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Microbiology Pt 2. - Coggle Diagram

- - - - = Gram -ve bacteria (ie Fusobacteria & Spirocetes)
    - - Increase in blood vessels = gives RED apperance
    - - albumin, IgG, IgA&M, Completement
  - - - enviornment: low O2 tension, higher pH, hemin products)
  - - - Predisposing factors
        
        • Enhanced biofilm
        
        • Overhangs
        
        Crowded teeth
      - Modifying factors
        
        • Altered immune response
        
        • Smoking
        
        • Stress
        
        Diabetes
        
        Poor glycaemic control is associated with more severe periodontal diseases
        
        Untreated periodontitis impairs glycemic control, which in turn can accelerate periodontitis
        
        50% of a gene component
        
        Ventilated associated Pnumonia (VAP)
        
        More common due to COVID-19
        
        Pathogens in oral cavity similar to those in the mouth (in 90% of cases)
        
        Prevention = Tooth burushing, antiplaque agent
        
        Interllectual disability
        
        They require meticuluous and comphrensive OH care done for them due to their reduced capacity - can help to reduce the risk of microbial loads travelling to the URT and LRT
    - - Porphyromonas. Gingivalis (keystone pathogen)
        
        Oppourtnuistic pathogen
        
        Strict anerobe
        
        Needs Hb [Blood] and Vit K for growth (contains porphyrin)
        
        Inflammophillic - DRIVES DISEASE
        
        RED COMPLEX
      - Challenges in defining them
        
        Difficult to culture, often in low numbers, pathogens may differ in virulence
        
        Nb: Socransky's Clusters
        
        RED COMPLEX
      - Diversity changes throughout disease progression
      - Spirochaetes (Treponema denticola)
        
        Strict Anerobe
        
        Haemophillic
        
        Binds P. gingivalis - aids in its transport
        
        RED COMPLEX
      - Aggregatibacter. Actinomycetemcomitans
        
        Capnophilic
        
        Gram negative cocco bacillus
        
        Leukotoxins and other virulence factors = aggressive forms of periodontal disease
  - - - Removes bacteria and LPS
      - Encourages healing = long epithelial attachement, ?regenration
      - Access for debridement
  - - - ○ Malnutrition, Poor OH, Smoking
        ○ Immunosuppression, Severe emotional stress
    - - ○ Severe pain (often cause for presentation)
      - ○ Profuse bleeding
      - ○ Interdental papillae are ulcerated with necrotic slough, and appear "punched out"
      - Others
        
        ▪ Oral malodour (halitosis), Oral malodour (halitosis), Malaise, fever and/or cervical lymph node
  - - - Local
        
        Microbial challenge (PG and AA, LPS and gram -ve )
        
        host immuno-inflammatory response, WBCs and cytokines invade
        
        Cause connective tissue and bone metaolism changes
        
        Periodontitis
        
        Bacteremias = systemic exposure to LPS and host mediators (IL1, IL6, TNFa and CRP)
      - Systemic
        
        Bacteremias = systemic exposure to LPS and host mediators (IL1, IL6, TNFa and CRP)
        
        Other factors
        
        Atherogenesis (fatty deposits in blood vessels)
- - - - Derived from saliva
      - Variations due changes in enviornement: O2 tension, fluid movement, and substrate
    - - ○ Carious exposure
      - ○ Lateral canals = periodontitis
        
        Similar/identical bacteria = treat endo often first
      - ○ Cementum tears in trauma
      - Tooth fracture in trauma
  - - - Irrigants
        
        ○ NaOCl 1-5% (proteolytic agent and oxidant, alkaline ph 11)
        
        ○ EDTAC 15% (Ethylene diamine tetra acetic acid – demineralizing agent, chelates calcium)
        
        ○ Peroxide 1-3% (oxidant, disinfectant)
      - Mechanical
        
        Hand files or Rotary
      - Cavitation
        
        Endosonics and Lazers
    - - Abx (e.g. tetracyclines, clindamycin)
      - Biocides
        ▪ (CHX 2-4%) - effective against E. faecalis in re Tx cases
        ▪ Ca(OH)2 – bactericidal/antifungal, biofilm penetration, blocks some LPS cytokines, HIGH pH + greater microbial properties
    - - ○ Better mechanical debridement (rotary NiTi)
      - ○ New improved inter visit medicaments
      - ○ Double seal for intervisit dressing and following obturation
      - ○ Protection of tooth structure from fracture using coverage restorations
      - Novel Smear Layer removal
        
        Lazer agitataed EDTA
        
        Photoactivated disinfectatnts (PAD) irrigants
    - - Pus = DO NOT LET THE SUNSET
      - Prevents spread of infection into deeper spaces
  - - - most notably from third molars = which may go sublingual or submandibular or from max anterior into the danger triangle
        
        NB: Cavernous Sinus Thrombosis
        
        III, IV IX = opthalmoplegia, proptosis and ICA opthalmic artery vision issues
        
        nb: Ludwigs Angina
        
        Retrophrayngeal and Danger Space
        
        tongue is forced upward and backward, causing airway obstruction
        
        Decompression and Management w/ Ab therapy
    - - Ex. Neutropenic, HIV, Leukaemia, Methotrexate pts, Poor tissue healing pts
- - - - • Alpha Group
        
        Herpes Simplex Virus 1&2 (HSV-1, HSV-2)
        
        Herpes labalis (recurrent) infection seen as a cratered appearance on the lip (mental nerve V3)
        
        Nb: Infected fluids from blisters can be transmitted to us (dentist) if we are not wearing eye protection
        
        ○ Varicella Zoster Virus (VZV or HHV3) --> Chicken Pox or Shingles
      - • Beta Group
        
        ○ Cytomegalovirus (CMV or HHV5) --> immunosuppression
        
        Fetal infection with CMV may cause neurological effects
        
        Human Herpes Virus 6 (HHV6
      - • Gamma Group
        
        ○ Epstein-Barr virus (EMV or HHV4) ---> mononucleosis, black hairy leukoplakia
        
        Oedematous and erythematous posterior soft palate and uvula, and painful ulcerated palatine tonsils
        
        EBV on tongue - white hairy patch seen on lateral surface of the tongue
        
        Kaposi's Sarcoma (HHV8)
        
        Infects endothelial cells which line the blood vessels
    - - Sequester/Evasion
        
        Hiding in sensory ganglia, epithelial cells or salivary glands
        
        ▪ HSV-1 and 2 – trigeminal V3 ganglion
        ▪ VZV – sensory ganglion
      - Reactivation
        
        Can lay domant
        
        Stress, trauma or sunlight can cause reactivation
    - - • Gingivostomatitis (HSV 1, 2)
      - • Genital Herpes (HSV 1, 2)
      - • Whitlows (HSV-1, 2) [hands and fingers]
      - • Conjunctivitis or keratitis (HSV-1, 2)
      - • Chicken Pox (VZV)
        
        Singles (reactivation) - along a dermatome
      - • Infectious Mononucleosis (EBV)
        
        Mononuclear (immature B lymphoctes) is where the virus is found
      - Dense inflammatory infiltrate including Cytotoxic T-lymphocytes, NK cells, Macrophages seen during HHV infections ---> can lead to blistering and spread of infection
      - Management of Primary Infections
        
        • Drink plenty fluids – monitor signs of dehydration
        
        • Analgesics and antipyretics PRN
        
        • Avoid touching the saliva, skin or mucous membranes that are ulcerated
        
        Ulcer symptoms clear up ~2-3 weeks
        
        Use of antivirals = Acyclovir or valcyclovir
  - - - Keratinocyte Types 6 and 11
      - Balloing eptheliuma and proliferative connective tissue
      - Can be sexually transmitted (also seen in anal region)
    - - Oncogenic Types 16 and 18
      - (Oral and Cervical)
    - - Managed w/ lazer ablation
      - Required N95 or 100 surgical respirators due to possibily for aersol transfer
  - - - Summer/Sping
        
        Rhinovirus
        
        Stuffy nose, headache and runny nose
      - Winter
        
        Adenoviruses, parainfluenza viruses, coronaviruses and influenza viruses
        
        May cause fever and bronchitis
    - - Compared to a Cold?
        
        More severe, longer lasting symptoms
        
        Pyrexia (raised temperature)
        
        More contagious
        
        spread by coughs, sneezes and conversation
        
        Dry cough
      - Pre-procedural Mouth Rinse!
        
        Antimicrobial rinses Reduce number of microorganisms in aerosols/spatter and those into blood stream
        
        Especially prior to scaling or exo
      - Structure
        
        Enveloped RNA Virus
        
        Attachement: Hemmagglutinin (H)
        
        Release: Nueraminidase (N)
        
        Variations w/ H & N are seen in humans and animals and are responsible for the varitions of the virus
      - Dental Considerations
        
        WHO Exclusion periods for dental treatment
        
        = Children (12 or younger): 3 weeks
        
        = Adults: 2 weeks
        
        Risk-based precautions for treating and infected patient
        
        Preacutions around Contact (direct and indirect)
        
        Equpment/enviornment, hands and injections
        
        Preacutions around Droplet
        
        Protocol for urgent dental
        
        ○ Last Pt of the day
        
        ○ Immunized staff provide care
        
        ○ Pre-procedural rinses'
        
        ○ Minimize aerosol generation
        
        ○ Well fitted masking
        
        ○ Double clean surfaces
      - Pharmaceutical agents
        
        Tamiflu (oseltamivir)
        
        10 doses (75mg tabs)
        
        nb: Relenza (alternative) inhaled version
        
        Blocking NA (Neuraminidase Inhibitors) prevents the release of new virions
        
        benefits are only proven if started within 48 hours of onset
        
        Side effects: (adults) nausea and abdominal pain, (children) nausea and nightmares
      - Pandemics
        
        1918 1919 Spanish Flu (H1N1), 1957 1958 Asian Flu (H2N2), 2003-2009 Avian Flu (H5N1), 2009 2010 Swine Flu (H1N1)
        
        Nb: In avian flu - a lot of people who contract it die, proposed mechanism is a hyper inflammatory response causing fluid build up in the lungs and respiratory arrest
        
        Antigenic Drift (occurs every year, epidemics)
        
        Small “point” mutation changes
        
        New variants
        
        Antigenic Shift (more for pandemics)
        
        Re assortment of strains
        
        Everyone susceptible and spreads uncontrollably
  - - - Antibiotics such as flucloxacillin, azithromycin, clarithromycin
      - Antifungals such as polyenes and azoles
    - - Faecal-oral route
        
        Hep A
        
        Hep E
      - Blood-blood route
        
        Hep B
        
        HBcAg (nucleocapsid core) and HBsAg (surface antigen)
        
        Antibody to HBV core antigen (anti HBc) =
        Positive anti HBc IgM indicates recent infection
        
        Antibody to HBsAg (anti HBs)
        = Positive anti HBs indicates immunity to HBV
        
        HBsAg is present in blood, semen and vaginal fluids in large concentrations, so only a small volume is need to transmit HBV infection
        
        Transmission
        
        Vertical – Perinatal (mother-child
        
        ○ Blood-blood contact
        
        ▪ Sharps injuries, tattooing an body piercing
        
        ▪ IV drug use
        
        Sexual Transmission
        
        HBV Incubation period: 60-90 days
        
        Symptoms
        
        Acute =
        Jaundice (robust response)
        
        Chronic sequelae =
        Cirrhosis or hepatocellular carcinoma
        
        Less likley to become chronic the later you are infected with the Hep B antigen
        
        Hep C
        
        Marker heterogencity - mutates frequently
        
        Enveloped RNA virus (the gene for the envolope = responsible for the multi mutations)
        
        Often asymptomatic infection
        
        Usually results in a chronic infection
        
        Sequale
        
        Cirrhosis (hepatic fribrosis)
        
        1 more item...
        
        LAtered Hepatic function (ALT and AST elevated)
        
        Liver Failure
        
        Prolonged bleeding
        
        1 more item...
        
        Extra-hepatic Disorders
        
        3 more items...
        
        Testing
        
        EILSA (97% sensitivity) = detects cicrulating HCV ab
        
        Elevated ALT
        
        (often the best indicator for chronic progression as Ab tests can take up to 6 months)
        
        Hep D (defective B)
        
        HDV coinfection with HBV
        
        Results in severe acute infection, but less likely to develop chronic infections
        
        HBV immunity aids in the protection against HDV, due to this dependency
    - - Hep B vaccine = rapid opsonization of coated particles and prevents the spread of the virus
      - Enters the hepatocytes and cause injury/inflammation
    - - Liver Function Tests
        
        ○ ALT (Alanine aminotransferase)
        
        ▪ Increased ALT = levels are associated with hepatocellular damage
        
        NB: physical trauma, antifungal agents, statins can also raise ALT
        
        ○ AST (Aspartate aminotransferase)
        hepatocellular damage
        
        Increased AST = levels are associated with
        
        ALT is more specific for hepatocellular damage than is AST, and remains elevated for longer
      - Liver Biopsy
        
        for chronic hepatitis or cirrhosis
  - - - DNA
        
        More stable
      - RNA
        
        More unstable (mutate)
      - Hydrophillicity
        
        Hydophillic = small protein coat, more resistant to alcohol based hand gels ie Papilloma, Enteric Viruses
      - Lipophillicity
        
        Lipophillicity = lipid component to coat, has to be replicated by host cell e.g HIV, HHV & Respiratory viruses
    - - Host Entry
        
        N95 masks help to prevent this
      - Attachement
        
        Antibodies on surfaces aggregating virus to prevent their attachment onto the cells
      - Intergration of viral nuclei into host genome
        
        Drugs which target reverse transcriptase for RNA viruses
      - Replication of new viral components
        
        Drugs which are proteases to breakdown components
      - Assembly of viral particles (virions)
        
        Drugs which are proteases to breakdown components
      - Release of viral partilces (w/ or w/o cell lysis)
- - - - mixed infection w/ C. albicans and Staph epidermidis
  - - - ○ Correcting fluid balance
    - - ○ Reducing the load and frequencies of Carbohydrates
    - - ○ Especially iron
    - - ○ Pre or probiotic
    - - ○ Stabilizing DM
    - - ○ Improve OH
    - - ○ Remove Irritants
  - - - Physical debridement of biofilm, regular bleaching disinfection, keep it out at night
    - - Antifungal agents
        
        Polyenes
        
        (Cause cell membrane leakage)
        
        Nystatin – Topical use only
        
        Amphotericin – Topical lozenges or IV
        
        Azoles
        
        (Prevent cell membrane synthesis)
        
        Miconazole – topical cream, plus action against staphylococci
        
        Fluconazole – oral tabs or IV
  - - - Into local tissues (ie under the denture)
    - - Hematogenous dissemination may then occur with formation of abscess
- - - - Pathogen
      - Suseptible Host
        
        ?vaccine
      - Source
        
        Entry and Mode
        
        Social distancing, quarantine, practice restrictions, hand hygiene
    - - Bats and Pangolins, illegal wet markets in Wuhan
    - - Cough and sore throat
      - Fever
      - SOB
    - - Incubation from 1-14 days
        
        Most people symptomatic at day 11, up to 19% of case are hospitalized and has a 1-3% fatality rate
      - Transmission
        
        Floaters, Droplets (Sinkers) = Airborne and Direct/Indirect contact
      - R0 value = 1.4-5.5 (no. people one case infects)
      - Risk Factors
        
        Increases w/ age (>50)
        
        Hospitalised = Above 30% amongst adults aged 85 years or more
        
        Fatalities = 80% of deaths are in adults aged 60 years or more
        
        Underlying medical condition
        
        ○ CVD
        
        ○ HTN
        
        ○ DM
        
        ○ COPD
        
        ○ CKD
        
        ○ Immunocompromised
    - - Stays in the air for ~ 1.5 hours
        = Risk to later patients after appt
      - Virus present in high levels in sinus, nasopharynx, saliva
        
        Important for HCWs in E.g ENT, Dental and ophthalmology
      - Penetrates through regular masks (ie need for N95s)
      - Can live on surfaces for up to 72hrs
    - - Conhorting Concept
        
        Seeing a patient cohort of younger patients (possible carriers) at a different time of the day from older patients (those most at risk)
        
        Seeing fewer patients and having longer visits reduces the number of patients in the waiting room at any one time
      - Triaging
        
        Urgent care
        
        Active infections (pain/swellings)
        
        Dental Trauma
        
        Immunocompromised patients
        
        Non essential tx
        
        Hyigenes
        
        Routine or restorative treatment
      - Suppression
        
        Social Distancing
        
        Avoid gatherings in the waiating rooms
        
        Enviornmental Cleaning
        
        Debridement of regularly touched surfaces
        
        Respiratory Hygiene
        
        Mask wearing + Sneeze/cough into flexed elbow
        
        Surgical Masks/respirators
        
        N95 (95%) = FFP2 (94%)
        
        Hood testing to test the seal and fit of this!!
        
        SARS-CoV-2 particle sizes (0.03 microns) can penetrate a normal surgical mask
        
        Procedural/surgical masks loose effectiveness over time
        
        Hand hygiene
        
        Alcohol-based rubs or soap/water
        
        Remove jewlery and watches
        
        Wash = 15-20 sec wash and whole procedure 1min
        
        Rub = 20-30 secxs
      - Risks for dental professionals
        
        Aersol generating procedures can generate droplets and spread to dentists directrly or indirectly (via contaminated surafces)
        
        Covid-19 present in saliva (multi studies)
        
        Minimized via use of dental dam?! and use of pre-procedural rinses?!
      - Room Air Filters
        
        Air purifiers (HEPA vs. non-HEPA)
        = High Efficiency Particulate Airfilter (HEPA)
        
        nb: Nanocapture - a chemical capture not a virus capture
      - Infodemics
        
        Reliable
        
        • High reputation peer review journals with rapid online publishing of peer reviewed papers
        
        • ADA Information Control Committee
        
        • CDC, WHO
        
        Unreliable
        
        • Mass media promulgation of bad behaviour (e.g. hoarding, racism)
        
        • Twitter conspiracies (e.g. The UK 5G conspiracy –mobile towers were destroyed)
        
        • Misuse of antibody tests – Cheap tests for IgG showing people HAD the infection not HAVE the infection