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TRANSCRIPT
General Pathology
Basic Principles of Cellular and Organ
Pathology
Infection - I
Jaroslava Dušková
Inst. Pathol. ,1st Med. Faculty, Charles Univ. Prague
Infection–I – table of contents
Defenses against infection
Interaction of organism and microorganism Bacteriemia (transient)
Sepsis/ Septicemia
Pyemia
Toxemia
Viremia
Bacterial toxins & their action
Host & microorganism encounter
Infection versus disease
Infectious agents of humans – part one
– most important representatives and related pathology
bacteria
fungi
parasites
worms
insects
Inflammation - causes
nonliving
physical
chemical
living
prions
viral
bacterial
mycotic
parasitic
AUTOIMMUNE
Defenses Against Infection – 1.
Surface
– barriers: skin, conjunctiva, mucous membranes
– mechanical removal: shedding, tears, mucus,
ciliary action, coughing, salivation, swallowing,
urination, defecation
– normal bacterial flora
– chemical inhibitors: gastric acid, lactic acid, fatty
acids,bile salts..
– antimicrobial substances: lysozym, secretory IgA
Defenses Against Infection – 2.
Nonspecific resistance factors– fever, interferon, complement, lysozyme, C-reactive
protein, lactoferrin, α1- antitrypsin
Inflammation- soluble factors– clotting system –Hageman fc. (XII)
– complement system: chemotactic fc, anaphylatoxins
– kinin system: bradykinin
Inflammation- phagocytes– circulating: neutrophils, eosinophils, monocytes, macrophages
– fixed: alveoli, spleen, liver, bone marow, brain
Defenses Against Infection – 3.
Immune response
– humoral: B-cells, plasma cells, immunoglobulins
– cell-mediated: T-cells, lymphokins
Interaction of Organism and
Microorganism – Terms
Bacteriemia (transient)
Sepsis/ Septicemia
Pyemia
Toxemia
Viremia
Sepsis / Septicemia (Severe Bacteremia)
increasing numbers
of microbes (& their toxins)
in the bloodstream
Sepsis/Septicemia
Def.
systemic response to infection
presenting as
tachypnoe > 20/min. tachycardia > 90/min. temperature > 39 st. C. (ev. < 36st.C)
leucocytosis > 15 000/1l (ev. < 4000/1l)
Sepsis – Pathogenetic Factors
Endotoxin, toxins G+
Macrophages
Cytokins
NO
PAF (Platelets
Activating Factor)
TNF, IL–1
TNF, IL–1, IL–6
NO synthesis
vasodilation
coagulation
Syndrome of Systemic Inflammatory ResponseDef.
systemic response to an AGENTmanifestating as
tachypnoe > 20/min. tachycardia > 90/min. temperature > 39 st. C. (ev. < 36st.C)
leucocytosis > 15 000/1l (ev. < 4000/1l)
AGENT : pancreatitis, injury, burns…..
Endotoxin
lipopolysaccharide component
of G- bacteria outer wall
effects: fever, shock, DIC, RDS
effects mediated by IL-1, TNF
Exotoxins -1
often enzymes (leukocidins,
hemolysins, hyaluronidases,
coagulases, fibrinolysins)
others………….
Exotoxins -2
diphteria toxin – inhibition of cellular
proteosynthesis
botulotoxin – block of the cholinergic
transmission
choleratoxin – increase in cAMP, losses of
isoosmotic fluid via enterocytes
Host & Microorganism
Encounter
General
Natural
defenses
Inflammation
Immune status
Successful
transmission
Site of attack
Number of microorg.
Pathogenicity
HostGeneral
– age, race, nutrition, other diseases (diabetes)
Natural defenses– skin, mucose integrity
– mucus, cilliary action, unobstructed flow
– protective secretion (lysosym in tears, gastric acid, IgA
Inflammation– leucocytes– macrophages -
phagocytosis
Immune status
– immunity (or lack of it)active, passive
immunisation, contact
– lymphocytes
– immunoglobulins
– complement
Microorganism
Successful transmission
Site of attack
Number of microorg.
Pathogenicity invasivenesstoxin productionmultiplicationresistence to host
defence mechanismsability to cause necrosisenzyme release
Inflammation - causes
non
infectious
physical
chemical
infectious
prions (non living, but
transmissible)
viral
bacterial
mycotic
parasitic
AUTOIMMUNE
Infectious Agents of Humans
prions (non living, but transmissible)
viruses (DNA, RNA)
bacteria (incl. chlamydia, mycoplasma,
rickettsia – obligatory intracellular parasites)
fungi (yeasts, molds)
parasites (protozoa, helmints, ectoparasites-
insects: lice, mites, ticks; spiders)
Infectious Agents of Humans Bacteria
simple cells – prokaryotes
both DNA and RNA
cocci, bacilli (AFB!), spirochetes….
Gram positive /negative
extra- and/or intracellular
aerobic/ anaerobic
G+ cocci
Staphylococcus aureus
Staphylococcus epidermidis
Staphylococcus
saprophyticus
Streptococcus α-hemolyticus
Streptococcus β-hemolyticus
Skin: impetigo,
furunculus, carbunculus,
panaritium,
hidradenitis
mastitis
osteomyelitis
pharyngitis
enterotoxicosis
impetigo
tonsilitis, angina
scarlet fever
erysipelas (St. Anthony´fire)
complications: rheumatic fever, glomerulonephritis
G+ rods
non-spore forming aerobes
– Corynebacterium diphteriae
– Listeria monocytogenes
– Erysipelothrix rhusiopathiae
spore forming aerobes
– Bacillus anthracis
Diphteria
Listeriosis
Erysipeloid
Anthrax
G- rods Bordetella pertusis
Pseudomonas aeruginosa
Legionella pneumophilla
Brucella abortus, Francisella
tularemiae, Campylobacter
Helicobacter pylori
Escherichia coli
Klebsiella pneumoniae
Salmonella typhi
Shigella dysenteriae
Vibrio cholerae
Haemophillus influenzae,
Ducreyi
Pertussis
respir and urinary inf.
pneumonia
granulomatous, typhoid,
pneumonia
gastritis, ulcers, tumours
urinary inf.
pneumonia
typhoid fever
dysenteria
cholera
pneumonia, ulcus molle
Anaerobic bacteria
non-spore forming anaerobs
– Actinomyces israeli G+
– Fusobacterium G-
spore forming anaerobs G+
– Clostridium tetani
– Clostridium botulinum
– Clostridium perfringens,
septicum, histolyticum
– Clostridium difficile
Actinomycosis
cellulitis
Tetanus
Botulismus
Gangrene
pseudomembranous
colitis
Infectious Agents of Humans Fungi
complex cells – eukaryotes
both DNA and RNA
yeasts, molds (hyphae, pseudohyphae…)
PAS, impregnation
extra- or intracellular
mostly opportune pathogens
Infectious Agents of Humans Parasites -1
Protozoa
complex cells – eukaryotes
both DNA and RNA
extra- or intracellular
(Amebas, Trichomonas,Trypanosoma,
Toxoplasma, Plasmodium, Pneumocystis…)
Infectious Agents of Humans Parasites -2
Metazoa (helmints and flukes)
multicellular
both DNA and RNA
flat and round worms
extracellular
(Taenia, Ascaris, Enterobius, Trichuris
Echinococcus, Clonorchis, Schistosoma,
Wuchereria…)
Infectious Agents of Humans Parasites -3
Insecta, Arachnida
multicellular
both DNA and RNA
extracellular
(Sarcoptes scabiei, fleas, ticks, lice……)
The tick-borne diseases
Babesiosis (a malaria-like infection Babesia microti)
Ehrlichiosis (rickettsia Ehrlichia canis)
Lyme disease (Borelia Burgdorferi)
Rocky Mountain spotted fever (Rickettsia rickettsi)
Tularemia (rabbit fever Francisella tularensis )
Tick paralysis (virus a member of the family Flaviviridae)