Infection Symposium Summary Flashcards
ANTIBIOTIC RESISTANCE
Define intrinsic resistance.
Common structural feature i.e. thick capsule.
ANTIBIOTIC RESISTANCE
Define acquired resistamce.
Mutation or acquisition of new DNA.
ANTIBIOTIC RESISTANCE
What are three mechanisms of antibiotic resistance ?
Altered target site.
Enzymatic inactivation.
Decreased uptake.
ANTIBIOTIC RESISTANCE
Mechanisms of antibiotic resistance - explain ‘altered target site’ mechanism and an example of a microbe.
Bacteria alters binding site for antibiotic drug.
e.g. viridans group S. Mitis - penecillin resistant due to modified penicillin binding proteins.
ANTIBIOTIC RESISTANCE
Mechanisms of antibiotic resistance - explain ‘enzymatic inactivation’ mechanism and an example of a microbe.
Ezymes released by bacteria which alters antibiotic binds i.e. release of beta lactamase enzymes by hydrolysing beta lactam ring in common in all beta-lactam antibiotics preventing them from binding to PBPs and inhibiting cell wall synthesis.
Example - P. Intermedia and fusobacterium.
ANTIBIOTIC RESISTANCE
Mechanisms of antibiotic resistance - explain ‘decreased uptake’ mechanism.
Thick LPS capsule making it difficult for antibiotics to penetrate.
ANTIBIOTIC STEWARDSHIP
Define antibiotic stewardship.
Multidisciplinary team action plan to promote responsible antimicrobial use.
ANTIBIOTIC STEWARDSHIP
National Action Plan - what two ways do they suggest dentists practice antibiotic stewardship.
- Reduce need for and unintentional exposure to antimicrobials through prevention i.e. OH, national OH programmes.
- Optimise use of antimicrobials by making appropriate clinical decisions.
ANTIBIOTIC STEWARDSHIP
What antibiotics is S. Anginosus sensitive to ?
PenV and amoxicillin.
ANTIBIOTIC STEWARDSHIP
What antibiotic should be used in first line therapy for odontogenic infection ?
PenV - lowest spectrum - effective against streptococci, anaerobes, select gram-negative cocci.
ANTIBIOTIC STEWARDSHIP
What is the second line antibiotic for odontogenic infection ?
Amoxicillin - wider spectrum antibiotic, more effective against gram negative cocci and other bacteria (vs. PenV).
Always review patient 24-48 hours after commencing amoxicillin therapy.
ANTIBIOTIC STEWARDSHIP
What is the first line antibiotic used to treat periodontal infection ?
Metronidazole.
Effective against strict anaerobes i.e. P. Intermedia, fusobacterium nucleatum, P. Gingivalis.
MICROBIOLOGICAL TESTING AND SAMPLING
What is the ideal specimen for dental abscess ?
Pus aspirate - less salivary contamination.
MICROBIOLOGICAL TESTING AND SAMPLING
What bacteria are associated with dental abscess ?
Strict anaerobes i.e. S. Anginosus (+ cocci), P. Intermedia (- bacilli).
MICROBIOLOGICAL TESTING AND SAMPLING
What is your first line antibiotic of choice for management of dental abscess ?
PenV (second line - amox).
MICROBIOLOGICAL TESTING AND SAMPLING
What microbes are associated with periodontal abscess ?
S. Anginosus and P. Intermedia.
MICROBIOLOGICAL TESTING AND SAMPLING
What microbes are associated with pericoronitis ?
S. Anginosus and P. Intermedia.
MICROBIOLOGICAL TESTING AND SAMPLING
What are the predisposing factors contributing to osteomyelitis ?
MRONJ, ORN, Paget’s, implants, compoud fractures, impaired defence.
MICROBIOLOGICAL TESTING AND SAMPLING
What microbes are most commonly associated with osteomyelitis ?
S. Anginosus, S. Aureus, Actinomyces israelii.
MICROBIOLOGICAL TESTING AND SAMPLING
What is the uses for microscopic examination and gram staining ?
Determines gram +/- bacteria or presence of microbes.
MICROBIOLOGICAL TESTING AND SAMPLING
What is the uses for culture and sensitivity testing ?
Assessment of microbe sensitivity to antibiotics.
MICROBIOLOGICAL TESTING AND SAMPLING
What is the used for PCR testing ?
Shows specific microorganisms responsible for infection through DNA and RNA sequencing - giving accurate diagnosis of causative agent.
MICROBIOLOGICAL TESTING AND SAMPLING
What is PCR testing ?
Molecular biology technique used to amplify and detect specific DNA sequences in a biological sample.
Used for detection of infectious agents, genetic mutations, and other biomarkers associated with diseases.
MICROBIAL TESTING AND SAMPLING
What are the benefits of PCR testing vs. culture and sensitivity testing ?
Faster results.
Greater sensitivity.
Greater specificity - less likely for false positive results.
No live organisms required.
MICROBIAL SAMPLING
You want to sample periodontal pocket for responsible pathogens causing periodontal disease - what is your best method of sampling ?
Paper point swab of subgingival plaque.
Then PCR testing.
MICROBIAL SAMPLING
You want to sample denture stomatitis to determine the treatment you should provide for your patient - what is your best sampling technique ?
Swab (if pseudomembranous) or mouthrinse.
MICROBIAL SAMPLING
Your patient has a severe odontogenic abscess and requires systemic treatment - what is your preferred method of sampling ?
Pus aspirate.
Then PCR testing.
MICROBIAL SAMPLING
You wish to sample bacteria of multiple persons in research of the bacteria causing caries - what is your best method of sampling and testing ?
Oral swab - easier.
Then microscopic examination and gram staining if you want to determine - gram +/- or cocci/bacillus or anaerobic/aerobic ?
If you wish more specific information i.e. exactly what bacteria is causing the caries - PCR testing.
MICROBIOLOGY
What are the two bacteria responsible for caries ?
S. Mutans and lactobacillus.
MICROBIOLOGY
What is the microbe associated with implant failure/infection ?
Pseudomonas aeruginosa.
MICROBIOLOGY
What are the three microbes associated with endodontic infection ?
E. Faecalis, fusobacterium neucleatum, prevotella.
MICROBIOLOGY
What is the microbes associated with PA abscesses ?
Anaerobes - fusobacterium, prevotella.
Facultative anaerobes - actinomyces, streptococci.
Enteric bacteria - E. faecalis.
