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PubMed1990

[Cloning of Brucella genes in Escherichia coli K12 cells and analysis of products of the cloned genes].

The libraries of Brucella melitensis 565 and Brucella abortus 99 in Escherichia coli cells have been constructed. Some clones of Escherichia coli producing the specific brucella antigens have been found in immunological tests with brucella antiserum. Two strains producing antigens have been characterized, one being from Brucella melitensis 565 and another from Brucella abortus 99 clone libraries . Both strains synthesize two antigens that were studied by immunoelectrophoresis, immunoblotting after treatment of antigen preparations with different physical and chemical agents substrate specific enzymes. Both strains are found to synthesize the specific brucella antigens of protein nature. One of them has the mol mass about 15 kD, another--31-32 kD. The 31-32 kD antigen can be, evidently, referred to as the main protein of an outer membrane of brucella.

Antigens, Bacterial↗
PubMed1986

Experimentally induced Brucella abortus infection in pregnant goats.

Pregnant goats in midgestation (7 to 16 weeks) were conjunctivally exposed to Brucella abortus strain 2308 to evaluate their applicability as an animal model for bovine brucellosis. Brucellae were isolated from uterine fluid and/or placental specimens of 10 of 12 does at parturition. Six of the 10 infected does delivered dead fetuses and 1 of the 10 delivered live, premature twins. Dead fetuses typically contained brucellae in multiple tissues, whereas brucellae generally were not isolated at birth from live kids. After parturition, B abortus was excreted in the milk and uterine fluids of the infected does. At necropsy (6 weeks after parturition), organisms in the doe were primarily in the uterus and in the lymph nodes that drained the mammary glands, uterus, and head. Brucella abortus was most often isolated from the cranial lymph nodes of neonates that had remained with their dam for 6 weeks after parturition. Serum anti-Brucella antibody concentrations were determined by use of standard tube agglutination, mercaptoethanol agglutination, Rivanol plate tests, card tests, complement fixation, hemolysis-in-gel tests, and an enzyme-linked immunosorbent assay. Serologic responses were detected 2 to 3 weeks after exposure and remained detectable until parturition. Antibody titers increased after parturition in does shedding B abortus at parturition. Anti-Brucella antibody was not detected in neonates before colostrum intake. The neonate's postcolostral titers were similar to those in the dam at the time of parturition. Milk anti-Brucella antibody was detected in milk (milk ring test) from infected and noninfected mammary glands.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

A study of immunological cross-reaction between Yersinia enterocolitica 0:9 and Brucella abortus.

In this paper, the immunological cross-reaction between Yersinia enterocolitica 0:9 (Y-9) and Brucella abortus has been studied with the following results: It has been demonstrated that serological cross-reaction exists between the organisms and the agglutination titer of Y-9 antigen and anti-Brucella human sera is lower than that between Brucella antigen and Yersinia anti-sera. Y-9 antigen can only be agglutinated by Brucella monospecific serum "A", but not by serum "M" or "R". 24-48 hours after the injection of Y-9 antigen either in the form of whole cells or purified protein, a clear skin cross-reaction was observed in a guinea pig sensitized with Brucella 104M. But the skin cross-reaction of a guinea pig sensitized with Y-9 to Brucella antigen was rather weak. In case the antigen used in skin test is similar to that used for sensitization, similar results are obtained at 24 and 48 hours for Brucella antigen, but for Y-9, the reaction at 24 hours is stronger than that at 48 hours. In the protection test, the protection rate against B. melitensis M13 virulent strain in guinea pigs immunized with Y-9 and B. abortus are 33.3% and 90% respectively, while those against B. abortus 104M in C57BL inbred mice immunized with Brucella antigen and Y-9 are 90% and 50% respectively.

Agglutination Tests↗
PubMed2003

Type III secretion homologs are present in Brucella melitensis, B. ovis, and B. suis biovars 1, 2, and 3.

Protein sequences from characterized type III secretion (TTS) systems were used as probes in silico to identify several TTS gene homologs in the genome sequence of Brucella suis biovar 1 strain 1330. Four of the genes, named flhB, fliP, fliR, and fliF on the basis of greatest homologies to known flagellar apparatus proteins, were targeted in PCR and hybridization assays to determine their distribution among other Brucella nomen species and biovars. The results indicated that flhB, fliP, fliR and fliF are present in Brucella melitensis, Brucella ovis, and Brucella suis biovars 1, 2 and 3. Similar homologos have been reported previously in Brucella abortus. Using RT-PCR assays, we were unable to detect any expression of these genes. It is not yet known whether the genes are the cryptic remnants of a flagellar system or are actively involved in a process contributing to pathogenicity or previously undetected motility, but they are distributed widely in Brucella and merit further study to determine their role.

Bacterial Proteins↗
PubMed1962

Synergistic action of streptomycin with other antibiotics of intracellular Brucella abortus in vitro.

Richardson, Marvis (Michigan State University, East Lansing) and Jane N. Holt. Synergistic action of streptomycin with other antibiotics on intracellular Brucella abortus in vitro. J. Bacteriol. 84:638-646. 1962.-It has been found that streptomycin acts synergistically with penicillin and tetracycline to inhibit the growth of Brucella abortus within bovine cells cultured in vitro. Extracellular penicillin at 10 to 50 mug/ml was essentially bacteriostatic for intracellular brucellae. A combination of 5 to 50 mug/ml of streptomycin, which alone did not prevent the multiplication of intracellular brucellae, and 50 mug/ml of penicillin was bactericidal. Tetracycline at 0.5 to 1.0 mug/ml, which permitted growth or was bacteriostatic for brucellae within tissue cells, proved markedly bactericidal when combined with 10 mug/ml of streptomycin. Within certain limits, the synergistic effect of streptomycin and tetracycline did not appear to be a function of concentration. When the addition of streptomycin was delayed until 24 hr after the addition of tetracycline, the antibiotics acted synergistically on intracellular brucellae. To achieve intracellular synergism, five to ten times the effective extracellular concentration of streptomycin was required. Penicillin and tetracycline acted at the same concentration on extracellular and intracellular brucellae. These results suggest that tissue cell systems may prove useful for study of multiple drug therapy to be used in vivo against intracellular bacteria.

Animals↗
PubMed1964

MULTIPLICATION OF BRUCELLA IN CULTURED LYMPHOID AND NONLYMPHOID CELLS.

Richardson, Marvis (Michigan State University, East Lansing), and Jane N. Holt. Multiplication of Brucella in cultured lymphoid and nonlymphoid cells. J. Bacteriol. 88:1163-1168. 1964.-Growth curves were established for the multiplication of Brucella abortus in cultured bovine cells. The number of viable brucellae was determined by colony count after lysis of the parasitized tissue cells. It was found that the number of brucellae dropped during the first 3 to 6 hr. This was followed by intracellular growth. Brucellae multiplied in uterine mucosal and fetal skin cells at an exponential rate with a 4-hr generation time. In contrast, only limited multiplication occurred in spleen cell cultures, usually approaching the stationary phase by 20 to 30 hr. Preliminary results indicated an average generation time of 8 hr in calf spleen cells. Differences were apparent in the ability of spleen cells from individual calves to support intracellular growth. This suggests that a relationship may exist between the establishment of intracellular pathogens in vitro and the natural resistance of the animal. By the use of fluorescein-labeled antisera, some insight was gained into the fate of brucellae in lymphoid cells. Fluorescent antisera stained intact brucellae and also revealed soluble antigen in the cytoplasm of reticularlike cells.

Animals↗
PubMed1997

Detection and differentiation of the six Brucella species by polymerase chain reaction.

BACKGROUND: Brucelosis is a severe acute febrile disease caused by bacteria of the genus Brucella. Its current diagnosis is based on clinical observations that may be complemented by serology and microbiological culture tests; however, the former is limited in sensitivity and specificity, the latter is time consuming. To improve brucelosis diagnosis we developed a test which is specific and sensitive and is capable of differentiating the six species of Brucella. MATERIALS AND METHODS: Four primers were designed from B. abortus sequences at the well-conserved Omp2 locus that are able to amplify the DNAs of all six species of Brucella. RESULTS: Our test detected all six species of Brucella. Their differentiation resulted directly from differences in the amplification patterns or was achieved indirectly using a RFLP present in one of the PCR products. The sensitivity and specificity of the new test were then determined; it was applied successfully in confirming the diagnosis of a patient whose clinical history and serology indicated infection with Brucella. CONCLUSIONS: The results make possible the use of a PCR test for Brucella detection and differentiation without relying on the measurement of the antibodies or microorganism culture. Our first results showed that the PCR test can confirm the presence of Brucella in blood samples of infected patients.

Brucella↗
PubMed1970

Some structural and biological properties of Brucella endotoxin.

Hot phenol-water extraction of smooth Brucella abortus and B. melitensis cells yielded a toxic fraction which was recovered from the phenol phase (fraction 5). Chemically, fractions 5 from both Brucella species were lipid-carbohydrate-protein-2 keto-3-deoxyoctulosonic acid complexes which were stable to heat and resistant to Pronase digestion. Electron micrographs of the Brucella toxins were morphologically indistinguishable from those of enterobacterial endotoxins. Biologically, Brucella toxins were lethal for mice and immunogenic for rabbits. An intravenous injection of Brucella toxin induced severe leukopenia with subsequent leukocytosis in mice. Cross-tolerance experiments with mice demonstrated that pretreatment with B. abortus toxin lessened the hypoferremia produced by challenge with Escherichia coli endotoxin. Furthermore, fractions 5 from B. abortus and B. melitensis were able to form hybrids with E. coli and Salmonella enteritidis endotoxins and also with each other. Although Brucella toxins possess many structural and biological properties in common with endotoxins from the Enterobacteriaceae, some quantitative differences in their biological potencies were observed. Brucella toxins were relatively innocuous in tests for pyrogenicity in rabbits and lethality for chick embryos. In nonspecific protection tests, Brucella toxin had only 1/75 the potency of E. coli endotoxin in protecting mice against challenge with virulent S. typhi. However, on the basis of the data presented and on the work done previously, we concluded that the heat-stable toxins of B. abortus and B. melitensis were endotoxins.

Journal Article↗
PubMed1988

Effect of incubation temperature, ageing, and bisulfite content of unsupplemented Brucella agar on aerotolerance of Campylobacter jejuni.

A mutant strain of Campylobacter jejuni ATCC 29428 was isolated that grows on unsupplemented Brucella agar at O2 levels as high as 21% at 37 degrees C. While measuring the degree of aerotolerance of this mutant on unsupplemented Brucella medium and comparing it with that of the wild type, we found considerable variation among our estimates. As measured by colony counts on unsupplemented Brucella agar incubated at various oxygen levels, the degree of aerotolerance was affected by incubation temperature and the age of the medium. Aerotolerance was consistently higher on plates incubated at 42 degrees C than at 37 degrees C. When the commercial dehydrated Brucella medium that was used to prepare the Brucella agar was stored in a beaker for 2.5 months, the degree of aerotolerance of C. jejuni was decreased. Addition of 0.01% sodium bisulfite reversed this inhibition. Storage of bottles of hydrated Brucella agar for 1.5 months also resulted in a decreased aerotolerance; again, in addition of 0.01% bisulfite reversed the effect. Aerotolerance was greatly decreased when Brucella agar was prepared from all its individual components except 0.01% bisulfite. The results indicate that the bisulfite component of Brucella agar deteriorates during storage of the dehydrated and hydrated media, and that this deterioration can affect measurements of aerotolerance.

Aerobiosis↗
PubMed2002

Brucella evolution and taxonomy.

The genus Brucella contains alpha-Proteobacteria adapted to intracellular life within cells of a variety of mammals. Controversy has arisen concerning Brucella internal taxonomy, and it has been proposed that the DNA-DNA hybridization-based genomospecies concept be applied to the genus. According to this view, only one species, Brucella melitensis, should be recognized, and the classical species should be considered as biovars (B. melitensis biovar melitensis; B. melitensis biovar abortus; etc.). However, a critical reappraisal of the species concept, a review of the population structure of bacteria and the analysis of Brucella genetic diversity by methods other than DNA-DNA hybridization show that there are no scientific grounds to apply the genomospecies concept to this genus. On the other hand, an enlarged biological species concept allows the definition of Brucella species that are consistent with molecular analyses and support the taxonomical standing of most classical species. Both the host range as a long-recognized biological criterion and the presence of species-specific markers in outer membrane protein genes and in other genes show that B. melitensis, B. abortus, B. ovis, B. canis and B. neotomae are not mere pathovars (or nomenspecies) but biologically meaningful species. The status of B. suis is, however, less clear. These approaches should be useful to define species for the marine mammal Brucella isolates, as illustrated by the grouping of the isolates from pinnipeds or from cetaceans by omp2 gene analysis. It is shown that a correct Brucella species definition is important to understand the evolution of the genus.

Biological Evolution↗
PubMed1978

Resistance of normal or immunized guinea pigs against a subcutaneous challenge of Brucella abortus.

Guinea pigs were inoculated subcutaneously into a hind footpad with Brucella abortus. Unimmunized guinea pigs had little capacity for barring brucella from spreading to their spleens: the inoculum dose needed to infect 50% of the spleens one month after inoculation was about 10 brucella. When the size of the challenge inoculum reached approximately 5 x 10(3) ID50 a previous immunization with killed or virulent brucella: --did not prevent the challenge bacteria from reaching the lymph nodes near the inoculation site, but reduced the level of infection in these, --barred or reduced the spreading of brucella throughout the remainder of the reticuloendothelial system. Immunization with a small number of virulent brucella was more effective than immunization with a higher number of killed bacteria to produce such modifications of the repartition of challenge brucella.

Animals↗
PubMed1977

[Fatty acid makeup of various Brucella species and its relationship to the culture medium].

Gas chromatographic method was applied to the study of the fatty acid composition (in Br. melitensis, Br. abortus, Br. suis, and Br. ovis strains. Fatty acid composition was similar in the mentioned brucellae species, except Br. suis No. 1330 significantly differing by this sign. Methyleneoctadecanoic acid content was considerably elevated, and that of octadecenoic -- reduced in brucellae grown on liver agar with the addition of serum and on meat-peptone agar in comparison with brucellae grown on liver agar; apparently this represents one of the mechanisms of the microorganism adaptation to the less favourable conditions of the nutrient medium. Passage of Br. ovis strain through the guinea pig organism led to the appearance of brucellae forming two types of colonies when grown on liver agar with the addition of serum. The fatty acid composition of brucellae forming small transparent colonies was the same as that of the initial culture with the prevalence of methyleneoctadecanoic acid; as to brucellae with larger colonies with irregular margin and nontransparent centre of the colony--octadecenoic acid prevailed in their fatty acid composition, i.e. their composition was similar to such in brucellae of the melitensis and abortus species grown on liver agar.

Brucella↗
PubMed1961

Metabolic characterization of the genus Brucella. I. Statistical evaluation of the oxidative rates by which type I of each species can be identified.

Meyer, Margaret E. (University of California, Davis), and H. S. Cameron. Metabolic characterization of the genus Brucella. I. Statistical evaluation of the oxidative rates by which type I of each species can be identified. J. Bacteriol. 82:387-395. 1961.-The oxidative uptake rates on 11 amino acid and seven carbohydrate substrates were determined for 75 strains of brucellae that had been identified by the conventional determinative methods as Brucella melitensis type I, Brucella abortus type I, or Brucella suis type I. By calculating the standard deviation of the oxidative rates, it was demonstrated that a metabolic pattern that is characteristic and definitive for each of the species was formed by their differential oxidative utilization of substrate groups, and that qualitative as well as quantitative metabolic differences exist among the Brucella species. B. melitensis oxidized l-alanine, l-asparagine, and l-glutamic acid, but not l-arginine, dl-citrulline, l-lysine, dl-ornithine, l-arabinose, d-galactose, d-ribose, or d-xylose. B. abortus differed qualitatively from B. melitensis in that it oxidized the carbohydrate substrates. B. suis differed quantitatively from both of these species in its consistently low oxidative rates of l-alanine, l-asparagine, and l-glutamic acid, and its high rates of utilization of the carbohydrate substrates. It differed qualitatively in that it oxidized the four amino acid substrates that are components of the urea cycle.

Alanine↗
PubMed2000

Residual virulence of Brucella abortus in the absence of the cytochrome bc(1)complex in a murine model in vitro and in vivo.

To maintain survival in macrophages, Brucella must overcome a hostile phagosomal environment defined as low pH, limited nutrition and low oxygen tension. The specific mechanisms utilized by Brucella to surmount such unfavorable environmental factors in phagosomes are not well understood. In general, to adapt to a change in environmental oxygen tension, bacteria use different terminal oxidases that have different oxygen affinity. To survive in phagosomes where low oxygen tension exists, Brucella, like other bacteria, may require high oxygen affinity terminal oxidases that can accept electrons through a cytochrome bc(1)complex dependent or independent pathway. Using a Brucella abortus cytochrome bc(1)complex deficient mutant, delta fbcF, the requirement for a high oxygen affinity terminal oxidase governed by the cytochrome bc(1)complex dependent pathway was tested. The number of cfu from RAW 264.7 macrophage cells and spleens of BALB/c mice infected with wild-type or the cytochrome bc(1)complex deficient mutant was similar during the course of infection. These results suggest that B. abortus contains no essential terminal oxidase utilized at low oxygen tension in phagosomes requiring the cytochrome bc(1)complex. Alternatively, other branched cytochrome bc(1)complex independent respiratory mechanisms that contain the high oxygen affinity terminal oxidases likely exist to facilitate Brucella survival in phagosomes. This is the first investigation regarding the Brucella respiratory system at the molecular level and the involvement of a respiratory system in Brucella pathogenesis.

Amino Acid Sequence↗
PubMed2002

Molecular and cellular interactions between Brucella abortus antigens and host immune responses.

Host protection against Brucella abortus, is thought to be mediated primarily by a Th1 type immune response. Unfortunately, only few specific bacterial antigens involved in stimulating protective cellular immunity against Brucella are known. Therefore, identifying bacterial proteins that induce a T-lymphocyte mediated response is critical to determine Brucella immunity. Several library screening methods are discussed that have been used to identify Brucella proteins that stimulate T lymphocytes including cellular immunoblotting, Escherichia coli expressed Brucella proteins, green fluorescence reporter systems, and signature tagged mutagenesis. Future studies would likely examine how bacterial proteins expressed within host cells aid pathogen survival and/or induce host responses. Some of these newly identified bacterial gene products may serve as antigens to activate a protective host immune response. Also, identifying Brucella proteins expressed at particular times during infection will also yield insights into Brucella pathogenesis.

Animals↗
PubMed2000

Conservation of seven genes involved in the biosynthesis of the lipopolysaccharide O-side chain in Brucella spp.

Seven genes of the wb locus of Brucella melitensis 16M involved in the biosynthesis of the lipopolysaccharide O-side chain have been recently identified, i.e. wbkA, gmd, per, wzm, wzt, wbkB, and wbkC, coding, respectively, for proteins homologous to mannosyltransferase, GDP-mannose 4,6 dehydratase, perosamine synthetase, ABC-type transporter (integral membrane protein), ABC-type transporter (ATPase domain), a hypothetical protein of unknown function, and a putative formyl transferase. The seven genes have a G + C content lower (around 48%) than that typical of Brucella spp. (58%) and thus may have been acquired from a species other than Brucella. In the present study, we analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) the seven O-chain biosynthetic genes for polymorphism among Brucella spp. PCR-RFLP showed that the seven genes are highly conserved and occur even in the naturally rough species B. ovis and B. canis and also in rough strains of B. abortus and B. melitensis. Nevertheless, the few polymorphisms that were observed consisted of absence of additional restriction sites sometimes allowing differentiation at the species level (e.g. B. ovis) or at the biovar or strain level. There were no apparent deletions or insertions in the PCR-amplified genes in any of the Brucella strains studied. In conclusion, the seven O-chain biosynthetic genes studied appear to be highly conserved among Brucella spp. and thus may have been acquired before species differentiation. Some of the species- or biovar-specific markers detected could be used for molecular typing of brucellae in addition to those previously described.

Animals↗
PubMed1975

The serological relationship between Brucella spp., Yersinia enterocolitica serotype IX and Salmonella serotypes of Kauffmann-White group N.

The serological relationship between Brucella spp., Yersinia enterocolitica IX, and the group N salmonella serotypes S. godesberg, S. landau, S. morehead, S. neusdorf, S. soerenga and S. urbana was examined using agglutination, antiglobulin, complement fixation, immunodiffusion and fluorescent antibody methods. Antisera to the group N salmonella serotypes all reacted to significant titres in agglutination and complement fixation, but not antiglobulin or immunodiffusion tests with smooth brucella antigens. These antisera also reacted in agglutination, but not antiglobulin, tests with Y. enterocolitica IX. They did not react significantly in any tests with rough brucella antigens. Conversely, antisera to smooth Brucella spp. agglutinated group N salmonellas to low titre and Y. enterocolitica IX to titres similar to those given against the homologous strain. Antiserum to Y. enterocolitica IX on the other hand reacted with smooth brucella antigens to high titre in agglutination, complement fixation and antiglobulin tests, and with the group N salmonella antigens to substantial titres in agglutination tests. In direct fluorescent antibody tests, smooth Brucella strains and Y. enterocolitica IX reacted strongly with FITC-labelled antibody to Br. abortus whereas the group N salmonella strains reacted weakly. In tests with monospecific antisera to the A and M determinants of Br. abortus and Br. melitensis respectively, Y. enterocolitica IX reacted only with the antiserum to the A determinant whereas group N salmonellas reacted to low titre with both A and M antisera. The results of cross-absorption tests confirmed this relationship and suggested that the O30 antigens of group N salmonella serotypes contained antigenic determinants similar to, but not identical with, the antigenic structure shared by smooth Brucella spp. and Y. enterocolitica IX.

Absorption↗
PubMed2002

Evaluation of a selective medium for Brucella isolation using natamycin.

AIMS: To select an anti-fungal agent to replace cycloheximide in the media used for isolation of Brucella. METHODS AND RESULTS: One potential agent, natamycin, was evaluated using 28 Brucella isolates, 18 yeasts and 14 fungi. The material for the evaluation included 37 bovine milk samples, six bovine vaginal swabs and 45 milk samples artificially infected with Brucella. The recovery of Brucella only from the artificially-inoculated milk samples increased with the use of the medium containing natamycin instead of cycloheximide, at the same time significantly inhibiting the growth of yeasts, fungi and other bacteria. The inclusion of either anti-fungal agent allowed growth of the 28 Brucella isolates and totally prevented the growth of all 18 yeasts and 13 of the 14 fungi. CONCLUSIONS: Based on the results it was concluded that natamycin would be a suitable alternative to cycloheximide. SIGNIFICANCE AND IMPACT OF THE STUDY: Cycloheximide has become unavailable worldwide and is currently an anti-fungal constituent of the medium often used for isolation of Brucella organisms. The use of natamycin as a replacement in the formulation did not inhibit growth of Brucella and was effective at eliminating most contaminants.

Animals↗