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Pathogenic Microbiology > Ex2-Enterobacteriaceae,Campylobacter,Helicobacter > Flashcards

Ex2-Enterobacteriaceae,Campylobacter,Helicobacter Flashcards

1
Q

Enterobacteriaceae include which type of species?

A 
Enterobacter
Escherichia
 Salmonella
 Shigella
 Klebsiella
 Serratia
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2
Q

Are Enterobacteriaceae Gram negative or positive? And what is their carbon source?

A

gram negative rods
• facultative anaerobe
– oxidase negative

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3
Q

Enterobacteriaceae are opportunistic pathogens, what does that mean?

A

• community acquired
• cause disease in otherwise
healthy people

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4
Q

What syndromes are caused by Enterobacteriaceae?

A 
syndromes include
•  septicemia
•  pneumonia
•  meningitis
•  urinary tract infections •  gastrointestinal diseases
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5
Q

Which Enterobacteriaceae usually causes pneumonia?

A

Klebsiella pneumoniae

  • respiratory diseases
  • prominent capsule
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6
Q

Which Enterobacteriaceae causes urinary tract infections, and how does contamination occur?

A

Proteus spp.

  • urease (degrades urea)
  • alkaline urine
  • Fecal contamination of the urinary tract is the most common route that causes the bacteria to enter the urethra
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7
Q

Which Enterobacteriaceae are known to cause gastrointestinal diseases and are also excreted in feces?

A

– Escherichia-* Tests lactose positive and are apart of the normal flora of the GI tract.

*Lactose Negative
– Salmonella
– Shigella
– Yersinia entercolitica

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8
Q

Which organisms are known to cause Gastrointestinal disease but are not of the Enterobacteriaceae?

A
  • Campylobacter

- Helicobacter

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9
Q

What antigens are can be found on the surface of Enterobacteriaceae?

A

antigens include:

  • O (lipopolysaccharide) O1-O181
  • H (flagellar) H1-H56
  • K (capsular) 60
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10
Q

What species of E. colli are known to cause gastrointisis

A
  • Enterotoxigenic E. coli (ETEC)
  • Enteropathogenic E. coli (EPEC)
  • Enteroaggregative E. coli (EAEC)
  • Enterohemorrhagic E. coli (EHEC)
  • Enteroinvasive E. coli (EIEC)
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11
Q

What are the symptoms of Enterotoxigenic E. coli (ETEC)? And how are you able to diagnose it?

A 
•  acts in small intestine •  watery diarrhea
•  non-bloody stools 
•  vomiting
•  cramps
•  nausea
•  low-grade fever
•  diagnose by immunoassay
for ST or by PCR
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12
Q

What are the symptoms of Enteropathogenic E. coli (EPEC)? and how id it diagnosed?

A
  • acts in small intestine
  • watery diarrhea
  • non-bloody stools
  • vomiting
  • destruction of surface microvilli
  • diagnose by adherence to human HeLa or Hep-2 cells, presence of plasmid-encoded pili
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13
Q

What are they key features of Enterotoxigenic E. coli (ETEC)?

A 
•  “traveller’s” diarrhea, infant diarrhea
•  Heat labile toxin (plasmid)
 –  like choleragen
–  Adenyl cyclase activated
 –  cyclic AMP (up)
–  secretion water/ions (up)
•  Heat stable toxin (plasmid)
–  Guanylate cyclase activated
 –  cyclic GMP (up)
–  uptake water/ions (down)
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14
Q

What are the symptoms of Enterosggregative E. coli (EAEC)? How are you able to diagnose it?

A 
•  acts in small intestine
•  persistent watery diarrhea
•  non-bloody stools •  vomiting
•  dehydration
•  low-grade fever
•  aggregative adherence of rods •  diagnose by adherence to human
Hep-2 cells, presence of plasmid
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15
Q

What is the transmission route for Enterohemoryhagic E. coli (EHEC)?

A

• Contaminated meat, water, unpasteurized milk or fruit juice, raw vegetables, fruit

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16
Q

What are the key features known to identify and diagnose Enterohemoryhagic E. coli (EHEC)?

A

• Verotoxin (Stx-1, Stx-2) blocks protein synthesis
• Hemolysins
• Screen for O157:H7 on
sorbitol-MacConkey agar
• Confirm diagnosis by assay for presence of Stx toxins

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17
Q

What symptoms can be observed from a patient diagnosed with Enterohemoryhagic E. coli (EHEC)?

A 
•  hemorrhagic
–  initial watery diarrhea followed by
bloody, copious diarrhea with
abdominal cramps
 –  few leukocytes
–  little or no fever
•  may progress to hemolytic-uremic syndrome
–  hemolytic anemia
–  thrombocytopenia (low platelets) 
–  kidney failure
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18
Q

What are the symptoms of Enteroinvaasive E. coli (EIEC)? And how can it be diagnosed?

A 
•  acts in large intestine
 •  fever
•  cramping
•  watery diarrhea
•  non-bloody stools
•  may progress to dysentery
with scant, bloody stools
 •  diagnose by plaque assay in human HeLa cells (can’t be distinguished from Shigella species)
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19
Q

What is the common treatment when dealing with a Gastrointestinal Disease?

A

• fluid replacement
• antibiotics NOT used
– unless a systemic infection,
e.g. hemolytic-uremia syndrome

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20
Q

What is Salmonellosis (gastroenteritis) and what is the common route of transmission and incubation period for the disease to develop?

A 
–  the common salmonella infection of S. Enteritdis
 –  poultry, eggs
–  no human reservoir
–  gastroenteritis
•  nausea
•  vomiting
•  non-bloody stool
•  self-limiting (2 - 5 days)

Antibiotic therapy is not normally used unless the patient is immunocompromised.

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21
Q

What organism causes Typhoid Fever ?

A 
Salmonella typhi:
•  enteric fever
•  most severe salmonella disease
•  rare in US
•  epidemics
–  third world
–  Europe - historical

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22
Q

What are the common symptoms and incubation period that is associated with Typhoid fever?

A

Typhoid fever
• 10-14 day incubation period septicemia occurs
• initial symptoms (1 week or longer)
• gradually increasing fever
• headache,myalgias, malaise, anorexia
• these symptoms followed by GI symptoms
due to colonization of the gall bladder and reinfection of the intestines


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23
Q

What sis the capsular antigen located on the surface of S. Typhi?

A

S. typhi
• Vi (capsular) antigen
– protective antibodies made

24
Q

What is the common therapy given to patients who acquire S. Typhi?

A

Therapy
• Antibiotics – essential
• Vaccines
– ineffective

25
What are the common symptoms associated with Shigella?
``` • bacterial dysentery • shigellosis - bloody feces - intestinal pain - pus ```
26
What relevant are the most relevant species of Shigella?
- S. flexneri - S. boydii - S. sonnei - S. dysenteriae - Shigella sonnei
27
What is the transmission of Shiggellosis and what is its incubation period?
``` • humans the only "reservoir" • mostly young children – fecal-oral contact – children to adults • transmitted by adult food handlers – unwashed hands • within 2-3 days – epithelial cell damage ```
28
What are the key features of the shiga toxin?
• enterotoxic • cytotoxic • inhibits protein synthesis – lyses 28S rRNA
29
How do you treat Shingellosis?
• manage dehydration • patients respond to antibiotics – disease duration diminished
30
What are the common species of Campylobacter associated with human disease?
- C. Jejuni - C. Coli - C. Fetus - C. Upsaliensis
31
What is the common reservoir of C. Jejuni?What disease does it cause?
- Poultry - Cattle - Sheep - Diseases include: Gastroenteritis, extraintestinal infections, Guillain-Barré syndrome, reactive arthritis
32
What is the common reservoir of C. Coli? What disease does it cause?
- Pork - Poultry - Sheep - Birds - Diseases Include: Gastroenteritis, extraintestinal infections
33
What is the common reservoir of C. fetus? What disease does it cause?
- cattle - sheep - Diseases include: Vascular infections (e.g., septicemia to multiple organs, septic thrombophlebitis, endocarditis), meningoencephalitis, gastroenteritis
34
What is the common reservoir of C. Upsaliensis? What human Disease does it cause?
- Dogs - Cats - Diseases include: Gastroenteritis, extraintestinal infections, Guillain-Barré syndrome
35
what are some of the key features associated with a Campylobacter infection?
Most common disease is acute enteritis with diarrhea, malaise, fever, and abdominal pain • Guillain-Barré syndrome believed to be an autoimmune disease caused by antigenic cross- reactivity between oligosaccharides in bacterial capsule and glycosphingolipids on surface of neural tissues • Most infections are self-limited but can persist for a week or more
36
What is are some key features regarding the epidemiology of Campylobacter?
• Zoonotic infection; improperly prepared poultry is a common source of human infections • Infections acquired by ingestion of contaminated food, unpasteurized milk, or contaminated water • Person-to-person spread is unusual • Dose required to establish disease is high, unless the gastric acids are neutralized or absent • Worldwide distribution with enteric infections seen throughout the year
37
How are you able to Detect and diagnose a Campylobacter infection?
* Detection of thin, "S-shaped" gram-negative rods in stool specimens is insensitive but specific * Culture requires use of specialized media (e.g., Skirrow’s medium) incubated with reduced oxygen, increased carbon dioxide, and (for thermophilic species) elevated temperatures; requires incubation for 2 or more days * Detection of Campylobacter antigens in stool specimens is moderately sensitive and very specific compared with culture
38
How are you able to treat,prevent and control a campylobacter infection?
* For gastroenteritis, infection is self-limited and is managed by fluid and electrolyte replacement * Severe gastroenteritis and septicemia are treated with erythromycin or azithromycin * Gastroenteritis is prevented by proper preparation of food and consumption of pasteurized milk; preventing contamination of water supplies also controls infection.
39
What are the Helicobacter species associated with human disease?
- H. pylori - H. Cinaedi - H. Fenneliae
40
What are the common reservoir and clinical diseases associated with H. pylori?
- Humans - Pigs - primates -Diseases include: Gastritis, peptic ulcers, gastric adenocarcinoma, mucosa-associated lymphoid tissue B-cell lymphomas
41
What are the common reservoir and clinical diseases associated with H. Cinaedi?
- Humans - Hamsters Diseases include: Gastroenteritis, septicemia, proctocolitis
42
What are the common reservoir and clinical diseases associated with H. Fenneliae
-Humans Diseases include: Gastroenteritis, septicemia, proctocolitis
43
What are most common virulence factors associated with the helicobacter species?
* Urease production at very high levels is typical of gastric helicobacters (e.g., H. pylori) and uncommon in intestinal helicobacters (important diagnostic test for H. pylori) * Multiple factors contribute to gastric colonization, inflammation, alteration of gastric acid production, and tissue destruction
44
Why is H. Pylori important to human disease?
• H. pylori is an important cause of acute and chronic gastritis, peptic ulcers, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma
45
What are some key epidemiological features of the Helicobacter species?
• Infections are common, particularly in people in a low socioeconomic class or in developing nations • Humans are the primary reservoir • Person-to-person spread is important (typically fecal-oral) • Ubiquitous and worldwide, with no seasonal incidence of disease
46
How are we able to diagnose H. pylori?
* Microscopy: histologic examination of biopsy specimens is sensitive and specific * Urease test relatively sensitive and highly specific; urea breath test is a noninvasive test * H. pylori antigen test is sensitive and specific; performed with stool specimens * Culture requires incubation in microaerophilic conditions; growth is slow; relatively insensitive unless multiple biopsies are cultured * Serology useful for demonstrating exposure to H. pylori
47
How are we able to treat, prevent and control H. Pylori infection?
* Multiple regimens have been evaluated for treatment of H. pylori infections. Combined therapy with a proton pump inhibitor (e.g., omeprazole), a macrolide (e.g., clarithromycin) and a β-lactam (e.g., amoxicillin) for 2 weeks has had a high success rate * Prophylactic treatment of colonized individuals has not been useful and potentially has adverse effects, such as predisposing patients to adenocarcinomas of the lower esophagus * Human vaccines are not currently available
48
Is H. Pylori or C. Jejuni a typical cause for diarrheal illness?e
C. Jejuni is common not H. Pylori
49
What are the clinical manifestations associated with C. Jejuni?
Acute Gastroenteritis
50
What are the clinical manifestations associated with H. pylori?
Gastroduodenal inflammation, ulceration, gastric cancer
51
What is the common outcome of infection with C. Jejuni?
Usually self- limiting unless immunocomprimised
52
What is the common outcome of infection with H. pylori?
Persistent low-grade inflammation
53
What is the the affected host associated with C. Jejuni
IT is normal in all age groups often occurs in clusters.
54
What is the affected hosts associated with H. pylori?
Chiefly found in adults and prevalence of infection usually occurs more frequently with age.
55
what are the common Reservoir of C. Jejuni?
Birds and Mammals
56
What is the common Reservoir of H. pylori?
Humans
57
In what temperature range does C. Jejuni and H. pylori growand how is it isolated?
- C. Jejuni 32-42ºC Feces | - H.pylori 35-42ºC by Gastric and Duodenal Biopsy specimen

Pathogenic Microbiology (11 decks)

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