Type of cell that:
One circular chromosome
not in a membrane
Peptidoglycan cell wall (bacteria)
Type of cell that:
Paired chromosomes in a nucleus
Divides by mitosis
Base pairs A --> T, C --> G
All together forms nucleotide
Single stranded molecule
Shapes and arrangements of
- Shape = spherical
- Arrangement: pairs, clusters, chains
Shapes and arrangements of
- Shape = rod
- Arrangement: pairs, chains
What is a porin?
(proteins) form channels for entry and exit of solutes
Difference between Gr+ and Gr- cell walls
- THICK Peptidoglycan wall
- Thin Peptidoglycan wall
- Plasma membrane
- LPS (lipopolysaccharide)
- Porins (proteins) form channels for entry and exit of solutes
A substance produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction.
What is the function of ATP?
Transports chemical energy within cells for metabolism
Growth occurs only where high concentrations of O2 have diffused into the medium
Obligate Aerobes – Oxygen Required
Growth is best where most O2 is present, but occurs throughout tube
Facultative Anaerobes – Both aerobic and anaerobic, greater with O2
Growth occurs only where there is no O2
Obligate Anaerobes – Only Anaerobic, ceases in the presence of O2
Growth occurs evenly; O2 has no effect
Aerotolerant Anaerobes – Only Anaerobic, but continues in the presence of O2
Growth occurs only where a low concentration of O2 has diffused into medium
Microaerophiles – Only Aerobic growth, O2 required in low concentrations
What is a biofilm and what does it do?
- Microbial communities
- Usually found on solid substrates submerged in or exposed to an aqueous solution
- Cell to cell communication allows bacteria to coordinate their activity forming a functional community
- Resists antimicrobials
Name the stages of disease
- Incubation period
- Prodromal period
- Period of Illness
- Period of Decline
The interval between initial infection and onset of symptoms (time depends on microorganism, virulence, number, host resistance)
This follows incubation (when you first start feeling lousy)
The presence of severe symptoms
Period of illness
The symptoms subside (secondary infection vulnerability)
Period of decline
The time of recovery
microbes normally present in and on the human body
What is the function of normal microbiota?
- Prevent growth of pathogens
- Produce growth factors (folic acid and vitamin K)
- Resistance to ward off disease
What are Opportunistic organisms?
- Live outside normal habitat
- Cause problems outside their habitat
What is a Plasmid?
Genetic strand (piece) of DNA
What is the function of a Plasmid?
manipulation of genes, mutations in viruses/bacteria
disease constantly present in a population
disease acquired by many hosts in a given area in a short time
disease that occurs occasionally in a population (Typhoid)
symptoms develop rapidly and end shortly after (Flu)
disease develops slowly, continues for a long period and may reoccur (Malaria)
spread of microbes, especially bacteria or their toxins in the blood, lungs or other tissues
bacteria in the blood
toxins in the blood
viruses in the blood
blood poisoning, especially that caused by bacteria or their toxins.
acute infection that causes the initial illness (cold)
opportunistic infection after a primary infection (pneumonia)
habitat in which the agent normally lives, grows, and multiplies, and from which they can be transmitted
animal diseases that may be transmitted to humans
arthropods, especially fleas, ticks, and mosquitoes
hospital acquired infections
the incidence of disease
the proportion of deaths to population
the study of the cause of a disease
ability of bacterial cell to alter their surface antigens
Characteristics of Exotoxin
- produced within cell
- bacteria must be functional
- typically Gram+
Characteristics of Endotoxin
- Not secreted
- Part of the membrane of the cell
- Causes problem once then cell dies and lyses
leaves a clear zone around colony on blood agar
forms a green zone around colony on blood agar
no hemolysis on blood agar
What is meningitis?
inflammation of the meninges
What organism(s) cause meningitis?
- Haemophilius influenza
- Neisseria meningitides
- Streptococcus pneumoniae
What is the blood-brain barrier?
separation of the circulating blood from the brain’s extracellular fluid
What is the blood-brain barrier effect on treatment of infections
Restriction of molecules crossing into the CSF
What is encephalitis?
inflammation of the brain
Defenses of the human skin
- Salt inhibits microbes
- Lysozymes in sweat
What role does sebum play in acne?
- A lipid that clogs pores
- Propionibacterium uses sebum as a nutritional source to grow
What Staph and Strep organisms cause skin diseases?
- Staph aureus
- Staph epidermidis
- Strep pyogenes
What biochemical tests distinguish between Staph and Strep?
Catalase test – Staph+, Strep-
What biochemical tests distinguish between Strep species?
Strep: hemolysis on blood agar
What biochemical tests distinguish between Staph aureus and other Staph species
coagulase test differentiates from other staph
What bacteria cause intestinal disease and how does diarrhea occur?
- Staph aureus: kills cells = diarrhea
- Salmonella: inflammatory response = diarrhea
- E. Coli: toxin is released when cell lyses = diarrhea
How does Typhoid fever occur?
- Salmonella enterica typhi bacteria crosses the blood stream
- Endotoxins act on the vascular and nervous system
What does Mycobacterium cause?
Why is M. Tuberculosis and M. Leprae hard to treat?
- Distinctive cell wall: outer most layer is not LPS but a waxy water resistant layer
- Few antimicrobial drugs can enter the cell
Varicella-Zoster virus, what is causes after its latent period?
two or more strains of a virus combine to form a new subtype having a mixture of the surface antigens of the two or more original strains
changes to the flu virus that happen slowly over time
What causes tooth decay
ingestion of a preformed toxin (botulism)
growth of a pathogen in intestines
What is gastroenteritis?
inflammation of stomach and intestinal mucosa (diarrhea, dystentery)
What is Campylobacter jejuni?
- Leading cause of food borne illness in U.S.
- Caused by INFECTION
- causes diarrhea
C. Difficile info...
- Prolonged ABX use
- Predominately nosocomial
- Found in healthy adults
Why diseases like gas gangrene and bacterial endocarditis are difficult to treat with antibiotics
- Endocarditis: immune system response or ABX cannot directly reach the valves via the blood stream
- GAS gangrene: antibiotics may not penetrate the ischemic tissue
Types of virulence factors and the ways bacteria protect themselves
- Adherence to cells
- Obtains nutrition from host
ESKAPE +1 organisms; Name them
- Enterococcus faecium
- Staphylococcus aureus
- Klebsiella pneumoniae
- Acinetobacter baumannii
- Pseudomonas aeruginosa
- Enterobacter Species
- Clostridium deficile
Important things about Enterococcus faecium
- Propensity to mutate
- ABX resistance
- Produces thicker biofilms
Important things about Staphylococcus aureus
- Highly pathogenic due to virulence factors even in healthy patients
- Biofilms post-implanted medical devices
- ABX resistance
Important things about Klebsiella pneumoniae
- Thick capsule (fimbrial adhesins)
- ABX resistance
Important things about Acinetobacter baumannii
- Environmental persistence – survives on inanimate surface up to 5 months
- Widening of periplasmic space -> thickening of cell wall
- Grows at high temps, pH’s, nutrient levels = adaptation
- Efflux pump (pumps ABX back out of cell)
Important things about Pseudomonas aeruginosa
- Resistance to antimicrobials
- Degrades broad range of organic molecules for nutrition (diesel fuel)
- Efflux pump
Important things about Enterobacter Species
- ICU bug -> causes significant morbidity and mortality
- Risk factors = hospitalization 2+ weeks, invasive procedures -> 72 hours, ABX last 30 days
Important things about Clostridium deficile
- Responsible for 2/3 of all healthcare associated infections
- #1 catheter associated UTI’s
Why do antibiotics make an infection worse?
- ABX destroys bacteria
- Endotoxins/exotoxins linger around
- Endotoxin causes fever triggering immune response