Post-operative infection Flashcards
Learning outcomes
- List the six common infection sites that occur after operative surgery, explaining how each may arise
- Outline pre-operative, intra-operative and post-operative measures taken to prevent post operative infection
- Demonstrate an understanding of the rationale and use of perioperative prophylactic antimicrobials to prevent surgical site infection
- Identify and suggest suitable treatments for wound infections
- Describe the mode of action and spectrum of activity for three commonly prescribed antimicrobials: flucloxacillin, co-amoxiclav and vancomycin
6 common infection sites
- Superficial surgical site infection
- Deep surgical site infection
- Respiratory tract infection
- Venous access site infection
5.Urinary tract infection
(which may be associated with urinary catheters) - Gastrointestinal tract infection, specifically Clostridium difficile
- Superficial surgical site infection
Early onset versus late onset
-Commensal bacteria of the skin can become pathogenic
-Staphylococcus aureus the prime pathogen
-Contamination by the healthcare worker or environment may lead to a wider variety of organisms
MRSA possibly
-Foreign bodies get contaminated, the colonised, then possibly infected
- Deep surgical site infection
-The deep tissues manipulated, the organ space
-Sterile versus non sterile organ sites
-Clean (e.g bones, brain, peritoneal cavity etc) versus ‘Clean-contaminated’ surgery
-Skin organisms and organisms from the organ space microbiome
-Staph aureus, and GI or resp. tract microbiome
-Deep placed foreign bodies a specific risk:
Prosthetic joints
Prosthetic heart valves
- Respiratory tract infection
- Drugs to render you unconscious, pain free and to relax muscles
- Suppress respiratory funciton
- Pooling of secretions providing a nutritious environment for organisms
- Chest physiotherapy and breathing work important
- Organisms change over time in hospital
- Strep pneumo and H. Influenzae early, enterobacteriaceae and others later
- Venous access site infection
-Venous access a mainstay of patient care in perioperative period
-Peripheral Venous Cannulae (PVC) the commonest inserted devices used in Healthcare
-Staph aureus the commonest pathogen
-Foreign body infection:
Biofilm formation
Device removal
- UTI (may be associated with catheterisation)
-Urinary flow key to preventing overgrowth and ascension of bacteria from the perineum to the bladder and urethra
-Catheters used to manage the urinary tract, and sometimes to monitor fluid output
-Perineal bacteria contaminate, then colonise catheters. -Infection may result:
E. coli, other enterobacteriacaeae
Catheter removal ASAP
- GI Tract infection (specifically C.diff)
-Anyone in a hospital can acquire Clostridium difficile ( C. diff) infection
-Gram positive, Anaerobic, spore forming rod
-Other bacterial causes of hospital associated GI infections rare
Norovirus is a viral risk
-Antibiotics a key risk for this C diff infection
-Surgical cases often given antibiotics
-Perioperative antibiotic prophylaxis
Pre, intra and post operative measures taken to prevent post operative infection
Pre: -Screening for resistant organisms
-MRSA: may be given suppressive antibiotic/ antiseptic body wash
-Hair removal at the incision site on the day of surgery
-Clippers not razors
-Peri-operative prophylaxis
-Optimising nutrition and skin health
Intra- Ventilated operating rooms
-Negative pressure to the corridor and rapid air changes
-Sterile drapes, PPE and instruments
-Sterile: absolutely free from organisms including viruses and bacterial spores
-Skin preparation
-70% alcohol with Chlorhexidine/ Iodine
-Normothermia and tight glycaemic control
Post:-Wound care
-Antiseptic impregnated dressings
-Vacuum assisted wound closure
-Aseptic Non-Touch Technique ‘ANTT’
-Patient not to touch the wound
-Follow up for suture removal
-Many procedures use dissolvable closure material
Preoperative prophylaxis to prevent post-operative infection
-A prophylactic is intended to prevent the disease.
-Having a therapeutic level of antibiotic present within the tissues surrounding the surgical incision reduces the likelihood of post-operative surgical site infection
Clean (hernia, breast hip knee etc):
-Prophylaxis only if you are leaving something behind in the patient
Clean-contaminated (Cholecystectomy, bowel resection):
-Involving non-sterile sites without disruption: give prophylaxis
Contaminated (Gross contamination/spillage of GI tract, trauma wound):
-Give prophylaxis
Dirty/ infected (infected surgery, diverticulitis or empyema):
-Give Treatment rather than prophylaxis
Suitable treatments for wound infections
-Wound infections generally obvious clinically
-If suspected: samples please prior to antibiotics
-Not all SSI, or other wounds, need antibiotics
-Primary management is cleaning and dressing wounds
Silver dressings, antiseptics, honey, larvae etc
-Optimise skin and soft tissue health
-First sample, and dress appropriately
-If antibiotics needed treat empirically
Empirical: based on our knowledge of what commonly causes infection at a given site
-Staphylococcus aureus
-Always cover Staph aureus in wound infection
-Organ specific microbiome
-GI particularly. Organisms from the deep surgical site can cause superficial SSI
Flucoxacillin
-The drug: amended penicillin molecule to be stable against the staphylococcal beta-lactamase
-A ‘daughter’ drug of Meticillin which was first developed in 1950s
-Meticillin not used now, but MRSA named after it
-Different but similar drugs used in USA and Europe/Asia
In the UK this Flucloxacillin is the default choice for many non-severe skin infections, including superficial SSI, as long as there is no evidence the patient is colonised with MRSA.
* Staphylococcus Aureus
LECTURE 5 MSK FOR Tables
How flucoxacillin is used in practice
It has to be given 6 hourly at it has a relatively short half-life.
Patients at home taking PO antibiotic are not likely to take the drug every 6 hours overnight- as it would mean a midnight and 6am dose. The risk is prolonged intervals between dosing. This leads to a small amount of circulating antibiotic in the patient at certain times of the day: not enough to treat an infection, but possibly enough to encourage some drug resistance. We sometimes refer to ‘sub-lethal’ dosing of antibiotics and this is one of the ways that happens.
-Active against Staphylococcus aureus
-Per Oral or Intravenous (PO/ IV): Skin and soft tissue infection, including SSI Bone and joint infection Device related infection Endocarditis
Co-amoxiclav
-A combination of 2 drugs: a beta-lactam and a beta-lactamase inhibitor (increases spectrum of action)
-Amoxicillin and Clavulanic acid
-The beta-lactamase inhibitor makes the drugs Broader Spectrum
-Very commonly prescribed
“the antibiotic of choice for people who don’t like to think about antibiotics”
* streptococcus pneumoniae
How co-amoxiclav is used in practice
- Broad spectrum, can be given orally, safe
- PO/ IV
- Intra-abdominal infection (both aerobic and anaerobic gram-negative activity)
- Used for perioperative prophylaxis in clean-contaminated surgery
- Complicated ear/ nose/ throat/ paranasal sinus infections
Vancomycin
- Glycopeptide antibiotic
- Teicoplanin is a sister drug
- Cell wall active, but not at the transpeptidase enzyme/ penicillin binding protein
- Prevents the making of peptidoglycan chains
- Vancomycin usually given by IV infusion over some hours
- Fast administration causes ‘red man syndrome
Don’t penetrate or cross cell membranes well. So if you give them IV they tend to stay largely in the blood and they will be filtered into the kidneys. Likewise if you give them orally they tend to stay in the GIT.
At the bacterial cell these drugs embed themselves into the cell membrane of bacteria where they block the transport of peptidoglycan monomers from the cell cytoplasm (where they are synthesised) to the cell wall.
Act on different place to beta-lactam drugs- not affected by MRSA (produces beta lactamase)
Also used in penicillin allergic patients. In those settings it often has to be combined with another drug that has activity against gram negative species.
* C.diff
How vancomycin is used in practice
Gram positive cover
- PO* / IVI
- MRSA (and other resistant gram positives)
- Penicillin / Beta-lactam allergy
- Nephrotoxic potentially
*Oral Vancomycin only ever given for Clostridium difficile diarrhoea
