Systems for detections of pathogen is Flashcards
What are the 6 rapid based approaches to detecting pathogens?
→Molecular detection
→Gene targeting
→Genome targeting
→Biomarkers of virulence
→Rapid sequencing
→Future Directions
How many of the mycobacterium genus are obligate human pathogens?
→M .tu bercuolssi
→M .elprae
→M. uclerans
What is an example of commensal non pathogen?
→Bacterodies thetaoi taomciron
What are the three types of pathogen?
→Commensal Non pathogen
→Zoonotic Non pathogen
→Commensal Opportunist
Define pathogen
→microbe CAPABLE of causing a specific degree of host damage
What are non sterile sites in the body?
→faeces
→mouth
→skin
What types of samples have low pathogen load and what do they require?
→ CSF,
→Ascites,
→24 hr Urine
→requires concentration (centrifugation, filtering)
What are the two types of preparation phase?
→culture: Enrichment, Purification, Amplification
→direct: concentration and sample treatment
What is a benefit of light microscopy for detection?
→no need for DNA
→just need to know what organism looks like
What type of pathogens can be detected by EM?
→viruses
Give examples of virus detected by EM?
→Rotavirus
→Hepatitis B
→ Tonsillitis
→Rabies
What colour does gram negative bacteria stain and why?
→red
→thinner peptidoglycan wall
What colour does gram positive bacteria stain and why?
→purple
→thicker peptidoglycan wall
Give examples of gram positive bacteria
→staphylococci
→streptococci
→Cornynebacterium diphtheriae
→Bacillus anthracis
Give examples of gram negative bacteria
→Escherichia coli
→Salmonella
→Shigella
→Helicobacter
Give examples of spore forming bacteria
→Bacillus (aerobic)
→Clostridium (anaerobic)
What are advantages of microscopy for detection?
→Easy to perform
→Rapid screening
→Some parasites have SPECIFIC morphology
→Specific Immunoflourescence staining possible
What are the disadvantages of microscopy for detection?
→Not Sensitive
→screening sputum smears requires at least 10,000 orgs per ml to be visualised
→General stains are not specific
→Labour intensive (expensive)
→Requires specialist interpretive expertise (more expensive)
What are the 3 different types of media for culturing?
→Non Selective Media
→Semi Selective Media
→Selective growth temperatures
Example of non selective media
→blood agar
Examples of semi selective media
→MacConkey Agar, →DCA,
→CLED- Cysteine Lactose Electrolyte Deficient
Examples of selective growth temperatures
→Campylobacter species
What is deoxycholate agar?
→Selective for Shigella and Salmonella on a faecal sample
→produce colours depending on organism
What are facultative anaerobes?
→organism that is capable of producing energy through aerobic respiration and then switching back to anaerobic respiration depending on the amounts of oxygen
