Anti-microbials/anti-biotics Flashcards
How do beta-lactams fight disease
Inhibit cell wall synthesis or function
What is the structure of beta lactam
House shape (garage - beta lactam ring) R group added to ring
What is an example of a bata-lactam antibiotic
Penicillins
Cephalosporins
Carbapenems
Monobactams
What family of antibiotics does penicillin come from
Beta-lactam family
How do bacteria resist beta lactams
Produce beta lactamases
What are beta-lactamase inhibitors
Group of chemicals that block the active site of the bacterias beta lactamase
What is clavulanic acid
Beta-lactamase inhibitor
Where is the site of action of beta-lactamases in gram-negative bacteria
The cell wall, thin narrow (takes time for the beta-lactamase inhibitors to diffuse in)
How do extended spectrum beta lactamase infections occur (ESBL)
Initial infection is treated with a beta-lactam antibiotic, the bacteria produce beta-latamase, chemicals such as augmentin (beta-lactam inhibitor) are used to block the beta-lactamase but then the bacteria produce extanded spectrum beta-lactamase which overwhelms the inhibitors
How is an ESBL infection treated
Development of a new class of beta-lactam antibiotic (carbapenems)
What do enterobacteriacae/coliforms look like on a slide
Frog spawn (bacteria surrounded by a capsule)
What type of infections do CPE’s cause (carbopenamase-producing-enterobactericaea)
pneumonia
UTI
wound infections
Why do do we need to control CPE’s
They can be efficiently transmitted in healthcare
Plasmids can transfer resistance to other strains and species
What is the CPE screening algorithm
In the last 12 months has the patient:
Been in hospital outside of scotland
Received holiday dialysis outside of scotland
Been a close contact of a person who has had CPE
How is CPE screened
Rectal swab
How is CPE transmitted
Food
Animals
Travel
Family/friends
What bacteria are strict anaerobes
Anaerobic streptococci
Prevotella species
What is the recommended first line antibiotic for dental infections
Pennicillin V
What is MIC
minimum inhibitory concentration - minimum conc required to inhibit the growth of bacteria
What is a breakpoint
chosen concentration (mg/L) of an antibiotic which defines whether a species of bacteria is susceptible or resistant to the antibiotic.
What are pharmokenetics
the absorption, distribution, and elimination of drug
What are pharmacodynamics
relationship between concentration of drug and the antimicrobial effect
When do beta-lactams exert their killing effect
Depending on the time the conc is above the MIC
What are examples of opportunistic microorganisms
C.difficile
Candida
What is the disadvantage of amoxicillin
Can lead to overgrowth of opportunistic microoorganisms
What causes blood to become infected
Bacteria, fungi, viruses
What are examples of bacterial, fungal and viral infections of the blood
S.aureus - bacteria
Candida albicans - Fungi
Herpes simplex - Virus
What are the 2 most common microbes in blood stream infections
E.coli
S.aureus
Which streptococci cause endocarditis
Lancefeild group D - enterococcus
How does intravenous drug use endocarditis differ from native valve endocarditis
Younger age group
Staphylococcus aureus predominant microbe
Mostly affects valves on the right side of the heart
Can give rise to multiple lung abscesses (& elsewhere)
What should be avoided with patients who have endocarditis
Prescribing antibiotics
