3 - Microbiology and antimicrobials Flashcards
(34 cards)
Give an example of a gram positive cocci.
S. anginosus
Give an example of a gram negative cocci.
Veillonella species
Give an example of a gram positive bacilli.
Actinomyces israelii
Give an example of a gram negative bacilli.
Prevotella intermedia
What is antimicrobial resistance?
When micro-organisms change in ways that prevent medications from working
What are the different types of resistance?
- intrinsic resistance
- acquired resistance
What is intrinsic resistance?
Resistance through structure or metabolic pathway
What is acquired resistance?
- mutation
- acquisition of new DNA
What are the different mechanisms of antibiotic resistance?
- altered target site
- enzymatic inactivation
- decreased uptake
Give an example of a microorganism that uses altered target site for antimicrobial resistance.
Penicillin resistance
Give an example of a microorganism that uses enzymatic inactivation for antimicrobial resistance.
- prevotella
- fusobacterium
- both use beta-lactamase enzyme
What is the beta-lactamase resistance arms race?
- penicillin resistant bacteria produced penicillinase to destroy the antibiotic
- chemists produced a new penicillin resistant to penicillinase with a beta-lactam ring
- bacteria produced beta-lactamase
- chemists produced extended spectrum antibiotics
- bacteria produced extended spectrum beta-lactamase
- this reduces antibiotic choice for infection
How do you treat a ESBL infection?
Carbapenems
What are CPEs?
Carbapenemase producing enterobacterales
What is MDRI?
Multi drug resistant infection
Describe a dental abscess infection.
- endogenous infection (often mixed)
- strict anaerobes including S. anginosus and P. intermedia
What is the ideal specimen of a dental abscess?
- pus aspirate
- as oxygen is toxic to many of the bacteria involved
What bacteria are involved in a periodontal abscess?
- anaerobic streptococci
- p. intermedia
What bacteria are involved in pericoronitis?
- mixed oral anaerobes (p. intermedia)
- s. anginosus
What bacteria are involved in dry socket?
Mixed oral flora
What bacteria are involved in osteomyelitis?
- anaerobic gram negative rods
- anaerobic streptococci
- s. anginosus
- s. aureus
What bacteria are involved in salivary gland infection?
- s. aureus
- mixed anaerobes
What is the management of salivary gland infection?
- drainage
- flucloxacillin
- metronidazole
- if severe, 6 weeks IV antibiotics
What is the management of pericoronitis?
- local measures
- metronidazole if signs of spreading infection
