Antibiotics Flashcards
What are the spectrum of activities of antibiotics
Borad spectrum: affect a wide range of bacteria both gram posivit e and gram negative
narrow spectrum atnibiotics: affect certain types
Antibiotics that inhibit peptidoglycan are considered. why
narrow spectrum (gram + > gram .
greater dependence on peptidoglycan
decreased ability of certain antibiotics to move through the gram negative outer membrane
where do beta lactam anitbiotics differ
in the N-Acyl group
where does beta lactamsa target in beta lactam
beta lactam ring
What is lysozyme
An enzyme found on the skin, blood tears, saliva, micous. It is part of the innate host defence mechanism
How does lysozyme work
by cleaving the bond that links NAG awith NAM (1-4 beta glycosidase, and destroys srtuctual integrity)
What are L forms
treatment of cells with lysozyme or pennicillin in an osmotically protected enviromnet -> produce cell less. (in natural enviorment)
must be protected or else they will lyse
What are protoplasts
treatment will cells -> walllness in the lab (in the host)
What are spheroplasts
protoplasts with some outer membrnae material (gram negative)
Whats an ideal envrioemnt for protoplasrs, sphrooplassts
abscesses
How is lysozyme used int hea laboratory
treating gram postive with the enzyme -> makes protoplast
treat gram negative -> makes spheroplast
how is lysozume treated for gram neg
outer memrbane naturally excluses lysozume
treat cells with EDTA -> alow lysozyme to enter
protoplasts and spheroplasts will lyse if
not maitnaed in osomotically stable buffer
if protoplasts, spheroplasts and L-forms
are maintained in an osmotically stable
environment (isotonic) they can:
– carry out many metabolic activities including
toxin production
– no longer sensitive to cell wall antibiotics
why is it that during laboratoy culturing the abscess might appear to he sterile
labotoraty culturing: not osmotically stable environment -> cause L-forms to lyse -> absecess appear to be properly trated
What are abscesses and how do they help bacteira
its a localized bacterila infection usually a deep tissue infection. cntains pus.
reducuces permeiability of anitomenics,
gives an osmotically protected environment for wall-less cells (L-forms).
-> less sensitive to antibiotics
Are absecess different from cysts
yes. they do not carry bacteira
