1. Lee C. Ruotsi, MD, FACCWS, UHM

3. SIGNS AND SYMPTOMS
PRIMARY SECONDARY
 Rubor (erythema)  Delayed healing
 Dolor (pain)  Changes in wound bed color
 Calor (warmth)  Friable/hyper granulation
 Edema/swelling  Abnormal/increased odor
 Purulence  Increased drainage
 Fever

4. RISK FACTORS FOR WOUND INFECTION
SYSTEMIC LOCAL
 Vascular disease  Large wound area
 Edema  Increased wound depth
 Malnutrition  Degree of chronicity
 Anatomic location
 Diabetes
 Foreign bodies
 Alcoholism
 Necrotic tissue
 Prior surgery or radiation
 Mechanism of injury
 Drugs i.e. corticosteroids
 Degree of contamination
 Immune deficits  Reduced perfusion

5. CONTAMINATION TO INFECTION
INFECTION LOCAL/SYSTEMIC
CRITICAL COLONIZATION
COLONIZATION
CONTAMINA-
TION

6. WOUND CONTAMINATION
 Presence of non-replicating micro-organisms on
the wound surface that evoke no clinical host
response
 All chronic wounds are contaminated
 Bacterial colony counts low
 Wound healing occurs in spite of presence of bacteria
 Not the presence of bacteria but interaction with host that
determines their impact on wound healing

7. WOUND CONTAMINATION

8. WOUND COLONIZATION
 Presence of replicating micro-organisms
within a wound in the absence of any
detectable host injury
 Most organisms are normal skin flora
 Staph epi and other coag negative staph,
corynebacterium, propionibacterium,
 Gram negatives; Proteus and Pseudomonas

9. WOUND COLONIZATION

10. SUPERFICIAL CRITICAL COLONIZATION
 Replicating microbial burden in the wound
surface compartment with subtle clinical
signs of host injury
 aka: covert/localized infection, increased bacterial
burden

11. SUPERFICIAL CRITICAL COLONIZATION

12. DEEP WOUND INFECTION
 Level of microbial burden or virulence has
overwhelmed the host responses and the
micro-organisms cause clinical injury by
invading locally or deeply below the wound
base
 Stage before systemic sepsis

13. DEEP WOUND INFECTION

14. SYSTEMIC SEPSIS (BACTEREMIA)
 Relatively uncommon as a result of wound
infections
 Found in 10-20% of severely infected wounds;
diabetic foot wounds and deep pressure ulcers are
most common
 Small wounds, if infected with Group A Strep or
MRSA can rapidly progress from contamination to
systemic infection (sepsis)
 Example- MRSA outbreaks in athletes

15. CONFOUNDING VARIABLES
 Pain; may be absent in infected diabetic foot wound
 Warmth; may be absent with ischemia
 Erythema; may be absent in diabetes and ischemia
may be venous insufficiency, not infection
 Purulence; may be normal exudates produced by
healthy granulation tissue
 Fever; may be absent in compromised host
 Edema; may be manifestation of venous disease rather
than infection

16. INCREASED BACTERIAL BURDEN
 May only appear as mild erythema and hyperemia
 Objectively- wound may not appear infected
 Bacteria compete for nutrients and oxygen
 Exotoxins, endotoxins and proteases impair
normal cellular functions
 Wound Healing is compromised when:
a) more than 4 pathological species present
b) tissue bacteria levels > 105

17. PATHOGENS AS A FUNCTION OF TIME
 Early Acute
 4 weeks
 Long Term Chronic

18. EARLY ACUTE
 Predominance of usual skin flora
 Staph aureus and Beta Hemolytic strep follow in early
weeks

19. 4 WEEKS
 Facultative anaerobic gram – rods begin to colonize
 Most common: Proteus, E. Coli, Klebsiella
 As wound deteriorates, deeper structures become
affected and anaerobes become more common
 Environment becomes more polymicrobial (4-5 sp.)

20. LONG TERM CHRONIC
 Often more anaerobic than aerobic
 Also, aerobic Gram – rods:
Pseudomonas
Acinetobacter
Xanthomonas

21. LONG TERM CHRONIC

22.  THE WOUND
ENVIRONMENT  Chronic wounds differ biochemically
from acute ones
 Prolonged inflammatory response
leads to increase in inflammatory
cytokines and MMP’s
 Debridement, control of infection
and inflammation, moisture control
and excision of wound edges and
callous
 Sharp debridement gold standard

23.  DEBRIDEMENT
 Excisional or selective
 Excisional: surgical removal of
clearly identifiable tissue by
cutting outside wound margins
 Selective: removal of devitalized
tissue, ie slough, fibrin, crusts,
exudates
 Debridement changes wound
physiology; chronic to acute
 Universally accepted and should
rely on intuition
 Better healing with more
frequent debridement (Well
supported)

24. SURGICAL / SHARP DEBRIDEMENT
Scalpel, Curette
 ADVANTAGES:  DISADVANTAGES
 Fastest and most effective  Requires skill and
method of removal of advanced training
devitalized wound tissue  Can damage blood vessels,
 Very selective  Nerves, tendons, etc
 Stimulates wound healing  Can be painful and may
through release of
inflammatory cytokines
require anesthesia

25. ENZYMATIC DEBRIDEMENT
Collagenase
 Advantages:  Disadvantages
 Most selective of non-  Slow
surgical methods  Expensive
 Painless  Requires prescription
 Low risk of damage to  May cause inflammation
other structures but rare
 Daily, patient applied
therapy

26. AUTOLYTIC DEBRIDEMENT
Proteolytic enzymes, Hydrogels
 Advantages  Disadvantages
 Occurs naturally, to some  Slow
extent, in all moist wounds  Wound must be monitored
 Can be augmented with closely for signs of
hydrogels, etc infection – anaerobic if
 Safe occlusive dressing used
 Selective
 Inexpensive

27. MECHANICAL DEBRIDEMENT
Wet to dry, Pulse lavage, Whirlpool
 Advantages  Disadvantages
 Inexpensive  Non-selective
 Can be effective short-term  Traumatizes and debrides
in proper setting healthy as well as
devitalized tissue
 Painful

28. MISCELLANEOUS
 Pseudomonas: Frequently cultured from deteriorating
wounds and tends not to be invasive unless in
compromised host
 Enterococcus: Frequently cultured and need not be
treated unless only organism cultured and wound
clinically infected
 Candida: Same as above for Enterococcus

29. CULTURE METHODS
 Quantitative Deep tissue  “Gold standard”
Biopsy Culture  >105 org/gm of tissue
 Any level B Hemolytic
Strep
 Invasive
 Usually requires local
 Caution with PAD
 Time consuming/$$$
for lab

30. CULTURE METHODS
 Levine swab technique  Best supportive evidence
outside quantitative
biopsy culture
1) Cleanse/irrigate w
saline
2) Firm pressure of swab
tip in cleanest portion
of wound base
3) Rotate 360 degrees
4) Transport media

31. NERDS AND STONEES
 Cross sectional validation study of 112 patients
 Studied clinical assessment variables to determine
presence and quantity of wound bacteria
 Wounds evaluated using mnemonics to assess for:
1) Critical colonization (NERDS)
2) Infection (STONEES)
 Results compared to semi-quantitative swab cultures

32. NERDS
N Non-healing wound - Wounds that are not 20% - 40%
smaller in 4 weeks by hx or records
E Exudative wound - Increase in wound exudate with
>50% of dressing stained with exudate
R Red and bleeding – Wound bed tissue bright
red with exuberant granulation tissue. Bleeds easily with
gentle manipulation
D Debris – Presence of discolored granulation tissue,
slough and necrotic / nonviable tissue.
S Smell – Unpleasant or sweet, sickening odor

33. STONEES
S Size - Wound size is increasing. Longest length x widest width
(right angles). Only very deep wounds and most stage III / IV pressure
ulcers should have depth measured with probe.
T Temperature increased – Increased periwound margin
temperature by > 3˚ F difference between mirror image sites.
O Os (Probes to or exposed bone) - Wounds that have exposed
bone or probed to bone at time of exam
N New areas of breakdown or satellite lesions
E Erythema/Edema – Reddening/swelling in periwound skin
E Exudate - Increased amount of drainage
S Smell - Unpleasant or sweet, sickening odor

34. RESULTS
 Predictability compared to semi-quantitative cultures
obtained via Levine Technique

35. RESULTS
 Suggest that level of bacterial growth can be assessed
using the clinical variables in the mnemonics
NERDS: Scant to light growth
STONEES: Moderate to heavy growth
 When any 3 clinical signs were combined in either
group: Sensitivity = 73% for scant/light (NERDS)
Sensitivity = 90% for mod/heavy (STONEES)
Woo, Sibbald; OWM 2009;55(8):40-48

36. I.D.S.A. D.F.U. CLASSIFICATION
Clinical Description IDSA Class
 Wound without purulence or any  Uninfected
manifestations of infection
 >2 of following:(purulence, erythema,
 Mild
pain, tenderness, warmth, induration).
Cellulitis <2cm around ulcer and infection
limited to skin or superficial sub-cut.
tissues
 Systemically well with >1 of following:
Cellulitis >2 cm, lymphangitis, deep tissue  Moderate
abscess, gangrene, muscle, tendon, bone
inv.
 Systemic toxicity/metabolic instability
 Severe
(fever/chills, tachy, hypotension,
confusion, vomiting, increased WBC’s

37. ACCURACY OF SYMPTOMS AND SIGNS
 2 studies from Gardner, et al showed that likelihood of
infection increases when increased pain present.
 Absence of pain was not a useful predictor of absence
of infection
Gardner, Hillis, Frantz; 2009 Gardner, Frantz, Doebbeling; 2001

38. ACCURACY OF SYMPTOMS AND SIGNS
 Purulent exudate, erythema, heat and edema (classic
signs) not helpful in diagnosing infection in chronic
wounds
 Wounds without serous exudates or those healing
rapidly were less likely to be infected
 Foul odor did not significantly predict infection
 Examined application of IDSA DFU scale to chronic
wounds – 46% and 52% sensitivity. Not helpful.
Gardner, Hillis, Frantz; 2009

39. ACCURACY OF NONINVASIVE TESTS
 Four studies evaluated utility of swab cultures and lab
markers compared with deep tissue biopsy culture.
 4 studies included 198 patients
 Levine Technique: Positive culture predictive of
infection and negative culture predictive of absence of
infection
 Z - Technique: Not useful in predicting or excluding
wound infection
Reddy, Gill, Wu, Kalkar, Rochon; JAMA 2012

40. DR. OTTO VON SCRATCHANSNIFF

41. BOTTOM LINE
 Classic signs of infection not particularly helpful in
diagnosing infection in chronic wound
 Serous exudate more predictive (higher LR) than
purulent exudate in predicting infection
 Combinations of findings (IDSA DFU) not useful for
predicting chronic wound infection
 Increasing pain is the most useful indicator of
infection when there is suspicion of infection but
absence of pain does not predict absence of infection

42. MORE BOTTOM LINE
 Quantitative swab culture via Levine Technique has
highest quality evidence of any noninvasive test for
infection in chronic wounds; both positive and
negative predictive value
 Presence of increasing pain, along with a
quantitative swab culture, might help physicians
estimate the probability of infection.
Reddy, Gill, Wu, Kalkar, Rochon; JAMA 2012

43. 5 QUESTIONS
1) Which organisms, regardless of quantity, need to be
treated?
2) Which organisms usually do not need to be treated?
3) What are the most reliable clinical indicators of
chronic wound infection?
4) What constitutes the best combination of diagnostic
tools (clinical/lab) to diagnose chronic wound
infection?
5) Is TMP/SMZ still appropriate, in our community, to
treat MRSA wound infection without systemic
illness?

44. Which organisms, regardless of quantity,
need to be treated?
 Staph aureus; MSSA or MRSA
 Group A Strep (S. pyogenes)
 Group B Strep (S. agalactiae)
 Group C and G Strep
 Pseudomonas aeruginosa
 E.coli, Klebsiella pneumoniae, Proteus sp.

45. Which organisms usually do not need to be
treated?
 Coagulase negative Staph (epi, warneri, capitis)
 Stenotrophomonas
 Acinetobacter species
 Enterococcus
 Strep viridans isolates

46. What are the most reliable clinical
indicators of chronic wound infection?
 Pain in immediate periwound area
 Friable bloody granulation tissue
 Advancing pweriwound erythema
 Malodor
 Fever or other systemic signs and symptoms of illness
in absence of other identifiable source of infection
 Crepitance in surrounding tissues

47. What constitutes the best combination of
diagnostic tools (clinical/lab) to diagnose chronic
wound infection
 Positive swab (Levine) for appropriate organisms
 Increasing pain in and around wound
 Careful with validity of probe to bone for osteo

48. Is TMP/SMZ still an appropriate choice, in our
community, to treat MRSA wound infection
without systemic signs/symptoms?
 Yes – 90%
 Watch for acute adverse events, ie, Steven-Johnson