General Flashcards
A “nucleotide” refers to a three component structure containing what?
a sugar,
a phosphate, and
a nitrogenous base.
ADNA nucleotideincludes a nitrogenous base ion one of four forms. Name the four types of bases.
adenine (A), thymine (T),
cytosine (C), guanine (G),
There are two TYPES of nitrogenous bases.
What are they?
purines and pyrimidines.
Twopurines (adenine and guanine)
Twopyrimidines (cytosine and thymine)
In rna the nitrogenous base thymine is replaced by
Uracil (U)
T/F
Staphylococcus are nonmotile and non–spore forming organisms.
TRUE
“Competent”cells arebacterialcells that can do what?
accept extra-chromosomal DNA or plasmids (naked DNA) from the environment.
Name two Staphylococcal GPC’s producing a polysaccharide capsule.
S. aureus
S. epidermidis
Both produce a polysaccharide capsule that inhibits phagocytosis. The capsule may appear as a slime layer or biofilm and allows the organisms to adhere to inorganic surfaces and impairs or inhibits the penetration of antibiotics.
Tille, Patricia. Bailey & Scott’s Diagnostic Microbiology (p. 790). Elsevier Health Sciences.
Most strains of S. aureus produce this toxin, that disrupts smooth muscle in blood vessels.
alpha toxin
Most strains of S. aureus produce alpha toxin, which disrupts smooth muscle in blood vessels and is toxic to ____________, ___________, ____________, and ____________.
erythrocytes,
leukocytes,
hepatocytes, and
platelets.
Staphylococcal species produce a variety of cytotoxins including these four.
alpha toxin,
beta toxin,
delta toxin, and
gamma toxin.
Protein A serves as a virulence factor for S. aureus because Protein A does what?
Protein A has an affinity for Fc receptor of IgG and complement. As such it effectively “inverts” IgG, neutralizing the role of IgG in promoting phagocytosis.
S. aureus is coagulase-positive. Name three other coagulase-positive or variable staphylococci that are normal microbiota of a variety of animal species, including dogs.
Staphylococcus intermedius,
Staphylococcus pseudintermedius, and
Staphylococcus delphini.
The most common CoNS is likely what?
S. epidermidis is the most commonly encountered Coagulase Neg Staph’
Tille, Patricia. Bailey & Scott’s Diagnostic Microbiology E-Book (p. 795).
Infections involving implanted medical devices usually involve what three Staphylococcal species?
S. epidermidis and, less commonly,
S. haemolyticus and
S. lugdunensis,
Tille, Patricia. Bailey & Scott’s Diagnostic Microbiology E-Book (p. 796). Elsevier Health Sciences.
This organism is most frequently associated with community-acquired urinary tract infections in young, sexually active females but is not commonly associated with HAIs (health care–associated infections).
S. saprophyticus
