scholarly journals The epidemiology of salmonella in calves: the role of markets and vehicles

1991 ◽  
Vol 107 (3) ◽  
pp. 521-525 ◽  
Author(s):  
C. Wray ◽  
N. Todd ◽  
I. M. McLaren ◽  
Y. E. Beedell
Keyword(s):  
Salmonella Typhimurium ◽  
Environmental Contamination ◽  
Phage Types ◽  
Salmonella Serotypes ◽  
Cleaning And Disinfection ◽  
Marketing Chain

SUMMARYEnvironmental contamination has been shown to be an important aspect of the epidemiology of salmonellosis in calves. Markets and transport vehicles are important links in the calf marketing chain and these were investigated to determine the level of salmonella contamination.Salmonellas were isolated from 7 of the 14 markets surveyed, with 31 of 838 samples (3.7%) being positive. Nine different salmonella serotypes, of which the commonest was Salmonella typhimurium, were isolated. Four different phage types of S. typhimurium were detected, the commonest being DT204C.Salmonellas were isolated from 22 of the 107 vehicles (20.6%) examined before washing and from 4 of the 62 vehicles (6.5%) examined after cleaning. Twelve different salmonella serotypes were isolated, of which the most frequent was S. typhimurium. The commonest of the six different S. typhimurium phage types was DT204C.These results indicate that improved cleaning and disinfection routines both for vehicles and markets are necessary to control salmonellosis in calves.

scholarly journals The epidemiology of salmonella infection of calves: the role of dealers

1990 ◽  
Vol 105 (2) ◽  
pp. 295-305 ◽  
Author(s):  
C. Wray ◽  
N. Todd ◽  
I. McLaren ◽  
Y. Beedell ◽  
B. Rowe
Keyword(s):  
Salmonella Typhimurium ◽  
Profile Analysis ◽  
Phage Type ◽  
Plasmid Profile ◽  
Salmonella Infection ◽  
Plasmid Profiles ◽  
Salmonella Serotypes ◽  
Cleaning And Disinfection ◽  
Marketing Chain

SUMMARYSalmonellas were detected in the environment of 10 of the 12 calf dealers' premises studied. The cleaning and disinfection routines were often ineffective and salmonellas were isolated from 7·6 % and 5·3 % of the wall and floor samples before disinfection and 6·8% and 7·6% afterwards. Eight different salmonella serotypes were detected, of which the commonest wereSalmonella typhimurium, predominantly phage type DT204C, andS. dublin. Plasmid profiles were used to fingerprintS. typhimuriumDT204C and the results indicated that with the exception of one of the premises, prolonged salmonella-persistence in the environment was not occurring.Three separate epidemics of salmonellosis in calves were studied by use of plasmid profile analysis. The results illustrated the role of dealers, and their subcontractors, in the dissemination of salmonellas. The study concludes with suggestions for methods to reduce the spread of salmonellas in the calf marketing chain.

scholarly journals Recognition of the cryptic plasmid, pSLT, by restriction fingerprinting and a study of its incidence in Scottish salmonella isolates

1986 ◽  
Vol 97 (2) ◽  
pp. 193-197 ◽  
Author(s):  
D. J. Brown ◽  
D. S. Munro ◽  
D. J. Platt
Keyword(s):  
Salmonella Typhimurium ◽  
Restriction Enzymes ◽  
Cryptic Plasmid ◽  
Present Evidence ◽  
Phage Types ◽  
Salmonella Serotypes

SummaryThe plasmid pSLT is a cryptic plasmid of 60 megadaltons (Md) present inSalmonella typhimuriumLT2. We present evidence that it has a characteristic fingerprint when digested with the restriction enzymesPstIandSmaI. Among a representative collection ofS. typhimuriumisolates it was present in 67% of strains and was widely distributed amongst different phage types (DT) with the exception of DT10 and U285. Furthermore, its prevalence among veterinary isolates was significantly higher than among human isolates. It was not found among any of the 96 strains representative of other salmonella serotypes currently prevalent and thus appears to be serotype-specific.

scholarly journals Recent trends in human salmonellosis in England and Wales: the epidemiology of prevalent serotypes other than Salmonella typhimurium

1974 ◽  
Vol 72 (2) ◽  
pp. 185-195 ◽  
Author(s):  
J. A. Lee
Keyword(s):  
Salmonella Typhimurium ◽  
Strong Evidence ◽  
Poultry Products ◽  
Salmonella Infections ◽  
Threefold Increase ◽  
Human Salmonellosis ◽  
Recent Trends ◽  
Salmonella Serotypes ◽  
Animal Reservoirs

SUMMARYIn the period 1960–70 meat and poultry products caused over 70% of successfully investigated outbreaks of human salmonellosis. The number of human incidents of salmonellosis declined from 1960 to 1966, but then more than doubled between 1966 and 1971. This increase was mainly due to a threefold increase of incidents of salmonella serotypes other than Salmonella typhimurium. The serotypes which increased most and contributed significantly to this trend were S. enteritidis, S. panama, S. Stanley, S. virchow, S. Agona, S. 4,12:d:- and S. indiana.Strong evidence exists that these serotypes have a path of infection from animal feedingstuffs to the pig and poultry animal reservoirs to pork and poultry foods to man. Cattle appear to be a less important source than pigs and poultry and this may be because the nature and content of their feed is different.The importance of the control of the pig and poultry reservoirs of salmonella infections is stressed and a significant role of animal feedingstuffs in the maintenance of these reservoirs strongly suggested.

The role of a stress-response protein in Salmonella typhimurium virulence

1991 ◽  
Vol 5 (2) ◽  
pp. 401-407 ◽  
Author(s):  
K. Johnson ◽  
I. Charles ◽  
G. Dougan ◽  
D. Pickard ◽  
P. O'Gaora ◽  
...  
Keyword(s):  
Stress Response ◽  
Salmonella Typhimurium

sRNA STnc150 is involved in virulence regulation of Salmonella Typhimurium by targeting fimA mRNA

2021 ◽  
Vol 368 (18) ◽  
Author(s):  
Jing Li ◽  
Na Li ◽  
Chengcheng Ning ◽  
Yun Guo ◽  
Chunhui Ji ◽  
...  
Keyword(s):  
Salmonella Typhimurium ◽  
Target Genes ◽  
Reporter System ◽  
Stem Loop ◽  
Viral Loads ◽  
Virulence Regulation ◽  
Stem Loop Structure ◽  
Complementary Strain

ABSTRACT Small RNAs (sRNAs) are essential virulent regulators in Salmonella typhimurium (STM). To explore the role of sRNA STnc150 in regulating STM virulence, we constructed a STnc150 deletion strain (ΔSTnc150) and its complementary strain (ΔSTnc150/C). Then, we compared their characteristics to their original parent strain experimentally, identified the target genes of STnc150 and determined the expression levels of target genes. The results showed that the ΔSTnc150 strain exhibited delayed biofilm formation, enhanced adhesion to macrophages, significantly reduced LD50, increased liver and spleen viral loads and more vital pathological damaging ability than its parent and complementary strains. Further, bioinformatics combined with the bacterial dual plasmid reporter system confirmed that the bases 72–88 of STnc150 locating at the secondary stem-loop structure of the STnc150 are complementary with the bases 1–19 in the 5′-terminal of fimA mRNA of the type 1 fimbriae subunit. Western blot analysis showed that fimA protein level was increased in STnc150 strain compared with its parent and complementary strains. Together, this study suggested that STnc150 can down-regulate STM fimA expression at the translation level, which provided insights into the regulatory mechanisms of sRNAs in virulence of STM.

scholarly journals The role of phagocytosis-dependent activation of TFEB in the clearance of salmonella

2021 ◽  
Author(s):  
Erika Ospina Escobar
Keyword(s):  
Transcription Factor ◽  
Salmonella Typhimurium ◽  
Nuclear Translocation ◽  
Steady Increase ◽  
Phagosome Maturation ◽  
Salmonella Infection ◽  
Complex Interplay ◽  
Transcription Factor Eb ◽  
Insight Into

During phagocytosis, macrophages engulf and sequester pathogens into phagosomes. Phagosomes then fuse with acidic and degradative lysosomes to degrade the internalized pathogen. We previously demonstrated that phagocytosis of IgG-opsonized particles and non-opsonized E.coli causes activation of the Transcription Factor EB (TFEB), which enhances the expression of lysosomal genes, increases the degradative capacity of lysosomes and boosts bactericidal activity. However, pathogens like Salmonella typhimurium have evolved mechanisms to evade and/or alter phagosome maturation to promote their own survival. We investigated: i) whether pathogens like Salmonella can alter TFEB activation and ii) whether phagocytosis-dependent activation of TFEB can counteract the pathogenicity of microorganisms. Here, we show that non-viable (heat-killed) S. typhimurium, pathogenic (EHEC and UPEC) and non-pathogenic E.coli (DH5α) all caused TFEB nuclear translocation in RAW macrophages, while strikingly live S. typhimurium maintained TFEB in the cytosol in the first hours post-infection. By contrast, Salmonella mutants for ΔsifA, ΔsopD2, ΔphoP all triggered TFEB activation in the first hour of infection. However, Salmonella infection eventually triggered a steady increase in nuclear TFEB after 4 h of infection, suggesting a more complex interplay between TFEB and Salmonella infection. We dissected the importance of TFEB activation towards Salmonella survivability by pre-activating TFEB before infection within WT macrophages and macrophages with a CRISPR-based deletion of TFEB. Our work suggests that Salmonella actively interferes with TFEB signaling in order to enhance its own survival. These results could provide insight into using TFEB as a target for the clearance of infections.

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