Common Bacterial Zoonosis Research Articles

Molecular Epidemiology of Brucella abortus in Northern Ireland—1991 to 2012

BackgroundBrucellosis is the most common bacterial zoonoses worldwide. Bovine brucellosis caused by Brucella abortus has far reaching animal health and economic impacts at both the local and national levels. Alongside traditional veterinary epidemiology, the use of molecular typing has recently been applied to inform on bacterial population structure and identify epidemiologically-linked cases of infection. Multi-locus variable number tandem repeat VNTR analysis (MLVA) was used to investigate the molecular epidemiology of a well-characterised Brucella abortus epidemic in Northern Ireland involving 387 herds between 1991 and 2012.ResultsMLVA identified 98 unique B. abortus genotypes from disclosing isolates in the 387 herds involved in the epidemic. Clustering algorithms revealed the relatedness of many of these genotypes. Combined with epidemiological information on chronology of infection and geographic location, these genotype data helped to identify 7 clonal complexes which underpinned the outbreak over the defined period. Hyper-variability of some VNTR loci both within herds and individual animals led to detection of multiple genotypes associated with single outbreaks. However with dense sampling, these genotypes could still be associated with specific clonal complexes thereby permitting inference of epidemiological links. MLVA- based epidemiological monitoring data were congruent with an independent classical veterinary epidemiology study carried out in the same territory.ConclusionsMLVA is a useful tool in ongoing disease surveillance of B. abortus outbreaks, especially when combined with accurate epidemiological information on disease tracings, geographical clustering of cases and chronology of infection.

Characterisation of Brucella suis isolates from Southeast Europe by multi-locus variable-number tandem repeat analysis

Porcine brucellosis is a common bacterial zoonosis which can cause significant financial losses. Its diverse and often complicated factors have hampered efforts to control disease spread.The aim of the study was to assess the epidemiological situation of porcine brucellosis primarily in Croatia and its relationship to genotypes present in other, mostly European countries. One hundred and seven Brucella suis strains isolated from swine, hares, cattle, humans, wild hares, a wild boar and a mare originating mainly from Croatia (112), but also a few from Slovenia, Bosnia and Herzegovina, Serbia and Macedonia (15) were tested using classical microbiological testing, Bruce-ladder, RFLP, Multiplex-suis and genotyped using multi-locus variable-number tandem repeat analysis (MLVA).We determined 43 Brucella suis genotypes. Strains were grouped according to phylogenetic and geographic relationships, revealing both regional specificity and uniqueness and suggesting possible sources and modes of spread among animals. Our study also confirmed problems with Bruce19 locus that may hinder comparisons of new types with those in the international database.Forty-one novel genotypes were identified and deposited into the international database. Our study supports the idea of wild animals as a source of disease in domestic animals and also gives evidence to hypothesis of cross-border animal trafficking between former Yugoslavian countries. It also highlights the need to expand such research across more of southeast Europe, especially to countries with poorer social and economical situation in order to prevent a realistic outbreak and for better understanding of the biology of this pathogen.

Development of an improved competitive ELISA based on a monoclonal antibody against lipopolysaccharide for the detection of bovine brucellosis.

BackgroundBrucellosis is the most common bacterial zoonosis, and serological tests are routinely used in brucellosis control and eradication programs. In order to improve the accuracy of serological diagnostic method used in bovine brucellosis detection, this study developed an improved competitive ELISA with higher specificity and good sensitivity.ResultsThis study prepared 12 monoclonal antibodies against smooth Brucella lipopolysaccharide. One monoclonal antibody 3 F9, presented C epitope specificity, was used to develop a competitive ELISA for the serological detection of bovine brucellosis. The competitive ELISA, a commercial competitive ELISA kit, the rose-bengal plate agglutination test, and a microplate agglutination test were all used in the detection of 6 hyperimmune antisera against other commonly cross-reacted bacterial pathogens and 110 clinical bovine serum samples. The results of the test comparisons indicated that the competitive ELISA had higher specificity than the commercial competitive ELISA kit and RBT, and comparable sensitivity with the commercial ELISA kit.ConclusionsThis study provided a valuable detection tool with high specificity and good sensitivity, which prevent the wrong-culling of bovines in the eradication campaigns of bovine brucellosis.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-015-0436-3) contains supplementary material, which is available to authorized users.

Epidemiology of leptospira transmitted by rodents in southeast Asia.

BackgroundLeptospirosis is the most common bacterial zoonoses and has been identified as an important emerging global public health problem in Southeast Asia. Rodents are important reservoirs for human leptospirosis, but epidemiological data is lacking.Methodology/Principal FindingsWe sampled rodents living in different habitats from seven localities distributed across Southeast Asia (Thailand, Lao PDR and Cambodia), between 2009 to 2010. Human isolates were also obtained from localities close to where rodents were sampled. The prevalence of Leptospira infection was assessed by real-time PCR using DNA extracted from rodent kidneys, targeting the lipL32 gene. Sequencing rrs and secY genes, and Multi Locus Variable-number Tandem Repeat (VNTR) analyses were performed on DNA extracted from rat kidneys for Leptospira isolates molecular typing. Four species were detected in rodents, L. borgpetersenii (56% of positive samples), L. interrogans (36%), L. kirschneri (3%) and L. weilli (2%), which were identical to human isolates. Mean prevalence in rodents was approximately 7%, and largely varied across localities and habitats, but not between rodent species. The two most abundant Leptospira species displayed different habitat requirements: L. interrogans was linked to humid habitats (rice fields and forests) while L. borgpetersenii was abundant in both humid and dry habitats (non-floodable lands).Conclusion/Significance L. interrogans and L. borgpetersenii species are widely distributed amongst rodent populations, and strain typing confirmed rodents as reservoirs for human leptospirosis. Differences in habitat requirements for L. interrogans and L. borgpetersenii supported differential transmission modes. In Southeast Asia, human infection risk is not only restricted to activities taking place in wetlands and rice fields as is commonly accepted, but should also include tasks such as forestry work, as well as the hunting and preparation of rodents for consumption, which deserve more attention in future epidemiological studies.

Within-batch prevalence and quantification of human pathogenic Yersinia enterocolitica and Y. pseudotuberculosis in tonsils of pigs at slaughter

Yersiniosis is a common bacterial zoonosis in Europe and healthy pigs are known to be the primary reservoir of human pathogenic Yersinia enterocolitica and Y. pseudotuberculosis. However, little information is available about the prevalence of these pathogens within pig batches at time of slaughter. The tonsils of 7047 fattening pigs, belonging to 100 farms, were aseptically collected immediately after evisceration in two Belgian slaughterhouses. The batch size varied between 70 and 930 pigs. On average, 70 pigs were sampled per batch. The tonsils were examined by direct plating on cefsulodin–irgasan–novobiocin (CIN) agar plates and the number of suspect Yersinia colonies was counted. Pathogenic Y. enterocolitica serotype O:3 were found in tonsils of 2009 pigs (28.5%), originating from 85 farms. The within-batch prevalence in positive farms ranged from 5.1 to 64.4%. The number of Y. enterocolitica in positive pigs varied between 2.01 and 5.98log10CFUg−1 tonsil, with an average of 4.00log10CFUg−1 tonsil. Y. pseudotuberculosis was found in seven farms, for which the within-batch prevalence varied from 2 to 10%. In five of these farms, both Y. enterocolitica and Y. pseudotuberculosis were simultaneously present. Human pathogenic Yersinia spp. are widespread in slaughter pig batches in Belgium as 87% of the tested batches were infected with these pathogens at the time of slaughter. The large variation of the prevalence between batches may lead to different levels of contamination of carcasses and risks for public health.

Evaluation and Selection of Multilocus Variable-Number Tandem-Repeat Analysis Primers for Genotyping Brucella abortus Biovar 1 Isolated from Human Patients

ObjectivesBrucellosis is the most common bacterial zoonosis in the world. Multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) is a molecular method for genotyping bacterial species. Brucella abortus biovar I was isolated from most of the brucellosis-suspected patients in Korea. This study was conducted to investigate the ability of various MLVA primers that are used for molecular typing B. abortus isolates and for analyzing their epidemiological data. MethodsA total of 80 human isolates of B. abortus biovar I isolated from human patients and the reference strain were used for MLVA. Genetic diversity was determined by calculating the Simpson's diversity index (DI) of each VNTR locus. The Brucella strains were subcultured 30 times to determine the stability of each locus. The DNA of the strains cultivated in each passage was extracted and subjected to MLVA for further investigation. ResultsThe 15 VNTR loci were selected based on high DI values. The DIs of the 15 VNTR loci showed considerable discrimination power ranging from 59% for Bruce 43 to 87% for Bruce 22. Bruce 09, Bruce 11, Bruce 16, Bruce 42, and Bruce 43 were confirmed to remain stable in vitro among the 15 VNTR loci selected. ConclusionThe results of this study suggest that the five loci subsets may be a useful epidemiological tool for investigating B. abortus biovar 1 outbreak.

Pathological and molecular diagnosis of Brucella melitensis in the fetal and placental tissues of aborted ewes in Al-Najaf city

Brucellosis is one of the common bacterial zoonosis in the worldwide caused by organisms belong to the genus Brucella, However, animal Brucellosis is a serious problem worldwide and is endemic globally and disease of sexually matured animals and commonly transmitted to other animals by direct or indirect contact with infected animals or discharges such as: aborted fetuses, placental membranes or fluids. Fifty samples from internal organ of aborted fetus and the same number of aborted placenta were collected from aborted ewes positive to Rose Bengal test. For isolation and identification of Brucella from placenta and stomach contents , the standard procedures (Alton et al., 1988) were followed. The isolates were further confirmed by molecular techniques. The results showed that Br.melitensis was isolated from all animals that expressed Rose Bengal and serum agglutination test positive .The agglutination with monospecific A and M antisera were performed and these test revealed that the bacterial isolates expressed three Biovar as following ,Biovar 1(M,50%),Biovar 2 (A,26%) and Biovar 3 (0,24%). The number of this Biovar were varied according to collect area of the samples, high percentage (44%) was seen in the ALmanitherh ,,followed by AL Shabeka (30%) and AL Kuzweenah (26%) The results of PCR assay explained that 22 bacterial isolates showed a single amplified DNA product (44%) ,two bands at the level of 273 and 680 bp were seen in 8 isolates (16% ) and four bands at 273,680,750 and 850 bp were reported in 20 isolates(40%).

SAT0249 Novel cytotoxic T cell epitope in brucellosis-induced murine spondyloarthropathy

BackgroundBrucellosis is one of the most common bacterial zoonosis and causes significant human morbidity worldwide1. Osteoarticular complications are the most frequent clinical manifestations in patients2,3. However, pathophysiological and immune mechanisms...

Cytomorphological Changes and Inhibition of Inclusion Body Formation in Leptospira interrogans on Treatment with the Extracts of Adhatoda vasica

Leptospirosis is most common bacterial zoonosis worldwide, caused by spirochetes of the genus Leptospira that are transmitted from animals to humans. To treat leptospirosis, traditional healers use phytoremedy. In the present study, a scientific study was made on the plants used by the traditional healers to cure liver problems with symptoms of leptospirosis. Methanolic and ethanolic extracts of four plants were screened for antiLeptospiral activity. Of the four plants, Adhatoda vasica extracts exhibited a good anti-Leptospiral activity. On treatment of Leptospira interrogans culture with leaf extracts of the plant Adhatoda vasica, the cellular architechure of lengthy spirochaete L. interrogans was severely damaged. An electron microscopic observation showed breaks at different locations in the lengthy cell, and inhibition of the development of inclusion body responsible for virulence. The minimum inhibitory concentration of extracts was observed to be 5 mg/ml. The antiLeptospiral effect of A.vasica was compared with that of penicillin, and it was found that the medicine used by traditional healers to cure liver disorders has very effective inhibition activity over the microbe responsible for Leptospirosis. Hence, an alternate phytotheraphy can be recommended and the bioactive compound present in leaves of A.vasica has to be identified.

CD4+CD25+ T regulatory cells limit effector T cells and favor the progression of brucellosis in BALB/c mice

Brucellosis is one of the most common bacterial zoonoses worldwide. Infection is usually chronic and sometimes lifelong. Different mechanisms can be postulated as to the basis for the induction of the chronic status of brucellosis, but a comprehensive knowledge is still lacking. Here, we carried out a series of experiments in order to assess if the persistence of Brucella abortus could be ascribed to the effect of a down regulation of the immune response due to activity of regulatory T cells. We demonstrate that CD4 + CD25 + T regulatory cells are able to limit the effectiveness of CD4 + T cells and are able to favor the maintenance and the progression of B. abortus infection.

Design and influence of γ-irradiation on the biopharmaceutical properties of nanoparticles containing an antigenic complex from Brucella ovis

Despite vaccination campaigns, brucellosis is still one of the most common bacterial zoonosis in the world. This work describes the development of a novel formulation strategy to the delivery of the Brucella ovis antigenic extract (HS) into ovine mucosal surfaces. Thus, HS was entrapped in conventional and mannosylated poly(anhydride) nanoparticles by the solvent displacement method, and the resulting nanosystems were γ-irradiated to accomplish the sterilization required for the ophthalmic administration route. Sterilization, at either 10 kGy or 25 kGy, did not modify the size, morphology and antigen content of the nanoparticles. Similarly, the integrity and antigenicity of the entrapped antigen were not affected by γ-irradiation. The 25 kGy γ-irradiation dose seemed to influence negatively the HS release from the carriers. However, and in accordance with the Pearson's correlation, all the release patterns followed a similar tendency. Furthermore, the stability of the vaccine systems on lachrymal and nasal ovine fluids, showed that γ-irradiation had no significant effects on the vaccine systems. Since all the vaccine systems accomplished the pharmacopoeial biological tests required for γ-irradiation doses under 25 kGy, these results are highly suggestive for the use of HS loaded poly(anhydride) nanoparticles as an efficient vaccine delivery system for brucellosis immunoprophylaxis, especially for ophthalmic administration.

Optimization of pulse-field gel electrophoresis for Bartonella subtyping

Bartonella is a significant human pathogen and is the world's most common bacterial zoonosis acquired from companion animals. However, there is no uniform method for Pulse-Field Gel Electrophoresis (PFGE) for Bartonella population genetics studies. Further, some genes of Bartonella can mutate frequently and may affect the use of PFGE for Bartonella. Here we designed methods to solve these problems. We standardized the bacterial concentration, selected the appropriate digestion enzyme, optimized the electrophoretic parameters and characterized reproducibly two Bartonella species strains. Thus we optimized the PFGE procedure and determined how often Bartonella mutated. Our data shows a practical protocol for inter- and intra-species identification of Bartonella and was reproducible using two species strains that showed no mutation occurred after two passages for B. elizabethae; but mutation did occur in B. henselae.

Evaluation of Brucella MLVA typing for human brucellosis

Human brucellosis is still the most common bacterial zoonosis worldwide. Neither well-known molecular tools nor the classical biotyping methods are satisfactory for subtyping of Brucella spp. Loci containing Variable Number of Tandem Repeats (VNTRs) have recently proved their usefulness in typing strains from animal origin despite the high genetic homogeneity within the genus Brucella (DNA–DNA homology > 90%). The aim of this study was to evaluate MLVA (Multiple Locus VNTR Analysis) for diagnostic and epidemiological use in human brucellosis. One hundred and twenty-eight B. melitensis isolates of all three biovars were typed using eight minisatellite (panel 1) and eight microsatellite (panel 2) markers. One hundred and ten different genotypes were identified. The MLVA clustering pattern correlated with the geographic origin of the strains. Brucella strains isolated from different patients within the same outbreak or from the same patient before first-line therapy and after relapse showed identical genotypes. Fuchsin sensitive B. melitensis strains were found in closely related clusters giving evidence for an association between VNTRs and some phenotypic characteristics. However, the validity of biovars established by classical microbiological methods could not be confirmed by MLVA clustering. The original data can be queried on the genotyping web page at http://bacterial-genotyping.igmors.u-psud.fr. The MLVA assay is rapid, highly discriminatory, and reproducible within human Brucella isolates. MLVA can significantly contribute to epidemiological trace-back analysis of Brucella infections and may advance surveillance and control of human brucellosis.