Utilizing the
microbiology laboratory
for optimal patient care
Dr Shobhana P Kulkarni
Medical Microbiologist
MBBS, FRCPath, FRCP(C)
Faculty /Presenter Disclosure
• Faculty: [Shobhana Kulkarni]
• Relationships with commercial interests:
– Grants/Research Support: None to disclose
– Independent medical contractor to DynaLIFEDX diagnostic
laboratories
– Speakers Bureau/Honoraria: None to disclose
– Consulting Fees: None to disclose
– Other: none
to disclose
Disclosure of Commercial
Support
• This program has received financial support
from DYNALIFEDX in the form of
EDUCATIONAL PROGRAM
• This program has received in-kind support
from DYNALIFEDX in the form of
LOGISTICAL SUPPORT
• Potential for conflict(s} of interest:
•
•
Dr. Shobhana Kulkarni has received NO
HONOURIAMUM AND IS A CONTRACTOR WITH
DYNALIFEDX
DYNALIFEDX PROVIDES LABORTAORY SERVICES
WHICH WILL BE DISCUSSED IN THIS PROGRAM.
Mitigating Potential Bias
•
DYNALIFEDX OPERATES IN ACCORDANCE WITH ALBERTA HEALTH
SERVICES, TESTING AND SOLUTIONS ARE A DIRECT RESULT OF PROVINCIAL
STANDARDS.
Objectives
Good patient care relies on 3 critical steps in
laboratory testing:
1. Ordering a test only when indicated
2. Providing a good quality specimen
3. Interpreting the report correctly
Case vignette
• An 82-year-old LTC resident with fever
and productive cough
– No urinary/ other symptoms
– Chronic ulcer on the lower extremity is
unchanged
• A “pan-culture” is initiated:
– Sputum and blood
– Urine
– Ulcer
6
Culture results
• CXR: Normal
• Sputum: Gram stain: no WBCs, no organisms
• Sputum culture: 1+ Candida albicans
• Urine culture: ≥107 CFU/L of E. coli
• Wound culture: 4+ VRE
7
• The patient is treated with:
– Fluconazole for the Candida in the sputum
– Cipro for the E. coli in the urine
– Linezolid for the VRE in the wound
• Two weeks later the patient has diarrhea
and C. diff toxin assay is positive
8
• The only infection this patient ever had
was a viral upper respiratory tract
infection!!!!
2 types of microbiology tests
• Screening in asymptomatic patients
– MRSA, VRE
– Asymptomatic bacteriuria in pregnancy
– HIV, CT/GC etc.
• To confirm diagnosis in symptomatic
patients
– UTI, wound infection, pneumonia etc.
Limitation of diagnostic tests
• A positive culture doesn’t always mean
infection. “False positives” caused by:
• Contamination from patients’ flora, collectors’
hands, or environment
• Overgrowth during storage/transport
When to order diagnostic tests
• Diagnosis of infection is based on clinical
findings, not laboratory testing alone
• Tests should be ordered ONLY if
symptoms/signs of infection present
– “Choosing Wisely Canada” – April 2014
Outcomes of unnecessary tests
Patient distress Waste of finite resources
Unnecessary antibiotic treatment
Effects of unnecessary antibiotics
• HARMS patient
– Unnecessary drug adverse effects, e.g.
C.difficile
– Increased risk of getting infection
• Increases antibiotic resistance
• Wastes valuable and finite healthcare
resources
CASE VIGNETTE
75y diabetic lady
with worsening leg
ulcer.
Clinically infected.
Culture is indicated.
Dressing removed
and swab taken of
pus.
Case vignette
• Smear of specimen: 4+ WBC, 4+ bacteria
(many types)
• Culture: 4+ coliforms x3, Enterococci x2
• Report: “Mixed growth suggestive of
contamination with colonizing flora.
Repeat swab AFTER cleaning.”
DELAY in result and therefore treatment
Collecting wound
swabs
Clean surface of
wound with sterile
saline – to remove
colonizing flora
Then rub swab
firmly on wound to
collect offending
pathogen
What is good laboratory utilization?
2. Providing good quality specimen
1. Ordering tests ONLY when symptoms of infection
3. Correctly interpreting result
Optimal patient care
Good quality specimen
1. To ensure pathogen is recovered:
• Collect BEFORE starting antibiotics
• MSU – PREFERABLY, collect 2-4hrs after last void
• Tissues and fluids/pus better than swabs
2. For accurate result:
• Prevent contamination during collection:
–
–
–
–
MSU – verbal AND written instructions
CSU – remove old if >14d; aseptically side port
Wound – CLEAN superficial slough/pus first
BC – skin antisepsis first
Good quality specimen
3. To prevent overgrowth of pathogen/commensal
flora after collection:
• Urine: Transfer within 20 mins into grey-top, boric
acid tubes
• Sputa, swabs: Store in fridge if transport to lab>2h
4. For quick result:
• Label requisition and specimen FULLY
• Provide clinical details – why test is being
requested
• Transport to laboratory ASAP
Correct interpretation of the report
• 76y male. Chronic venous leg ulcer
Wound swab report:
–1+ WBC, 2+ GPC, 2+GNB.
–Growth: 4+ S.aur S/clox, SXT; 2+E.coli
• 50y female; indwelling catheter; urine cloudy
Urine report:
≥ 107 E.coli. ESBL+. S/ gentamicin, ertapenem
Comment: Do NOT treat if asymptomatic
Getting the correct answer
• JOINT responsibility of the submitter AND
laboratory
– Laboratory processes are quality assured
– Submitter processes are not – major influence on
quality of result
• Responsibilities differ
• BOTH equally important
Enhancing specimen quality is everyone’s
responsibility!!
Improving laboratory utilization
1. Clinical decision support tools
•
DL website - test directory, other educational
information
•
Lab dedicated phone line, on call microbiologist –
24/7
•
Electronic Physician Order Entry -in development
•
Diagnostic algorithms, e.g. UTI checklist in LTC
Improving laboratory utilization
2. Education
•
Ongoing education/training of all staff and students
• In service, posters in specimen collection areas, apps
on test ordering and result interpretation for students
3. Format of reporting
•
•
Reporting with interpretive comments
Restrictive reporting – if clinical indication not stated. Need
to phone in for result
Take home message
3 Critical steps in ordering a test
1. Are symptoms/signs of infection present?
2. If so, obtain a good quality specimen
3. Correlate the result with patient’s
symptoms BEFORE decision to Rx
Enhancing specimen quality is everyone’s job!!