Lect 17 Flashcards
clostridium species
- gram status
- oxygen?
- gram postive bacilli
- obligate anaerobes
pathogen that causes tetanus
clostridium tetani
pathogen that causes botulism
clostridium botulinum
clostridium tetani
- gram status
- spores have what appearance
- gram positive
- spores are terminal
- tennis racket appearance
clostridium tetani toxin production is mediated by
plasmid-mediated
how is clostridium tetani transmitted
- initial event is trauma which allows entery of spores
- contaminated soil
- or human/animal feces
what potent exotoxin does clostridium tetani release? what does it do?
- tetanospasmin
- absorbed by local nerve endings and transported through neurons
- disruption of central motor control, autonomic function and NMJ
clinical presentation
- lockjaw or trismus: spasm of masseter muscles
- risus sardonicus: grimace
- opisthotonos: arching of back
- may lead to respiratory complications and cardiac complications -> usually causes death
clostridium tetani
prevention of clostridium tetani
- routine immunization with tetanus toxoid
- DTap and Td
- Human tetanus immune globulin (HTIG) is recommended for passive immunization
DOC for clostridium tetani
penicillin plus antitoxin
clostridium botulinum
- describes spores
spores are subterminal
- give bacillus a distended shape
- great heat resistance
describe toxins of clostridium botulinum
- 8 serologically distinct botulinum toxins (A-G)
- toxin is neurotoxic
clostridium botulinum can enter via what two mechanism
- wound botulism
- food poisoning: results from ingestion of neurotoxin in incompletely processed food that contains bacteria
what is infant botulism
- results from germination of spores and multiplication of bacteria, along with release of neurotoxin
- systemic effects are lethal (probable cause of sudden infant death)
how is clostridium botulinum diagnosed
- confirmation is related to demonstration of toxin presence
- fecal samples
treatment of clostridium botulinum
- neutralization of toxin
- abx typically not recommended
explain basic features of Fungi
- eukaryotic
- consists of
- Yeasts (unicellular)
- molds
- mushroons
differentiate between Blastomyces and candida
- Blastomyces: primary pathogens
- candida: opportunistic pathogens
- *any fungus capable at growing at 37 C is considered a potential pathogen
cell membranes of fungi contain
ergosterol
which type of fungi are unicellular
yeasts
fungal cell wall is composed of what 4 major components
- Mannan
- PLM
- Chitin
- B-glucan
what are function of secreted asparyl proteases (SAPs)
destroy host tissue at the site of infection
Dimorphic fungi
- are fungi that can reproduce as either a mycelial or a yeast-like state. Generally the mold form grows at 25° C, and the yeast-like pathogenic form at 37° C.
Polyene antimycotics such as Amphotericin B and Nystatin have what MOA
interfere with ergosterol that is embedded in a fungal cell membrane
MOA of Azoles
- interfere with synthesis of new ergosterol
MOA of Terbinafine
- allylamine drug that blocks ergosterol biosynthesis in fungal cell membrane (by blocking squalene epoxidase)
when is Terbinafine used
used in dermatophyte infections (parasitic fungal infections)
route of administration of Terbinafine
- topical
- tablet: risk of hepatic toxicity
MOA of Echinocandins (Echinocandin B)
- inhibits the production of glucan in the cell wall
- known as the “penicillin of antifungals”
when is Echinocandins (Echinocandin B) used
systemic candidiasis and aspergillosis
