Search results for "bacteria."
showing 10 items of 4757 documents
Evaluation of a modified single-enzyme amplified fragment length polymorphism (SE-AFLP) technique for subtyping Salmonella enterica serotype Enteriti…
2006
Salmonella enterica subsp. enterica serotype Enteritidis is not readily subtyped beyond the level of phage type (PT). Pulsed field gel electrophoresis (PFGE) is generally acknowledged to be the most discriminating typing method for Salmonella, but only a restricted variety of PFGE types has been described for S. enterica serotype Enteritidis. In the present study, a modification of the SE-AFLP typing method was used to investigate both outbreak and apparently sporadic isolates of S. enterica serotype Enteritidis belonging to different PTs and/or PFGE types. The method proved to be as discriminatory as PFGE when combined with phage typing, and provided subtyping data consistent with epidemio…
Epidemiological analysis of Salmonella enterica from beef sampled in the slaughterhouse and retailers in Dakar (Senegal) using pulsed-field gel elect…
2007
Seventy-eight isolates of Salmonella spp. isolated from beef sampled from the official city slaughterhouse and from retailers in Dakar, Senegal were analyzed using serotyping, antimicrobial testing and macrorestriction profiling by Pulsed-Field Gel Electrophoresis (PFGE). These analyses were done to identify clonal relationships and potential transmission routes in beef channel. XbaI macrorestriction allowed defining 17 genotypes among the six main analyzed serotypes: Salmonella bredeney (3 genotypes), S. muenster (6), S. waycross (1), S. corvallis (3), S. kentucky (1) and S. brandenburg (3). The cross analysis of PFGE profiles and origin of the beef samples reveals a wide range of contamin…
Distribution and characteristics of Listeria monocytogenes isolates from surface waters of the South Nation River Watershed, Ontario, Canada
2007
ABSTRACT Listeria monocytogenes is a facultative intracellular pathogen thought to be widely distributed in the environment. We investigated the prevalence and characteristics of L. monocytogenes isolates from surface waters derived from catchments within the South Nation River watershed (Ontario, Canada). This watershed is dominated by urban and rural development, livestock and crop production, and wildlife habitats. From June to November 2005, a total of 314 surface water samples were collected biweekly from 22 discrete sampling sites characterized by various upstream land uses. Presumptive Listeria spp. were isolated using a selective enrichment and isolation procedure, and 75 L. monocyt…
Prevalence and antibiotic-resistance of Salmonella isolated from beef sampled from the slaughterhouse and from retailers in Dakar (Senegal)
2005
A study was made of Salmonella contamination in beef sampled from a slaughterhouse and from retailers in Dakar, Senegal. The serotypes as well as antibiotic-resistance patterns of the Salmonella isolates were determined. A total of 435 meat samples (236 from the slaughterhouse, 199 from retailers) were tested. Among them, 275 (63%) were positive for Salmonella, 43% (101/236) from the slaughterhouse and 87% (174/199) from the retailers. Furthermore, 97% of the investigated retailers had at least one beef sample contaminated by Salmonella. The 286 Salmonella isolates were divided into 51 serotypes. The most prevalent serotypes were Salmonella bredeney (25%), S. muenster (8%), S. waycross (7%)…
An indirect immunofluorescent antibody technique for detection and enumeration of Vibrio vulnificus serovar E (biotype 2): delevopment and applicatio…
2000
The applications of an indirect fluorescent antibody technique (IFAT), developed to detect and enumerate the pathogenic bacterium Vibrio vulnificus serovar E from water and clinical samples, are described. This technique proved accurate for detecting V. vulnificus, even under starvation conditions and in the non-culturable state, and could differentiate this species from other bacteria which share the same habitats. The IFAT was successfully used to diagnose vibriosis from naturally- and artificially-infected eels. The overall data suggest that applying this technique properly in environmental and epidemiological/epizootiological studies could significantly increase our knowledge of this ba…
Host-Nonspecific Iron Acquisition Systems and Virulence in the Zoonotic Serovar of Vibrio vulnificus
2014
ABSTRACT The zoonotic serovar of Vibrio vulnificus (known as biotype 2 serovar E) is the etiological agent of human and fish vibriosis. The aim of the present work was to discover the role of the vulnibactin- and hemin-dependent iron acquisition systems in the pathogenicity of this zoonotic serovar under the hypothesis that both are host-nonspecific virulence factors. To this end, we selected three genes for three outer membrane receptors ( vuuA , a receptor for ferric vulnibactin, and hupA and hutR , two hemin receptors), obtained single and multiple mutants as well as complemented strains, and tested them in a series of in vitro and in vivo assays, using eels and mice as animal models. Th…
Protocol for Specific Isolation of Virulent Strains of Vibrio vulnificus Serovar E (Biotype 2) from Environmental Samples
2004
ABSTRACT The eel pathogen Vibrio vulnificus biotype 2 comprises at least three serovars, with serovar E being the only one involved in both epizootics of eel vibriosis and sporadic cases of human infections. The virulent strains of this serovar (VSE) have only been recovered from clinical (mainly eel tissue) sources. The main objective of this work was to design and validate a new protocol for VSE-specific isolation from environmental samples. The key element of the new protocol is the broth used for the first step (saline eel serum broth [SEB]), which contains eel serum as a nutritive and selective component. This approach takes advantage of the ability of VSE cells to grow in eel serum an…
A method to diagnose the carrier state of Vibrio vulnificus serovar E in eels: Development and field studies
2006
Abstract The pathogen Vibrio vulnificus serovar E (VSE) has been related to both human infections and to epizootics causing high mortality in brackish water eel farms. To control the spread of the eel vibriosis and prevent VSE transmission to humans we designed and tested a protocol to detect carriers, which involves isolating the pathogen. To identify the organs where VSE persists in survivors we infected eels with different degrees of immunity against the pathogen (non-immune [NI], immune [I, eels vaccinated 1 year before] and freshly vaccinated [V]) by bath challenge. Then, we followed the pathogen survival in selected external and internal organs for 72 h post-infection. VSE was isolate…
Efficacy of a bivalent vaccine against eel diseases caused by Vibrio vulnificus after its administration by four different routes
2003
Vulnivaccine, a vaccine against vibriosis caused by Vibrio vulnificus serovar E (formerly biotype 2), confers acceptable levels of protection to eels after its administration by prolonged immersion in three doses. Recently, a new pathogenic serovar, named serovar A, has been isolated from vaccinated eels in a Spanish freshwater eel farm. The main objective of this work was to design a bivalent vaccine, and to study its effectiveness against the two pathogenic serovars. With this aim, eels weighing around 20 g were immunised with the bivalent vaccine by oral and anal intubation, intraperitoneal injection (i.p.) and prolonged immersion. The overall results indicated that: (i) the new vaccine …
Serotyping and genotyping of encapsulated Escherichia coli K1 sepsis isolates with a monoclonal IgG anti K1 antibody and K1 gene probes
1987
Among infectious diseases caused by E. coli the capsular type K1 plays a predominant role. E. coli K1 isolates account for 80% of cases of E. coli neonatal meningitis and 30% of E. coli sepsis strains. Serotyping of K1 strains has conventionally relied upon the use of K1-specific bacteriophages or serum agar methods with polyvalent anti K1 serum. In the study present here, 187 E. coli sepsis isolates have been analysed for production of the K1 antigen using K1 phages, K1 serum agar plates and Latex agglutination and ELISA using an IgG2a anti K1 monoclonal antibody. In total, 33 sepsis isolates (about 18%) were identified as K1 positive, with three of these strains proving negative in all te…