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Microbiology > Hosptial Acquired Infections > Flashcards

Flashcards in Hosptial Acquired Infections Deck (28):
1

How is the nature of HAI changing?

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

2

Why are organisms increasingly resistant?

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

3

How does the environment effect transmission?

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

4

How many patients that come into UK experience hai?

10%

5

What is the most common HAI?

GI system- c diff, norovirus
UTI
Surgical site

6

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

15%

7

What has driven reductions in mrsa and c diff?

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

8

What is the most common organism causing ha- UTI?

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

9

What are UTI coli forms?

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

10

What is the relationship between UTI and catheters?

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

11

What resistant mechanisms are common with hai UTI?

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

12

What is the mechanism of resistance for carbapenem?

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

13

What key organisms have resistance?

E. coli, kleb, pseudo, strep pneumo
Carbopenemase producing enterobacteria- increased

14

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

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

15

What are the contributors to SSI?

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

16

What two factors relate to pathogens in SSI?

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

17

What factors relate to the wound environment in SSI?

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

18

What factors relate to host defence in SSI?

Shock
Hypoxia
Hypothermia
Glycemic control
Chronic illness
Immunosuppressive agents

19

What are the 7 high impact interventions?

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

20

Who should undergo mrsa screening and decontamination?

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

21

What percentage of HAI are preventable?

15-30%

22

What is c diff?

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

23

What are the virulen factor for c diff?

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

24

What is c diff management?

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

25

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

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

26

What is the management for recurrent c diff?

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

27

What are novel approaches to manage c diff?

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

28

How does Mrsa infection occur?

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