Flashcards in Microbiology Deck (186)
Loading flashcards...
1
Gram positive structure
Cell wall present; major surface antigen
Composition:
- Peptidoglycan
- Lipoteichoic acid--> TNF, IL-1 induction
2
Gram negative structure
No cell wall, only outer membrane
- Site of Endotoxin= LPS (lipopolysaccharide)= major surface antigen
Composition:
- Lipid A--> activate macrophages--> increased TNF and IL-1
- Antigen= O polysaccharide
- Periplasm= space between cytoplasmic membrane and outer membrane; contains hydrolytic enzymes (beta-lactamases)
3
Spore structure
Resistant to dehydration, heat, chemicals
- Must autoclave (121 C for 15 min)
Composition:
- Keratin-like coat
- Dipicolinic acid core
- Peptidoglycan
Seen in:
- Soil: B. anthracis, Clostridium perfringens, c. tetani
- Other: B. cereus, C. botulinum, Coxiella burnetti
4
Gram-positive cocci
Staphylococcus
Streptococcus
5
Gram-negative cocci
Neisseria
6
Gram-positive rod
Clostridium
Corynebacterium
Bacillus
Listeria
Mycobacterium (high lipid= acid fast)
Gardenerella (gram variable)
7
Gram-negative rods
Almost everything else:
1. Enterics:
- E. Coli
- Shigella
- Yersinia
- Klebsiella
- Proteus
- Enterobacter
- Serratia
- Vibrio
- Campylobacter
- Helicobacter (silver stain+)
- Pseudomonas
- Bacteroides
2. Respiratory:
- Haemophilus (pleomorphic)
- Legionella (intracellular; silver stain +)
- Bordetella
3. Zoonotic
- Francisella
- Brucella
- Pasteurella
- Bartonella
** resistant to Penicillin G (gram-negative outer membrane inhibits Pen G/Vanco from entering)
** Susceptible to Ampicillin, amoxicillin
8
Spirochetes
Gram-negative (too thin)
- Leptospira
- Borrelia
- Treponema
9
Pleomorphic bacteria
Giemsa-stain
- Rickettsiae (intracellular)
- Chlamydiae (intracellular, no muramic acid)
10
Bacteria with no cell wall
Mycoplasma= no staining
- Sterols with no wall
11
Giemsa-positive
Certain Bugs Really Try my Patience:
- Chlamydia
- Borrelia
- Rickettsiae
- Trypanosomes
- Plasmodium
12
Carbol Fuschin stain (Ziehl-Neelsen)
Acid-fast organisms
- Nocardia
- Mycobacterium
13
India ink positive
Cryptococcus neoformans
- can also stain with mucicarmine
14
Exotoxin
Derived from gram + and gram -
- Secreted from cell
- Polypeptide
- Located on plasmid/bacteriophage
- Highly toxic
- Antigenic= Induces antitoxins (titer antibodies)
- Vaccine= toxoids
- Destroyed at 60C (besides staph enterotoxin)
Seen in: Tetanus, botulism, diphtheria
15
Endotoxin
LPS= structural component of outer cell membrane in gram negative; released when lysed (NOT secreted)
Activates:
1. Macrophages:
- IL-1--> fever
- TNF--> fever, hypotension
- NO--> hypotension
2. Complement
- C3a--> hypotension, edema
- C5a--> neutrophil chemotaxis
3. Tissue factor
- Coagulation cascade--> DIC
- Located on Bacterial chromosome
- Low toxicity
- Causes: Fever, shock
- Mode of action:Induces TNF and IL-l
- Antigenic: Poorly antigenic
- Vaccines= none
- Stable at 100C for 1 hour
Seen in: meningococcemia, gram-negative sepsis
16
Obligate aerobes
Nagging Pests Must Breathe
- Nocardia
- Pseudomonas aeruginosa
- Mycobacterium tuberculosis (apices of lung)
- Bacillus
17
Obligate anaerobes
Can't Breathe Air
- Clostridium
- Bacteroides
- Actinomyces
Seen in GI tract, pathogenic anywhere else
** Can't treat with aminoglycosides= need O2 to enter cell
18
Obligate intracellulars
Rickettsia
Chlamydia
19
Facultative intracellular
Now Listen Sally, Yer Friend Bruce Must Leave
- Neisseria
- Listeria
- Salmonella
- Yersinia Pestis
- Francisella
- Brucella
- Mycobacterium
- Legionella
20
Encapsulated bacteria
Positive Quellung reaction--> swelling
SHiNE SKiS
- Streptococcus pneumoniae
- Haemophilus infiuenzae type B
- Neisseria meningitidis
- Escherichia coli
- Salmonella
- Klebsiella pneumoniae
- group B Strep.
21
Catalase-positive
Degrades H2O2 before converted to microbicidal products by Myeloperoxidase (MPO)
PLACESS for your cats:
- Pseudomonas
- Listeria
- Aspergillus
- Candida
- E. Coli
- S. Aureus
- Serratia
22
Urease-positive
CHuck norris hates PUNKSS:
- Cryptococcus
- H. pylori
- Proteus
- Ureaplasma
- Nocardia
- Klebsiella
- S. epidermidis
- S. saprophyticus
23
IgA protease
Enzyme cleaving IgA--> colonize respiratory mucosa: SHiN
- S. pneumoniae
- H. influenza (B)
- Neisseria
** These can all take up naked DNA from environment as well= Transformation
24
Protein A
S. Aureus
- Binds Fc region of Ig--> no opsonization/phagocytosis
25
M Protein
Group A strep
- Prevents phagocytosis
26
Pigment-producing bacteria
Actinomyces Israelii= yellow (Israel= yellow sand)
S. Aureus= yellow (pus/gold)
Pseudomonas aeruginosa= blue/green (pyocyanin)
Serratia marcescens= red (maraschino cherry)
27
Novobicin
Used to ID catalase-positive, coagulase-negative staphylococci
- Staph Saprophyticus= resistant
- Staph Epidermis= sensitive
28
Optochin
used to ID catalase-negative alpha-hemolytic streptococci:
- Viridans= resistant
- Penumoniae= sensitive
29
Bacitracin
Used to ID Catalse-negative, beta-hemolytic streptococci:
- Agalactiae= resistant
- Pyogenes= sensitive
30
