetus (n = 7) and Leptospira spp. (n = 4) including co-infections (n = 2) of C. fetus and Leptospira spp. were identified from the Brucella negative samples of cattle. Goats (100.0%, 10/10) were brucellosis seropositive on RBT and i-ELISA. Mixed infections caused by B. melitensis and B. abortus were isolated from the vaginal swabs (n = 3) and aborted tissues (n = 1).
DISCUSSION AND CONCLUSIONS
This is the first identification of abortion-associated pathogens in aborted cattle indicating the enormous financial losses and a threat to public health. It is therefore essential to include these identified pathogens in the surveillance scheme of veterinary and human services.
Topics: Animals; Brucella; Brucella abortus; Brucella melitensis; Brucella ovis; Brucella suis; Brucellosis; Cattle; Cattle Diseases; Female; Goat Diseases; Goats; Leptospira; Male; Pregnancy; Rwanda
PubMed: 35420251
DOI: 10.1002/vms3.805 -
FEBS Letters Oct 2011"In vivo" bacterial nutrition, i.e. the nature of the metabolic network and substrate(s) used by bacteria within their host, is a fundamental aspect of pathogenic or... (Review)
Review
"In vivo" bacterial nutrition, i.e. the nature of the metabolic network and substrate(s) used by bacteria within their host, is a fundamental aspect of pathogenic or symbiotic lifestyles. A typical example are the Brucella spp., facultative intracellular pathogens responsible for chronic infections of animals and humans. Their virulence relies on their ability to modulate immune response and the physiology of host cells, but the fine-tuning of their metabolism in the host during infection appears increasingly crucial. Here we review new insights on the links between Brucella virulence and metabolism, pointing out the need to investigate both aspects to decipher Brucella infectious strategies.
Topics: Adaptation, Physiological; Animals; Brucella; Brucellosis; Humans; Mutation; Quorum Sensing; Virulence
PubMed: 21864534
DOI: 10.1016/j.febslet.2011.08.011 -
Frontiers in Cellular and Infection... 2015Brucella spp. are intracellular bacterial pathogens that cause infection in domestic and wild animals. They are often used as model organisms to study intracellular... (Review)
Review
Brucella spp. are intracellular bacterial pathogens that cause infection in domestic and wild animals. They are often used as model organisms to study intracellular bacterial infections. Brucella VirB T4SS is a key virulence factor that plays important roles in mediating intracellular survival and manipulating host immune response to infection. In this review, we discuss the roles of Brucella VirB T4SS and 15 effectors that are proposed to be crucial for Brucella pathogenesis. VirB T4SS regulates the inflammation response and manipulates vesicle trafficking inside host cells. VirB T4SS also plays crucial roles in the inhibition of the host immune response and intracellular survival during infection. Here, we list the key molecular events in the intracellular life cycle of Brucella that are potentially targeted by the VirB T4SS effectors. Elucidating the functions of these effectors will help clarify the molecular role of T4SS during infection. Furthermore, studying the effectors secreted by Brucella spp. might provide insights into the mechanisms used by the bacteria to hijack the host signaling pathways and aid in the development of better vaccines and therapies against brucellosis.
Topics: Animals; Brucella; Host-Pathogen Interactions; Humans; Protein Transport; Type IV Secretion Systems; Virulence Factors
PubMed: 26528442
DOI: 10.3389/fcimb.2015.00072 -
Animal Health Research Reviews Jun 2012Similar to other bacteria, Brucella strains require several biologically essential metals for their survival in vitro and in vivo. Acquiring sufficient levels of some of... (Review)
Review
Similar to other bacteria, Brucella strains require several biologically essential metals for their survival in vitro and in vivo. Acquiring sufficient levels of some of these metals, particularly iron, manganese and zinc, is especially challenging in the mammalian host, where sequestration of these micronutrients is a well-documented component of both the innate and acquired immune responses. This review describes the Brucella metal transporters that have been shown to play critical roles in the virulence of these bacteria in experimental and natural hosts.
Topics: Animals; Brucella; Brucellosis; Humans; Iron; Magnesium; Manganese; Metals; Nickel; Virulence; Zinc
PubMed: 22632611
DOI: 10.1017/S1466252312000047 -
Journal of Infection in Developing... Jul 2015Brucellosis is a zoonotic and contagious infectious disease caused by infection with Brucella species. The infecting brucellae are capable of causing a devastating... (Review)
Review
Brucellosis is a zoonotic and contagious infectious disease caused by infection with Brucella species. The infecting brucellae are capable of causing a devastating multi-organ disease in humans with serious health complications. The pathogenesis of Brucella infection is influenced largely by host factors, Brucella species/strain, and the ability of invading brucellae to survive and replicate within mononuclear phagocytic cells, preferentially macrophages (Mf). Consequently, the course of human infection may appear as an acute fatal or progress into chronic debilitating infection with periodical episodes that leads to bacteremia and death. The existence of brucellae inside Mf represents one of the strategies used by Brucella to evade the host immune response and is responsible for treatment failure in certain human populations treated with anti-Brucella drugs. Moreover, the persistence of brucellae inside Mf complicates the diagnosis and may affect the host cell signaling pathways with consequent alterations in both innate and adaptive immune responses. Therefore, there is an urgent need to pursue the development of novel drugs and/or vaccine targets against human brucellosis using high throughput technologies in genomics, proteomics, and immunology.
Topics: Brucella; Brucellosis; Host-Pathogen Interactions; Humans; Macrophages
PubMed: 26230118
DOI: 10.3855/jidc.6625 -
Frontiers in Cellular and Infection... 2012Brucella is a Gram-negative, facultative intracellular bacterium that causes zoonotic brucellosis in humans and various animals. Out of 10 classified Brucella species,... (Review)
Review
Brucella is a Gram-negative, facultative intracellular bacterium that causes zoonotic brucellosis in humans and various animals. Out of 10 classified Brucella species, B. melitensis, B. abortus, B. suis, and B. canis are pathogenic to humans. In the past decade, the mechanisms of Brucella pathogenesis and host immunity have been extensively investigated using the cutting edge systems biology and bioinformatics approaches. This article provides a comprehensive review of the applications of Omics (including genomics, transcriptomics, and proteomics) and bioinformatics technologies for the analysis of Brucella pathogenesis, host immune responses, and vaccine targets. Based on more than 30 sequenced Brucella genomes, comparative genomics is able to identify gene variations among Brucella strains that help to explain host specificity and virulence differences among Brucella species. Diverse transcriptomics and proteomics gene expression studies have been conducted to analyze gene expression profiles of wild type Brucella strains and mutants under different laboratory conditions. High throughput Omics analyses of host responses to infections with virulent or attenuated Brucella strains have been focused on responses by mouse and cattle macrophages, bovine trophoblastic cells, mouse and boar splenocytes, and ram buffy coat. Differential serum responses in humans and rams to Brucella infections have been analyzed using high throughput serum antibody screening technology. The Vaxign reverse vaccinology has been used to predict many Brucella vaccine targets. More than 180 Brucella virulence factors and their gene interaction networks have been identified using advanced literature mining methods. The recent development of community-based Vaccine Ontology and Brucellosis Ontology provides an efficient way for Brucella data integration, exchange, and computer-assisted automated reasoning.
Topics: Animals; Antigens, Bacterial; Brucella; Brucella Vaccine; Computational Biology; Genomics; Humans; Proteomics; Systems Biology; Transcriptome; Virulence Factors
PubMed: 22919594
DOI: 10.3389/fcimb.2012.00002 -
Veterinary Research Apr 2012Brucellosis is a zoonosis caused by Brucella species. Brucellosis research in natural hosts is often precluded by practical, economical and ethical reasons and mice are... (Review)
Review
Brucellosis is a zoonosis caused by Brucella species. Brucellosis research in natural hosts is often precluded by practical, economical and ethical reasons and mice are widely used. However, mice are not natural Brucella hosts and the course of murine brucellosis depends on bacterial strain virulence, dose and inoculation route as well as breed, genetic background, age, sex and physiological statu of mice. Therefore, meaningful experiments require a definition of these variables. Brucella spleen replication profiles are highly reproducible and course in four phases: i), onset or spleen colonization (first 48 h); ii), acute phase, from the third day to the time when bacteria reach maximal numbers; iii), chronic steady phase, where bacterial numbers plateaus; and iv), chronic declining phase, during which brucellae are eliminated. This pattern displays clear physiopathological signs and is sensitive to small virulence variations, making possible to assess attenuation when fully virulent bacteria are used as controls. Similarly, immunity studies using mice with known defects are possible. Mutations affecting INF-γ, TLR9, Myd88, Tγδ and TNF-β favor Brucella replication; whereas IL-1β, IL-18, TLR4, TLR5, TLR2, NOD1, NOD2, GM-CSF, IL/17r, Rip2, TRIF, NK or Nramp1 deficiencies have no noticeable effects. Splenomegaly development is also useful: it correlates with IFN-γ and IL-12 levels and with Brucella strain virulence. The genetic background is also important: Brucella-resistant mice (C57BL) yield lower splenic bacterial replication and less splenomegaly than susceptible breeds. When inoculum is increased, a saturating dose above which bacterial numbers per organ do not augment, is reached. Unlike many gram-negative bacteria, lethal doses are large (≥ 108 bacteria/mouse) and normally higher than the saturating dose. Persistence is a useful virulence/attenuation index and is used in vaccine (Residual Virulence) quality control. Vaccine candidates are also often tested in mice by determining splenic Brucella numbers after challenging with appropriate virulent brucellae doses at precise post-vaccination times. Since most live or killed Brucella vaccines provide some protection in mice, controls immunized with reference vaccines (S19 or Rev1) are critical. Finally, mice have been successfully used to evaluate brucellosis therapies. It is concluded that, when used properly, the mouse is a valuable brucellosis model.
Topics: Animals; Brucella; Brucellosis; Disease Models, Animal; Humans; Mice; Virulence
PubMed: 22500859
DOI: 10.1186/1297-9716-43-29 -
Microbiology Spectrum Mar 2019Bacteria of the genus colonize a wide variety of mammalian hosts, in which their infectious cycle and ability to cause disease predominantly rely on an intracellular... (Review)
Review
Bacteria of the genus colonize a wide variety of mammalian hosts, in which their infectious cycle and ability to cause disease predominantly rely on an intracellular lifestyle within phagocytes. Upon entry into host cells, organisms undergo a complex, multistage intracellular cycle in which they sequentially traffic through, and exploit functions of, the endocytic, secretory, and autophagic compartments via type IV secretion system (T4SS)-mediated delivery of bacterial effectors. These effectors modulate an array of host functions and machineries to first promote conversion of the initial endosome-like -containing vacuole (eBCV) into a replication-permissive organelle derived from the host endoplasmic reticulum (rBCV) and then to an autophagy-related vacuole (aBCV) that mediates bacterial egress. Here we detail and discuss our current knowledge of cellular and molecular events of the intracellular cycle. We discuss the importance of the endosomal stage in determining T4SS competency, the roles of autophagy in rBCV biogenesis and aBCV formation, and T4SS-driven mechanisms of modulation of host secretory traffic in rBCV biogenesis and bacterial egress.
Topics: Animals; Bacterial Proteins; Brucella; Brucellosis; Cytoplasm; Host-Pathogen Interactions; Humans; Life Cycle Stages; Phagocytes; Vacuoles
PubMed: 30848234
DOI: 10.1128/microbiolspec.BAI-0006-2019 -
Cellular Microbiology Jul 2015Bacteria of the genus Brucella are intracellular vacuolar pathogens of mammals that cause the worldwide zoonosis brucellosis, and reside within phagocytes of infected... (Review)
Review
Bacteria of the genus Brucella are intracellular vacuolar pathogens of mammals that cause the worldwide zoonosis brucellosis, and reside within phagocytes of infected hosts to promote their survival, persistence and proliferation. These traits are essential to the bacterium's ability to cause disease and have been the subject of much investigation to gain an understanding of Brucella pathogenic mechanisms. Although the endoplasmic reticulum-derived nature of the Brucella replicative niche has been long known, major strides have recently been made in deciphering the molecular mechanisms of its biogenesis, including the identification of bacterial determinants and host cellular pathways involved in this process. Here I will review and discuss the most recent advances in our knowledge of Brucella intracellular pathogenesis, with an emphasis on bacterial exploitation of the host endoplasmic reticulum-associated functions, and how autophagy-related processes contribute to the bacterium's intracellular cycle.
Topics: Animals; Brucella; Host-Pathogen Interactions; Humans; Mammals; Models, Biological; Phagocytes; Vacuoles; Virulence Factors
PubMed: 25916795
DOI: 10.1111/cmi.12452 -
Journal of Infection in Developing... Nov 2014Brucellosis is a highly contagious zoonosis that affects the public health and economic performance of endemic as well as non-endemic countries. In developing nations,... (Review)
Review
Brucellosis is a highly contagious zoonosis that affects the public health and economic performance of endemic as well as non-endemic countries. In developing nations, brucellosis is often a very common but neglected disease. The purpose of this review is to provide insight about brucellosis in animal populations in Egypt and help to understand the situation from 1986 to 2013. A total of 67 national and international scientific publications on serological investigations, isolation, and biotyping studies from 1986 to 2013 were reviewed to verify the current status of brucellosis in animal populations in Egypt. Serological investigations within the national surveillance program give indirect proof for the presence of brucellosis in cattle, buffaloes, sheep, goats, and camels in Egypt. Serologic testing for brucellosis is a well-established procedure in Egypt, but most of the corresponding studies do not follow the scientific standards. B. melitensis biovar (bv) 3, B. abortus bv 1, and B. suis bv 1 have been isolated from farm animals and Nile catfish. Brucellosis is prevalent nationwide in many farm animal species. There is an obvious discrepancy between official seroprevalence data and data from scientific publications. The need for a nationwide survey to genotype circulating Brucellae is obvious. The epidemiologic situation of brucellosis in Egypt is unresolved and needs clarification.
Topics: Animals; Animals, Domestic; Brucella; Brucellosis; Catfishes; Egypt; Seroepidemiologic Studies
PubMed: 25390047
DOI: 10.3855/jidc.4872