Bacteria Flashcards
What group of Ax target cell wall synthesis of bacteria
Penicillin Cephalosporin Carbapenem Glycopeptides Daptomycin
What Ax have B-lactam ring
Penicillin
Cephalosporin
Carbapenem
What Ax group target DNA synthesis
Quinolones
What Ax group target RNA synthesis
Rifampicin
What Ax group target protein synthesis
Macrolides Aminoglycosides Tetracycline Clindamycin Chloramphenicol Oxazolidones - Linezolid
What Ax group target folic acid synthesis
Sulfonmamides
Trimethoprim
Co-trimox = combination of both
What can Ax be
Bactericidal - kill
Bacteriostatic - stop reproduction
What is better
Use bactericidal
Esp if severe infection or immunocompromised
What do you think when choosing Ax
Likely organism Empirical vs results Known resistance Guidelines vs individual need Bactercidal vs static Single or combination SE
What do you think about for the regime
Route Dose SE Duration IV to oral switch Inpatient or OP Drug monitoring needed
When would you do oral over IV
No vomiting
No GI disturbance
No shock or organ dysfunction
Non-severe infection
When do you consider IV-oral switch
After 48 hours if
- improving
- able to tolerate oral
What criteria should be met
Able to swallow and tolerate fluid
Temp 36-38 for 48 hours
HR <100 for 12 hours
WCC 4-12
When would you continue IV
Oral compromised
Continuing sepsis
Special indication
Febrile neutropenia
How can bacteria acquire resistance
Acquire gene that inactivate Alternative metabolic pathway Alteration of target site so Ax can't bind Decreased permeability in cel wall AX removed from bacteria via pump
How do ESBL’s work
Acquire B-lactamase enzyme so penicillin’s will not work
What are common organisms
Coliforms e.g E.coli / Klebsiella
What is MRSA
SA resistance to B-lacytams
Ax spectrum of gram +Ve
MRSA Staph Strep Enterococcus Some anaerobes - strep / clostridia
Ax spectrum of gram -ve
Coliform - gut - E.coli Resp - H.influenza, M-catarrhalis Pseudomona's ESBL Atypical Some anaerobes - Bacteriodes
What do you say in OSCE
AS PER LOCAL POLICY
What do you use for empirical
Broad spec Ax then narrow once sensitivities known
How does gram +Ve stain on cultures
Purple as thick peptidoglycan wall that holds dye
How does gram -ve stain
Pink as no wall so doesn’t hold dye
What can bacteria be split up into
Gram -ve Rods Gram -ve Cocci Gram -ve Anaerobes Gram +Ve Rod Gram +ve Cocci Gram +Ve Anaerobes Atypicals Spirochaetes
What are gram -ve rods that come from the gut i.e. coliform
E.coli = most common Pseudomonas aeruginosa Salmonella Shigella Cambylocbacter Proteus Vibro cholera Klebsiella
Other gram -ve rods
H.influenza
Bordetella pertussis
H.pylori
Legionella
What are gram -ve Anaerobes
Bacteriodes fragillis = abscess
What are common Rx for anaerobes
Metronidazole
What are gram -ve cocci
Neisseria gonorrhoea
Neisseria meningitides
M.catarrhalis
What are gram +ve rods
ABCDLM Acitnomyces Bacillus anthrax Clostridia = anaerobe - Perfrinigen - Tetani - Botulinum - Dfficile Diptheria Listeria monocytogenes
What are gram +ve staphylococci
S.aureus = coagulase +Ve S.epidermidits = coag -ve
What is S.epidermidits
Usually contaminant of blood culture
Doesn’t usually cause issue unless metal work in bone / heart
What do both organism cause and issue
Joint infections
Form biofilm which prevent Ax working
What is MRSA
S.aureus that has become resistant to the beta-lactam Ax
How do you prevent
Screen before surgery with nasal or groin swab
Eradicate with chlorhexidine
What are Ax options for mRSA
Vancomycin
Doxycycline
Clindamycin
What are gram +ve strep
All catalase -ve S.pyogenes (A) = beta haemolytic S.pneumonia = alpha haemolytic S.viridans - found in mouth so common after dental = alpha haemolytic Enterococcus faecalis = non-haemolytic
What are gram +ve anaerobes
Clostridium
Listerai monocytogenes
Propionibacerium
Lactobacillus
What are atypical
Cannot gram stain or be cultured
Ma be weakly gram +ve
Examples
Mycobacteriua - need ZN showing acid fast bacilli - M.TB - M. pneumonia - M.avium Legionella Chlamydia psittaci Coxiella burnetti
What are spirochaetes
Boreellia Burgdoferi
Treponema pallidum
Leptospirosis
What are ESBL
Organism resistant to B-lactam Ax by producing beta lactase enzyme which destroy ring
What organisms
E.coli
Klebsiella
Typically cause UTI
What are they sensitive to
Carbapenem
