Specimen Collection for Infection Control

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Specimen Collection for Infection Control

• Jim Gauthier, MLT, CIC
• CHICA-Canada National Conference 2008

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Objectives

• To describe ideal specimen collection and
  handling techniques for the variety of specimens
  required in Infection Control
• To describe strategies for helping IPCPs help
  HCWs strengthen specimen collection and handling
  for the best possible results

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The General Laboratory Rules

• Provide as much information to the lab as
  possible
• site, appearance, time of collection, antibiotics
• Bad Nose
• Little Better Nares swab
• Best Nares swab for MRSA

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The General Laboratory Rules

• Get to lab as soon as possible
• delays will allow susceptible bugs to die
• delays will allow hardier bugs to grow

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The General Laboratory Rules

• Include patient room number (ward)
• Contact information if copy needed for IPCP

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Swabbing

• Moisten swab if swabbing dry body parts
• Dip into transport container, or use sterile
  saline
• Different swabs for different specimens
• CS May be clear or charcoal
• Anaerobic Not collected very often for IC

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Specimen Collection

• Label swab/container before collection or at
  bedside
• Place in biohazard bag without contaminating
  outside of bag
• Do not prepare specimen at nurses station clean
  area!

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The Infection Control Laboratory Rules

• Indicate organism under investigation on
  requisition MRSA, VRE, ESBL
• If notspecimen treated like CS
• Issues with looking for ARO if specimen
  contaminated with normal flora

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Normal Flora

• MSSA looks a lot like MRSA
• VSE looks a lot like VRE
• C. difficile is very difficult to grow (hence the
  name)
• Most tests detect toxins
• ESBL organisms look like other Gram negative
  organisms

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Normal Flora

• Laboratory Technologists understand this better
  than most health care professionals
• Can obscure organism under investigation

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Normal Flora

• Stool 1 gram 1x1012 organisms
• Mouth 1 ml saliva 1x108 organisms
• Skin upwards of 1x106 on a finger
• Decubitus ulcers skin, organism, fibers

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Mid Stream Urines

• Like it says
• First urine flow washes distal urethral flora
  away
• Very difficult with demented, elderly, physically
  challenged
• Catheters use alcohol cleaned collection port
  NOT drainage spout
• Catheter urine considered colonized 24h

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Urines

• Get to laboratory or refrigerator as soon as
  possible (within 48 hours)
• E. coli will reproduce every 20 minutes in urine
  at room temperature
• Explain collection to patient never assume!
• Use of cleanser controversial
• Water and gauze works well

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Stool Specimens (VRE, ESBL)

• Should be collected free from urine and water
• If possible!
• Can use CS transport
• Rectal swab
• Need feces on swab

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Stool Specimens (C. difficile, Viral Pathogens)

• No preservative
• C. difficile specimen should be soft enough to
  take shape of container
• Can freeze viral pathogen container if delay in
  shipping (check with your local lab on that!)

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Stool Specimens

• Most laboratories will not culture (CS) stool
  from inpatients who have been in hospital greater
  than 3 days
• C. difficile first
• Then CS/OP if proper whining is done
• Then looking for things like Salmonella,
  Shigella, Yersinia, Campylobacter

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C. difficile Results

• Clostridium difficile Indeterminate
• Color reaction neither negative nor positive.
• If patient remains symptomatic, may consider
  repeating.
• Clostridium difficile Positive
• Toxin positive, asymptomatic carriers do exist
• Treat symptoms, not report!

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SAY AHHHH
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Throats (Group A Strep Carriers)

• SWAB
• tonsillar crypt
• use tongue depressor
• Dont want roof of mouth
• Careful of gag reflex
• Say ahhhhhh
• Removes uvula from field of view

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Nose - MRSA

• Moisten swab
• Bilateral anterior nares
• Just hide the tip of the swab
• Only need one swab for both nares

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Eye Swab (Conjunctivitis)

• Do not want gunk in inner canthus
• Pull out lower lid and rub swab gently along
  conjunctiva and lid junction
• Presence of epithelial cells indicate surface.
• Gram stain should have very little in it if a
  good specimen has been collected.

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Eyes - General

• Eye lid glued together bacterial
• Eye lid crusty - viral
• Chlamydia needs a separate swab.
• Need to interpret significance of organisms, as
  can be colonized with potential pathogens (S.
  pneumonia, St. aureus)

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Sputum (TB)

• Acid Fast Bacilli (AFB)
• Collection is very important as is interpretation
  of results
• First morning specimen, good deep cough
• No indication for rinsing mouth with sterile
  water first

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Sputum (TB)

• Induced Sputum
• Patient inhales aerosolized saline
• Induces cough
• Needs to be done in negative pressure, by trained
  (and protected) staff

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Sputum (TB)

• If testing being ordered AIRBORNE PRECAUTIONS!

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Sputum - VAP

• If suctioning, use sterile suction catheter, into
  trap, do not use inline catheter unless new
• Many potential pathogens are colonizers esp. if
  endotracheal tube or trach present
• Staph. aureus, H. influenza, Pseudomonas, Gram
  negative coliforms

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Sputum - Pneumonia?

• Must look at signs and symptoms, X ray reports,
  other lab reports (Hematology)
• Gram stain can indicate predominating organism,
  but still could be colonizer
• Blood culture
• Comparison of potential pathogen to normal flora
  can also be helpful

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Other Respiratory

• BAL Broncho Alveolar Lavage
• growth is quantitated, usually gt106 is
  significant, lt106 is not
• Watch normal flora numbers
• Suction channel
• Bronchial Wash not as sterile, treated like a
  sputum
• PSB Protected Specimen Brush quite sensitive,
  but not used that much (cost)

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Wound Swabs

• Clean wound first (saline), then swab
• Better to aspirate leading edge of erythema
• Debride before culturing?
• Do not want to see lots of epithelial cells

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Wound Swabs
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Wound Swabs

• Many potential pathogens can be normal colonizing
  flora
• Generally treat on symptoms, unless patient
  septic
• Irrigation of wound
• 30 cc syringe with 18g needle

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Vaginal Swabs (GAS, Yeast)

• Vaginal crypt should visualize what you are
  swabbing
• May allow self swabbing for a screening swab
• Do NOT want mucous!

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Sterile Body Fluids

• Pericardial, peritoneal, synovial, pleural, etc.
• In a properly collected fluid, any organism is a
  pathogen
• abscess fluid??
• if multiple organisms, treat based on underlying
  cause!

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Sterile Body Fluids

• Can use other tests to help interpret results
• cell counts
• Chemistry analysis
• glucose, protein

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Blood Cultures

• Peripheral best, but lines can be used if poor
  venous access or if worried about line sepsis
• Use good antiseptic first, make sure to cleanse
  palpating finger, even if gloved
• Chlorhexidine, alcohol

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Blood Cultures

• Check with lab on preferred timing
• Pseudo-outbreaks have been described from
  contaminated gloves touching venepuncture site.
• Bacillus sp. can be common

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Indwelling Catheter Tips

• Submitted if suspected of causing sepsis.
• Should always be submitted with blood cultures
  peripheral and through line if possible before
  line is removed
• Lab will quantitate growth
• gt 15 colonies is considered significant IF same
  organism present in blood culture
• Must check with lab when removing for septic
  picture

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Viral Cultures

• Tricky!
• Need special swabs and transport
• Influenza, RSV, Rhinovirus, etc.
• Nasopharyngeal specimen
• Uncomfortable doing it right!
• Vesicle
• Aseptically open vesicle, swab fluid, then rub
  base of lesion

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Scabies

• Ectoparasite which burrows into skin
• Can mark burrows with ink, then wipe with alcohol
  swab
• Use mineral oil and scalpel blade
• Not that sensitive

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Scabies

• Skin folds are common areas
• Punch biopsy is definitive

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Summary

• If in doubt, check with the laboratory to find
  out what they mean or what they want!
• Never assume!
• Give the lab a good specimen and you will get a
  good result!

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Summary

• Normal flora can be very misleading!!
• The lab has NOT seen the patient, we are just
  reporting the facts!
• Infectious disease physicians and senior
  technologists are always available for consult!
• Give lots of information we love it!

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Questions?
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