Microbiology - 1st term (2013)

• pathogen: micro-org that has potential to cause disease.
• infection: invasion and prolif. of pathogenic microorganisms 
• Disease: infection causes damage to host tissues or function.

any inanimate object that carries infection (e.g. cell phone)

empiric: given before you know what is causing the disease, usually broad spectrum

specific: given when the sensitivity and identity of the offending organism are known. Usually narrower spectrum.

• 1) therapeutic index is low: (tmt conc/toxic conc)
• 2) if there is worry about Abx harming organ systems
• 3) genetic hypersensitivity to drug exists

• 1) fever
• 2) leukocytosis (WBC greater than 10 or 11)
• 3) local signs and symptoms
• 4) systemic signs and symptoms

• 1) patient comfort
• 2) harmful secondary effects
•   -febrile conulsions
•   -hypermetabolism
•   -encephalopathy
•   -hypercatabolic state

• 1) fever enhances immune activity: stumlates lymphocytes, and enhances their transformation.
• 2) complicates interpretation of: patient's illness, response to therapy

• The right specimen: One that should have the pathogen (e.g. CSF for neurological symptoms)
• The Right time: while patient is still symptomatic and before Abx
• The Right way: e.g. if sterile, KEEP it sterile from your own flora

• -hospitalizations: tubes, contact, multiple Abx
• -community: athletes, crowded, aboriginal, tattoos, IVDU

-hospitalization: tubes, multiple Abx, immunosuppression

• alpha: viridans, s. pneumoniae
• beta: Group A - S. pyogenes, Group B - S agalactial

• dental infections/abscesses
• abscesses of resp, abdo, pelvic origin
• CNS abscesses

• GNB walls have:
• -less rigid walls
• -thinner peptidoglycan layer
• -inner and outer membrane
• -no teichoic acid
• -LOTS of lipopolysaccharide (lipid A is an endotoxin)

• fever
• leukopenia
• hypotension
• DIC
• others

• 1) negative
• 2) facultative
• 3) bile acids
• 4) glucose

• 1) it is selective: contains crystal violet and bile acids which inhibit the growth of gram +ve bacteria
• 2) it is differential: contains a pH indicator; lactose fermenters make acid turning the media red; otherwise it stays clear

• 1) Skinny
• 2) Obligate
• 3) lactose
• 4) resistant
• 5) oxidase
• 6) nosocomial

• Landscape: GNB, lactose non-fermenter, oxidase positive, found in hospitals (ventilators), burn patients, 
• Landmarks: lung infections in cystic fibrosis, bacteremia in neutropenic patients
• Landmines: resistant to most Abx except gentamycin and a few others.

• Landscape: GNB, non-fermenter, oxidase negative
• Landmarks: treat with Septra
• Land mines: resistant to most Abx

• 1) Upper resp tract
• 2) periodontal disease
• 3) culture negative endocarditis

• 1) adsorption: attach to host cell
• 2) penetration/uncoating: virus enters host cell and shoots its nucleic acid inside
• 3) gene expression: viral genes expressed to make more viruses in hijacked cell
• 4) Assembly: new intact viruses inside cell
• 5) Release: virus particles exit host cell

• 1) lytic (acute) infection
• 2) persistant (chronic) infection
• 3) latent infection
• 4) host cell transformation

• 1) viral latency in recurrent infection
• 2) They are inside of cells
• 3) They use the cell's machinery to replicate
• 4) They display host antigens on exterior
• 5) Rapid mutation with rapid replication

• 1) Virucidal: directly inactivate intact viruses
• 2) Immunomodulatory: augment or modify host response to virus
• 3) Direct Acting: inihibit viral replication on a cellular level

• 1) HBV chronic
• 2) HCV chronic
• 3) HPV infection
• 4) HIV?
• 5) non-infectious: ITP, some leukemias

• 1) NRTIs (nucleotide/side analogue reverse transcriptase inhibitor)
• 2) non-NRTI's
• 3) protease inhibitors
• 4) fusion inhibitors
• 5) entry inhibitors
• 6) Integrase inhibitors

binds to ergosterol on the fungal cell membrane and causes holes

• 1) refractory to conventional AmpB
• 2) patient intolerant to AmpB
• 3) renal dysfunction
• 4) selected difficult to treat pathologies

fluconazole

Voriconazole

• 1) must be released from cells to have toxic effects
• 2) require specific receptors
• 3) small doses are lethal
• 4) most act remotely from the site of infection

• 1) pore formation
• 2) alteration of cytoskeleton
• 3) inhibition of protein synthesis
• 4) activate second messenger pathways
• 5) proteases
• 6) activate immune response (superantigen)

• 1) starts with cranial nerve symptoms and then descending paralysis
• 2) floppy people
• 3) Affects the SNARE proteins that are responsible for the release of ACh
• 4) irreversibly bound, need to grow new nerve terminals
• 5) most potent toxin known to man

• 1) muscle rigidity and spasms
• 2) blocks the release of inhibitory neurotransmitters (e.g. GABA)

• 1) terminates protein synthesis
• 2) toxicity is conferred by a bacteriophage (need this)
• 3) causes tissue destruction (remember psuedomembrane)

• 1) there are multiple toxins at work, complicated
• 2) basically attacks the mucociliary escalator

• 1) volume depleted because of the profuse watery diarrhea
• 2) It affects the secondary messenger, causes Cl to be shunted out of the cell, the Na and H2O follow
• 3) requires bacteriophage

• Lepromatous provides little or no CMI response.
• Tuberculoid produces a vigorous CMI response.
• 

• They are RIPE for treatment:
• R: Rifampin
• I: Isoniazid
• P: Pyrazinamide
• E: Ethambutamol

• 1) rapid killing of TB bacilli (reduce mortality, morbidity, contagousness)
• 2) prevent the emergence or existence of drug resistence
• 3) Prevent relapse after therapy and achieve cure

fever - the setpoint of body temp has been altered

hyperthermia - you go above the setpoint of the body

Temp for all of these is >38.3

Classical FUO: >3 wks, or at least 3 outpatient visits, or 3 days in hospital

Nosocomial FUO: 3 day of investigation with 2 days of cultures

neutropenic FUO: same as nosocomial with neutrophil count <500/ml

HIV-associated FUO: same as nosocomial with HIV, with > 4weeks duration outpatients or >3dys inpatient

• -Infectious
• -neoplastic causes
• -connective tissue diseases (SLE, RA, etc)
• -miscellaneous (drugs, etc)
• -no diagnosis

• -hematologic
• -hypernephroma: renal cell ca
• -hepatic: 
• -head: brain

• Roth spots: small ovoid hemorrhagic rings in retina
• Janeway lesions: small painless microemboli on the palms or soles
• Osler's nodes: painful, on thenar eminance
• clubbing
• splinter hemorrhages
• splenomegaly
• petechial rashes

viridians group strep

• CONS (late)
• S. Aureus (within first 12 months)

continuous bacteremia

• Fever
• Roth's spots
• Osler's nodes
• Murmur
• Janeway lesions
• Anemia
• Nail bed hemorrhages (aka. splinter hemorrhages)
• Emboli

Entamoeba histolytica - because it can cause symptoms outside of the gut

• large flask-shaped ulcers in in the large intestine
• liver abscesses 
• lung abscesses

• invasive: metronidazole
• asymptomatic: iodoquinol (need a compounding pharmacy)

giardia: metronidazole

• Giardia lamblia
• dientamoeba fragilis
• trichomonas vaginalis

they can parasitize helminth eggs

-worm burden: number of ADULT parasites in host

-autoinfection: completes their whole lifecycle in the host (pinworm and strongyloides only)

-systemic migration: eosinophilia, rashes, dyspnea

• Preservative: submit in the correct vial
• Provide clinical justification to justify microscopy

• GI: abdo discomfort, bowel obstruction, +-diarrhea
• Diet: malnutrition, hypoproteinemia(adema, ascites)
• Mental: decreased IQ, cognitive impairment

Bili, albimin, INR, ascites, ecephalopathy

• Hep B surface antigen
• Hep C antibodies
• Anti smooth muscle, antinuclear Abs
• Copper studies
• Ferritin
• alpha1 AT phenotype

PAIR

• Paraflu
• Adeno
• Influenza (flu)
• RSV

• RSV: bronchiolitis, pneumonia > croup, URI
• paraflu: croup, laryngitis, URI > bronchiolitis, pneumonia

• Paraflu: 2.5 days
• Adeno: 5.5 days
• Influenza: 1.5 d (A), 0.5 d (B)
• RSV: 4.5 days

• entero: 3-6 days
• hanta: usually 2-4 weeks

drift: point mutations in H or N, allows to re-infection every year

shift: Completely different H and N, no immunity at all, causes pandemics. Animal and human virus combine in pig cell to make a new virus.

corona viruses, rhinovirus

Influenza: neuramidase inhibitor for A or B (osetamvir, zanamivir), vaccine (2 A's and a B) for prophylaxis

Adeno: Cidofovir only in immunocompromised patients

The rest of them have no effective clinical treatment

• 1-2 weeks of cold symptoms
• 2-4 weeks of paroxysmal cough (+- the "whoop")
• Convalesce for 1-2 weeks: slow recovery with chance of rebound cough

bacterial: pneumoniae>H. flu>>M. Catarrhalis

viral: PAIR (paraflu, adeno, influenza, RSV)

• Bacterial: Group A strep, gonorrhea
• Viral: rhinovirus + PAIRs viruses + others
• Fingal: Candida albicans

Gp A strep, viridins (alpha) strep, oral anaerobes

• legionella
• HACEK
• borditella
• hemophilias

• 1) destruction of valve leading to free regurg
• 2) CHF
• 3) heart block
• 4) pericarditis

• 1) patient is symptomatic
• 2) no other parasites identified
• 3) lots of them seen in stool

• HBsAg: infection, either chronic or active
• HBsAb: immune, either through a past resolved infection or a vaccine
• HBcIgM: acute infection
• HBcIgG: chronic infection or immunity due to past resolved infection

• Confusion - 1 point
• Urea > 7 mmol - 1 point
• RR > 30 beats per min - 1 point
• Blood pressure low - <90 sys., <60 dia - 1 pt
• 65 or older - 1point
• 0-1: treat as outpatient
• 2: consider hosp.
• 3-5 consider ICU

• CAP: S. pneumoniae, Mycoplasma, Chlamydophile
• HAP: enteric GN rods (e.g. e. coli), psuedomonas, S. aureus