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The future of Laboratory Microbiology (and in particular bacteriology)

The future of Laboratory Microbiology (and in particular bacteriology). This is a work in progress!. Overview. Background/history Plate streakers Automated Urine Analysers Blood cultures Automated Susceptibility Testing Automated ID testing Malditof TLA Molecular assays in bacteriology

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The future of Laboratory Microbiology (and in particular bacteriology)

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  1. The future of Laboratory Microbiology(and in particular bacteriology) This is a work in progress!

  2. Overview • Background/history • Plate streakers • Automated Urine Analysers • Blood cultures • Automated Susceptibility Testing • Automated ID testing • Malditof • TLA • Molecular assays in bacteriology • Automation and volume • Automation and commerce

  3. Bacteriology: The Origins • 1881-Nutrient Gelatin first demonstrated by Robert Koch • 1887 agar plates developed • 1905 - MacConkey agar first used • 1900s Dyes used to make media selective • 1919 - Blood Agar first used to study haemolysis of streptococci

  4. So what's changed??, not much really • Agar plates are still the main media for the majority of microbial sub-culturing and the backbone of the bacteriology lab. • Disc diffusion is still used in the vast majority of laboratories – if not all to some degree • Automated ID/Sens machines (VITEK and PHOENIX) have improved – however many of the concepts are still the same, using broth dilution breakpoint methodology. • Development in molecular diagnostics.

  5. What about some other techniques? • Manual streaking of plates has not really changed since solid agar plates were first used • Microscopy is mostly unchanged – • Incubators while probably more reliable are essentially the same • Plate reading has not really changed over years – although you are not supposed to sniff plates anymore….but we know it happens

  6. Pre-analytical – Plate Streakers • Select appropriate media • Loads the samples • Spreading the inoculum to obtain isolated single colonies following incubation • Suppliers: WASP (Copan) Previ-Isola (BioMerieux) Innova (BD) and Inoqula (KIESTRA) • Not all systems include Gram stain preparation

  7. Automated Urine Analysers • Automated Dip-strip inoculation and reading • Cell counts performed automatically – either by flow cytometry or (more recently) high resolution optics taking pictures of cells • Present now in many labs

  8. Blood Cultures • Standard in most diagnostic labs, varying sizes. • Better detection times • More advanced media • Reduced total incubation before calling a bottle a final negative • Suppliers: BacT/Alert (BioMerieux) BACTEC FX (BD)

  9. The Automation of Susceptibility Testing • 1940s started playing with putting antimicrobial agents into agar, both for selective culture and susceptibility testing. • Late 1940s: diffusion techniques on filter paper, 6mm disc 1947 • 1966 Kirby/Bauer attempt to standardise with their disc diffusion technique • 1975 This technique becomes the basis for the NCCLS (CLSI) standards.

  10. The Automation of Susceptibility Testing • 1974 – First automated AST marketed by Pfizer called the Autobac • 1977 Abbott introduce the MS 2 System • 1977 McDonnell Douglas Corporation launch the AMS System – this was the predecessor to the first Vitek Machine • 1977 First standarised microtitre plates with Antibiotics introduced – leads the way for Microscan, Sensititre and BBL Spector

  11. Automated ID and Sens • Automated ID testing available since 1977 • Biochemical substrates miniaturised and read by colourmetric or fluormetric means • Available in many bigger labs • Multiple Antibiotics in different dilutions available on Cards or panels to ascertain MIC – Expert Functions • Suppliers: Microscan Walkaway (Dade Behring) Vitek2 (BioMerieux) BD Phoenix (BD) • Cost neutral on ID part but not on susceptibility testing. What will happen to these systems with introduction of Maldi-tof?

  12. MALDI-TOF • Protein based spectral identification of bacteria • Identifications available in literally minutes – not hours • Tiny amount of bacterial growth needed – not affected by media or incubation conditions • Minimal cost per test, virtually no consumables • Suppliers : BD/Bruker, BioMerieux

  13. What is coming? • What is next in the world of Microbiology Automation?? • Some companies are in the process of producing TLA for Microbiology – similar to those seen in Biochem/Haem. • Putting specimens on a track – with no human intervention until plate reading time – and even then its not like you know it…

  14. Hands Off Microbiology!!

  15. Spanner in the works…. • All of this new automated technology assumes that bacterial culture on agar plates will remain the cornerstone of microbiological diagnosis for the forseeable future. • However molecular assays becoming more commonplace….even in bacteriology. • Virology now becoming increasingly molecular. Viral culture will eventually disappear from the diagnostic scene.

  16. Some of the current molecular assaysavailable commercially for bacteriology • Chlamydia + gono PCR • Illumigene (LAMP) for C.difficile toxin, Gp B strep • PCR for Group B strep and MRSA and VRE & ESBL enzymes • PCR Bordetella and C.difficile toxin • PCR and gene probe for mycobacteria • DNA probes for enteric specimens. • DNA probes for candida/BV/trichomonas • 16sRNA identification

  17. What is in the pipeline for molecular assays in bacteriology? • Microarrays Still in research phase. Still need extraction and amplification step.

  18. Why is bacteriology not completely molecular? • Cost: Cost of Culture even including labour is inexpensive. • Culture allows Quantification of bacteria (but does it matter that much really?) • Looking for a range of different pathogens. Current methods aren’t that good at it. PCR gives up at about 5.

  19. Will the agar plate eventually become defunct? • Yes, but possibly not in my working lifetime. • The companies producing culture automation are not daft. If they thought that agar plates would disappear in the next ten years, then they would not be R&Ding plate streakers, smart incubators etc. • Leasing, not buying outright such equipment would be prudent.

  20. Automation and Volume • Automated methods most cost-effective when handling large volumes of samples. • Favours larger laboratories. • Interfacing is key • Most of the cost savings are in labour.

  21. Automation and Commerce • Two main market players currently in this field, BD and Biomeurieux. • As the number of pieces of automated equipment in a lab increases, there is more and more incentive for laboratories to “affiliate” with a company for all their automation requirements. • Interesting times ahead….

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