FoM:L1 - Infection and Superbugs Flashcards
What are 5 classes of microbes? Outline each one
- bacteria: prokaryotes
- fungi: eukaryotes, chitin cell walls
- viruses: obligate intracellular, non-living
- protozoa: eukaryotes, single-cellular
- helminths: eukaryotic parasites
What is a pathogen?
organisms capable of causing disease
What is a commensal?
an organism that colonises the host but cause no disease in normal circumstances
What is an opportunist pathogen?
microbe that only causes disease if host defences are compromised
What is virulence/pathogenicity?
the degree to which a given organism is pathogenic/is likely to cause disease
What is asymptomatic carriage?
when a pathogen is carried harmlessly at a tissue site where is causes no disease
Where can diseases be transmitted?
- skin (bacteria, viruses, fungi)
- airway (bacteria, viruses, fungi, helminths)
- alimentary tract (bacteria, viruses, helminths, protozoa)
- genital tract (bacteria, viruses, protozoa)
- blood-borne (bacteria, viruses, protozoa)
What are the different routes of transmission?
- contact
- airborne
- faecal-oral
- vectors
- sexual
- blood-borne
What shape are cocci bacteria?
circular under a microscope
What shape are bacillus?
rod shaped
What are bacterial toxins?
- endotoxins: component of outer membrane of bacteria
- exotoxins: secreted by proteins of gram positive and negative bacteria
What are gram positive bacteria?
- blue in gram stains
- high in peptidoglycan
What are gram negative bacteria?
- stains pink/red in gram stains
- low in peptidoglycans
- contain lipopolysaccharides
What shape are spriochaetes?
spiral rod
Give 3 examples of spirochaetes… (grown as single cells)
- Leptospira (leptospirosis)
- Treponema (syphilis)
- Borrelia (Lyme disease)
What are 2 examples of gram negative cocci?
- Neisseria: N. Meningitidis and N. gonorrhoeae
What are 2 examples of gram positive cocci?
- staphylococcus (aureus and epidermidis)
- streptococcus
Give an example of a Ziehl-Neelsen stain positive rod bacteria
Myobacteria
- M. tuberculosis
- M leprae
What are common gram positive rods?
- Clostridium (botulinum, difficile, tetani)
- Listeria (monocytogenes)
What are common examples of gram negative rods?
- E-coli
- salmonella
