Identify 4 bacterial or viral pathogens not discussed in class.

Assignment 4

Identify 4 bacterial or viral pathogens not discussed in class. For each list their species name, how they are transmitted, one major clinical presentation and one procedure for the treatment or prevention of each infection.

Please submit in Excel format. Use proper citation.

Assignment 5:

Identify 5 different careers for which utilize the field of microbiology. Describe how it is applied, but be very specific and concise in your description (less than 3 sentences for example). Use proper citation.

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Basic principles of infectious

disease I

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Pathogens and pathogenesis

pathos = sorrow

genesis = beginning

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“…the beginning of sorrow”

where does disease manifest?

…disease is an infection causing significant overt damage to the host

gain entry & colonize/invade

The course followed by all pathogens is:

context of

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Mechanical

Cellular injury/

death

Pharmacologic

alterations

Immunopatho-

logical

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Damage

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Mechanical

Occlusion of vital passages

ex. acute appendicitis

Occlusion and vital passages

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Acute appendicitis

Occlusion of vital passages

Occlusion of the lumen

Gallstones; tumor(s)

Infection & inflammation

Occlusion of intraluminal venous/arterial passages by

distension

Perforation/burst

Abscess

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Cellular injury/death

Toxins, replication, colonization & invasion

ex. AE lesion formation

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Intestinal AE lesions

Colonization of the gut by some E. coli leads to the formation of attaching/effacing (AE) lesions***a.k.a. “pedestals”

AE lesions damage the intestinal mucosa, interfere with membrane function (PMF) leading to cell death***

***also clinical manifestations of diarrhea, and hemorrhage

(Pierard et al 2012)

AE lesions

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Pharmacologic

alterations

Toxins

ex. ADP-ribosylation

 any man-made, natural, or endogenous molecule which exerts a biochemical and/or physiological effect on the cell, tissue, organ, or organism.

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ADP-ribosylation

(adapted from Fishman PH 1980)

Enzymatic (ribosyl-transferase) addition of ADP-ribose to target protein(s)

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ADP-ribosylation, cont’d

(adapted from Fishman PH 1980)

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Immunopathological

Toxins, superantigens, inflammation & immune response

ex. Lymphadenopathy

Bubonic plague

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Acute appendicitis

Occlusion of vital passages

Occlusion of the lumen

Gallstones; tumor(s)

Infection & inflammation

Occlusion of intraluminal venous/arterial passages by

distension

Perforation/burst

Abscess

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Mechanical

Cellular injury/

death

Pharmacologic

alterations

Immunopatho-

logical

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Damage

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OBLIGATE vs. OPPORTUNISTIC pathogens

obligate pathogens are dependent on disease for transmission (reproduction)

…for opportunistic pathogens, disease is incidental*** often a consequence of immunologic compromisation

exogenously- vs. endogenously-acquired disease: the means by which microbiological disease is contracted

“primary”

“facultative”

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OBLIGATE vs. OPPORTUNISTIC?

exogenous vs. endogenous?

AE E. coli?

Y. pestis?

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any native/resident microorganism can cause

disease in a compromised individual

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Transmission

…Exchange of “infectious agent(s)” between individuals/groups…

vertical

sexual

oral

damage

aerosols

food/water

iatrogenic

fomites

vectors

DIRECT contact

INDIRECT contact

Intrapartum infections with S. agalactiae

S. agalactiae (Group B Streptococcus, GBS)

Vertical transmission during childbirth

leading infectious cause of neonatal morbidity/

mortality into the 1970s (CFR ≤50%)

carriage rate ≈20% healthy adults

ascending spread of GBS to the amniotic

sac & fluid

neonatal sepsis and meningitis

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Arthropod VECTORS & Lyme disease

Borrelia burgdorferi

Zoonotic spirochete transmitted by the bite

of deer ticks: (Ixodes scapularis and I. pacificus)

Prodrome of erythema migrans

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…tissues colonized by microbiota also serve as common routes

of entry for exogenously-acquired infectious agents…

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Portals of entry

The means by which a microorganism gains access to host tissues…

Entry by INGRESS

…entry w/o crossing epithelial barriers…

gastrointestinal tract

respiratory tract

genitourinary tract

Mucous membranes:

conjunctiva

Epidermis?

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…entry through a break in tissue(s)…

PARENTERAL entry

Vector (tick) transmission of

B. burgdorferi

Puncture/deep wounds

Burns

Any trauma which jeopardizes the

integrity of the epidermis (tissues)…

COLONIZATION factors

Adherence factors

Receptors for adherence factors:

cell surface expressed receptors

-glyco-proteins/-lipids

serum proteins

-plasminogen

extracellular matrix (ECM) type receptors

-fibronectin, collagen, & laminin

COLONIZATION factors

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…time lapsed between exposure to an infectious agent, and the presentation

of clinical symptoms…

incubation times dictated by:

low molecular weight nutrients and minerals (C, N, P, & Fe)

physiological/anatomical factors (pH, temperature, ROS, volatile fatty acids, mucin, peristalsis, etc.)

…clinical presentation of disease is rapid, and is often severe …

ACUTE infection

LATENT infection

…clinical presentation of disease is delayed/subclinical; manifestation of

symptoms is conditional…

immune response

MULTIPLICATION

incubation time

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Pathogen life-history

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SPREAD and DISSEMINATION

…lateral propagation from the point of entry to contiguous tissues…

SPREAD

…spread to distal tissues (metastasis)…

DISSEMINATION

erythematous rash

spread

annular lesions; meningitis;

musculoskeletal pain

hematogenous dissemination

acute illness

disseminated infection

1 week to 6 months

latent infection

6 months to 30 years

encephalopathy;

chronic arthritis

Lyme borreliosis

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portals of ESCAPE/EXIT

mucous membranes:

respiratory  oropharynx (aerosolization)

gastrointestinal  feces

urogenital  contact

epidermis:

lesions

blood:

vectors (arthropods; needles)

hemorrhage

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context of

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Occlusion and vital passages

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AE lesions

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any man-made, natural, or endogenous molecule which exerts a biochemical and/or physiological effect on the cell, tissue, organ, or organism.

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