Session 1 Flashcards
(29 cards)
What is an infection?
An invasion of a host’s tissues by microorganisms
What 3 things cause disease?
Microbial multiplication
The toxins they produce
The hosts’ response
What symptom can C. diff cause? Where is it particularly common?
Diarrhoea
Hospitals
Why is is it difficult to remove C. diff from the environment?
Remains latent in the environment for weeks/months as spores
What is a spore?
Resistant form of bacteria that can resist extreme conditions
What is the human microbiota?
The microorganisms (including bacteria, fungi, archaea and viruses) found in the human body
What does the human microbiota not include?
Micro-animals which live ON the human body
What is the human microbiome?
The genome (genetic material) of the microbiota
Where are microbiota commonly found? When do they cause disease?
On skin and mucosal surfaces
When they are transferred from their normal sites to different parts of the body
What are 5 different modes of horizontal transmission?
Physical Contact (e.g. STIs)
Inhalation - Aerosols (e.g. Chickenpox)
Vectors (e.g. Malaria)
Inhalation - Droplet infection - drops of saliva
Ingestion - Faecal-Oral Transmission (e.g. Norovirus)
What is vertical transmission? Give an example?
Transmission of infection from mother to child before or after birth
HIV
How can you prevent HIV from being transmitted from mother to child? (2)
Avoiding breastfeeding
Delivery via c-section
What are virulence factors?
Factors which help the virus to survive but also do damage to the host
What are exotoxins?
Material released from a pathogen
What are endotoxins?
Material produced and kept inside the pathogen - has an effect on the cell once the pathogen dies
Why is invasion of a host cell essential for a virus?
They are incomplete particles and can’t survive without a host cell
What are disease determinants?
Factors affecting whether disease results from a pathogen
Name 3 disease determinants related to the pathogen
The virulence factors
Inoculum size
Antimicrobial resistance
What is meant by inoculum size?
The size of ‘dose’ of pathogen
Name 2 disease determinants related to the patient?
The site of infection
Co-morbidities
What is a supportive investigation? What is a specific investigation?
Investigation to work out how unwell the patient is and not what is specifically causing it
Investigations to identify the cause of the infection
What are some examples of supportive investigations? (5)
Full blood count CRP Kidney/liver function test Imaging Histopathology
What are specific investigations used to identify the cause of BACTERIAL infections? (6)
Specimens are taken (swabs, fluids, tissues etc.)
Microscopy (e.g. Gram stain)
Culture
Antibiotic susceptibility investigations
Antigen detection
Nucleic acid detection
What are specific investigations used to identify the cause of VIRAL infections?
Antigen detection (the virus) Antibody detection (the patient's response) Detecting the viral nucleic acid (DNA or RNA?)
