Microbial Infection Flashcards
What is the classical pathway of the complement cascade?
Antigen+Antibody complex
Pro-inflammatory molecules - C3a, C5a, anaphylatoxins = Leads to C3b
What is the Lectin pathway of the Complement cascade?
Antibody Independent
Mannan Binding Lectin C reactive Protein
= C3b
What is the Alternative pathway of the Complement cascade?
Bacterial surfaces
Main opsonin
= C3b
* C3b initiates Membrane attack complex which forms pores in lysis
Characteristics of prokaryotes?
Haploid
Poorly developed cytoskeleton
Cell wall of Peptidoglycan
Binary fission
What are the characteristics of Shigella?
Dose: 10-100 bacteria
Faecal-Oral transmission
Affects GI tract
What are the characteristics of Neisseria Meningitidis?
Goes from commensal to pathogen due to
Multiple serogroups of bacteria
Rapid progression
Septic shock
Severe inflammation
Septicaemia –> CSF meningitis
What are 2 examples of nosocomial infections?
Hospital-acquired
Clostridium difficile
MRSA
What are the characteristics of TB?
Advances and treatment
infected by Mycobacterium Tuberculosis
New drugs: against resistance and shorten treatment
Better vaccines
Better tools for early diagnosis
- recognise X-ray and PET-CT scan imaging of TB
X ray - can see TB cavity
PET-CT - use 18F-fluorodeoxyglucose ( FDG ), orange colour depicts FDG uptake
What are the characteristics of Helicobacter pylori?
Causes peptic ulcers and gastric cancer
How are fungi divided into three groups?
Whether they cause:
- cutaneous
- mucosal
- systemic mycoses
What are the characteristics of fungi?
Occur as yeasts, filaments or both
yeasts bud or divide
Filaments ( hyphae ) have cross walls/septa
What are the characteristics of Candida albicians?
Fungal infections which can affect Mouth, skin, genetils
How do protozoa cause illness?
Include intestinal, blood and tissue parasites
Binary fission in host or form trophozoites in cell
May involve two hosts
What are the characteristics of Malaria?
Plasmodium
Via mosquito vector
Blood and tissue parasite
Formation of trophozoites in cell\
protozoa
What are the characteristics of Leishmaniasis?
Via Sandfly vector
Blood and tissue parasite
Formation of trophozoites
cutaneous and visceral disease
protozoa
What are Helminths?
Metazoa ( eukaryotic )
Visible to naked eye
Life cycle involves outside human host
-Faecal oral transmission
e.g. Roundworms - ascaris
Flatworms - flukes
Tapeworms
What are the characteristics of Schistisomiasis?
Disease caused by Flukes
Eggs in tissue cause inflammation
Extra info :
Viruses: obligate parasites, contain genetic material, host specificty, divide by budding or cytolysis, faecal oral, airborne, insect vectors, blood borne
HIV : retrovirus, DNA makes RNA makes protein , RNA genome needs reverse transcriptase
pressure chambers used to treat polio virus
Human papilloma virus causes cervical cancer
Organism point mutation rate : human 10-8, bacteria 10-8, viruses 10-4 ( similar mutation rates but different generation times )
- generation time Ecoli - 20 mins, Candida 60 mins, M TB 20 hours, plasmodium 1-2 days, human 26 years
