Microbiology- bacteria Flashcards
(34 cards)
What is the meaning of the word opportunistic pathogen?
only cause disease in compromised host, sometimes part of Normal Flora
What is the meaning of the word , virulence? How does LD 50 link in?
the quantitative ability of a microbe to cause disease
LD 50 stands for lethal dose 50 and indicates the dose of the organism required to kill 50% of the host under experimental conditions
What are Archaea bacteria?
live in extreme environments
not associated with disease in humans
What is the Type of DNA is found in bacteria?
Either a single circular chromosome or a plasmids (smaller circular DNA)
How do bacteria divide?
Binary fission
List 6 key features of bacteria? How do they help it be pathological
- No mitochondria (euk has)
- 70s ribosomes (euk,80s)
- Flagella- motility
- pili/fimbriae- adherence
- capsules- evade immune responce
- spores (resistant to physical and chemical agents)
- cell wall- protects against osmotic and mechanical shock. Adheres to host surfaces. protects against host immune system
What are the two main types of bacterial cell walls?
Gram positive
Gram negative
What is the difference between gram positive and gram negative bacteria?
Gram positive
- Thick peptidoglycan
- Techoic acid
- No outer membrane
Gram negative
- Thin peptidoglycan
- porins
- protein/lipids
- outer membrane
What are the different shapes of bacteria? And which type of bacteria (positive or negative) do these shapes coincide with?
Cocci- Gram positive
Rod- positive and negtaive
Curved- Gram negative
What are the different shapes of bacteria? And which type of bacteria (positive or negative) do these shapes coincide with?
Cocci- Gram positive
Rod- positive and negative
Curved- Gram negative
What colour are gram negative and gram positive bacteria after staining?
Gram negative- Pink
Gram positive- purple- thick cell wall holds stain
How are gram positive cocci divided then further subdivided?
Catalase test-
Staphylococci are catalase positive
Streptococci are catalase negative
Staphylococci divided into- coagulase positive or negative
Streptococci divided into- beta-haemolytic, alpha-haemolytic and non-haemolytic
How are gram positive cocci divided then further subdivided?
Catalase test-
Staphylococci are catalase positive
Streptococci are catalase negative
Staphylococci divided into- coagulase positive or negative
Streptococci divided into- beta-haemolytic-
alpha-haemolytic and non-haemolytic
When grown in blood agar beta heamolytic will leave a zone of red cell lysis around each colony
Which bacteria causes scarlet fever? What are hall mark symptoms?
Streptococcus pyogenes
Strawberry tongue (rash)
Fever
Which bacteria causes Erysipelas?What are hall mark symptoms?
Streptococcus pyogenes
infection of upper dermis; skin rash on legs, toes, face, arms and fingers.
Fever, chills, fatigue, headaches
Which bacteria causes Cellulitis?What are hall mark symptoms?
Streptococcus pyogenes/Staphylococcus aureus
spreading infection of the soft tissues
red, hot, swollen and painful- extreme sepsis
Which bacteria causes Carbuncle?What are hall mark symptoms?
Staphylococcus aureus
Cluster of boils
fever, general illness
Which bacteria causes impetigo?What are hall mark symptoms?
caused by Staphylococci and or Streptococci
Skin infection
Name 2 conditions caused by Staphylococcal enterotoxins
Acute staphylococcal enterocolitis
Staphylococcal “scalded skin” syndrome- upper skin layer lesions and high fever
What causes Toxic Shock Syndrome? List some symptoms
Staphylococcal Superantigens
High fever, low Bp, coma
Which bacteria causes chancre?What are hall mark symptoms?
Treponema pallidum
superficial skin lesion formed during syphilis
How is Protozoa classified?
Motility pseudopodia flagella cilia sporazoa (gliding)
What is Plasmodium species (malaria) classified as?
Apicomplexa (SPOROZOA)
Protozoa disease
What is Giardia (diarrhea, malabsorption) and Leishmania (leishmaniasis) classified as?
FLAGELLATES
Protozoa disease
