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58 Cards in this Set
- Front
- Back
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What are the 2 subspecies of Salmonella? |
S. bongori subsp. V and S. enterica |
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What are the 3 main Salmonella serotypes? |
S. typhimurium, S. dublin, S. enteritidis |
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What family is Salmonella in? |
Enterobacteriaceae |
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Is Salmonella gram-negative or gram-positive? |
Gram-negative |
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Does Salmonella form spores? |
no |
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Are Salmonella aerobes or anaerobes? |
facultative anaerobes |
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What 2 habitats do Salmonella have? |
GIT of humans and environment |
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What does NTS stand for? |
non-typhoidal Salmonella |
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How many serovars of Salmonella are known? |
2500 |
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What percentage of outbreaks is Salmonella responsible for between 2004-2009? |
85% |
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What are the 3 steps of Salmonella infection? |
Ingestion of contaminated food/water, passage through digestive system and invasion of intestinal epithelia, subsequent passage to vasculature system can lead to systematic infection |
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Which two Salmonellas are responsible for the majority of salmonellosis cases? |
S. enteritidis and S. typhimurium |
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How many defined serotypes of Salmonella are there? |
2610 |
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How many cases of Salmonellosis are there worldwide? |
1.3 billion |
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How many deaths are estimated worldwide? |
3 million |
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How long does it take to get results from traditional culture methods? |
up to 5 days |
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What kind of a pathogen is Salmonella? |
Zoonotic |
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What 2 measures aid animal health and food safety? |
On-farm biosecurity and proper storage and use of animal excreta as a fertilizer |
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What causes difficulty stopping disease from Salmonella? |
Ability to interact with and persist in the environment between animal hosts, changes in geno- and phenotype |
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What introduces new bacterial strains into countries? |
International trade in food and food animals |
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What helps Salmonella adapt? |
sigma factors allow for differential gene expression via RNA polymerase |
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How does Salmonella survive environmental changes? |
some sigma factors direct expression of stress proteins which allow bacterium to survive environmental changes |
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What is RpoS? |
RNA polymerase S, produced in response to starvation, changes in pH and temp. |
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What kind of strain is Salmonella? |
mutator strain |
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What did a heat map show about Salmonella? |
a diverse phenotype among isolates |
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What explains under-cooked contaminated foods are an important vehicle of infection? |
Shifting temp from 20 to 45*C changes Salmonella's acid and heat tolerance |
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What special abilities does Salmonella have? |
ability to colonise intestines, invade tissues, to be found inside eggs |
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What causes S. enteritidis to enter eggs? |
unknown, stress may have role |
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How are Salmonella infected eggs prevented in Ireland? |
Laying flocks screened for Salmonella and any positive flocks are slaughtered |
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What role does adrenaline play in infection? |
Promotes uptake of iron which is needed for bacterial survival |
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What 6 factors does the infectious dose of Salmonella depend on? |
degree of host resistance, age extremes, immuno-suppressive illness, bacterial numbers in contaminated food, nature of food matrix, physiological status of bacterial cells |
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Why does Salmonella survive transit through gastric barrier? |
Pre-exposed to sub-lethal conc of acids |
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What has a protective effect? |
High fat content in food matrix |
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What is the typical infectious dose of Salmonella? |
10^6 - 10^8 CFU |
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What 3 control measures are used on food to prevent Salmonella growth? |
refrigeration, treatments designed to lower pH or Aw |
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Where and when was the Salmonella Ealing? |
1985 in UK |
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What was the estimated cost of the Salmonella Ealing outbreak? |
£50M |
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What caused the Salmonella Ealing outbreak? |
Entered in raw milk from infected local cow herd, contamination linked to spray dryer in factory |
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Where and when was the Salmonella Anatum outbreak? |
UK and France in 1996/1997 |
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Who was affected by the Salmonella Anatum outbreak? |
young children |
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What is the doubling time of Salmonella? |
20-24mins |
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How long are D-values of Salmonella at 60*C? |
very short (<0.3min), suggests isolates couldn't survive pasteurisation during PIF manufacturing |
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How long are D-values of Salmonella at pH 2? |
Also short <1.4min |
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How long are D-values of Salmonella at pH 3? |
Much longer 20-80mins |
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Why can salmonella survive in infants stomach? |
Infants stomach pH is 4-5 and doubling can still occur |
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How many Salmonella isolates are motile and non-motile? |
47 motile, 3 non-motile |
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What is different about planktonic cells? |
no resistance to biocides |
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What does a biofilm cause? |
More resistance to biocides |
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What effect do bile salts have on Salmonella? |
very little effect on growth, may survive exposure in intestines |
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What food showed good growth of Salmonella? |
infant formula milk, reconstitution could have increased rapidly |
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What happens to Salmonella in the bloodstream? |
May be phagocytosed by macrophages, may persist, proliferate and travel to other parts of the body |
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How long did Salmonella survive in murine macrophages? |
over 72 hours |
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How does survival in macrophages increase virulence? |
will prevent clearance and increase chance of systemic infection |
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How many S. Agona isolates were reported by the Irish National Salmonella Reference Laboratory at July 15? |
6 |
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How many cases of S. Agona were reported in the UK July 17th? |
47 |
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What was the new phage type found in UK July 17? |
phage type 39 |
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What happened July 18? |
International outbreak declared |
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How many total cases of S. Agona were there from 1st week of April - 1st week August?
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161 (11 in Ireland) |
