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Which Yersinia species has acquired additional plasmid DNA to enable colonization and transmission via the flea vector and survival in blood?
Which Yersinia species has acquired additional plasmid DNA to enable colonization and transmission via the flea vector and survival in blood?
What is the type of secretion system found in all pathogenic Yersinia?
What is the type of secretion system found in all pathogenic Yersinia?
What property has Y.pestis lost in order to enable colonization of mammalian host?
What property has Y.pestis lost in order to enable colonization of mammalian host?
Which of the following is NOT a characteristic of Y.pestis?
Which of the following is NOT a characteristic of Y.pestis?
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What is the name of the publication that discusses the pathogenesis, epidemiology, and antibiotic resistance of Salmonella?
What is the name of the publication that discusses the pathogenesis, epidemiology, and antibiotic resistance of Salmonella?
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Which of the following publications discusses the phenotypic adaptation of Yersinia to distinct niches within mammalian tissues?
Which of the following publications discusses the phenotypic adaptation of Yersinia to distinct niches within mammalian tissues?
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What is the title of the publication that discusses the evolution, virulence determinants, immune subversion, vaccination, and diagnostics of Yersinia pestis?
What is the title of the publication that discusses the evolution, virulence determinants, immune subversion, vaccination, and diagnostics of Yersinia pestis?
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Which of the following is NOT a reference for further reading?
Which of the following is NOT a reference for further reading?
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What is the optimum temperature for the growth of Salmonella, Klebsiella, and Enterobacter?
What is the optimum temperature for the growth of Salmonella, Klebsiella, and Enterobacter?
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What is the characteristic of the flagella in Salmonella, Klebsiella, and Enterobacter?
What is the characteristic of the flagella in Salmonella, Klebsiella, and Enterobacter?
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What is the range of G+C content in the genome of Salmonella, Klebsiella, and Enterobacter?
What is the range of G+C content in the genome of Salmonella, Klebsiella, and Enterobacter?
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What is the characteristic of the nitrate reductase enzyme in Salmonella, Klebsiella, and Enterobacter?
What is the characteristic of the nitrate reductase enzyme in Salmonella, Klebsiella, and Enterobacter?
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What is the common habitat of Salmonella, Klebsiella, and Enterobacter?
What is the common habitat of Salmonella, Klebsiella, and Enterobacter?
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What is the characteristic of the lactose fermentation in Salmonella?
What is the characteristic of the lactose fermentation in Salmonella?
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What is the characteristic of the indole test in Salmonella?
What is the characteristic of the indole test in Salmonella?
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What is the characteristic of the serovars of Salmonella?
What is the characteristic of the serovars of Salmonella?
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What is the primary characteristic of XLD media and SS media?
What is the primary characteristic of XLD media and SS media?
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What is the approximate number of deaths caused by typhoid fever each year?
What is the approximate number of deaths caused by typhoid fever each year?
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What is the primary difference between typhoid fever and enteric fever?
What is the primary difference between typhoid fever and enteric fever?
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What is the approximate number of foodborne cases of non-typhoid Salmonella each year?
What is the approximate number of foodborne cases of non-typhoid Salmonella each year?
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What is the primary cause of invasive non-typhoid Salmonella (iNTS) in regions with immunocompromised individuals?
What is the primary cause of invasive non-typhoid Salmonella (iNTS) in regions with immunocompromised individuals?
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What is the characteristic of the typhoid state in typhoid fever?
What is the characteristic of the typhoid state in typhoid fever?
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What is the primary source of non-typhoid Salmonella in the UK?
What is the primary source of non-typhoid Salmonella in the UK?
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What is the name of the media used to detect Shigella?
What is the name of the media used to detect Shigella?
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What is the consequence of the lysis of Y. pestis bacteria?
What is the consequence of the lysis of Y. pestis bacteria?
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How does Yersinia enter the host?
How does Yersinia enter the host?
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What is the site of Yersinia colonization and establishment?
What is the site of Yersinia colonization and establishment?
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What is the mode of transmission of pneumonic plague?
What is the mode of transmission of pneumonic plague?
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What is the fate of Yersinia in macrophages?
What is the fate of Yersinia in macrophages?
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What is the common pathway of host entry for all pathogenic Yersinia?
What is the common pathway of host entry for all pathogenic Yersinia?
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What is the percentage of elderly individuals with asymptomatic bacteriuria?
What is the percentage of elderly individuals with asymptomatic bacteriuria?
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Which of the following is NOT a type of UTI?
Which of the following is NOT a type of UTI?
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What is the percentage of people who have the P blood group antigen?
What is the percentage of people who have the P blood group antigen?
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What is the mechanism by which UPEC is propelled into the bladder during infection?
What is the mechanism by which UPEC is propelled into the bladder during infection?
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What is the name of the fimbriae that must bind to the P blood group antigen for UPEC infection to occur?
What is the name of the fimbriae that must bind to the P blood group antigen for UPEC infection to occur?
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What is the typical location of UPEC in healthy individuals?
What is the typical location of UPEC in healthy individuals?
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What is the consequence of periurethral contamination with UPEC?
What is the consequence of periurethral contamination with UPEC?
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What is the name of the bacteria associated with meningitis?
What is the name of the bacteria associated with meningitis?
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All pathogenic Yersinia species have a type 4 secretion system.
All pathogenic Yersinia species have a type 4 secretion system.
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Y.pestis has gained motility and cell adhesive properties to enable colonization of mammalian host.
Y.pestis has gained motility and cell adhesive properties to enable colonization of mammalian host.
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The type 3 secretion system (T3SS) is only found in Y.pestis.
The type 3 secretion system (T3SS) is only found in Y.pestis.
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Y.pestis has lost the ability to survive in blood.
Y.pestis has lost the ability to survive in blood.
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Davis (2018) discussed the pathogenesis, epidemiology, and antibiotic resistance of Salmonella.
Davis (2018) discussed the pathogenesis, epidemiology, and antibiotic resistance of Salmonella.
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Eng et al. (2015) discussed the evolution, virulence determinants, immune subversion, vaccination, and diagnostics of Yersinia pestis.
Eng et al. (2015) discussed the evolution, virulence determinants, immune subversion, vaccination, and diagnostics of Yersinia pestis.
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Octavia and Lan (2014) discussed the pathogenesis, epidemiology, and antibiotic resistance of Yersinia.
Octavia and Lan (2014) discussed the pathogenesis, epidemiology, and antibiotic resistance of Yersinia.
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Croxen et al. (2013) discussed the phenotypic adaptation of Yersinia to distinct niches within mammalian tissues.
Croxen et al. (2013) discussed the phenotypic adaptation of Yersinia to distinct niches within mammalian tissues.
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E. coli is a major cause of CNS infections in infants older than 1 month.
E. coli is a major cause of CNS infections in infants older than 1 month.
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80% of E. coli strains involved in CNS infections synthesize K-2 capsular antigens.
80% of E. coli strains involved in CNS infections synthesize K-2 capsular antigens.
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Intestinal pathogenic E. coli is a common cause of urinary tract infections in the UK.
Intestinal pathogenic E. coli is a common cause of urinary tract infections in the UK.
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ETEC is typically associated with severe bloody diarrhoea.
ETEC is typically associated with severe bloody diarrhoea.
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EPEC is a common cause of vomiting, abdominal pain, and fever in children.
EPEC is a common cause of vomiting, abdominal pain, and fever in children.
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All pathotypes of intestinal pathogenic E. coli can cause haemolytic uraemic syndrome (HUS).
All pathotypes of intestinal pathogenic E. coli can cause haemolytic uraemic syndrome (HUS).
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The formation of ulcers is a characteristic of the 1st phase of typhoid fever.
The formation of ulcers is a characteristic of the 1st phase of typhoid fever.
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The global burden of non-typhoid Salmonella is approximately 50 million cases each year.
The global burden of non-typhoid Salmonella is approximately 50 million cases each year.
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Shigella grows on XLD media and produces a yellow color.
Shigella grows on XLD media and produces a yellow color.
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The primary difference between typhoid fever and enteric fever is the severity of the disease.
The primary difference between typhoid fever and enteric fever is the severity of the disease.
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Salmonella Enteritidis is the most common serovar of non-typhoid Salmonella in the UK.
Salmonella Enteritidis is the most common serovar of non-typhoid Salmonella in the UK.
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The typhoid state is characterized by a coma or muttering delirium.
The typhoid state is characterized by a coma or muttering delirium.
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The approximate number of deaths caused by typhoid fever each year is 1.5%.
The approximate number of deaths caused by typhoid fever each year is 1.5%.
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Invasive non-typhoid Salmonella (iNTS) is a common cause of disease in healthy individuals.
Invasive non-typhoid Salmonella (iNTS) is a common cause of disease in healthy individuals.
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The T3SS is only found in Shigella.
The T3SS is only found in Shigella.
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The family Yersniaceae has a G+C content of 47% and a genome size of 5 Mbp.
The family Yersniaceae has a G+C content of 47% and a genome size of 5 Mbp.
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The Enterobacteriaceae family has an optimum temperature of 28-29°C.
The Enterobacteriaceae family has an optimum temperature of 28-29°C.
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The SHI-1 chromosomal factor in Shigella codes for siderophores.
The SHI-1 chromosomal factor in Shigella codes for siderophores.
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The Stx-phage p27 in Shigella codes for a type 3 secretion system.
The Stx-phage p27 in Shigella codes for a type 3 secretion system.
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The genus Yersinia is part of the Enterobacteriaceae family.
The genus Yersinia is part of the Enterobacteriaceae family.
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The oxidation of nitrate is negative in the Enterobacteriaceae family.
The oxidation of nitrate is negative in the Enterobacteriaceae family.
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All members of the Enterobacteriaceae family are motile via peritrichous flagella.
All members of the Enterobacteriaceae family are motile via peritrichous flagella.
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The infectious dose of EHEC/STEC is higher than that of EPEC.
The infectious dose of EHEC/STEC is higher than that of EPEC.
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Shigella sonnei is the most severe cause of epidemics.
Shigella sonnei is the most severe cause of epidemics.
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EPEC and EHEC/STEC have the same site of damage in the body.
EPEC and EHEC/STEC have the same site of damage in the body.
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Phylogenetic typing shows that Shigella spp. and E. coli are closely related.
Phylogenetic typing shows that Shigella spp. and E. coli are closely related.
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EHEC/STEC exports its own receptor called Tir.
EHEC/STEC exports its own receptor called Tir.
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The treatment for EPEC infection typically involves antibiotics.
The treatment for EPEC infection typically involves antibiotics.
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Shigella flexneri is the most severe cause of Shigella infections.
Shigella flexneri is the most severe cause of Shigella infections.
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The toxins produced by EHEC/STEC include proteases.
The toxins produced by EHEC/STEC include proteases.
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Study Notes
Yersinia Virulence Factors
- Type 3 secretion system (T3SS) is found in all pathogenic Yersinia.
- Y.pestis has acquired additional plasmid DNA that enables: • Colonization and transmission via the flea vector • Survival in blood • Lost motility and cell adhesive properties to enable colonization of mammalian host
Enterobactericeae: Common Aspects
- Optimum temperature: 37°C
- Gram-negative, non-spore forming rods
- Facultative anaerobes
- Catalase positive, oxidase negative, nitrate reductase positive
- G+C content: 38-60%, genome size: ~5 Mbp
- Motile via peritrichous flagella (a few exceptions)
- Habitats: gastrointestinal tract of hosts, including humans, animals, and insects
- Widespread contamination of environment: sewage, soil, water, plants, and food
- Routes of infection: oral, via wounds, urinary tract, and respiratory tract
- Disease patterns: diarrhea, sepsis, urinary tract, CNS, and brain
Genus Salmonella
- Classification of Salmonella species is complex
- 2 species, 7 subspecies, and >2,600 serovars
- Some serovars are host-restricted (e.g., Typhi, human; Abortusovis, sheep)
- Most serovars infect a wide range of hosts (e.g., Typhimurium)
Genus Salmonella: General Characteristics
- Non-lactose fermenter (E. coli ferments lactose, but Shigella does not)
- Indole test negative (E. coli positive, Shigella variable)
- Various selective media can distinguish Salmonella from E. coli/Shigella by: • H2S production • Acid production during carbohydrate fermentation • XLD media, SS media
Typhoidal Salmonella: Impact and Disease
- Typhoid fever (S. Typhi): ~15 million new cases each year, with about 1% deaths
- 1st phase: slow fever, rose spots, mild, bacteremia
- 2nd phase: organism reaches gallbladder, formation of ulcers, hemorrhage, death (20%)
- Typhoid state: “muttering delirium” or “coma vigil” (picking at bedclothes and imaginary objects)
Non-Typhoid Salmonella (NTS): Impact
- Global burden: ~94 million cases (155,000 deaths) each year, of which about 80 million were estimated as foodborne origin
- UK data: 8-9,000 confirmed cases per year
- Predominant serovars: Salmonella Enteritidis, Salmonella Typhimurium, Salmonella Heidelberg, Salmonella Newport
- NTS causes self-limiting enteritis in healthy individuals
- Can be invasive (iNTS) in regions with immunocompromised/malnourished individuals (e.g., in sub-Saharan Africa)
Mechanism of UPEC Infection
- Intestine of healthy individuals contains UPEC
- Periurethral contamination with UPEC can occur after a bowel movement or be propelled into the bladder during sexual intercourse
- For infection, P fimbriae must bind to the P blood group antigen, which is found in 99% of people (D-galactose-D-galactose)
Yersinia
- Yersinia use M cells to enter the host but remain extracellular on macrophages
- Despite different routes of host entry, all pathogenic Yersinia cross the epithelial barrier
- Yersinia does this via M (microfold) cells, specialized epithelial cells of mucosal-associated lymphoid tissue (MALT)
- Yersinia quickly traffics to lymph nodes or tissues and establishes itself
- Yersinia spreads systematically by accessing the bloodstream and colonizing deep tissue sites, such as liver and spleen
Yersinia Virulence Factors
- Type 3 secretion system (T3SS) is found in all pathogenic Yersinia.
- Y.pestis has acquired additional plasmid DNA that enables colonization and transmission via the flea vector and survival in blood, but has lost motility and cell adhesive properties.
Salmonella
Typhoidal Salmonella
- Typhoid fever (S.Typhi) affects ~15 million people each year, with a 1% death rate.
- The disease has two phases:
- 1st phase: slow fever, rose spots, mild, bacteremia.
- 2nd phase: organism reaches gallbladder, formation of ulcers, hemorrhage, death (20%).
- Typhoid state is characterized by "muttering delirium" or "coma vigil" (picking at bedclothes and imaginary objects).
- Enteric fever (S.Paratyphi) is similar to typhoid fever but less severe and rare.
Non-Typhoidal Salmonella (NTS)
- Global burden: ~94 million cases (155,000 deaths) each year, with ~80 million cases being foodborne.
- UK data: 8-9,000 confirmed cases per year.
- Predominant serovars: S.Enteritidis, S.Typhimurium, S.Heidelberg, and S.Newport.
- NTS causes self-limiting enteritis in healthy individuals, but can be invasive (iNTS) in regions with immunocompromised/malnourished individuals, e.g., in sub-Saharan Africa.
E. coli (MNEC)
- Affects 1 in every 2,000-4,000 infants.
- Major cause of CNS infections in infants <1 month old.
- Primary bloodstream infection with secondary distribution to the CNS is the mechanistic basis of infection.
- 80% of E. coli strains involved synthesize K-1 capsular antigens, which is a major virulence factor.
Intestinal Pathogenic E. coli
- Common cause of gastrointestinal infections (1 in 5 people affected each year in the UK).
- Transmitted by infected food and water (or via person-to-person).
- Symptoms vary depending on pathotype:
- Mild watery diarrhea: typically ETEC.
- Dysentery: typically EIEC.
- Severe bloody diarrhea: typically EHEC.
- Persistent diarrhea: typically EPEC, EAggEC.
- Vomiting, abdominal pain, fever: all; haemolytic uraemic syndrome (HUS): only EHEC.
Genus Shigella
- 4 Shigella species based on serological typing:
- A: S.dysenteriae (most severe, ancient cause of epidemics).
- B: S.flexneri (most frequent, 60% cases in developed world).
- C: S.boydii (confined to the Indian sub-continent).
- D: S.sonnei (mildest infection, developed world).
- Phylogenetic typing (16S rRNA) shows that Shigella spp. and E. coli are closely related.
Shigella Virulence Factors
- Plasmid-borne factors (pINV):
- Entry region: codes for type 3 secretion system (T3SS), which allows the bacterium to inject proteins directly into the host cell.
- T3SS is pivotal to infection.
- Chromosomal factors:
- SHI-1: enterotoxins (SigA, Pic, Set1A,1bB).
- SHI-2: siderophores (IucA-D, IutA).
- SHI-3: siderophores (IucA-D, IutA).
- SHI-O: serotype conversion/O-antigen.
- Stx-phage p27: shiga toxin.
Order: Enterobacterales
-
General morphological and biochemical characteristics:
- Emended family Enterobacteriaceae.
- 29 genera, including the type genus Escherichia.
- Optimum temperature: 37°C.
- Gram-negative, non-spore forming rods.
- Facultative anaerobes.
- Catalase positive.
- Oxidase negative.
- Nitrate reductase positive.
- G+C content: 38-60%.
- Genome size: ~5 Mbp.
- Motile, via peritrichous flagella (a few exceptions).
-
Family Yersiniaceae:
- 7 genera, including the type genus Yersinia.
- Optimum temperature: 28-29°C.
- Some lack nitrate reductase.
- G+C content: ~47%.
- Genome size: 4.6 Mbp.
- Non-motile at 37°C (with all but Y.pseudotuberculosis).
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This quiz covers the virulence factors of Yersinia, including the Type 3 secretion system. Learn about the pathogenic mechanisms of Yersinia bacteria.
