Transcript Blood Culture Dilemmas - British Society for Microbial

Dr Peter Cowling
Chair Bacteriology SMI Committee
UK Standards for Microbiological
Investigations (SMIs)
 Steering Committee
 Syndromic Algorithm Committee
 Virology/ Serology SMI Committee
 Bacteriology SMI Committee
Our responsibility
..does not start at the
laboratory door
Starts at the point the
clinician considers the
differential diagnosis
Our involvement in specimen pathway
 From start
 To finish
Partnership Working
 Equal partners
 Nominated representatives
 Regular two way reporting
 Optimal consultation processes
 Increased joint ownership
 Increased authority
NICE Accreditation
 NHS Evidence accredited processes for SMIs
 Follows AGREE protocol
 Sets the UK standard for diagnostic microbiology
 Covers whole specimen pathway
 Also certified to ISO 9001:2008
SMI B 37
Investigation of Blood Cultures
 Issued 27 March 2013
 Issue number 7
Acknowledgements 1
 Dr Shabnam Iyer
 Dr Mike Weinbren
 Mr Ian Sturgess
Consultation
 Consultation through usual process
 Additional parallel consultation through BIA
 Total responses
 Accepted
 Partially accepted
 Rejected
 No action
59
23
6
7
23
B37 Amendments
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Standards for TaTs
Inclusion of SIRS and neonatal sepsis
Removal of differential quantitative culture
Direct sensitivity testing
Inclusion of molecular methodologies
Contamination target <3%
Pre-incubation advice
Lab management of transportation
Dilemmas
 TaTs and Transforming Pathology agenda
 Meeting the needs and expectations of users (e.g
paediatricians)
 Pre-loading handling of bottles (requesting/
transportation/ off site incubators/ off site culture)
 Empirical blind antimicrobial treatment
 Existing plate-based methodologies
Turnaround times (TaTs)
Proposals for improvement
 Mike Weinbren, Shabnam Iyer, Ian Sturgess
 Set standards for TaTs
 Collection to loading
 Initial positive reports and sens testing
 Endorse rapid tests on positive bottles
 Set standards for satellite/peripheral labs
 Request CPA to formally include b.c audits
 Request BSAC to recommend direct sens testing
Mike Weinbren’s audits
 Load delay average 7h (max 20h)
 Unload delay average 5h (max 14h)
 On site laboratory
 Worst out of hours and weekends
 2nd audit of transport delays showed little delay on site
 60% loaded within 2h of receipt but long tail on graph
(n=191). Bottles rec’d 24h but loaded only 08.00-19.00
 Potential for saving up to 2 days of TaT if
loading/unloading delays are reduced + rapid testing
Kavi, Weinbren & Sturgess
survey
 Telephone survey of blood culture methods in UK
 43 respondents across UK
 4/16 off site blood cultures stored in incubator
 0/43 load during night
 21/43 pre-incubate overnight, 22/43 at RT
 31/43 have 24h on site shift systems (blood sciences)
 1/43 rapid sens on GNBs, 41/43 do direct sens discs
Loading on
Blood Culture
Machine
Receipt in
Laboratory
Blood Culture
Collection
Transport Time
to Laboratory (TT)
Time from Receipt
to Loading
Time from Collection to Loading
Blood Culture
Flags Positive
Time to Detection
(TTD)
Time from
Placement to
Detection
Time from Flagging
Positive to Removal
Laboratory Turnaround
Time (LTAT)
Variable Time –
Opportunity to
Improve
Time Variable – NO
Opportunity to
Improve
Identification
and
Sensitivities
Time from Removal to
Results of Gram Stain,
Identification and
Sensitivities
Reporting of
Results
Time from Results
Availability to
Reporting Results
Time from Flagging Positive to Identification
Time to Reporting
and Susceptibility Results
Time to Positivity
(TTP)
KEY
Removal and
Initial Work
Turnaround Time (TAT)
Symptoms
Start
Patient seeks
medical
advice,
treatment
initiated
Patient dependent time
variable.
No opportunity to improve.
Treatment
ends
Appropriate Treatment
Therapeutic Window
Time
Patient
Survives
Symptoms
Start
Patient seeks
medical
advice,
treatment
initiated
Treatment
ends
Patient dependent time
variable.
No opportunity to improve.
Inappropriate Treatment
Therapeutic Window
Time
Patient
Dies
Symptoms
Start
Patient seeks
medical
advice,
treatment
initiated
Delayed Blood
Culture Result
Patient dependent time
variable.
No opportunity to improve.
Inappropriate Treatment
Therapeutic Window
Time
Treatment
ends
Appropriate
Treatment
Critical
Time
Patient
Dies
Symptoms
Start
Patient seeks
medical
advice,
treatment
initiated
Patient dependent time
variable.
No opportunity to improve.
Rapid Blood
Culture Result
Inappropriate Treatment
Therapeutic Window
Time
Treatment
ends
Appropriate Treatment
Critical
Time
Patient
Survives
Summary Table 1: Pre-Analytical Standards
Inoculated bottles should be incubated as soon as possible, and within a maximum of
four hours.
Investigative Stage:
Standard:
Pre-Analytical
Time Period
Collection to Incubation
≤4hr
The four hour turnaround time from collection to incubation for blood culture
samples reflects their clinical significance.
Summary Table 2: Analytical Standards
Results of the following identification and sensitivity tests (if performed) should be
completed within the following time frames from flagging positive:
Investigative Stage:
Analytical
Flagging Positive to Microscopy, Identification
and Sensitivities
Criteria:
Standard:
Test (if test performed)
Gram Stain
Rapid Antigen Testing
Molecular Assays
Isolate Identification (Direct/Automated)
Isolate Identification
(Conventional Methods)
Isolate Sensitivities (Direct/Automated)
Isolate Sensitivities
(Conventional Methods)
Time Period to Result
≤2hr
≤2hr
same day
≤24hr
24-48hr
≤24hr
24-48hr
Summary Table 3: Post-Analytical Standards
Standards have also been set for the laboratory turnaround time (the time between
receipt in the laboratory and reporting):
Investigative Stage:
Post-Analytical
Criteria:
Standard:
Report Type
Turnaround time
48hr *
Negative Report
Preliminary Negative Report
(dependant on local policy)
≤5 days
(from receipt in laboratory to negative reporting)
Final Negative Report
Preliminary Positive Report
(Telephone/Fax/Email)
Positive Report
(from receipt in laboratory to positive reporting)
Final Positive Report
(or greater if extended incubation
required)
Immediately, within 2hr of
identity/sensitivity availability.
(see Summary Table 2 above)
≤5 days
(or greater if extended incubation
required, or if isolates are sent to a
reference laboratory for confirmation)
*Refer to neonatal sepsis section of the introduction for further information
regarding negative reporting of neonatal blood culture.
User expectations
Neonatal blood cultures
 NICE guideline CG 149 Aug 2012
 Requirement for 36h reporting of a negative culture
 Allows cessation of antimicrobials, 2nd gentamicin
dose
 Allows timely discharge
 Is cost effective
Duration of antibiotic treatment:
early-onset neonatal infection without meningitis
Positive blood culture or strong suspicion of infection
 Usual antibiotic duration should be 7 days. Consider
longer if baby has not recovered or if advised.
Negative blood culture
 Consider stopping antibiotics at 36 hours.
 If continuing beyond 36 hours, review the baby at least
once every 24 hours to consider whether antibiotics
can be stopped.
NICE (CG 149) Aug 2012
Duration of antibiotics treatment:
decisions 36 hours after starting antibiotic treatment
 To fully implement the guideline, hospital systems to
provide real time blood culture results at 36 hours are
needed.
 Consider stopping antibiotics at 36 hours: if
•
•
•
•
blood culture is negative and
initial suspicion of infection was not strong and
baby’s clinical condition reassuring (no clinical
indicators) and
levels and trends of C-reactive protein are
reassuring.
NICE (CG 149) Aug 2012
Rationale for 36h decision
“Since the health economic analysis conducted for the
guideline showed that stopping antibiotic treatment at
36 hours in the babies listed above will be cost saving,
and one of the criteria for stopping treatment depends
on the result of blood culture, the cost savings can be
realised only if the blood culture results are available
within 36 hours.”
NICE (CG 149) Aug 2012
Antibiotics for suspected infection in the baby
 Use intravenous benzylpenicillin with gentamicin as first-
choice.
 Benzylpenicillin 25 mg/kg every 12 hours.
 Gentamicin, starting dosage of 5 mg/kg.
 If a second gentamicin dose is required, give 36 hours after
the first (interval may be shortened based on clinical
judgment).
(My emphasis)
NICE (CG 149) Aug 2012
Therapeutic monitoring for gentamicin
Trough concentrations
 Measure trough immediately before second dose.
 Concentrations should be available in time to inform the
next dose (If not, do not withhold dose unless renal
dysfunction is evident).
 Consider repeating measurement of trough
concentrations at least before every third dose.
NICE (CG 149) Aug 2012
Neonatal blood cultures 36h rule:
UK experience
 4/31 significant isolates >36h incl. 1 baby discharged
home
 11/119 +ve cultures >36h post loading (9 contaminants,
2 CNS infections already on treatment). 23/119 >36h
post collection (4 significant but on antibiotics pre b.c.
and clinically septic)
 92% 4410 cultures +ve <36h (100% of paediatric)
 18/76 +ve cultures post collection (16 contaminants, 2
significant, 1 on treatment)
 “nearly all signalled within 18h, never mind 36!”
Acknowledgments 2
 Dr Tom Lewis
 Dr Sarah Abu Hassan
 Dr John Cheesbrough
 Dr Alaric Colville
 Dr J Kavi
 Dr Martin Sheppard
Future dilemmas
 Emergence of multi-resistance
 Less effective & more toxic blind treatment
 Need for replacement of 19th Century Microbiology
 Rapid, molecular methodology for whole specimen
pathway (“Star Trek” vision)
 Near patient testing
The Embarrassing Truth?
 Blood Sciences
 Microbiology
Laissez faire
 Long TaTs generally accepted as the norm by
laboratories, users and patients
 Technology available to revolutionise Microbiology
 Insufficient challenge to status quo
Wrong focus
 Laboratory accreditation-focussed
 Not patient-focussed
 ISO standards are an improvement
Purchaser Provider Model
Voice of the Customer
 Purchaser - Provider
(adversarial)
 Customer involvement
and joint ownership
(partnership)
Acknowledgements 3
 The Standards Unit, PHE
 Ruhi Siddiqui, Head of Unit
 Clare Harris, Standards Microbiologist
 Ayuen Lual, Standards Microbiologist
 Ijeoma Ezeajughi, Research Scientist
 Nicola Day, Technical Support Officer
 Caroline Lawson, Information Office
 Shirley Boland, Administrative Assistant
 and……….Val Bevan and Brian Duerden
Thank you