L2 Gram Positive Rods Flashcards
Genus Bacillus
- > 60 species
- Diverse ecological niches
- Most are non pathogenic to humans
- Not anaerobic (is not poisoned by oxygen)
- Phenotypic differences conferred by genes on plasmids
Bacillus cereus
Typically found in rice especially reheated rice dishes
Produces enterotoxin - works in bowels
Food poisoning including diarrhoea
bacillus thuringiensis
Used as an insecticide
Produces protein crystals when producing spores
□ destroy the gut function of certain insects
□ Genetically over 500 different types
□ Encoded by cry genes which are located on a plasmid
□ Toxic to mosquitos and moths and caterpillars
Cry genes can be inserted into crop genomes to make them insect resistant
Used to control river blindness caused by onchocerca volvulus transmitted by blackflies breeding in fast flowing streams in Africa
□ Causes microfilaria damage to the eye
□ Used to poison blackflies
Used to control Ross River virus in Australia in the south west where mosquitos breed by dropping a sludge from helicopters
food poisining from reheated rice dishes is caused by
bacillus cereus
insecticide that destroys the gut function of insects
bacillus thuringiensis
cry genes
- encode protein crystals which destroy gut functions of some insects
- encoded on a plasmid in bacillus thuringiensis
- toxic to mosquitos, moths, and catarpillars
- can be inserted into crop genomes to make them insect repellant
bacteria used to control Ross River virus in south west
- bacillus thuringiensis
- used to control mosquitos
bacteria used to control river blindness
- bacillus thuringiensis
- controls onchocerca volvolus transmitted by blackflies
- causes microfilarial damage to the eye
anthrax caused by
bacillus anthracis
bacillus anthracis
Highly virulent pathogen Soil organism Zoonotic infection for animals that graze on grass and plants on the ground eg. Sheep, horses Worldwide distribution Causes economic disruption to farming
Anthrax Belt
strip of land in New South Wales from Victoria to Queensland
□ Main focus of human and animal cases in Australia
- Introduced from India in blood and bone meal and infects cattle herds
infective form of bacillus anthracis
- spores
- survival in the environment
- may remain viable for over 100 years
anthrax
- caused by bacillus anthracis
- Humans acquire infection when in contact with infected animals, their meat or other animal products
□ Their spores are the infective form
□ Clinical manifestations are determined by transmission routes
□ Used in biological warfare
3 types of anthrax infection
- cutaneous
- inhalational
- gastrointestinal
cutaneous anthrax
◊ through breakages in the skin
◊ Most common form
◊ Produces papule, vesicle, ulcer and then an eschar
} Eschar: an elevated black scab surrounded by cellulitis and swelling
◊ Swelling and redness
◊ Untreated mortality 10-40%
inhalational anthrax
◊ aerosol or dust causing pulmonary anthrax
◊ Spores are inhaled and enter the lung
◊ Macrophages within the alveoli engulf the spores, but the bacteria survives within the macrophages creating a form with an incubation period of up to 60 days, after which the organism grows within the macrophage
◊ Macrophage carries the bacteria into the surrounding lymph nodes and into the mediastinal lymph nodes where they cause haemorrhagic necrosis of perihilar and other thoracic lymph nodes
◊ Mediastinum: area around heart and in between lungs
◊ Causes a widening of the mediastinum which can be seen on an X-ray
◊ Eventually gets into the lungs and causes haemorrhagic necrosis
◊ 100% untreated mortality rate
gastrointestinal
◊ Though ingestion
◊ contaminated meat causing gastrointestinal anthrax
◊ Inflammation, swelling, haemorrhaging from mouth to caecum
◊ Up to 50% untreated mortality
how are phenotypic differences conferred between species of bacillus
genes on plasmids
genus clostridium
- Spore forming anaerobic bacteria
- Spores persist in the environment and are the infective form
- Produce toxins responsible for their diseases
Classified according to which toxins they produce