BAC PATHO
Initiation of infectious process
-PATHOGENESIS
Mechanism development to signs and symptoms of disease
-PATHOGENESIS
microorganism that is capable of causing diseases
-pathogen
Major initial step in the infection process.
-Adherence
Multiplication of an infectious agent w/in the body.
-Infection
not an infectious process
-Multiplication
part of normal microbiota
-multiplication
Process where bacteria, animal parasites, fungi, viruses
enter host cells or tissues and spread in the body.
-invasion
microorganism that does not cause disease
-Nonpathogen
could be part of normal flora
-Nonpathogen
this happens when bacteria causes immunologic reaction
and significant harm to the host.
-diseases
microbial flora within the normal healthy
individual.
-Microbiota
capable of causing diseases only when the
hosts’ resistance is impaired
-opportunistic pathogen
Quantitative ability
-VIRULENCE
Can infect the host even in small quantities
-virulent agent
involves adherence, persistence, and toxigenicity.
-virulence
characteristics that both pathogens and opportunistic bacteria have
-adherence, persistence, toxigenicity
Protein toxins that activate the immune system by binding to
major histocompatibility complex molecules or T cell
receptors.
-SUPERANTIGENS
Protein toxins
-superantigens
binds to major histocompatibility complex molecules (mhc)
-SUPERANTIGENS
binds to t cells/stimulate large number
-superantigens
activate immune system
-superantigens
produce massive number of cytokines
-superantigens
part of normal microbiota
-streptococcus pneumoniae, staphylococcus aureus
pathogenic
-salmonella typhomurium
Present but the infection is inapparent or asymptomatic
-salmonella typhimurium
Microorganism causing disease
-pathogen
Ability of an infectious agent to cause disease.
-Pathogenicity
Ability of a microorganism to produce toxin that will
contribute to the development of disease.
-Toxigenicity
Microorganism should be found in all cases of the disease in
question, and its distribution in the body should be in
accordance with the lesions observed.
-koch’s postulates
microorganism should be grown in pure culture in vitro
(outside the body of host) for several generations.
-koch’s postulates
2 exceptions in koch’s postulates
-Treponema pallidum and Mycobacterium leprae
causes syphilis
-Treponema pallidum
CAUSES leprosy
-Mycobacterium leprae
Cannot be grown in vitro, but has animal model
-Treponema pallidum and Mycobacterium
leprae
Readily cultured in vitro, but no animal model
-neisseria gonorrhoeae
Experimental infection in humans has been used as a
substitute
-neisseria gonorrhoeae
this leads to a measurable decrease in
pathogenicity or virulence.
-Specific inactivation of gene(s) associated with the suspected
virulence trait
should lead to restoration of pathogenicity or
virulence.
-Reversion or replacement of the mutated gene
is used to amplify microorganism-specific nucleic acid
sequences from host tissues or fluids
-POLYMERASE CHAIN REACTION (PCR)
Readily meet the criteria of Koch’s postulates.
-pathogens
part of the normal microbiota but can also
frequently cause disease
-E. COLI
Causes UTI and Traveler’s Diarrhea
-e. coli
pathogens not part of normal flora
-Mycobacterium tuberculosis and. yersinia testis
Pseudomonas species, Stenotrophomonas
maltophilia, yeasts, and molds.
-opportunistic pathogens
primarily exist in
animals and incidentally infect humans; transmitted through food
-Salmonella and Campylobacter
organisms are not
adapted to humans, and the resulting disease may be severe
-INADVERTENT HUMAN INFECTION
Well-established life cycle in rodents and
rodent fleas
-Yersinia pestis
causes plague
-Yersinia pestis
Lives in the environment
-bacillus anthracis and clostridium species
occasionally infects animals
-bacillus anthracis
Transmitted to humans via products like raw hair from infected animals
-bacillus anthracis
Ubiquitous in the environment;
-Clostridium species
transmitted to humans by ingestion
-Clostridium species (C. perfringens gastroenteritis, C. botulinum
[botulism])
wound contamination
-C. perfringens [gas gangrene], C. tetani[tetanus]).
what type of infection do these belong: salmonella, campylobacter, clostridium perfringens, botulinum (canned), vibrio cholerae, e coli?
-ingestion of contaminated food
what is it called when bacteria spread via lymphatics to the bloodstream?
-bacteremia
present in nasopharynx of 5-40% of healthy individuals
-streptococcus pneumoniae
this bacteria can spread through the bloodtsream. 10-20% patients of this type of disease devolop bacteremia from this bacteria
-streptococcus pneumoniae
chemotactically attracted to the gut epithelium and attaches
v. cholerae
Penetrates the intestinal mucus layer using pili and
adhesins.
v. cholerae
leading to massive water and chloride loss into the intestinal lumen.
v. cholerae
Results in severe diarrhea, fluid and electrolyte imbalance
v. cholerae
labile and heat stable enterotoxins cause diarrhea
-e. coli
hemolysin (cytotoxin)
-e.coli
causes uti
-e. coli
Adherence factors involved in mucosal invasion
-E. coli and Shigella sp.
Plasmid- encoded
-e. coli, shigella
phage coded:
-clostridium botulinum, Corynebacterium
diphtheriaeVibrio cholera
causes paralysis
-Clostridium botulinum
inhibits human protein Synthesis.
-Corynebacterium diphtheriae
cause severe watery diarrhea.
-Vibrio cholera
causes diarrhea
-Enterotoxin
causes UTI
-cytotoxin or hemolysin
mechanisms on how bacteria transfer virulence factors
-bacterial pathogenicty
mechanisms where bacteria exchange gene info and transmit mobile gene elements
-bacterial pathogenicty
this is when DNA from one organism is released into the environment and istaken up by a diff. organism which is capable of recognizing and
binding the DNA
-natural transformation (part of bac patho)
extrachromosomal dna
-plasmid
capable of replication
plasmid
lead to recombination between extrachromosomal dna
-transposons
Bacterial viruses which DNA can be moved from 1 org. to another
-bacteriophages
Large groups of genes associated with pathogenicity and are located
on the bacterial chromosomes.
-pathogenicity islands
have 1 or more virulence genes
-PATHOGENICITY ISLANDS (PAIs)
● present in pathogenic members of species but absent in
non-pathogenic members
-PATHOGENICITY ISLANDS (PAIs)
● large
-PATHOGENICITY ISLANDS (PAIs)
● have different guanine plus cytosine content
-PATHOGENICITY ISLANDS (PAIs)
● associated with tRNA genes
-PATHOGENICITY ISLANDS (PAIs)
● often with genetic instability
-PATHOGENICITY ISLANDS (PAIs)
Toxic shock syndrome “toxin-1”
-Enterotoxin for S. aureus
Methicillin & other antibiotic resistance
-Staphylococcus aureus
Alpha hemolysin, fimbriae, adhesions, UTI
-for E. coli
Cytolysin
-Enterococcus faecalis
biofilm formation
-Enterococcus faecalis
Invasion & damage of host cells; diarrhea
-Salmonella tyhi
Neuramidase, utilization of amino sugars
-Vibrio cholera 01
growth (or toxin production) becomes greatly
enhanced in a low iron medium
-corynebacterium diphtheriae
causes whooping cough
-bordetella pertussis
antiphagocytic molecule
m protein
cause adherence to streptococci to buccal ep. cells
-lipoteichoic acid and protein f
cause symptoms of sore throat.
-corynebacteria diphteriae
causes plague)
-Yersiniae
adheres and invades the intestinal mucosa,
-Listeria monocytogenes
adheres to macrophages and
induces formation of long, thin pseudopods which coils
-Legionella pneumophila
uses pili as primary adhesins to host
cells.
-Neisseria gonorrheae
heat labile
-CLOSTRIDIUM BOTULINUM
Found in soil or water
-CLOSTRIDIUM BOTULINUM
inhibit Acetylcholineresulting in lack of
muscle contraction and paralysis.
-CLOSTRIDIUM BOTULINUM
has a necrotizing
effect
-Theta toxin
Questions:
Which of the following organisms or microorganisms cannot be grown in vitro (outside of the body of the host)?
A. Treponema pallidum
B. Neisseria Gonorrhoeae
C. Mycobacterium Leprae
-D. A and C
Which microorganism can readily be cultured in vitro but no animal model for study?
B. Neisseria Gonorrhoeae
Which microorganisms are part of the normal microbiota of humans and animals but frequently cause disease?
-Escherichia Coli
4. Which organisms are considered opportunistic pathogens because they can cause disease in debilitated and immunocompromised individuals?
Pseudomonas aeruginosa
E. coli
Salmonella typhi
-All
5. Microorganisms that exist in animals primarily and incidentally infect humans through food products?
Salmonella
Pseudomonas
Campylobacter
-A and C
All
6. Microorganisms that live in the environment, and when they contaminate the wounds, the wound results in disease.
-Clostridium tetani
-clostridium Perfringens
7. What physical factors of clostridia and bacillus anthracis protects it from nucleic acid, from UV light and desiccation, and detergents?
-Spores
8. Which of the ff. is transmitted by ingesting contaminated fresh salt water like seafood?
-Vibrio Cholerae
9. Which microorganism is commonly found in human anterior nares and through hands, disease can be transmitted from one person to another person?
-Staphylococcus aureus
3. Microorganism that can cause syphilis
-Treponema pallidum