Week 2 - Sepsis Flashcards
What are antibiotics?
Substances produced naturally by microorganisms which can kill (microbiocidal) or inhibit the growth (microbiostatic) of other microorganisms
What is selective toxicity?
Harming the infectious agent without harming the host’s cells.
e.g. penicillin stops peptidoglycan formation in the bacterial cell wall.
What is the difference between Bactericidal and Bacteriostatic?
- Bactericidal: lyse and kill microbes by directly damaging specific cellular targets.
- Bacteriostatic: inhibit reproduction
What are Cephalosporins and how do they work?
A class of drugs that have the same basic structure as the penicillins but have a broad spectrum of activity. They cause lysis of bacteria by interfering with the ability of bacteria to form cell walls. e.g. Ceftriaxone
Explain how tetracyclines work?
- very broad spectrum ‐ act against G+ and G‐
– bacteriostatic ‐ inhibit protein synthesis
How does penicillin lead to an allergic reaction?
the penicillin molecules become antigens when the breakdown products of penicillin combine with blood proteins to form larger molecules that stimulate the immune system.
What is a major concern with broad spectrum antibiotics?
They destroy normal flora, leading to other microbes resistant to the drug invading the unoccupied body sites and multiplying rapidly. This is called superinfection.
What is the process by which bacteria become antibiotic resistant?
Resistance is due to the possession by bacteria of a resistance gene(s)
Resistance genes stop drug action in a number of different ways: • inactivation of drug by enzyme • alter the drug target • stop entry or increase exit
Resistant genes arise by mutation or plasmid transfer
What is the sequence for putting on and removing PPE?
Putting on: Gown - mask/respiratory - goggles/face shield - gloves
Removing: gloves - goggles - gown - face shield
Define the following terms:
- Sterilisation
- Disinfection
- Antisepsis
- Asepsis
- Sterilisation: complete removal of all forms of microbial life
- Disinfection: process of destroying vegetative pathogens but not necessarily endospores or viruses.
- Antisepsis: chemical disinfection of the skin or other living tissue
- Asepsis: the absence of pathogens from an object or area
What factors affect the removal of microorganisms?
- Number of microbes - die at a constant rate
- Type of microbe - G- bacteria are harder to kill with disinfectants, Mycobacteria are resistant to disinfectants
- Organic matter - pus or vomit protect by covering the microbe
What are the main types of disinfectants?
- Halogens: good against bacteria, viruses, fungi but inactivated by organic matter
- Virkon S: contains potassium peroxymonosulfate and a detergent which increases its effectiveness in dirty conditions
Both bleach and Virkon oxidize proteins to disrupt the cell membrane and have wide spectrum of activity against viruses and bacteria. - Alcohols: good against bacteria, do not penetrate organic matter, act rapidly
- Chlorhexidine: used for disinfection of skin and mucous membranes, good against gram positive bacteria, inactivated by organic matter
What is viral Hepatitis and what is it caused by?
Inflammation and damage to the liver resulting in fever, anorexia, nausea, vomiting and jaundice, maybe liver failure.
Caused by a wide variety of viruses: hepatitis A & E - faecal-oral spread, B/C/D/G - blood-borne
Diagnosis is based on serology
Explain Hep A epidemiology: spread, replication, incubation
Excreted in faeces and contaminates food or water (can also be spread sexually), replicated in intestine wall then goes via blood to the liver producing a cell mediated immune response which causes liver damage. Incubation period is 2-6 weeks followed by symptoms lasting 2-3 months.
Most at risk groups include child care centres, men who have sex with men, IV drug users
Hep A, B and C epidemiology:
Standard, Contact and Droplet precautions for patients with Hepatitis
- A: excreted in faeces, can also spread sexually; virus replicates in intestine wall then goes via blood to the liver; incubation period 2-6 weeks, once you have had it you cannot get it again, vaccine is available
- B: 100x more infectious than HIV, half with chronic hep B are undiagnosed, Hep B vaccine being part of infant immunisation schedule
- C: 20% have moderate to severe liver disease, needle sharing is principle route of hep C in Aus, no vaccine
