Wound Bench Flashcards
Ideal way to collect a specimen from a wound
Asperate
Ideal way to transport a wound specimen to the lab
As soon as possible in specific transport media
Delay shorter than 6 hours
kept at ambient temperature
Delay longer than 6 hours
refrigerated
What is specimen collection is preferred?
Specimens aspirated with a needle and syringe are preferred to those collected on swabs
Common submitted specimen
- Sterile body fluids
- Biopsy/Tissue
- Eye
- Ear
- Foreign body
- Catheter tips
- Wounds
What media should be inoculated from a wound?
- BAP
- CHOC
- MAC
- CNA
- ANA BAP
- PEA
- THIO
- Direct Smear
Purpose of BAP
All purpose medium, best for hemolysis, detects stalemating of Haemophilus around organisms such as Staphylococcus aureus
Purpose of MAC
Selective for Gram negative rods, (look for Lactose pink). (does not determine fermenter or non fermenter of glucose)
Purpose of CNA
Selective for Gram positive organism (do not determine hemolysis)
Purpose of CHOC
Enriched medium that will grow most any organism (supports fastidious organisms)
Purpose of ANA BAP
Prereduced, growth supplements added (enriched with Vitamin K. Hemin and cysteine)
Purpose of PEA
Phenyl Ethyl Alcohol Agar
Inhibits swarming of proteus
Purpose of THIO
Enhances growth of aerobes, facultative organisms, as well as obligate anaerobes
Purpose of direct smear
Very important to correlate with plate morphology
How does gas gangrene (myonecrosis) present on a gram stained direct smear from an infected wound
Necrotic background and gas bubbles
How long are anaerobic plates typically incubated before initial examinations?
2 days (48 hours)
How is quantitation determined for wound cultures
Quantitation is dependent on the quadrant where organisms are growing (1+ first quadrant; 2+ second quad, 3+ third quad, 4+ fourth quadrant)
What skin flora organisms would likely be seen in surface wound cultures
- Alpha and Gamma Strep
- Corynebacterium spp
- Coag Neg staph
- Propionibacterium spp.
- Staphylococcus saccharyolyticus
- staphylococcus epidermidis
Biochemical Tests Used to Identify:
- Coag Neg Staph
Gram Stain: GPC in clusters
Coagulase test: neg
Biochemical Tests Used to Identify:
- Corynebacterium spp
Gram Stain: GPR palisading
Catalase: pos
Nonmotile
opaque and or alpha
Biochemical Tests Used to Identify:
- Strep Viridian’s (alpha or gamma strep; not group D)
Gram Stain: GPC in chain
Biochemical Tests Used to Identify:
- Propionibacterium spp.
Anaerobe
Most common organism in burns
Pseudomonas aeruginosa
MRSA
Enterococcus
Klebsiella
Conventional biochemical tests (and reactions) that would be used to identify the organisms that are in burns
Pseudomonas aeruginosa is Oxidase Positive
Most common organism causing Impetigo, Erysipelas, Cullulitus, Folliculitis, Furuncle, Carbuncle, etc.
Staph aureus
Conventional biochemical tests (and reactions) that would be used to identify the organisms that cause Impetigo, Erysipelas, Cullulitus, Folliculitis, Furuncle, Carbuncle, etc.
S. aureus:
- Cat +
- Coagulase +
- Beta hemolytic
- Furazolidone Susceptible
- Novobiocin Susceptible
Most common organism causing dog/cat bite infections
Pasteurella multocida/ canis, bacteroides spp., Fusobacterium, Prevotella, staph, capnocytopaga canimorsus
Conventional biochemical tests (and reactions) that would be used to identify the organisms that cause dog/cat bite infections
GNCB
- nonmotile
- facultatively anaerobic
- form nitrites from nitrates
- ox pos
- cat pos
Most common organism causing human bite infection
Eikenella corrodens,
Straptococcus anginosis, S. aureus, Fusobacterium nucleatum, prevotella melaninogenica
Conventional biochemical tests (and reactions) that would be used to identify the organisms that cause human bite infection
E. corrodens GNCB nonmotile ox pos asaccharolytic cat neg "pit" smell like chlorine
Most common organism causing surgical wound (head neck) infection
Mouth Flora anaerobes: Anaerobe: Prevotella spp. Alpha and gamma streptococci Corynebacerium spp CoN Staph Non-Pathogenic Neisseria spp Porphyromonas spp.
Conventional biochemical tests (and reactions) that would be used to identify the organisms that cause surgical wound (head neck) infection
*
Most common organism causing surgical abdominal wound infections
GI flora: Bacteroides frag Clostridium Bifidobacterium anaerobic cocci Fusobacterium E. coli (other Enterobacteriaceae) Enterocuccus
Conventional biochemical tests (and reactions) that would be used to identify the organisms that cause surgical abdominal wound infections
*
Most common organism causing Myonecrosis (gangrene)
Clostridium perfringens (most common) - C. histolyticum, C. septicum, C. novyi
Conventional biochemical tests (and reactions) that would be used to identify the organisms that cause Myonecrosis (gangrene)
GPR
- double zone beta hemolysis
- 4+ gas
Most common organism causing Necrotizing fasciitis
Enterobacteriaceae and anaerobes (type 1) S. pyogenes (type 2) Clostridium perfringens (type 3 or Gas gangrene)
Conventional biochemical tests (and reactions) that would be used to identify the organisms that cause necrotizing fasciitis
KIA series / anaerobe tests (GLC) / strep test
