Wound Bioburden Flashcards
(30 cards)
What are the roles of skin, microflora, and immune cells in preventing wound infection?
- Skin acts as a mechanical barrier; oils and sweat chemically prevent bacterial entry.
- Microflora on skin and in the digestive tract protect against pathogens.
- Immune cells and an acidic pH also contribute to defense.
What local factors and host characteristics increase the risk of wound infection?
- Local factors include ischemia, necrotic tissue, wound debris, and chronic wounds.
- Host factors include breaks in skin integrity, diabetes, malnutrition, obesity, steroid use, immunocompromise, and advanced age.
What are the adverse effects of high microbe concentrations in wounds?
- They compete with host cells for oxygen/nutrients, release exotoxins (cytotoxic) and endotoxins (activate inflammation), delaying/preventing wound healing.
How do the cardinal signs of inflammation differ in inflamed vs. infected wounds?
- Rubor:
- Inflamed – defined border
- Infected – poorly defined, streaking possible.
- Calor:
- Inflamed – localized
- Infected – large area, potential fever.
- Tumor:
- Inflamed – proportionate
- Infected – disproportionate, indurated periwound.
- Dolor:
- Inflamed – proportionate
- Infected – new-onset or disproportionate pain.
- Function Loss:
- Inflamed – temporary
- Infected – systemic signs (maliase, tachycardia, hypotension, altered mental status, altered function of affected area)
How does wound drainage differ in inflamed vs. infected wounds?
- Inflamed: Thin, serous or serosanguinous, proportionate to wound size.
- Infected: Thick, purulent (creamy white/green/blue), distinctive odor, disproportionate.
What indicates a decline in wound status, differentiating infection from normal healing?
- Infected wounds show a plateau/increase in size, reduced/friable granulation tissue, color change to dusky, and increased necrosis.
- Healthy wounds follow 3 phases of healing, showing a steady decline in non-viable tissue.
What are planktonic organisms, and how do they impact wound healing?
Planktonic organisms are free-floating single cells that contaminate wound surfaces and can be neutralized by antibiotics.
Define biofilm and its impact on wound healing.
- Biofilm is a layer of microorganisms on wound surfaces protected by an extracellular matrix.
- It’s found in 60% of chronic wounds, resists antibiotics, reduces bacterial metabolism, and stalls healing by evading immune responses.
What do the acronyms NERDS and STONEES indicate in chronic wounds?
- NERDS: Critical colonization (e.g., Non-healing, Exudate, Red friable tissue, Debris, Smell).
- STONEES: Infection (e.g., Size increase, Temperature increase, Osseous exposed, New breakdown, Erythema/Edema, Exudate, Smell).
What are silent infections, and which patients are at risk?
- Silent infections occur in immunocompromised patients or those with inadequate perfusion.
- They may present without obvious signs; systemic signs (e.g., fever) should be checked.
What methods are used for wound cultures, and how do they help in managing infections?
- Biopsy: Gold standard, identifies infection/disease processes.
- Swab: Quantifies bacteria type/number.
- Aspiration: Samples tissue fluid. They confirm infection and guide treatment choice.
How are aerobic and anaerobic cultures collected in wound assessment?
- Aerobic: Swab rotated over 1 cm² of wound for 5 seconds. add enough pressure to express tissue fluid
- Anaerobic: Swab moved in a 10-point pattern within wound bed.
What staining methods differentiate gram-positive and gram-negative bacteria?
- Gram-positive: Stained by crystal violet.
- Gram-negative: Stained by safranin.
How does bacterial fluorescence imaging assist in wound assessment?
- It identifies bacteria by their metabolic byproducts.
- Collagen fluoresces green; porphyrins fluoresce red (Staph aureus); pyoverdines fluoresce cyan (Pseudomonas).
What are the strategies for treating wound bioburden and biofilm?
- maximize host resistance (e.g., diabetes control, nutrition),
- minimize bioburden (e.g., antimicrobials)
- disrupt biofilm (e.g., sharp debridement)
- eliminate invasive organisms
What agents are used for antimicrobial and antibacterial treatments in wounds?
- Antimicrobials: Include antibiotics, antivirals, antifungals, antiparasitics.
- Antibacterials: Target large bacteria, not other organisms.
How do wound cleansers affect healing, and which are effective?
- Saline/water do not kill organisms or enhance healing.
- Polyhexanide and povidone-iodine improve healing rates against contaminants.
What defines resistant vs. sensitive bacteria in wounds?
- Resistant: Bacteria continue to multiply in drug presence (e.g., MRSA, VRE).
- Sensitive: Bacteria cannot grow in presence of certain antimicrobials.
What are the characteristics of MRSA, and how is it treated?
- MRSA spreads via environmental/person contact, can cause cellulitis/abscesses, and lives on surfaces for hours to days.
- Treatment: mupirocin.
What is Vancomycin-Resistant Enterococci (VRE), and where is it found?
VRE is common in surgical wounds/UTIs and treated with ampicillin-amoxicillin.
What causes resistant bacteria, and how can it be prevented?
- Causes: Misuse of antimicrobials, improper prescriptions, incorrect usage, agricultural overuse.
- Prevention: Proper prescription, full course completion, limited antibacterial use.
What are the advantages and disadvantages of topical antimicrobial therapy?
- Advantages: Lower cost, reduces bacteria, effective in compromised circulation.
- Disadvantages: Higher cost than non-antimicrobials, frequent application, potential resistance.
What topical agents are commonly used for wound infections?
Acetic acid, chlorhexidine, honey, iodine, methylene blue-gentian violet, mupirocin, PHMB, potassium permanganate, silver.
When should topical antimicrobial therapy be used, and when should it stop?
- Use when infected and stop when infection signs resolve.
- Exceptions: prophylactic use in high-risk wounds, two-week trial on non-healing pressure ulcers.
