Community Acquired Bacterial Infection Flashcards
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
give an example of a bacteria with a Capsule?
- Streptococcus pneumonia.
give an example of a bacteria with endospores
Bacillus sp. And Clostridium sp.
give an example of bacteria with biofilms?
- Pseudomonas aeruginosa and Staphylococcus epidermidis
what are exotoxins?
toxins that damage biological systems
what are neurotoxins? examples?
neurotoxins act on nerves
eg. Tetanus or Botulinum toxins.
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.
what are Pyrogenic exotoxins? examples?
Pyrogenic exotoxins stimulate the release of cytokines eg. Staph aureus or Strep. pyogenes.
what are invasive exotoxins? examples?
- enzymes that allow bacteria to tunnel through the tissue
- eg. Staph. aureus, Strep. pyogenes, Clostridium perfringens.
what are Misc. exotoxins? examples?
- specific to certain bacteria function
- not very well understood
- eg. Bacillus anthracis, Corynebacterium diphtheriae.
what are endotoxins?
- they are only produced by gram-negative bacteria
- it is not a protein
- these are lipids
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
what is the definition of an outbreak?
a sudden increase in the incidence of a disease in a particular place at a particular time.
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.
how can outbreaks be detected?
- Surveillance
- Good and timely reporting systems
- PCR.
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).
