Hosptial Acquired Infections

Question 1

How is the nature of HAI changing?

Answer 1

Invasive procedure, prosthetic and implantable decises
Obesity
Diabetes
Extremes of age
Immunosuppression
Emerging organisms/ resistance
Scanning of EM or biofilm on vacs cath 24 hours post insertion

Question 2

Why are organisms increasingly resistant?

Answer 2

Widespread prolonged used of broad spectrum abx
Mrsa
Vre/gre 
Esbl 
Multi resistant gram negatives

Question 3

How does the environment effect transmission?

Answer 3

Environmental hygiene- c diff, norovirus, acinetbacter breakouts
Environmental sources- legionella in cooling towers, aspergillus in building works
Negative pressure isolation- TB, chicken pox and RSV

Question 4

How many patients that come into UK experience hai?

Answer 4

10%

Question 5

What is the most common HAI?

Answer 5

GI system- c diff, norovirus
UTI
Surgical site

Question 6

What percentage of HAI do mrsa and c doff account for?

Answer 6

15%

Question 7

What has driven reductions in mrsa and c diff?

Answer 7

Mandatory surveillance
Code of practice
Inspections
Not the same reductions in other avoidable HAI

Question 8

What is the most common organism causing ha- UTI?

Answer 8

E. coli 
S saprophytic 
Proteus
Kleb and other coli forms 
Enterococcus and pseudo

Question 9

What are UTI coli forms?

Answer 9

Gram negative rods, commensals in colon
Lactose fermenting- E. coli, klebsiella, enterobacter, serratia, citrobacter
Non lactose fermenting- proteus, pseudomonas

Question 10

What is the relationship between UTI and catheters?

Answer 10

Catheters become rapidly colonised 
60% colonised within 96 hours 
Predispose to invasion
Heavy bacterial load in bag
Asymptomatic bacteruria in elderly 
Catheter infections- treat sepsis only

Question 11

What resistant mechanisms are common with hai UTI?

Answer 11

Chromosomal, plasmid mediated
E. coli less than klebsiella, less than enterobacter
ESBl- enzymatic mechanism

Question 12

What is the mechanism of resistance for carbapenem?

Answer 12

Hydrolysis of carbepenam
Very transmissible
Lots of resistance 
Prolonged carriage part of gut flora 
Meropenem use for esbl urosepsis

Question 13

What key organisms have resistance?

Answer 13

E. coli, kleb, pseudo, strep pneumo

Carbopenemase producing enterobacteria- increased

Question 14

What is the spectrum of activity for following bacteria?
Flucloxacillin 
Co amxiclav
Metro
Pipeqcillin- tazobactem
Amoxicillin
Ciprofloxacin 
Gentamicin 
Meropenem 
Colistin

Answer 14

Flucloxacillin- gram positive, narrow
Co amxiclav- pos, neg, anaerobes, broad
Metro- anaerobes, narrow
Pipeqcillin- tazobactem- hosp neg, some pos, anaerobes, pseudo, broad
Amoxicillin- positive, negative, anaerobes, broader than co- amox
Ciprofloxacin- gram neg, pseudomonal, broad
Gentamicin- gram neg, narrow
Meropenem- hosp gram neg, gram positive, anaerobes, pseudo, broad
Colistin- hosp gram neg including carb resistant, broad

Question 15

What are the contributors to SSI?

Answer 15

Host defence- pre op care
Wound environment- intra op care and skill
Pathogens- decontamination

Question 16

What two factors relate to pathogens in SSI?

Answer 16

Innoculum- bacteria from skin tissue, intrinsic
Bacteria from air, instruments, HCW, extrinsic
Largest when site is heavily colonised
Small bowel less than right colon less than sigmoid
Intra operative contamination
Virulence- MSSA more than coag neg staph

Question 17

What factors relate to the wound environment in SSI?

Answer 17

Haemoglobin
Necrotic tissue
Foreign bodies, absorbable sutures better than silk
Dead space

Question 18

What factors relate to host defence in SSI?

Answer 18

Shock 
Hypoxia 
Hypothermia 
Glycemic control
Chronic illness 
Immunosuppressive agents

Question 19

What are the 7 high impact interventions?

Answer 19

Central venous catheter care 
Peripheral intravenous cannula care 
Renal dialysis catheter care 
Prevention of SSI 
Care for ventilated patients or tracheostomy 
Urinary catheter care 
Reducing risk of c diff

Question 20

Who should undergo mrsa screening and decontamination?

Answer 20

All patients undergoing implant, cardiothoracic, orthopaedic and neuro procedures
Large bowel, small bowel, cholecystectomy, bile duct, liver and pancreatic surgery most common
Deep space infection 1/3
Organisms changing over time- s aureus falling, enterobacteria more prevalent

Question 21

What percentage of HAI are preventable?

Answer 21

15-30%

Question 22

What is c diff?

Answer 22

Gram positive spore forming anaerobes
Spores transmissible, contaminate environment, persist
Ingested spores germinate in gut
Gut flora disturbed by abx exposure to different extents

Question 23

What are the virulen factor for c diff?

Answer 23

Toxins a and b, diarrhoea and colitis
Dehydration, pseudomembranous colitis, perforation
Worse in older, debilitated, abx treated

Question 24

What is c diff management?

Answer 24

Recognise or suspect cases, test stool and isolate patient 
Stop abx for other infections 
Stop gi active drug 
Assess severity 
Fluid resus, electrolyte correction, nutrition review 
Metro for 2 weeks, vanco second line 
Severe- vanco oral, qds for 2 weeks 
Fidaxomicin- role in reducing recurrence

Question 25

What is the management for severe and life threatening c diff?

Answer 25

Vanco- 500 mg oral qds
Plus minus iv metro
Iv immunoglobulin
Life threatening- colectomy, vanco, intracolonic vanco, iv metro, ivig

Question 26

What is the management for recurrent c diff?

Answer 26

Relapse common, repeat treatment with same agent 
Prolonged taper oral vanco
Pulsed dosing oral vanco 
Faecal transplant 
Ivig

Question 27

What are novel approaches to manage c diff?

Answer 27

Faecal transfer- fresh faeces, healthy donor, in saline, filtered, administer NG
Tablets formulations of faeces becoming available
Reduction in recurrence
Administr Non-toxigenic c diff- non pathogenic, may occupy the niche of pathogenic types

Question 28

How does Mrsa infection occur?

Answer 28

Preceded by colonisation
Skin breach- skin disease, chronic disease resulting in skin lesions
Invasive procedure, device