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MIC2000: Microbiology, Unusual but serious infections (environmental…

- - - - Screening swabs:
        detect only a specific organism
        taken from specific body sites (MRSA)
    - - Anything to do with viruses: NEED virus transport media/universal transport media
      - Rayon bud (tip) "transportation of aerobes/anaerobes"= bacteria
      - eSwab media "eSwab"= bacteria
      - Flocked swab in UTM "UTM"= for viral/PCR testing
      - Formalin: for histopathology, looking at biopsy samples of cancer. This will kill pathogen on it
      - Make sure sample is leak proof: tighten cap + in biohazard bag
        
        2 patient identifiers
  - - - Collecting urine sample: midstream,
        UTI most common infection (caused by 1 bug)
        
        Urinary catheter UTI caused by multiple bugs: sample from sampling port
    - - Stool sampling: 1/3 full
        REJECTED: Hard stools: non-diarrhoeal
    - - Poor quality sample = presence of epithelial cells (specimen from upper respiratory)
      - For ICU patients: Broncho-alveolar lavage: rigid scope into lungs and sucking
    - - Dermatophytes: infecting skin, hair nails
- - - - Bacterial conjugation: +ve to the -ve bacteria, transfer of plasmid
    - - Gram negative bacteria have second outer membrane called lipopolysaccharide (endotoxin)
        
        Systemic release of vasodilation
        Trigger white cells to be released
        Fluid leaks out of capillaries
        Affects clotting system
        
        SEPSIS Blood supply to organs decrease/compromised -> deprived of oxygen -> end organ failure
        
        Over-stimulation of body reaction
        BALANCE OF PATHOGEN ON HOST AND BODY RESPONSE TO HOST
      - Gram positive: absorbs blue dye
        Gram negative: does not absorb blue dye (appears red) due to second outer membrane
      - Different sizes and shapes
    - - Flagella: allow bacteria to move
      - Fimbriae and pili: allow adhesion to other bacteria
      - Capsule: protect bacteria from host immune response
        
        Difficult to phagocytose
- - - - Botulinum toxins: most poisonous natural substances
      - Preformed toxin absorbed in GI tract. Botulinum toxin binds irreversibly to presynaptic nerve endings --> inhibiting acetylcholine release
    - - Descending motor loss with flaccid paralysis
      - Speech and swallowing difficulty
      - Eyes affected first (double vision, drooping eyelids)
      - Breathing difficulty
      - Death from cardiac/respiratory failure
    - - home preserved food, home canned products
      - Very rare
  - - - Lock jaw
      - Sardonic grin
      - Stiffness
      - Opisthotonus (extreme arching of back)
    - - Affects nervous system, toxin causes sustained excitation of motor neurons causing motor spasms
    - - Can get from superficial cut, contaminated splinters, thorn prick etc
      - Rare in SG
- - - - Full of bacteria
- - - - Gram negative
    - - Jaundice
      - Red eyes
    - - Contaminated water contact
      - Bacteria through skin/mucous membranes
  - - - Infection very common
      - of those who are infected, immune system keeping infection at bay
    - - During pregnancy infection, can pass congenital infection (Earlier in pregnancy the transmission, the more severe the damage to baby)
      - Miscarriage, stillborn child
      - Child born with toxoplasmosis (Retinitis, brain damage with calcification, microcephaly)
      - Infacts infected before birth can show no symptoms at birth but may develop them later in life with potential vision loss, mental disability and seizures
      - HIV patient infected first time = severe primary infection
        
        OR may develop reactivation of toxoplasma infection
        
        Fever, confusion, headache, seizures, nausea and poor coordination
        
        Manifestations: seizures, fits, headache, fever, confusion lesions in brain, cyst in head
    - - Cook food + treated water
      - Good care of cats: keep cats indoors, feed cats commercial food, do not adopt stray cats
      - Good hand hygiene
      - Antibiotic prophylaxis lifelong for immunocompromised: Cotrimoxazole
  - - - May cause severe disease in mother and foetus
    - - Swinging fever
        
        Consist of cold/hot stage and finally a sweating stage
      - Fever, chills, sweats, headaches, nausea and vomiting, general malaise
    - - Blood film. Parasite in RBC
      - Rapid diagnostic test
    - - Prophylaxis before travel
        
        Beware of drug-drug interaction
        
        Treatment continued 7-30 days after travelling
- - - - Direct, prolonged skin-to-skin contact
        
        Nursing homes, extended care facilities, prisons, child-care facilities
        
        Can be contamination of used objects
        
        Scabies in adults frequently sexually acquired
    - - Burrows in skin, lays eggs
      - Intense itching + pimple-like skin rash (especially at night)
      - Rash with tiny vesicles- scratching rash can cause skin sores which can become infected by bacteria
    - - Skin scraping
    - - Scabicides (doctor only prescription) lotion applied all areas of body
        
        treatment also is recommended for household members and sexual contacts, particularly those who have had prolonged skin-to-skin contact with the infested person. All persons should be treated at the same time in order to prevent reinfestation.
        
        Retreatment may be necessary if itching continues more than 2-4 weeks after treatment or if new burrows or rash continue to appear.
    - - decontaminate bedding/clotting by machine-washing in hot water and drying using hot cycle/dry-cleaning
      - Remove contact of contaminated object frominfected person for at least 72 hrs
      - Careful vacuuming of furniture and carpets in rooms used by persons is necessary
      - Fumigation of living areas
    - - If a person has never had scabies before, symptoms may take 4-8 weeks to develop. It is important to remember that an infested person can spread scabies during this time, even if he/she does not have symptoms yet.
      - If a person who has had scabies before, symptoms usually appear much more sooner (1-4 days) after exposure
    - - (On a person, scabies mites can live for as long as 1-2 months. Off a person, scabies mites usually do not survive more than 48-72 hours. )
      - If itching continues more than 2-4 weeks after initial treatment or if new burrows or rash continue to appear (if initial treatment includes more than one application or dose, then the 2-4 time period begins after the last application or dose) retreatment with scabicide may be necessary;
      - Children and adults usually can return to child care, school, or work the day after treatment.
- - - - Treatment: correct antibiotics
      - Take out foreign body if possible
        
        source control not eliminating the source of infection
  - - - Take note that lower than expected white blood cell also a sign of infection
- - - - Itchy, blister-like rash that spreads all over the body including inside mouth, eyelids or genital area. Takes 1 week for blisters to turn into scabs
      - Other symptoms: fever, tiredness, loss of appetite, headache
    - - Person-to-person (close contact) with those who never had chickenpox + no vaccination
        
        Considered contagious begining 1-2 days before rash onset
        
        Vaccinated people who get chickenpox may develop lesions that do not crust. Considered contagious until no new lesions have appeared for 24 hrs
      - Fluid-person from blister fluid
      - Breathe in virus particles
      - If they get infected, they will develop chickenpox not shingles
    - - High risk for lower immunity populations (infants, pregnant women etc)
      - Bacterial infections of skin/soft tissues in children (including Grp A strep)
      - Lung infections (pneumonia)
      - Bleeding
      - Bloodstream infection (sepsis)
      - Dehydration
      - May cause shingles in adulthood
    - - Congenital varicella/neonatal varicella
        
        Scars on skin
        
        Problem with arms, legs, brain and eyes
        
        Gastro complications
        
        Low birthwweight
    - - do not use aspirin to relieve fever from chickenpox. Associated with Reye's syndrome
      - Home remedies: calamine lotion with cool bath
      - Hand hygiene
      - Antiviral for people who may develop more serious
    - - Yes
    - - Chickenpox vaccine
  - - - Fever, sore throat, fatigue, swollen glands
      - Ocassionally cause mononucleosis, hepatitis
    - - Many do not require medical treatment.
      - Congenital CMV: antiviral medications may improve hearing and developmental outcomes
    - - Congenital CMV: complications that develop later, or death of unborn baby
      - Usually people do not know infected, immune system keeps it at bay
    - - Congenital CMV
        
        Retinitis
        
        Microcephaly
        
        Rash
        
        Jaundice
        
        Seizures
    - - Direct contact with saliva/urine especially from babies and young children
      - Sexual contact
      - Breast milk
      - Transplants
      - Transplacental (mother to baby)
    - - No
    - - Reduce contact with salivra/urine from babies and young children. Lessen chances of getting it
  - - - Fever + flu-like symptoms
      - Mouth sores
      - Skin rash on soles and palms
    - - Person-to-person (including contaminated objects/surfaces)
      - Fluid from blisters/scabs + feces
      - Respiratory droplets coontaining virus particles
    - - Dehydration: painful mouth sores prevent swallowing
      - (Rare) Fingernail + toenail loss + viral meningitis
        Encephalitis/paralysis
    - - Depending on how far along in pregnancy, can affect sittuation (complications rare)
    - - Most people get better on their own in 7-10 days
      - Treat symptoms and prevent dehydratioon
    - - No vaccine
    - - Hand hygiene, avoid close contact with infected
  - - - Person-to-person
      - Coontaminated food
    - - Usually short term, does not becoome chronic
      - Highly contagious
      - RARE can cause liver failure and death, common in oolder people and in people with other serious health issues
    - - Yes
  - - - Common flu: fever, cough, sore throat, runny/stuffy nose, headache
    - - Person-to-person
    - - 65 years or older
      - Adults with chronic conditions
    - - Reduce risk of flu-associated acute respiratory infection in pregnant people by about one-half
    - - Antiviral drugs
    - - Yes
    - - Flu vaccine
      - Take everyday precaution too prevent infections
  - - - Considered contagious from 4 days before to 4 days after rash appears
      - Sometimes immunocompromised do NOT develop rash
      - Fever, malaise, cough, conjunctivitis, coryza (common cold) The 3Cs.
      - Macupopular rash
    - - Moost contagious of all infectious diseases
      - Close contact
      - Airborne spread
    - - Acute encephalitis which can result in permanent brain damage
      - May die from respiratory and neurologic coomplications
      - Subacute sclerosing panencephalitis: rare but fatal degenerative disease of CNS
      - Infants/children <5years, adults >20, pregnant woman, immunocompromised population are people at high risk
    - - Premature birth
    - - no antivirals
      - Medical care is supportive and to help relieve symptoms and address complications such as bacterial infections
      - Hospitalised, treated with vitamin A
    - - yes
    - - Vaccine
  - - - Low grade fever, headache, mild pink eye, general discomfort, swollen and enlarged lymph nodes, cough, runny nose
      - Red rash typically first sign, appear on face and spread to other parts of body
    - - Transplacental
      - Airboorne: cough/sneezes
    - - Woomen may experience arthritis
    - - Miscarriage/stillbirth
      - Birth defects: heart problems, loss of hearing and eyesight, intellectual disability and liver/spleen damage
    - - No specific medicine
      - Bed rest
    - - Yes
    - - Vaccine
  - - - Puffy cheeks, tender and swollen jaw (Swollen salivary glands: parotitis)
      - Fever, headache, muscle aches, tiredness, loss of appetite
    - - Airborne: saliva/respiratory droplets, sharing items that may have saliva on them
      - Cloooose contact activities with others
    - - Especially in adults
      - Inflammation of testicles/ovaries, pancreas, brain, tissue covering brain and spinal cord, deafness
    - - Usually not benign
      - May increase risk of miscarriage
    - - No speciiific, plenty of bed rest and fluids
    - - Yes
    - - Vacciine
  - - - Runny nose, decrease in apetite, coughing, sneezing, fever, wheezing
    - - Virus droplets from coough sneeze
      - Person-to-person. Touching surface with virus
    - - bronchioolitis (inflammation of small airways in lung)
      - pneumonia: infection of lungs
    - - No specific treatment, manage fever and paiin + drink enough fluids
    - - No
    - - hand hygiene, avoid close contact, clean surfaces frequently
- - - - Mimics other benign acute febrile illnesses
      - Typically young children or those experiencing first infection (without diagnostic testing, diagnosis of dengue missed)
    - - Up to 50% of all dengue infected individuals
    - - Critical
        
        Day 3-7 of illness, increase in capillary permeability + increasing hematocrit levels
        
        Usually 24-48 hrs
        
        Progressive leukopenia + rapid decrease in platelet usually precedes plasma leakage (rising haematocrit reflects plasma leakage)
        
        Improve after defervescence, non-severe dengue
        
        Those who deteriorate: dengue with warning signs
        
        Persistent vomiting
        
        Clinical fluid accumulation
        
        Abdominal pain/tenderness
        
        Mucosal bleed
        
        Lethargy, restlessness
        
        Liver enlargement >2cm
        
        Increase in hematocrit + rapid decrease in platelet count
        
        APCMLLH
        
        Some even deteriorate to severe dengue
        
        Severe plasma leakage --> shock + fluid accumulation with respiratory distress
        
        Severe bleeding
        
        Severe organ involvement: Liver, CNS, heart and other organs
        
        Considered shock IF
        
        poor capillary perfusion (cold extremities, high pulse rate, delayed capillary refill)
        
        in adults, pulse pressure of <20 may indicate more severe shock
        
        pulse pressure: considered shock if <20 (children)
        
        Systolic - diastolic
        
        Shock -> thrombocytopenia, hypoxia, acidosis -> multiple organ failure -> DIC -> massive bleeding
        
        Critical phase of plasma leakage without defervescence: changes in FBC used to guide onset of critical phase and plasma leakage
      - Recovery
        
        Survives 24-48 hr critical phase, reabsorption of extravascular compartment fluid takes place in the following 48-72hr
        
        General well being improve
        
        White island in sea of red rash
        
        White blood cell, hematocrit and platelet recovers (WBC then platelet)
        
        heart failure/respiraatory distress from massive pleural effusion/ascites will occur at any time if excessive IV fluid therapy is continued
        
        Discharge criteria
        Clinical: no fever for 48hrs, improved general well-being
        Laboratory: increasing trend of platelet count, stable hematocrit without IV
      - Febrile
        
        Sudden high grade fever for 2-7 days
        
        Facial flushing, skin erythema, generalised body anorexia, nausea, vomiting
        
        Can be difficult to distinguish dengue clinically from other infections (monitor progression to critical)
        
        positive tourniquet test in this phase increases probability of dengue
        
        FBC: drop in total white cell count (leukopenia)
        
        mild haemorrhagic symptoms such as petechiae may be found
    - - Dengue haemorraghic fever
        
        DHF is a more severe form of dengue
      - Dengue shock syndrome
        
        DSS – presentations are the same as those in DHF but the plasma leakage is so severe that the patient develops shock.
      - Dengue fever
  - - - NS1 glycoprotein produced by flaviviruses in form of immunocomplexes detected
      - NS1 Ag, IgM, IgG LOOK THROUGH GRAPHS
- - - - Fever and jaundice
      - Liver enzymes increase to indicate inflammation
      - (Complications are rare)
    - - Hygiene,
      - Sanitation
      - Vaccine
      - Immunoglobulin prophylaxis
- - - - Leads to AIDS, especially when CD4 count drops <200/ultra m3
    - - Blood-borne
      - Unprotected intercourse
        
        IF HIV viral load is undetectable, there is no transmission
      - Contact between damaged skin/mucosa with body secretions
        (lower risk compared to other 2)
      - Transplacental
    - - First line test: antibody + p24 antigen combined screening test
      - "window" period: although infected, still not antibodies detected in blood
        
        p24 antigen/PCR (to determine viraemia) useful during window
        
        seroconversion of antibody ranges from 7days up to 90 days post infection
      - To confirm, second blood sample is tested
    - - Lifelong Highly active antiretroviral therapy (HAART)
      - Increase CD4 above 200
        
        Monitor using blood test
      - Suppress HIV viral load to undetectable level
        
        Monitor using blood PCR
      - Antibiotic prophylaxis against opportunistic infections
        
        Trimethoprim/sulfa (bactrim): prevent PCP and toxoplasma
        
        Clarithromycin/azithromycin: prevent mycobacfterium
      - Genotyping HIV may be indicated to detect viral mutation which could help predict/confirm drug resistance
    - - No
    - - 78-83 years (depends on initial response to treatment)
    - - Dendritic cells in mucosa
      - CD4 T cells
        
        Viraemia occurs -> patient become symptomatic (primary HIV infection/seroconversion syndrome -> self-limiting)
        
        Immune response reduce level, achieve partial control
        
        Progressive reduction in CD4 thereon -> AIDS varies from 1-2 years post infection to >10 years post infection
- - - - Facial abnormalities
        Saber shins
        Sensorineural deafness
- - - - HSV1: Oral
      - HSV2: Genital
    - - Virus stays for life
        
        Immune system weakens, reactivation of VZV
        
        HSV, reactivation triggered by a variety of factors: menstruation, tiredness, stress, sunlight
  - - - Persistent infection with high risk HPV types increases risk of cancer
        
        HPV-16:
        
        HPV-18:
      - Low risk type: genital warts
        
        HPV 6
        
        HPV 11
- - - - Example: Madura foot
      - Inoculation injuries, chronic and deforming, some very hard to treat
  - - - Talaromyces marneffei
        
        Dimorphic fungus
        
        Predisposing factors
        
        Immmunocompromised (HIV/AIDS)
        
        Diagnosis
        
        Microscopy and culture
        
        Manifestations
        
        Systemic symptoms
        
        Fever, weight loss
        
        Lymphadenopathy
        
        Cough, skin lesions
      - Others
    - - Mucor and related species
      - Infections of immunocomproomised
        
        Does not affeect normal people, rare
        
        Diabetes mellitus
      - Diagnosis
        
        Microscopy and culture
      - Therapy poor
        Surgical debridement important
        Include antifungals
    - - Aspergillosis
        
        Filamentous fungus
        
        Aspergillus fumigatus most common
        
        Predisposing factors
        
        Immunocompromised patients
        
        neutropaenia (absense of neutrophils = invasive aspergillosis)
        
        Building work releases large numbers of fungal spores into the air
        
        Diagnosis
        
        Antigen tests
        
        Culture less predictive, biopsy more specific
        
        cannot biopsy because people might bleed too death
        
        empirical amphotericin often used
      - Cryptococcosis
        
        Transmission
        
        Inhaled systemic spread
        
        pigeon droppings
        
        Manifesations
        
        Pulmonary, meningitis, skin lesions
        
        Capsulated yeasts
        
        Predisposing factors
        
        Compromised patients: HIV/AIDS
        
        Diagnosis
        
        India ink (CSF)
        
        Culture (CSF, urine, BAL, biopsy)
        
        Antigen test (serum/CSF)
      - Systemic candidiasis
        
        Predisposing factors
        
        Skin and nails
        
        Wet hands
        
        Recurrent infection in HIV/AIDS
        
        Mucosal
        
        Antibiotics
        
        Immunocompromised: infancy, old age, pregnant
        
        GIT perforation/surgery
        
        Intravascular line
        
        Preterm neonates
        
        Treatment
        
        Insensitive blood culture? Still, must treat it
        
        Treat early Anticipate candida in intensive care
        
        Stop antibiotics + remove central lines
        
        Antibiotics predispose to candiasis
        
        C. albicans single most common candida species
        
        dimorphic
        
        Invasive candidiasis: susceptibilities are routine
    - - Lung infections in immunocompromised
      - Common in HIV/AIDS patients with low CD4
      - do not respond too antifungal drugs: use cotrimoxazole
      - Diagnosis
        
        Microscoopy/PCR
  - - - Sources
        
        humans, animals, environment
      - 'Ring worm' - skin (not common in SG)
        'Athlete's foot' - soles, and toe webs
      - Filamentous fungi that digest keratin
      - Disease named after body site
      - Identify by characteristic macroconidia
    - - Malassezia furfur: skin colonisation in 20-100%
      - Itchy, scaly rash
        
        Face, neck, chest, back, shoulders, limbs
        
        often aggravated by excessive sweating
        
        White/pink/brown patches
      - Very common in hot humid climates
      - Hyper/hypo pigmentation
    - - Predisposing factors
        
        Mucosal, skin and nails
        
        Recurrent infection in HIV/AIDS
      - Found in
        
        Mucosae; mouth & GIT, vagina
        
        Skin/nails
- - - - positive pressure room: air from inside room pushed out of room into environment
      - negative pressure room: vacuum
    - - negative pressure: isolation rooms, keep patient with infectious illnesses/patients who are susceptible to infections from others
      - positive pressure: rooms for immunocompromised
  - - - Should be in positive pressure room
      - Cooked food
      - Receive various antibiotic/antifungal prophylaxis
      - Avoid soil and dirt
      - No sick visitors
      - Strict hand hygiene
      - Strict infection control
    - - Immunosuppression
        
        To eradicate T cell activation
        
        Removal of T cell
        
        Inhibit proliferation of T cell
      - Infection after organ transplantation
        
        Derived from: donor + recipient
        
        Screening of both
        
        prophylaxis
        
        Vaccination
      - Steps in organ transplantation
        
        Acute rejection prophylaxis
        
        Chronic therapy
        
        Immediate post transplant: intense, high dose immunosuppression
        
        0-1 mth
        
        Risk of infection
        
        Opportunistic infection generally absent: require plronged use of immunosuppressive agents
        
        Post-op infection (etc. wound infection, ischaemia)
        
        Nosocial infection (MRSA, multidrug resistant organism, clostridium difficile, candida)
        
        90 days: continuous intense immunosuppression
        
        Start to see prolonged effect of T cell suppression
        
        Return to community
        
        Environmental exposure: aspergillosis, mucormycosis
        
        Risk of reactivation
        
        HSV
        
        Toxoplasma + Strongyloidiasis
        
        TB
        
        After 90 days: lowest maintenance immunosuppression
        
        CAI: can be severe manifestation
        
        Minimal opportunistic infection
        
        Immunosuppression reduced
        
        Start to see malignancy from prolong immunosuppression, infection related
        
        Induction therapy
      - Care after solid organ transplant
        
        Strict hand hygiene + infection control
        
        No sick visitors
        
        Single room, no need pressure control
        
        'Safe living' counselling
        
        Cooked food
  - - - 3 phases after stem cell transplant
        
        Immediate post-engraftment
        
        3 weeks-3months
        Start to see increasing RBC
        
        Neutrophil recovery first but impaired adaptive immune response
        
        Latent virus reactive -> infection
        
        Fungal infection
        
        Late post-engraftment
        
        After 3 months
        
        Still impaired adaptive immune
        
        TB/mycobacteria, bacteria, viral, fungal,parasitic infection possible
        
        Pre-engraftment
        
        3 weeks after stem cell infusion
        
        Depress all immune system at risk of bacterial and fungal infection
- - - - Orange: gross blood-contaminated linen
      - Green, colourless: normal, soiled linen
      - Red (water soluble bag): linen from SARS, COVID19, cholera, typhoid, virus cases
    - - Droplet
        
        Family PPE requirements
        
        Influenza, mumps, rubella, invasive neisseria meningitis
        
        Mask + eyewear
      - Airborne
        
        Single, negative pressure room + family PPE
        
        Measles, chicken pox, PTB
        
        n95 mask
      - Contact
        
        Active Multidrug resistant organism surveillance
        
        MRSA, VRE, Cdiff, CP-CRE
        
        PPE + use dedicated equipment
    - - Hand hygiene compliance rate
      - Multidrug resistance surveillances
    - - Indwelling catheter
      - Intravascular access devices
      - Ventilator associated event
        
        Elevate head of bed to 45 degrees
- - - - For example,
        Candida albicans = flucanisol
        Candida glabrata = not sensitive to flucanisol
  - - - Cryptococcal antigen test
      - Galactomannan
      - India ink
      - no culture sensitivity
- - - - (HAP) hospital acquired pneumonia: pneumonia occurs 48 hours or more after hospital admission
      - (VAP) ventilator associated pneumonia: pneumonia which occurs 48-72 hours after endotracheal intubation
      - CAP: community acquired pneumonia
      - Aspiration pneumonia: from aspiration of food/mouth flora/ gastric content in patients with poor gag reflex, difficulty swallowing (stroke or loss of consciousness
      - Emphysema: infection of pleural space, usually due to consequence of pneumonia
      - Abcess: pus collection within lung parenchyma
      - Mycobacterial infection: due to mycobacterium tuberculosis or NTM (non-tuberculous mycobacteria)
    - - CAP
        
        Typical bacteria: streptococcus pneumoniae, haemophilus influenzae
        
        Atypical bacteria: Mycoplasma pneumoniae, chlamydia pneumoniae, legionella pneumophila
        
        Others: staphyloccocus aureus (especially post influenza), klebsiella pneumoniae
        
        Viruses: influenza
      - HAP
        
        Coliforms
        
        Pseudomonas aeruginosa
        
        Other gram negative bacilli- acinetobacter
        
        MRSA (if patient is MRSA positive or high prevalence)
        
        Streptococcus pneumoniae, haemophilus influenzae
      - Aspiration pneumonia
        
        HAP pathogens
        
        Patient mouth flora
    - - Sputum
        Endotracheal aspirate/ bronchio-alveolar lavage (more accurate)
        
        Gram stain
        
        Culture and sensitivity
        
        Overnight incubation: 18-20 hours
        Sensitivity: perform day 2 if present of bacteria in culture
        
        If epithelial present = sample poorly taken
        
        PCR = for virus!
      - Urine = legionella pneumophila (difficult and takes time to grow)
        Strep pneumoniae (quick detection but beware of false positive result)
      - Blood culture if patient febrile/septic
  - - - Cellulitis: Red, hot, tender leg
        Impetigo: honey coloured crusted lesions
        Intertrigo: sticky redness under skin folds
        Lymphangitis: lymph vessel that is red
        Erysipelas: light, red tender on face
        Gas gangrene: skin punctured with soil and faeces
        
        Above fascia: can be treated by antibiotics alone
        Below superficial fascia: surgical debridement + antibiotics
    - - Erysipelas
        
        Group A Strep
      - Lymphangitis
        
        Common and acute- Group A Strep
        Acute (Cat scratch) Pasteurella multocida
      - Cellulitis
        Impetigo
        Folliculitis
        Furuncles
        Carbuncles
        
        Staph aureus
        Beta-haemolytic Strep (especially Group A Strep)
        
        Cellulitis: 7-10 days
      - Nectrotising fasciitis
        
        Group A strep
        (Flesh-eating bug)
        
        14 days
      - Gas gangrene
        
        Clostridium perfringens
        
        Group A strep
    - - Staph aureus is typical bug causing these infections
  - - - Pylonephritis diagnosis
        
        Same as cystitis
        
        Blood culture: if patient febrile/septic
      - Catheter associated UTI
        
        Urine culture may be polymicrobial: positive does not mean infection
        
        dipstix: white cell/RBC, result completely unhelpful for catheter associated UTI
      - Cystitis diagnosis
        
        Midstream urine
        
        Bag urine (children)
        
        Suprapubic urine (children)
        
        Catheter sample (positive culture may be colonization of bag)
      - Lower UTI (Cystitis): go on to get septic. Bacteria concentration so high that it can travel up to the kidney
    - - GRAM NEGATIVE
        E.coli: commonest
        Klebsiella pneumonia
        Proteus
        Enterobacter, citrobacter, morganella, serratia
        Pseudomonas aeruginosa (esp. previous antibiotic experience/presence of urinary catheter)
        GRAM POSITIVE
        Enteroccocus
      - Concentration of bacteria in the urine determines if there is UTI (more than 10 to power of 5 CFU/ml)
        Even if not reach that level, patient may be immunocompromised, lots of UTI in the past, abnormal anatomy
    - - Lower UTI (cystitis, catheter associated UTI)
        
        Oral antibiotics
        
        Short course (3-7 days)
        Presence of catheter usually requires min. 5 days antibiotics
        May require longer course than women
      - Upper UTI (pyelonephritis, urosepsis)
        
        Start of IV antibiotics, then oral if improving after 48 hrs
        
        7-14 days
      - Have high concentration but asymptomatic (common in patients >65 years old): Asymptomatic bacteruria
        
        Treat patient, not the lab result
        
        Antibiotic should not be given unless
        
        Pregnant women: pass infection to baby, complications
        
        Undergoing urological procedure/surgery: bacteria present when damage to tissue = allow it to go to bloodstream and then sepsis
      - Long term antibiotic prophylaxis
        
        Particular antibiotic = bacteria after months/years they will just become resistant forming new infection
        
        With time, the bacteria would just adapt themselves
        Long term antibiotic prophylaxis encourages bacterial adaptation and resistance Leading to multidrug resistant UTI
        
        Exceptions: children with repeated UTIs, immunocompromised, kidney transplant patient
        (Frequently and severely affected by UTI less admissions: Benefit vs risk, long run still lose)
  - - - Non-tuberculous mycobacteria (NTM)
      - Mycobacterium leprae (leprosy)
      - Mycobacterium tuberculosis complex
    - - AFB (acid-fast aerobic bacilli) stain
        Waxy, lipid outer wwall prevents effective staining using Gram stain technique
        Lipid wall also helps protect MTB from disinfectants, probably helps MTB survive within macrophages for prolonged period of time
        
        AFB smear positive: highly infectious
        AFB smear negative: culture positive - less infectious
    - - Inhale, proliferate inside lungs, immune response try to stop. Macrophages get infected, travel all over the body (through bloodstream and lympathic vessels)
        => swollen armpit lymph node? TB travel all over the body
        
        Type 4 hypersensitivity reaction
        Most of us good immune response, unaware of what is going on
        
        Immunocompromised/not strong immune response/infection too strong unable to successfully envelope
      - Contain TB infection: quiescent infection
        Body has contained it = latent TB infection are asymptomatic and non-infectious
        
        Can reactive later to cause active disease and symptoms
        
        Immunocompromised
        
        Inhale large amount
        
        Test for latent TB
        1. TST (tuberculin skin test)
        2. IGRA (Gamma Interferon (IFNgamma) Release Assay)
        
        Depend on cell-mediated immmunity (T cell response) and neither can distinguish between LTBI and active TB disease
      - Active TB
        
        Post Primary tuberculosis: occurs months/years after primary TB
        either due to reactivation of latent TB/reinfection (can occur in any organ of body)
        
        Miliary Tuberculosis: disseminated haematogeneous tuberculosis
        Many organs affected
        
        Unwell and symptomatic
        
        0.5-1mm nodules typical of miliary TB
        
        Primary tuberculosis: minority who progressed to TB disesae
        
        Symptoms: fever, weight loss, cough
        
        Test for active TB
        
        Early morning sputum: 2
        
        Send for AFB staining and culture (not Gram stain)
        
        1 e. coli to baby e.coli = 6 minutes
        1 TB to 1 baby TB = 15-20 hrs
        TB culture come back weeks later
        
        TB PCR test = on the day itself can say if TB present/multidrug TB
        AFB stain does not distinguish if Mycobacterium TB
        
        AFB on the same day
        
        Duration of treatment for TB: 6 months
        
        Multidrug resistant TB (MDR-TB)/Extensively drug resistant TB (XDR-TB) treatment options not as effective + associated with side effects
        Prolonged treatment duration is required
        Usually on foreigners
        
        BCG live-attennuated vaccine
        
        To prevent progression to clinical TB disease
        
        Prevent miliary TB in young children
- - - - Causes
        
        Most common: virus. E.g. rhinovirus (common cold)
        
        Self limiting
        
        Group A streptococcus (aka Strep pyogenes)
        Also in cellulitis, skin infection, necrotising fascia
        
        Treat with antibiotics to prevent complications
        Complications of Group A strep
        
        Rheumatic fever
        
        Rheumatic heart disease
        
        Glomerulonephritis
        Antibiotic prophylaxis to prevent rheumatic fever
        
        Diptheria: corynebacterium diphtheriae
        
        Form pseudomembrane causing swollen neck
        Form toxin = cause cardiac arrythmia
    - - Causes
        
        Haemophilus influenzae type B
        Causes CAP
    - - Malignant OE: invade adjacent bone, blood vessels etc
        
        Due to pseudomonas aeruginosa
      - Causes
        
        Staph aureus
        
        Pseudomonas aeruginosa
    - - Causes
        
        Haemophilus influenzae
        
        Streptococcus penumoniae
      - Can cause mastoiditis, leading to brain abscess
  - - - Meninges:
        
        Dura mater
        
        Arachnoid
        
        Pia mater
        
        Meninges very tightly packed together
        Very tight junctions = forms blood brain barrier
        
        Antibiotics used to treat very limited!
      - Less glucose in CSF = most likely bacteria
    - - Meningitis: infection of the meninges
        
        Bacterial meningitis
        
        Causes
        
        Normal population
        
        Streptococcus pneumoniae
        (CAP, sinutitis, otitis media)
        
        Haemophilus influenzae
        
        Neisseria meningitidis
        
        Others
        
        Group B strep (neonates)
        
        E. coli (neonates)
        
        Listeria monocytogenes (neonates, pregnant women, immunocompromised)
        
        Pasteurised milk, certain types of cheese, yogurt
        
        1 more item...
        
        How do pathogens invade the meninges?
        
        Prevention
        
        Vaccination against
        Streptococcus pneumoniae
        Haemophilus influenzae
        Neiserria meningitidis
        
        Household and close contact chemoprophylaxis given
        
        Complications
        High mortality (It can kill in hours!)
        Brain damage
        Hearing loss
        
        Bacterial meningitis treatment: 5-7 days of treatment
        
        Symptoms of bacterial meningitis:
        -generalised headache
        -neck stiffness
        -abnormal mental state/reduced conscious level
        -vomiting
        -rash
        -PHOTOPHOBIA: bright light
        
        Cryptococcus neoformans menigitis (fungus)
        
        Risk factors: immunocompromised,especially HIV
        
        Symptoms
        A bit slower
        Manifestation a bit more subtle
        
        Diagnosis:
        
        Positive india ink in CSF
        
        Positive Cryptococcal antigen in CSF
        
        CSF culture
        
        Treatment: months of antifungal therapy
        
        Tuberculous meningitis
        
        Fatal within 5-8 weeks of onset if untreated
        
        Viral meningitis
        
        Symptoms
        Similar to bacteria meningitis
        
        Diagnosis: PCR
        
        Management: supportive, self-limiting MUCH MORE COMMON THAN BACTERIAL MENINGITIS
      - Brain abscess: abscess of cerebral cortex
        
        Causes
        
        Adjacent spread
        
        Bacteraemia from various deep seated infections in the body
        
        Latrogenic - neurological procedure
      - Encephalitis: inflammation of cerebral cortex
        
        Viral encephalitis
        
        Viral encephalitis: most important cause HSV-1/HSV-2 (Herpes Synthax Virus)
        
        Symptoms
        -hallucinations
        -repetitive higher motor activity
        -seizures
        -severe headache
        -unsteady gait
        
        Causes
        
        Mosquito
        
        Animal (Rabies)
        
        Human to human
        
        Diagnosis: CSF PCR
        
        TreatmentL early detection of HSV and treatment with Aciclovir
        14% mortality with complication of long term neurological complication: seizures
  - - - Shigella spcieis
        
        From person to person, usually self limiting, maintain good hydration
      - Campylobacter jejuni
        
        From chicken, usually self limiting
      - Salmonella typhi (typhoid fever)
        Salmonella paratyphi
        
        Waterborne
        Person to person (ingestion of food and water contaminated by faeces of first infected person)
        IMPORTED INFECTION
        May be treated with antibiotics
        Patient at risk of sepsis/seeding of infection if not treated
      - Vibro species
        
        From raw seafood/sushi, usually self-limiting
      - Salmonella species (S enteriditis: most common)
        
        From food, usually self limiting
      - Clostridium difficile
        
        Antibiotic exposure (too many courses) -> person to person
        Contaminated hospital environment (can produce spores!)
        
        Needs treatment, may lead to colitis/toxic megacolon/death
        
        Treat Cdiff with antibiotics (specific for Cdiff) + try to stop other antibiotics that patient is on
        Colectomy removal of large intestine (though not all may be fit for surgery)
    - - Rotavirus
        
        Person to person
        
        Most common cause of infant/paediatric diarrhoea
        Usually self limiting
      - Adenovirus
        
        Person to person
        
        2nd most common cause of infant/paediatric diarrhoea
        Usually self-limiting
      - Norovirus
        
        Contaminated food (shellfish)/water -> human -> rapid human to human via faecal oral or even formites
        EXTREMELY INFECTIOUS
        
        Well known cause of uncontrolled diarrhoea in hospitals
        Self limiting
    - - Clostridium difficile
        
        Stool for C diff toxin
      - Viruses
        
        Stool for Enzyme immunoassay (EIA) or PCR
      - Salmonella
        Shigella
        Campylobacter
        Vibrio
        
        Stool for culture and sensitivity
      - Parasites: Ova, Cysts and Parasites (microscopy OCP)
    - - Giardiasis (common in HIV patients)
      - Amoebiasis: infection caused by Entamoeba
        
        Cause diarrhoea, can travel to bloodstream and start causing abcesses everywhere
        Drain pus in liver = "anchovy sauce"
    - - Peritonitis: caused by perforation of intestine or gall bladder or other organs within abdomen (usually peritoneum is sterile)
        
        Liver disease -> Ascites -> spontaneous bacterial peritonitis
        
        Secondary peritonitis associated with peritoneal dialysis
        
        Organisms:
        
        Coliforms
        
        Pseudomonas aeruginosa
        
        Anaerobes
        
        Enterococci
        
        Candida (Type of yeast)
        
        If contaminated tube for peritoneal dialysis: Organisms from skin
  - - - Causes
        -Prosthetic heart valve => bacteria latch on and form biofilm
        -line related infection => through bloodstream => into heart
      - Risk factors
        -congenital heart disease
        -more common in men, elderly
        -left side of heart more commonly affected (aortic/mitral valve)
        Right sided endocarditis typically on IV drug users
      - Complications
        -congestive cardiac failure
        -stroke
        -brain abscess
        -lung abscess/kidney abscess
      - Organisms
        
        Staphylococci: IV drug users
        
        Streptococci: most common one
      - What samples to give
        
        3 blood cultures, 10ml each BEFORE antibiotics given
        
        To confirm causative pathogen + increase chances of growing pathogen
      - Treatment
        Weeks of antibiotics
        
        Requires valve surgery
- - - - depression, psychosis, hearing loss, hepatitis, kidney impairment
  - - - Broad spectrum -> narrow spectrum
      - Monitor local antibiotic resistance + adverse effects from antibiotics + antibiotic consumption trend
      - Check if antibiotic really necessary. If so, make sure dose not excessive or too short
  - - - Beta lactams. Same family as penicillins
      - Always ineffective against MRSA
  - - - Even though carbapenems are very broad spectrum – they have no activity against MRSA
      - Counter to this: Carbapenem resistant enterobacteriaceeae (CRE/ CP-CRE)
        
        If resistant to carbapenems, most likely resistant to other antibiotics refer to photo in slides