2. Why Wound Swabs are
Important in Patient Care
Wound Swabs are one of the Important
Specimens sent to Microbiology
Departments for Bacteriological and
Fungal isolation and Antimicrobiologial
Evaluation. However many basic lacuna
in Collection, Laboratory identification
and reporting makes the Deficit in
Effective care of the Patients and
increases the potentials for Morbidity
and Mortality
Dr.T.V.Rao MD 2
4. Obtaining a Specimen
Methods of obtaining a specimen from
a wound include wound swabbing,
needle aspiration and wound tissue
biopsy. Although wound swabbing is
the most practical and widely used, it is
important to use a technique that
produces reliable samples for
microbiological analysis.
Dr.T.V.Rao MD 4
5. Wound Culture Protocols
Soft skin and tissue infections with open or draining
lesions (Appearance of) insect/spider bite with
necrotizing centre, drainage & erythema
âą Abscess - ulcer
âą Infected laceration
â Culture wound prior to initiation of antibiotics if
signs or symptoms of infection are present. If Culture
& Sensitivity is obtained after antibiotics have been
started, list the drug on the laboratory C& S request.
Dr.T.V.Rao MD 5
6. What are guideline to
Follow for
The technique usually employed
transferring clinical samples from wounds to
microbiology laboratories is the wound swab;
however definitive guidelines for this
relatively simple procedure have yet to be
established. Uncertainty about when swabs
should be taken, the correct collection
procedure and the appropriate protocols for
submitting swabs for investigation have
led to a situation where clinicians regularly
collect and process unsuitable sample
Dr.T.V.Rao MD 6
7. Swabs should be collected
with Suspected Infection
Swabs should
therefore be
collected only when
clinical criteria
point to a wound
infection and
before any
antimicrobial
interventions have
been initiated
Dr.T.V.Rao MD 7
8. Are there are Standard Protocol
in Collection of Specimens
It should be noted that the best technique for swabbing
wounds has not been identified and validated. The
following recommendations can be used as a guide and
should be used in conjunction with local protocols:
When a swab is indicated, the patient should be given a
concise explanation of the need for microbiological
investigation and what the procedure involves, for
example, that swabs are mainly used to recover species
from the surface layers rather than from the deep tissues
of a wound.
Dr.T.V.Rao MD 8
9. Cleaning the contaminating
materials is a priority
Before a representative
sample is collected, any
contaminating materials
such as slough, necrotic
tissue, dried exudate
and dressing residue
should be removed by
cleansing the wound
with tap water, sterile
saline or debridement
Dr.T.V.Rao MD 9
10. Appropriate Specimen is
Important
Do not
culture
purulent or
necrotic
debris or
drainage over
hard eschar.
Dr.T.V.Rao MD 10
11. Collecting the Optimal
Specimen
Sterile swabs with cotton or
rayon tips are usually used.
If the wound is moist a
swab can be used straight
from the packaging - if the
wound is dry, then the swab
tip should be moistened
with sterile saline to
increase the chances of
recovering organisms from
the site . Swabs with a
transport medium that
incorporates charcoal
enhance the survival of
fastidious organisms
Dr.T.V.Rao MD 11
12. Basic care in Collecting
the Specimen
Care should be
taken to ensure
that the swab
only comes
into contact
with the
wound surface.
Dr.T.V.Rao MD 12
13. Care in When Collecting the
Swabs
1.Cleanse wound by removing excess debris from
wound base with normal saline
2. Thoroughly flush wound with sterile saline.
3. Gently blot excess saline from wound bed with
sterile gauze.
4. Remove soiled gloves; apply hand sanitizer.
5. Apply clean gloves
Dr.T.V.Rao MD 13
14. Practical Approach to
Collections of Swabs
The swab should be
moved across the
wound surface in a
zigzag motion , at the
same time as being
rotated between the
fingers . Downward
pressure to release
fluid from the wound
surface has been
advocated, but this
may be painful for the
Dr.T.V.Rao MD 14
patient.
15. Bigger Wounds Needs
Multiple Specimens
A representative area of the
wound should be sampled.
If the wound is large, it may
not be feasible to cover the
entire surface, but at least
1cmÂČ should be sampled and
material from both the
wound bed and wound
margin should be collected.
If pus is present, the
clinician should ensure that
a sample is sent to the
laboratory.
Dr.T.V.Rao MD 15
17. Collecting the Swabs
Open sterile culture collection/transport kit containing
Amies or Stuarts transport medium and remove swab.
If wound is dry, moisten tip of swab with transport fluid
at the bottom of the transport sleeve or sterile
preservative-free saline (pink saline fish or saline bullet). If
wound is moist (weepy) after cleaning, this might not be
necessary.
Without touching swab to surrounding wound edges or
skin, rotate tip of swab over a 1cm area of open wound for
5 seconds (preferred method), or rotate the swab while
making a zigzag pattern across the wound at 10 points
Dr.T.V.Rao MD 17
18. Steps in Collection in
Specimen
Cleanse intact skin with antiseptic and allow to dry.
Expel all air from a 10mL syringe with a 22 gauge
needle prior to aspiration. Insert needle into intact
skin and apply suction (aspirate).
Aspirate approximately 0.5mL of wound fluid.
Label syringe (see Swab Culture, above).
. After labelling syringe, place in lab biohazard
transport bag and transport to the Laboratory
Dr.T.V.Rao MD 18
19. Transport the Swabs
Promptly
Immediately
following
collection, the swab
should be returned
to its container
(placed into the
transport medium)
and accurately
labelled
Dr.T.V.Rao MD 19
20. Label and Promptly
Transport
Label culture
collection/transport
kit with name, birth
date, specimen
source, date and
time of culture.
Place in lab
biohazard transport
container
Dr.T.V.Rao MD 20
21. Swabs should be Transported
without delay
Swabs must be transferred to the laboratory
as quickly as possible and ideally processed
within four hours of collection
The laboratory report should list the
potential pathogens isolated and the amount
of growth observed. The antibiotic
susceptibilities of any organisms present in
the wound may be included, but whether the
isolates are of pathogenic and relevant to the
Clinical Details furnished
Dr.T.V.Rao MD 21
22. Appropriate Culturing Yields
Precise Results
Apply sufficient
pressure to cause
tissue fluid to be
expressed. It is
the bacteria in
the tissue fluid
that is desired
for culture.
Dr.T.V.Rao MD 22
23. Clinicians should Support
with Information
Any supporting documentation for the
laboratory should immediately be
completed and a note included in the
patient's records. It is important to
provide information to the laboratory
staff that will aid their use of the
standard operating protocol, such as
any underlying co-morbidities, the
patient's age, on-going treatment and
wound location
Dr.T.V.Rao MD 23
24. Microbiological and Clinical
Correlation is the Best Option
Antibiotic susceptibilities of any
organisms present in the wound may be
included, but whether the isolates are of
clinical significance or whether antibiotic
therapy is required is a matter of clinical
judgement. Spreading cellulitis and
clinical infections will require systemic
antibiotics.
Dr.T.V.Rao MD 24
25. Limitation of Swab
Techniques
To examine the diagnostic validity of swab
techniques, analyses of the accuracy as
compared to tissue cultures in identifying
microbial load provide insight into the utility of
swab techniques used for this purpose. The
accuracy of swab specimens based on Levine's
technique was significantly higher than those
based on Z-technique and approached
significance when compared to swabs based on
wound exudates
Dr.T.V.Rao MD 25
26. Programme Created By Dr.T.V.Rao MD
for Medical and Paramedical
Professionals in the Developing World
Email
doctortvrao@gmail.com
Dr.T.V.Rao MD 26