Wound Bioburden Flashcards
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.
What are antiseptic agents, and what are their proper uses?
- They prevent infection by killing microorganisms, used for surgical scrubs, hand washing, and cleansing intact skin.
How does systemic antimicrobial therapy differ from topical therapy?
- Systemic therapy is physician-prescribed, used for sepsis/advancing infection, and may be combined with topical treatment.
What are the disadvantages of systemic antimicrobial therapy?
Higher cost, adverse reactions, resistance risk, missed doses.
What are the main steps to minimize bioburden and disrupt biofilm in wounds?
Sharp debridement is most effective for biofilm disruption; antimicrobials target bioburden.
How should wound bioburden be managed in diabetic patients?
- control blood glucose
- promote tissue perfusion
- manage comorbidities to maximize host resistance
What are the benefits and risks of using antiseptic agents on wounds?
They prevent infection but can be cytotoxic, potentially slowing healing depending on microbial load.
