T1 Flashcards
Genera of Gram + bacteria
Actinomyces Bacillus Bifidobacterium Clostridium Corynebacterium, Propionibacterium (& other diphtheroids) Enterococcus Gardnerella Lactobacillus Listeria Mobiluncus Peptostreptococcus Staphylococcus Streptococcus
med-important G+ cocci
Strep
Staph
Enterococcus
general of bacterial endospore-formers
Clostridium
Bacillus
Genera of acid-fast + pink bacteria
Mycobacteria
Nocardia (usually)
cell shaped determined by
murein sacculus and cytoskeleton
cocci arrangements
diplococcus (pairs) G- : (kidney bean) G+: (lancet) chains (strep) clusters (staph)
bacillus/rod
v. short: G- short, thin: G- short, thin, needle-like: fusiforms, G- long, thick: G+ short, thick: G+ clubbed-shaped: G+ -thin, branching filamentous rods w. club ends *arranged as single cells, pairs (doublet) or chains
helicoidal
curved, comma: (G-)
curved, comma: (G+)
spirochetes
*arranged as single cells, pairs, chains
pleomorphic
can vary in size/shape:
flagella
H-Ag, protein composition
plain: extend out from cell surface
endoflagella: internal structure (spirochetes)
motility, sensory system (chemotactic), surface translocation, aids in identification, virulence factor (chemotactic)
Pili (Fimbriae)
protein composition
normal (I-IV) and sex pili extend out into environment
adherence (virulence factor), antiphagocytic, surface translocation (v.f.)
sex pilus: conjugation
capsule
glycocalyx, exopolysaccharides (EPS)
mucoid-like coat around cell, slime layer
polysacch. polymers: K-Ags: single, complex, D-glutamic acid repeating units OR O-Ag: LPS (G-)
biofilms
communal, protected, complex, 3-D structure (bac/yeast)
in exopolysacch. film, sometimes protein amyloid fibers
CDC: 50% human bac inf. involved biofilms
phenotypic changes: become sessile in biofilm, MDR, quorum sensing–>activation?
can revert to normal/planktonic form–>recurrent inf.
D-A.A. can disrupt amyloid protein connections–>release bad
*are a capsule
clin sig of EPS/biofilms
adherence, anti-phagocytic, anti-antibiotic, anti-dessication, Ag used to ID some human pathogen
HKO Ag
H: flagella K: capsular O: LPS (acts as capsule) G+: capsule or no capsule G-: O+K-, O+K+, O+,K- (again)
S-layers
A- or T-layers, (glyco)protein composed, 10-20% cell mass
present on some human normal flora AND pathogens
on cell wall, rigid layer w. pores of fixed diameter
virulence factors: anti-complement (C3b), anti-phago(PMN)
translocation
thru human cells to new site
paracellular, sliding motility (biofilms)
cell membrane contains no sterols except
Mycoplasma
Helicobacter
Ehrlichia
Anaplasma spp.
Type III secretion system
injectosome; conserved multiprotein system used by G- bac to insert protein toxins into human cells
cell membrane contains respiratory system
ETC, ATP synthase, PMF/ion current
cell membrane systems
perm/transport, respiration, cell wall synthesis components, cellular replication components, osmoreg/sensory (chemotactic) mechanisms (hypertonic to ext. environ.)
G+ or G-: polysacchs are covalently linked to peptidoglycan layer in cell wall and lipoteichoic acid polymers are anchored in cell membrane
G+
G+ or G-: contains an outer membrane with LPS, peptidoglycan layer located in periplasm
G-
cell wall functions
sieve, prevents bursting, mech. strength, vir/tox factors, Ag-comps, rec. for Abs, sex pilus, bacteriophages; anchors external bac structures (flag, pili, caps)