IWII Curriculum All modules Usage This slide

IWII Curriculum All modules

Usage This slide set belongs to the International Wound Infection Institute (IWII) and is meant to accompany a suggested curriculum outline for persons training in the clinical management of wound infection management. The IWII gives permission for it to be used by our members for educational purposes on condition that the IWII is acknowledged at all times and that this formatting is maintained. The IWII is grateful to Jacqui Fletcher, Caroline Dowsett and Val Edwards-Jones for the provision of this content

Infection All modules

Cellulitis All modules

Wound Bed Preparation Care Cycle Start with The patient No Prevention Yes Healed Wound Bed Preparation Identify wound aetiology Care Cycle Treat & evaluate TIME interventions Dowsett 2004 Modules 1 - 3 Perform TIME Assessment Agree goals

What is WBP? • Wound bed preparation (WBP) is a way of focusing systematically on all of the critical components of a non-healing wound to identify the possible causes of the problem…. it focuses on the components of local wound care: debridement, bacterial balance and moisture balance Sibbald et al, 2000; Dowsett and Ayello, 2004 Modules 1 - 3

Time*‡ - Principles of wound bed preparation Clinical Observations Proposed Pathophysiology WBP Clinical Actions Effect of WBP Actions Clinical Outcome TISSUE Defective matrix and cell debris impair healing Debridement (episodic or continuous) • Autolytic, sharp surgical, enzymatic, mechanical or biological • biological agents Restoration of wound base and functional extra -cellular matrix proteins Viable wound base INFECTION OR High bacterial counts or prolonged inflammation inflammatory cytokines protease activity growth factor activity • remove infected foci Topical/systemic • antimicrobials • anti-inflammatories • protease inhibition Low bacterial counts or controlled inflammation: inflammatory cytokines protease activity growth factor activity Bacterial balance and reduced inflammation MOISTURE Desiccation slows epithelial cell migration Apply moisture balancing Restored epithelial cell dressings migration, desiccation avoided Excessive fluid causes maceration of wound margin Compression negative pressure or other methods of removing fluid Oedema, excessive fluid controlled, maceration avoided Non migrating keratinocytes Non responsive would cells and abnormalities in extracellular matrix or abnormal protease activity Re-assess cause or consider corrective therapies • debridement • skin grafts • biological agents • adjunctive therapies Migrating keratinocytes and responsive wound cells. Restoration of appropriate protease profile NON-VIABLE OR DEFICIENT INFLAMMATION IMBALANCE EDGE OF WOUND – NON ADVANCING OR UNDERMINED *Courtesy of International Advisory Board on Wound Bed Preparation 2003 Adapted from table 6 - ‡Schultz GS, Sibbald RG, Falanga V et al. Wound Rep Reg (2003)11: 1 -28 Wound Bed Preparation and TIME are clinical concepts supported by Smith & Nephew Medical Ltd Modules 1 - 3 Moisture balance Advancing edge of wound

Comparison of commonly used antimicrobials Gram +ve Gram -ve Fungi Endospores Viruses Resistance Chlorhexidine +++ ++ + 0 + + Honey +++ +++ 0 Iodine +++ +++ ++ 0 Maggots +++ ++ ND ND ND 0 Silver +++ + ND + + Modules 1 - 3

Significance of bacteria in wounds • Bacterial colonisation is of no clinical significance and should not be confused with wound infection • A recognised definition of wound infection is if a wound contains 106 bacteria per gram of tissue • Chronic wounds may contain 108 without any obvious signs of infection (host reactions) Modules 1 - 3

Continuum Modules 1 - 3

Occasion al & shortlived state following thermal trauma Usual microbe start point at wound initiation Normal state: normal healing progress Delayed healing, Wound deteriorati on and / or extension Sterility Contaminati on Colonisati on Local infection Deteriorati on, spreading cellulitis, systemic signs of infection Systemic infection Abnormal progression for primary intention wounds Abnormal progression for all wounds Normal progression for secondary healing wounds Increasing microbial bioburden; increasing severity Modules 1 - 3

Uncertainties with swabs 1. Difficulties in removing adherent microbes 2. Uncertainty around the efficiency of recovering organisms attached to the swabs 3. Change in the local environment during transport may affect the viability of the organisms 4. Clinical specimens should ideally reach the lab within 4 hours 5. Specialist facilities and expertise are essential for the characterisation of anaerobes Modules 1 - 3

The cost of wound care in a local UK community (population = 590, 000) Wound care costs Dressings and other materials 2005 £ 3. 21 m Percent 15. 3% Nurse time £ 6. 71 m 31. 9% Hospital costs £ 11. 1 m £ 21. 02 m 52. 8% 100. 0% Total Drew P, Posnett J, Rusling L. The cost of wound care for a local population in England. Int Wound J 2007; 4: 149 -155 Modules 1 - 3

Examples of Clinical Disease Viruses Bacteria Fungi Influenza Tuberculosis Ringworm Malaria Hepatitis Cholera Thrush Tapeworm Rabies Tetanus Aspergillosis Schistosomiasis HIV/AIDS Gas gangrene Cryptosporidium Polio Gonorrhoea Giardia Chicken pox Diphtheria UTI Wound infections Modules 1 - 3 Parasites

Terminology • Bacteria are classified in a structured manner and their names are assigned accordingly – Eg Families – Enterobacteriacae (coliform) – a group name that contains a number of different genera! – Genera – Staphylococcus – Species – aureus – Strain (sub-type) – phage type 29/52 – Methicillin resistant Staphylococcus aureus – Common terms, MRSA, MSSA, VISA, GISA – EMRSA 15, EMRSA 16 • Epidemic MRSA Modules 1 - 3

Staphylococci and streptococci in gram stain of pus Modules 1 - 3

Gonococcus in urethral pus Modules 1 - 3

Common wound sampling procedure using a moist swab Modules 1 - 3

Identifying Bacteria in the Wound 10 point Method Cleanse bed Zig Zag and rotate 360 o Avoid debris and frank pus Levine Method: Cleanse bed Rotate over 1 cm sq Press firmly into tissue C Preliminary analyses of 78 study wounds Levine’s best of 3 swab techniques in terms of 4 validity parameters: sensitivity. 70, specificity. 90, positive predictive value. 79, accuracy. 81. www. hsrd. research. va. gov/research/abstracts/NRI_01 -005. htm (Levine, Lindberg, Mason, Pruitt. (2004) Advances in Skin & Wound Care) Levine, Lindberg, Mason, Pruitt.

Should we just sample the infected looking areas? Imagine how many swabs would be generated per wound! Modules 1 - 3

IWII Curriculum Module 1 - Fundamental

Goal and Objectives Aim is to give the student an understanding of microbiology and epidemiology within the context of wound infection On completion of the module, students will be able to: • Explore how microbes exist and function • Differentiate the different types of microbes and their significance in wounds • Describe common microbes relevant to wounds (common causative agents) • Review the frequency of wound infection in healthcare environment • Relate this knowledge to your clinical practice • Describe common terminology related to wound infection

Patient assessment 1. 2. 3. 4. 5. Host risk factors Levels of bacteria Local or systemic infection Impact on the patient Impact on the wound Module 1

When reading the literature a good understanding of the techniques and their shortcomings is essential in order to make reasoned comparisons. Module 1

Host risk factors - systemic • • Vascular disease Diabetes Malnutrition Immuno suppressed Patients on corticosteroids Smoking & alcoholism Surgery or radiation Module 1

Host risk factors – local • • Large wound area Increased wound depth Degree of chronicity Anatomic location: distal extremity, perineal Foreign body Necrotic tissue Reduced perfusion

Using antimicrobials • Antimicrobials are agents that either kill or inhibit the growth and division of micro – organisms. • They include: – antibiotics - act on specific cellular target sites – antiseptics, disinfectants and other agents - act on multiple cellular target sites Module 1

IWII Curriculum Modules 1 & 2 Fundamental / Intermediate

What is important? • • Numbers Clinical signs and symptoms Systemic signs Both Modules 1 & 2

Recognising infection Traditional criteria • Cellulitis • Redness • Heat • Swelling • Discharge • Pus Cutting & Harding 1994 Modules 1 & 2 Additional criteria • Delayed healing • Friable tissue/bleeds easily • Pain • Pocketing at wound base • Abnormal smell • Wound breakdown

Indications for topical antimicrobials Wounds with necrotic or poor blood supply Wounds continually recontaminated or infected Patients with Wounds benefiting specific AB allergy from delayed 1 o or AB resistant closure infections Systemic antibiotics may not penetrate infected ischaemic tissue at therapeutic doses; local agents may be more successful High levels of bacterial contamination at wound site delays healing. Prolonged AB cover is undesirable. Topicals reduce burden and may prevent re infection Particularly where prolonged systemic AB therapy has failed in infected open wounds Melling, Gould and Gottrup 2006 Modules 1 & 2 May initially be left open and treated with topical antimicrobials. Usual free form infection after few days & can be cleaned and closed with prophylactic AB

Choosing an antimicrobial agent Factors to consider Agent • Specificity • Efficacy • Cytotoxicity • Allergenicity Modules 1 & 2 Dressings • Absorbency • Conformability • Odour management • Pain management • Wound size • Wound location • Patient preference • Sustained antimicrobial activity • Provides a moist wound healing environment • Allows consistent delivery over the entire surface of the wound • Allows monitoring of the wound with minimum interference • Comfortable • Conformable

Starting point… There is no evidence that bacteria need to be removed from wounds in order to make them heal… Modules 1 & 2

Definitions • Antibiotic – An agent that kills selectively and requires metabolic activity for it’s action. Antibiotics can be bacteriostatic or bactericidal • Antiseptic – A non selective agent that does not require metabolic action for efficacy. Always bactericidal and usually surface acting. • Antimicrobial – An umbrella term Modules 1 & 2

Common bacteria in wounds Aerobic Anaerobic • • • • Staph. Aureus Staph. epidermidis MRSA Enterococcus faecalis Streptococcus pyogenes Pseudomonas aeruginosa Enterobacter Escheria coli Klebsiella spp Proteus spp Modules 1 & 2 Bacteriodes spp Prevotella spp Peptostreptococcus spp Clostridia

Major wound pathogens • • Staphylococcus aureus Pseudomonas aeruginosa and other Gram-negative bacilli Streptococcus pyogenes Other streptococci Enterococci Candida sp and Aspergillus sp Anaerobes (dependant upon site) Viruses (Herpes and CMV) Modules 1 & 2

Diagnostic signs of infection • Clinical signs • Pain, redness, swelling, increased exudate, change in exudate colour, bad wound odour, increased wound temperature • Properties of the microbe • What infects a wound? – mixed skin flora from the patient – endogenous pathogens – exogenous pathogens Modules 1 & 2

Typical ‘normal’ skin flora • Highly diverse – hundreds of bacterial species amongst 6 individuals • Only a few bacteria are common among the individuals These included – – Propionibacteria, Corynebacteria, Staphylococcus spp, Streptococcus spp. Davies CE et al Wound Repair Regen 2001, 9: 332 -340; Dekio I et al J Med Microbiol 2005, 54: 1231 -1238. Modules 1 & 2

Staphylococcus aureus – 1882 • Staphyle (Greek for bunches of grapes) Sir Alexander Ogston (Scottish Physician) Modules 1 & 2

Antimicrobial agents • • Antibacterial agents Antifungal agents Antiviral agents Antiparasitic agents Modules 1 & 2

Numbers • May be expressed as +, +++ or heavy moderate or light growth. • Identifies relative proportions of isolates from the distribution on the primary isolation plates • Level of detail is usually sufficient to make clinical decisions if use in conjunction with clinical signs and symptoms Modules 1 & 2

Taking a swab • Gently irrigate the wound ensuring any remnants of dressings / creams are removed • Apply the swab in a zig zag motion lightly across the whole surface of the wound whilst rotating the swab backwards and forwards or use the Levine method • Transport the swab in transport medium • Store at 40 C if processing is likely to take more than 24 hours Lawrence 1999 Modules 1 & 2

The Levine Technique Step 1: Debride the wound Step 2: Irrigate the wound Step 3: Rotate swab over 1 sq cm of the wound bed with sufficient pressure to encourage fluid to ‘bubble up’ around the swab Modules 1 & 2

Skin Characteristics • • • Limited moisture Acid p. H of normal skin Surface temperature Salty sweat Excreted chemicals; sebum, fatty acids and urea Normal flora Modules 1 & 2

Skin • Alterations to the normal flora upsets the ecological balance and predisposes to infection • Some microorganisms can overcome the natural barrier of the skin to cause disease – arid areas colonised predominantly by Gram positives – moister areas colonised by numerous species and also Gram negatives Modules 1 & 2

Breaches of the skin • Acute wounds – minor trauma • accidental lacerations / superficial • minor burns – major trauma • major burns • surgery • Chronic Wounds • pressure sores • leg ulcers • non healing wounds Modules 1 & 2

Infectious process Contamination Colonisation What tips the balance? Local infection Spreading Infection Modules 1 & 2 This is a dynamic process and depends upon a number of important factors

Immunological status of the host Nutritional status of the host Bacterial population Infection vs colonisation Depth and site of infection Modules 1 & 2 Environment dressings Virulence factors

IWII Curriculum Module 2 - Intermediate

Biofilms Module 2

IWII Curriculum Modules 2 & 3 Intermediate / Advanced

Minimum inhibitory concentration (MIC) • Minimum concentration of silver required to inhibit bacterial growth / division • Does not equal death of bacteria • MIC and zone of inhibition (ZOI) may contribute to development of resistance • Use of solutions such as sodium thiosulphate will also affect the test (use for extracting metal ore, gives a very stable (i. e. not bioavailable) silver thiosulphate) Modules 2 & 3

Minimum bacterial concentration • Used to assess killing activity • Data in the literature supports the use of silver concentrations above 30 mg Ag+ / l • A silver concentration identified as effective in in vitro killing assays, may represent a threshold concentration for in vivo activity Spaccioli et al 2001 Yin et al 1999 Modules 2 & 3

Log reduction • Measured by: the number of bacteria present at the start, minus the number of bacteria present at the end – e. g. 109 – 107 = Log reduction of 2 – 109 – 102 = Log reduction of 7 • Therefore the log reduction of 7 shows a greater reduction in bacterial count Modules 2 & 3

Kill time • Translocation of bacteria occurs if the kill time is slow • Gives deep tissue infection • Gradient of kill, maximum lethal concentration occurs centrally to the silver ion • Practically better to overlap the dressing onto the good skin and gradation occurs here (may get skin staining) Modules 2 & 3

Systemic signs • Raised white cell count • Raised serum C- reactive protein Modules 2 & 3

Numbers • Usually expressed as CFU’s per gram or cm 2 of tissue • 105 widely accepted as the threshold which indicates infection if exceeded • Bowler (2003) suggests treatment should be based on a host manageable burden Modules 2 & 3

Clinical signs and symptoms • • • Several definitions CDC NPS Sepsis ASEPSIS WIS Modules 2 & 3

To diagnose infection laboratory results must be evaluated in conjunction with local findings such as erythema, oedema, pain, purulence and lymphadenitis or systemic factors such as fever, leukocytosis or glucose intolerance in patients with diabetes. Organisms in wound fluid are not necessarily invading and may only be indicative, not diagnostic of infection. Mc. Gukin et al (2003) Modules 2 & 3

Debridement • • Mechanical Enzymatic Autolytic Larval Sharp Hydrosurgery Surgical Modules 2 & 3

Acute vs Chonic Wounds Acute wounds Chronic wounds Healing Process Regulated Haphazard Pathology None Underlying Time to healing Rapid Slow Inflammatory response Short Prolonged Exudate Reduced after 48 hours Promotes cellular proliferation Prolonged Inhibits cellular proliferation Bacterial Load Low High Fibroblast proliferation Active Inactive Excoriation/maceration Infrequent Frequent Extracellular matrix Normal remodelling Defective remodelling Vascular network Good Poor Complications Infrequent Frequent Progress Heal Fail to heal / recur Modules 2 & 3

Acute wounds Chronic wounds Time bound Of short duration Do not heal within 4 weeks (Cullum et al 1997) Recurrence Unlikely to recur Characterised by episodes of recurrence Pathophysiology No underlying disease process Multiple underlying pathologies Healing process Orderly healing Disordered healing, wound may improve and then deteriorate in a cyclical fashion Inflammatory response Progresses through inflammation to proliferative phase Appears to be ‘stuck ‘ in late inflammatory phase (Hart 2002) Exudate Thought to be beneficial, exerts antimicrobial effect and contains growth factors May be detrimental due to imbalance in production of MMPs and suppression of TIMPS Quantity of exudate Reduces as healing progresses May remain high due to persistent inflammation Aetiology Surgical wounds, traumatic wounds, burns Pressure ulcers, leg ulcers, diabetic foot ulcers, fungating wounds Modules 2 & 3

Determinants of wound costs • Dressings and other materials typically represent 10%-15% of total wound care costs • Nursing time typically represents 25%-30% • Hospital inpatient costs represent the largest single component of cost at 50%+ The key to reducing cost is to prevent hospital admission and/or delayed discharge by preventing wound complications Modules 2 & 3

Wound healing stages I. Inflammatory phase II. Proliferative phase III. Remodelling phase Modules 2 & 3

Factors that delay healing • Age • Social factors • Poor nutrition • Reduced oxygen supply to the wound • Glycated growth factors • Metalloproteases • INFECTION

Diagnosis of Infectious Disease Non-cultural methods Cultural methods Media Atmosphere Temperature Microscopy Most bacteria & fungi Modules 2 & 3 Antigen Detection Toxin Detection Molecular Methods Serology TB UTI Parasites Hepatitis Rotavirus RSV Cl difficile Chlamydia Hepatitis Diptheria Meningococcus Most TSS MRSA viruses

Microscopy Light microscopy • Uses normal light and stained or unstained preparations. – Detects parasites, fungi and bacteria. Fluorescent microscopy • Uses special stains that fluoresce under UV light. – Detects fungi and bacteria Dark ground microscopy • Uses indirect lighting to visualise difficult organisms. – Detects special bacteria such as spirochaetes Electron microscopy • Uses an electron beam to visualise the smallest particles. – Detects viruses and large molecules Modules 2 & 3

Antimicrobial therapy History • • Plant extracts Arsenic compounds Paul Erhlich 1854 -1915, selective affinity for dyes Domagk, sulphonamides Fleming 1929, Penicillin Florey and Chain 1939 Waksman, 1944, soil microbiologist, streptomycin Modules 2 & 3

Bacterial cell- target sites Modules 2 & 3

Sterile culture media in petri dishes Modules 2 & 3

Conventional techniques +++ ++ + Modules 2 & 3

Typical bacterial growth from clinical specimen Modules 2 & 3

Beta-haemolysis on blood agar Modules 2 & 3

Bacterial identification Modules 2 & 3

Staph aureus sensitivity by Stokes’ method Modules 2 & 3

Modules 2 & 3

Microorganisms reported causing SSI's for all categories of procedure 3 2 1 53% 4 4 26 5 21 14 3 8 Modules 2 & 3 9

Infection • When is a wound infected? – Clinical signs – Pain, redness, swelling, increased exudate, change in exudate colour, bad wound odour, increased wound temperature • Properties of the microbe • Wounds sterile immediately after trauma but inevitably become colonised • What infects a wound? – Mixed skin flora from the patient – Endogenous pathogens (from other body sites) – Exogenous pathogens (from other patients, staff) Modules 2 & 3

Classifying Infection • Superficial or localized infection: – Non-healing, Bright red granulation tissue, Friable and exuberant granulation, New areas of breakdown or necrosis, Increased exudate, Bridging of soft tissue and the epithelium, Foul odour • Spreading infection: – Deep wound infection: Pain, induration, Erythema (> 2 cm), Wound breakdown, Increased size or satellite areas, Undermining or tunnelling, Probing to bone, Flu-like symptoms • Systemic infection: In addition to deep wound infection, Fever, Rigours, Chills, Hypotension, Multi-organ failure

Microbial colonisation • Highly nutritious surface for bacteria to colonise – Moisture, protein, optimum temperature… • Incidence of serious infection varies with the size and depth of the wound – Non-invasive infection is confined to the superficial layers • Organism can invade from heavily colonised wounds into viable tissue – Destruction of tissue due to extracellular enzymes and toxins Modules 2 & 3

Stationary phase production of toxins and invasive enzymes Log phase (Exponential Multiplication) Production of competitive factors Quorum sensing 10^6 cfu/ml Lag phase (Adaptation) Production of adhesions CONTAMINATION COLONISATION LOCAL INFECTION SPREADING INFECTION This is a dynamic process and a number of factors can alter the process Modules 2 & 3

Chronic wounds – why do they not heal? ? • Static • Matrix metalloproteases (MMPs) – endogenous – cellular – exogenous – bacterial • Inhibition of growth factors • Local infection? – what does this really mean? Modules 2 & 3

A Biofilm – What is it? • Complex aggregation of microorganisms marked by the excretion of a protective and adhesive matrix. • Often characterized by surface attachment, structural heterogeneity, genetic diversity, complex community interactions, and an extracellular matrix of polymeric substances. • Single-celled organisms generally exhibit 2 distinct modes of behavior: – planktonic - free floating, form in which single cells float or swim independently in some liquid medium. – sessile- an attached state in which cells are closely packed and firmly attached to each other and usually a solid surface. • Change in behaviour is triggered by many factors, including quorum sensing, as well as other mechanisms that vary between species. Modules 2 & 3

Biofilm Modules 2 & 3

Interaction with the environment • Wound dressings – Increased / decreased TSST-1/protease production • Buck et al 2004 Ph. D thesis • Topical antimicrobial compounds – Increased / decreased TSST-1 production – Inhibition of staphylococcal metalloproteases • Edwards-Jones, V and Foster, H. A 2002. The effects of silver sulphadiazine on the production of exoproteins by S. aureus J Med Micro 51(1): 50 -5. What affect will superantigens have on the immediate wound environment? Modules 2 & 3

Should we take punch biopsies to measure invasiveness? Quantitative versus qualitative data? ? Modules 2 & 3

Virulence factors • Enzymes – spreading factors, proteases (8 types including MMP’s) collagenases, hyaluronidase, elastase • Toxins – lecithinase, superantigens , eg TSST-1, staphylococcal enterotoxins, streptococcal exotoxins, Pseudomonas exotoxins • When are these produced? ? Modules 2 & 3

Zone of inhibition (ZOI) • Shows the area across which spread of bacteria is inhibited (NB not killed) • Zones are not proportional to silver release • Should not be used as silver complexes with many of the components of the media making the observations purely qualitative Modules 2 & 3

IWII Curriculum Module 3 - Advanced

Basic bacterial classification Bacterial Shape Coccus (spherical) Bacillus (rod shaped) Gram reaction Gram positive Gram negative (Staphylococcus Streptococcus) (Neisseria: gococcus) (Bacillus Clostridia) (‘Coliforms’ Pseudomonas) Coccus (pl. cocci) comes from the Greek and Latin kokkus meaning berry. Bacillus (pl. bacilli) is from the Latin baculum meaning rod or stick. Staphylo is from the Latin staphule – a bunch of grapes. Module 3

Molecular techniques • Population analysis studies – PCR- Amplify 16 s ribosomal DNA – separate using Denaturing Gradient Gel electrophoresis- (DGGE) – sequence the gene fragments James et al (2008) - Biofilms in Chronic Wounds Wound Repair and Regeneration 16: 37 -44 Davies CE et al (2004) Use of 16 S ribosomal DNA PCR and denaturing gradient gel electrophoresis for analysis of the microfloras of healing and nonhealing chronic venous leg ulcers. J Clin Microbiol. ; 42: 3549 -57 Module 3

Polymerase chain reaction (PCR) Increase the number of copies of the genes Module 3

Denaturing gradient gel electrophoresis (DGGE) Module 3

DNA sequencing Different coloured bases (ATCG)-capillary sequencing Module 3

Antimicrobial activity depends upon several factors • • • Exposure (time) Concentration Temperature p. H Presence of organic matter Use of permeabilisers Module 3

Break point sensitivity Module 3

Module 3

Module 3

Quorum sensing • Effector molecules are produced by individual cells and cumulated within the environment – Homoserine lactones (gram negatives) – Octapeptides (gram positives) • At certain concentrations they can switch on (or off) genes in a coordinated manner Use as vaccines? ? Module 3

Regulatory stimuli • • p. H Temperature Iron availability Calcium Trace metals (including silver, but zinc most common) Oxygen availability Carbon dioxide Accumulation of ppp. Gpp (phosphorylated dinucleotides) Can we use these to our advantage? Module 3