2017/2018 SAQ Flashcards
stages in the biofilm life cycle.
- Attachment
- Colonization
- Growth
- Maturation
- Detachment
Attachment
Biofilm
bacterial cells attaches to a surface
Colonization
Biofilm
Bacteria multiplies
Extracellular matrix produced
Allows stick to surface and each other
Growth
Biofilm
As more bacteria joins community
Biofilm grows in thickness and complexity
Maturation
Biofilm
Biofilm is more stable
resistant to external factors
Detachment
Bacteria/ Small clusters of cell detach from Biofilm
Disperse
Cycle restarts
Method 1
16S rRNA sequencing
DNA-based methods
Classification of Bacteria
Identify bacteria
sequencing of conserved region of 16 rRNA gene
Varies between bacterial taxa
Method 2
Whole-genome sequencing
DNA-based methods to classify bacteria
Sequence entire genome of bacterial strain
high-resolution phylogenetic analysis
Identify unique genetic marks
Method 3
Multi-locus sequence typing
DNA- based methods to classify bacteria
MLST
Sequence several different genes across bacterial genome
More detailed analysis of genetic diversity
Allows strain level identification
Key characteristics of cytopathogenic viruses in terms of their pathogenecity
visible damage to infected cells
lead to cell death
altered cell function
cell rounding
syncytium formation (fusion of multiple cells)
Inclusion body formation
Changes in cell morphology
Cytopathic effects of cytopathogenic viruses
tissue damage
organ dysfunction
leads to clinical symptoms and disease
One characterstic distinguish fungi from animals
fungi - hetertrophic
> absorb nutrients from environment
Animals
> ingest good and digest internally
Characteristics distinguish fungi from plant kingdom
Fungi: No chorophyll> no photosynthesis; plants do to produce own food
Celll wall : chitin(fungi) cellulose (plants)
Fungi: Reproduce by spores > dispersed by wind
Plants: Reproduce by seeds. begetative propagation
5main fungal phyla
mycota
- Ascomycota
- Basidiomycota
- Zygomycota
- Chytridiomycota
- Glomeromycota
Ascomycota
fungal phylum
largest fungal species
characterized by production of sexual spores in sac-like structures called asci.
Basidiomycota
Fungal phylum
produces sexual spores on basidia structures
Important decomposers
mycorrhizal fungi
Zygomycota
Fungal phylum
Produces tough, resistant zygospores as a result of sexual production
includes many soil dwelling and plant associted species
Zygomycota
Fungal phylum
Produces tough, resistant zygospores as a result of sexual production
includes many soil dwelling and plant associted species
Chytridiomycota
Motile zoospores
most primitive fungal group
many aquatic and soil dwelling species
Glomeromycota
Fungal phylum
Fungi forms mutualistic associations with th eroot of plants
Known as arbuscular mycorrhizae
Sexual reproduction: zygomycotina and ascomycontina
Zygo
- by producing thick walled zygospores as a result of fusion between 2 diff mating types
**
Asco
- produce sexual spores in asci (sac-like)
Asexual reproduction: zygomycotina and ascomycontina
Zygo- by producing sporangia
Asco- producing conidia
Habitat: zygomycotina and ascomycontina
zygo- Soil dwelling fungi
asco- wider range of habitat: oil, water, symbionts of plants or animals
> econimocally important: yeasts, molds and plant pathogens
Uncomplicated UTIs
Healthy individuals w/ normal unirnary tracts
By single bacteria species
e.coli
Infections: uncomplicated UTI
Bladder (cystitis)
Urethra (urethritis)
Painful urination
Frequent urination
Strong urge to urinate
Complicated UTIs
people w/underlying UT abnormalities/comorbidities
>kidney stones,UT obstruction, dibaetes/immunosupression
Mutiple bacterial species
Complicated UTIs infections
Kidney damage
systemic infection
Complicated UTI treatment
Long course of antibiotic treatment
Surgical intervention to address the underlying condtion (some cases)
List 4 protective characteristic of lactobacilli in vagina (chai)
- Acidification
- Hydrogen peroxide production
- Competitive exclusion
- Immunimodulation
Lactobacilli: Acidification
Lactobacilli produce lactic acid
maintain acidic environment
ph 3.5-4.5
inhibit growth of pathogenic bacteria
Lactobacilli: Hydrogen peroxide production
Some strains produce h2o2
has antimicrobial activity against wide range of bacteria and virus
Lactobacilli:competitive exclusion
Lactobacilli compete w/pathogenic bacteria for adhesion sites on vaginal epithelium
Preventing colonization
Lactobacilli:immunomodulation
Lactobacilli stimulate immune system
enhance production of antimicrobial peptides and cytokines
Protect against infection
Species associated with intestinal health
Gut
Probiotic bacterium
Called Bifidobacterium
Effector molecules produces Bifidobacterium
Short-chain fatty acids (SCFA) = butyrate
Modulates the balance of T-helper cells in the gut
Function of butyrate
Promote differentiation and activity of regulatory T cells (Tregs)
Maintain immune tolerance
Prevent inflammation and autoimmunity
Inhibit pro-inflammatory T-helper 17 differentiation (Th17)
Promote anti-inflammatory T-helper 2 cells differentiation (Th2)
Overall effect: T- helper cel balance, promote intestinal health, prevent inflammatory bowel disease (IBD)
Function of butyrate
Promote differentiation and activity of regulatory T cells (Tregs)
Maintain immune tolerance
Prevent inflammation and autoimmunity
Inhibit pro-inflammatory T-helper 17 differentiation (Th17)
Promote anti-inflammatory T-helper 2 cells differentiation (Th2)
Overall effect: T- helper cel balance, promote intestinal health, prevent inflammatory bowel disease (IBD)
4 opportunistic pathogens associated with cystic fibrosis
`
- Pseudomonas Aeruginosa
- Burkholderia cepacia complex
- Staphylococcus aureus
- Aspergilluus fumigatus
4 opportunistic pathogens associated with cystic fibrosis
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- Pseudomonas Aeruginosa
- Burkholderia cepacia complex
- Staphylococcus aureus
- Aspergilluus fumigatus
Name 5 viral infection which may lead to viral encephalitis (inflammation and swelling of the brain tissue)
- HSV = Herpes Simplex Virus
- VZV = Varicella-zoster virus
- WNV = West Nile virus
- JEV = Japanese encephalitis virus
- TBEV = Tick-borne encephalitis virus
2 virulence factprs essential to meningeal invasaion by Neisseria meningitis
- Capsule
- Type IV pili
Role of capsule
Meningeal invasIon by Neisseria meningitis
Thick polysaccharide layer that surroynds the bacteral cell
Protects it from phagocytosis by host immune cells
Essential for bacteria to survive in bloodstream and cross the blood-brain barrier to infect the meninges
Role of IV Pili
Meningeal invasIon by Neisseria meningitis
long, thin protein appendages extending from bacterial surface
Mediate adherence to host cells and tissues
Enable bacteri to bind to and invade thecells of the blood- brain barrire
Facilitate entry into the central nervous system
