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Microbiology without culture - is this the future?

Microbiology without culture - is this the future?. Professor Brian Duerden Inspector of Microbiology and Infection Control, Department of Health. Historical perspective. 1850 – 1900 1850s: Pasteur; liquid culture 1870-80s Koch: solid media 1894 Gram’s stain 1900 – 1980

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Microbiology without culture - is this the future?

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  1. Microbiology without culture - is this the future? Professor Brian Duerden Inspector of Microbiology and Infection Control, Department of Health

  2. Historical perspective • 1850 – 1900 • 1850s: Pasteur; liquid culture • 1870-80s Koch: solid media • 1894 Gram’s stain • 1900 – 1980 • Serotyping; phage typing • DNA discovered • 1980s Biochemical analyses • Metabolic products (GLC) • Proteins – whole cell; cell wall (SDS-PAGE) • Whole cell (pyrolysis) • All needed culture first

  3. 1990s – age of immediacy! • Rapid tests • Same day results • Short turnaround times • Immediate answers • Point of care (POC) testing • And automation; computerisation ………non-culture methods

  4. Methods • Molecular detection – nucleic acid • Probes • PCR • Antigen detection ......who does the tests? where are they done?

  5. Why are we doing the tests? • Cost? • Diagnosis • Guide treatment • Antibiotic or not? Which? eg. GpA streptococcus • Start infection prevention and control action • Take public health actions • Screening for carriage/colonisation • Infection control & public health actions • Prophylaxis (eg. GpB streptococcus) • Speed is of the essence

  6. How urgent are the answers? • Primary care • While the patient is there? • Organisation? • STDs – GUM clinics; strong history • Now in pharmacies??? • Public health – TB • Days not hours • Healthcare Associated Infections (HCAI) • Treatment; isolation; infection control action

  7. NB. Primary culture then non-culture? • Identify organisms in primary cultures • Rapid non-culture methods • Probes; PCR; rRNA • Resistance genes • How vital? • Blood cultures • Early CORRECT antibiotic improves survival • But will clinicians change antibiotic?

  8. MRSA screening • DH requirement – all admissions to be screened before or on admission • All elective admissions by March 2009 • Includes day cases • Not ophthalmic day cases; not maternity • All admissions asap, at latest by March 2011 • Methods – conventional culture; rapid; automated? • Needs clinical organisation; ability to take action • Laboratory? Point of admission? Pre-admission clinic?

  9. C. difficile diagnosis • DH target – 30% reduction by 2010-11 • Baseline 2007-8: c. 60,000 • SHA and PCT targets based on population • Standardised to 8.4 cases per 10,000 as target • Acute trust targets within PCT packages • Standardised to admissions • Surveillance figures depend upon accurate diagnosis • Infection control actions depend upon rapid results in all healthcare settings • Methods: toxin detection (A+B); +/- antigen?

  10. Norovirus • Major cause of ward closure • Respond to clinical diagnosis • Isolation; cohorting; closed to admissions • Staff restrictions (cohorting) • Cleaning and disinfection • Quick confirmation needed to reassure actions • Not every case needs testing

  11. Pandemic (or seasonal) flu? • Primary care • Confirm diagnosis for antiviral use? • Current policy • Diagnose on clinical grounds when flu known to be circulating • Keep infected patients away from GP surgeries

  12. Cautionary tales • Loss of epidemiological and surveillance data • Antimicrobial susceptibility data? • POC – whose responsibility • Quality and standards • Serendipity

  13. Loss of data • Antimicrobial susceptibility • Few non-culture tests • Epidemiology • Typing • Can it be done on non-culture testing? • Most needs the isolate • Surveillance • POC – loss of data • Unless systems linked to reporting systems

  14. POC testing • Who does it? • What training? Who assesses competence? • Who manages them? • Equipment maintenance • Who is responsible? • QC and QA? • Links to the laboratory • Reporting system? • Accreditation?

  15. Quality issues • Quality control • Records; links to laboratories • EQA • NEQAS programmes? • Accreditation • CPA; UKAS

  16. Current developments • POC Accreditation • Pathology modernisation project • Working with UKAS • Benchmarking • Primary care use of Pathology services • Keele team • Microbiology pilots soon • ??? Impact of POC; rapid results

  17. Serendipity • What could be causing that? • I would not have thought of that? • We don’t have a DNA probe for that! • Where is experience, ‘nose’, knowledge? • With non-culture tests ……..you only find what you know you are looking for

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