- they are only produced by gram-negative bacteria - it is not a protein - these are lipids

Community Acquired Bacterial Infection Flashcards by Anavi Prakash

show the structure of bacteria:

and state the functions of the virulance features

Flagella - for movement and attachment
Pili – adherence
Capsule – protect against phagocytosis
Endospores – metabolically dormant forms of bacteria
Biofilms – aggregates of bacteria embedded in a polysaccharide matrix = contributes towards antibiotic resistance

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give an example of a bacteria with a Capsule?

Streptococcus pneumonia.

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give an example of a bacteria with endospores

Bacillus sp. And Clostridium sp.

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give an example of bacteria with biofilms?

Pseudomonas aeruginosa and Staphylococcus epidermidis

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what are exotoxins?

toxins that damage biological systems

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what are neurotoxins? examples?

neurotoxins act on nerves

eg. Tetanus or Botulinum toxins.

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what are Enterotoxins? examples?

these are toxins that act on the GI

Infectious diarrhea – Vibrio cholera, E. coli, Shigella dysenteriae, Campylobacter jejuni.

Food poisoning – Bacillus cereus, Staph. aureus.

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what are Pyrogenic exotoxins? examples?

Pyrogenic exotoxins stimulate the release of cytokines eg. Staph aureus or Strep. pyogenes.

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what are invasive exotoxins? examples?

enzymes that allow bacteria to tunnel through the tissue
eg. Staph. aureus, Strep. pyogenes, Clostridium perfringens.

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what are Misc. exotoxins? examples?

specific to certain bacteria function
not very well understood
eg. Bacillus anthracis, Corynebacterium diphtheriae.

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what are endotoxins?

they are only produced by gram-negative bacteria
it is not a protein
these are lipids

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what might happen if a patient with endotoxins is treated with antibiotics?

if you treat a patient with antibiotics it can make it worse
the bacteria lyse it might release large quantities of endotoxins
this causes septic shock

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what is the definition of an outbreak?

a sudden increase in the incidence of a disease in a particular place at a particular time.

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what is a possible epidemic case?

what is a probable epidemic case?

what is a confirmed epidemic case?

possible epidemic case = any person that has developed the symptoms AND has met a laboratory criteria
probable epidemic case = Any person that has met the above criteria AND has been in the epidemic country
confirmed epidemic case any person meeting criteria for a possible case AND has had strain isolated.

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how can outbreaks be detected?

Surveillance
Good and timely reporting systems
PCR.

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how might a PCR identify an outbreak?

samples of stool from potential patients can be screened using multiplex PCR
this can confirm if they are suffering from the outbreak strain or not

in the case of the E.coli outbreak in Germany how did PCR identify the virus?

in this example, the samples were showing combinations of genomic features of two previous strains (EHEC and EAEC)
therefore allowing the conclusion that this was a new strain =
EAHEC

what features of EAEC and EHEC strains did the PCR identify to allow it to come to the conclusion that it was a combination of both strains?

EAEC =

2 plasmids
Contains ESBL plasmids that code for extended-spectrum beta-lactamases.

EHEC =

prophage that encodes for the Shiga toxin
this is characteristic for EHEC strains

what were the features of the new E.coli outbreak given the combined features of the EAEC and EHEC strains?

Shiga toxins from the EHEC strain are produced
Shiga toxins are encoded on bacteriophages and contribute to horizontal gene transfer
EAEC can colonize the larger and small bowel -> this affects the gut flora
EAECs have the virulence factor of Aggregative Adherence Fimbriae (AAF)
AFF causes adhesion to enterocytes and stimulates IL-8 response
it also allows for a biofilm formation.

what are the communicable disease types in the EU?

Respiratory tract infections
Sexually-transmitted Infections
Food- and waterborne diseases and zoonoses
Emerging and vector-borne disease

give examples of communicable respiratory tract infections?

Legionnaire’s disease
Tuberculosis

give examples of communicable STIs?

Chlamydia
Gonorrhoea

give examples of communicable food- and waterborne diseases and zoonoses?

Campylobacteriosis
Salmonellosis
Cholera
Listeriosis

give examples of communicable Emerging and vector-borne diseases?

Plague
Q fever
smallpox

Legionnaire’s disease respiratory tract infection example bacteria: location: route of infection: Virulence factor:

* Legionnaire’s disease is caused by Legionella pneumophilia (gram-) * lives in amoeba in water and air conditioning * inhalation of aerosols * type IV secretion system, legionella replicates in legionella containing **vacuoles** (LCVs) inside cells.

TB bacteria? Virulence factor?

* TB is caused by Mycobacterium tuberculosis * Virulence factor – has an extra lipid layer & can enter a dormant state for reactivation.

Chlamydia bacteria? dangerous clinical feature epidemiology?

Chlamydia is caused by Chlamydia trachomatis gram -ve most common STI in europe and causes blindness Gonorrhoea is caused by Neisseria gonorrhoeae (gram-ve Urogenital tract infection infecting non-ciliated epithelial cells.

Gonorrhea bacteria? features? Gonorrhea virulence factor?

* Gonorrhoea is caused by Neisseria gonorrhoeae (gram-ve): * Urogenital tract infection infecting non-ciliated epithelial cells * Virulence factor - pili (allows adherence) , antigenic variation mechanism

Campylobacteriosis what is it caused by? Virulence factors? epidemiology? infection route?

* caused by Campylobacter sp * virulence factors = adhesion, invasion factors, flagella motility, T4 secretion systems, toxins. * Most infectious GI disease in the EU * The infection route via uncooked poultry but does not cause outbreaks.

Salmonellosis what is it caused by? Epidemiology? Virulence factors?

* Caused by Salmonella * Virulence factors = T3 secretion systems encoded on pathogenicity islands. * the highest risk in children * Common GI infector from undercooked poultry but causes outbreaks.

cholera what is it caused by? Virulence factors? other features?

* caused by Vibrio cholera (gram-ve) * Virulence factors – T4 fimbria, cholera toxin carried on phages. the cholera toxin causes increased cAMP, therefore, causes opening of Cl- channels and expulsion of water from cells

Listeriosis what is it caused by? at-risk groups? Virulence factors?

* caused by Listeria monocytogenes (gram +) * Risk groups of immunocompromised and pregnant people. Virulence factors – actin-based cell mobility

what are the following Emerging and vector-borne diseases caused by?

* Plague – Yersina pestis (gram-ve) * Q fever – Coxiella burnetti (gram-ve) * Smallpox (A VIRUS) – eradicated.

what are vaccine-preventable diseases? what are they caused by?

* a. Diphtheria – Clostridium diphtheriae (gram+ve) * b. Invasive HA disease – Haemophilus influenzae (gram-ve) * c. Invasive meningococcal disease – Neisseria meningitides (gram-ve) * d. Invasive pneumococcal disease – Streptococcus pneumoniae (gram+ve) * e. Pertussis – Bordetella pertussis (gram-ve) * f. Tetanus – Clostridium tetani (gram+ve).