Combatting Bacterial Infection Flashcards
What are the routes for diagnosis
Self test, point-of-care, and laboratory
What does a case history cover
Symptoms, duration, contact with other infected individuals, medication and other clinical conditions
Why is Point of Care (POC) diagnosis beneficial
Saves time as no sample transport to laboratory required
What processes can sample handling in laboratory consist of
Isolation of target e.g. DNA, Detection of target e.g. specific gene, quantification e.g. PCR and interpretation of data
What are the 5 most common clinical microbiology tests
Culture, serology, biochemical assays, PCR and mass spectrometry
What does a sample microbial culture method consist of
Plating sample onto agar/ growth medium, microscopy and antimicrobial testing or gram staining or extraction
What is latex agglutination
Exploiting antibody antigen interactions for rapid diagnosis the specific antibody bound to inert carrier e.g. latex beads is used to clump bacteria together
What are the advantages of latex agglutination
- confirm identity of isolates
- identify pathogen-associated antigens in specimens when isolation fails
What is serology
diagnostic identification of antibodies in the serum eg. latex agglutination tests (only the relevant antigens will be bound by the specific antibody)
What is serotyping
Serotyping determines the subtype of organism e.g.
Salmonella has >2,500 serotypes (but less than 5% infect humans). Knowing which serotype is present allows effective treatment. Serotypes often correlate with antibiotic resistance patterns
What are the 3 standard enzyme tests in biochemical assays
Oxidases, catalase, urease
What are the advantages of molecular diagnosis of infections
Bacterial genomes are unique
Genetic material can be extracted from infected specimens
DNA is easy to detect and even quantify
Extremely sensitive 1-10 CFU / reaction
What are the disadvantages of molecular diagnosis of infection
Technology is still being developed
Some tests require the bacteria to be isolated first
Some tests are TOO sensitive
Standardisation from lab to lab can be problematic
What are antibiotics
Natural or synthetic or pounds that prevent microbial growth
What is the Minimum Inhibitory Concentration (MIC)
The minimum concentration of antibiotics needed to inhibit growth
How are we modifying approaches to treating infections (due to antibiotic resistance)
Limiting antibiotic use (antimicrobial stewardship and One Health approach)
Last resort antibiotics (e.g. polymyxin)
Combination therapy
Phage therapy
Faecal transplant (e.g. for treatment of C. difficle)
How do we decide on the antibiotic to use (factors to consider)
History, species, gram of bacteria, MIC and severity of infections
What antibiotics should be used for gram positive
Vancomycin and daptomycin
What antibiotic should be used for gram negative
Aztreonam, gentomycin
What antibiotics should be used for both gram negative and positive
B-lactams(penicillin)
What is UKHSA
The UK Health Security Agency
What is the role of UKHSA
In an outbreak detected where and who reported it, type of outbreak, who is affected and the population at risk
