Bacterial Nutrition Flashcards
(113 cards)
1
Q
The metabolic capacity of bacteria is enormous because
A
have large SA to volume ratios, close contact with environment, accumulate nutrients quickly, grow rapidly
2
Q
bacteria can be fulminant, meaning
A
infection begins suddenly, worsens quickly
3
Q
Autotrophic metabolism
A
fix CO2, CO2 is used as building blocks
4
Q
Chemoautotroph
A
fixing CO2 from the oxidation/reduction of inorganic ions
5
Q
Photoautotroph
A
fixing CO2 from light energy
6
Q
Heterotrophic bacteria
A
utilize organic molecules as building blocks via the oxidation of organic compounds
7
Q
All bacteria that cause disease in humans are
A
heterotrophs
8
Q
heterotrophs utilize organic molecules in what order
A
carbohydrates, proteins, lipids
9
Q
fastidious
A
complex growth requirements, will not grow on blood agar
10
Q
Non-fastidious
A
will grow on blood agar
11
Q
optimal growth occurs closer to the __________ temperature
A
maximum
12
Q
the minimal temperature growth range for bacteria is defined by
A
reduced enzyme activity and reduced membrane fluidity
13
Q
the maximal temperature growth range for bacteria is defined by
A
protein denaturation
14
Q
Mesophile
A
growth occurs between 20 - 55C
15
Q
Thermophile
A
growth occurs at >55C
16
Q
Psychrophile
A
growth occurs at <20C; a few human pathogens are facultative psychrophiles
17
Q
Most pathogens are ________ and growth best at __________ temperature
A
mesophiles; 35-36C
18
Q
Is refrigeration a good means to obtaining sterile conditions? why?
A
No, some human pathogens are facultative psychrophiles and grow at <20C
19
Q
Obligate aerobic organisms
A
ONLY grow in the presence of O2
20
Q
Examples of Obligate aerobic organisms
A
Mycobacterium tuberculosis
21
Q
Microaeropilic organisms
A
grow in the presence of reduced concentrations of O2
22
Q
Examples of Microaeropilic organisms
A
Campylobacter
23
Q
Facultative anaerobic organisms
A
use aerobic respiration when O2 is plentiful (initial infection), switch to fermentation when O2 is unavailable (number of bacteria increase at infection site)
24
Q
aerotolerant anaerobic organisms
A
can grow in the presence of O2, but grow best without
25
Obligate anaerobic organisms
only grow in the absence of O2 and utilizes fermentation
26
Examples of aerotolerant anaerobic organisms
Lactobacillus
27
Examples of Obligate anaerobic organisms
Clostridium and Bacteroides
28
Most human pathogens are
facultative anaerobic organisms
29
Most human pathogens are
heterotrophic, mesophilic, facultative anaerobes
30
Th effect of O2 on anaerobes
generation of toxic superoxides and hydrogen peroxides (O2-, H2O2), inhibiting growth or causing death
31
Oxygen tolerant (aerobes) bacteria
produce enzymes that detoxify superoxides and hydrogen peroxides (superoxide dismutase (SOD), catalase)
32
Superoxide dismutase
catalyzes the reaction of a superoxide anion + H2 = H2O2 + O2
33
Catalase
catalyzes the reaction of H2O2 to 2 H2O + O2
34
Oxygen intolerant (anaerobes) bacteria
toxic by products are produced from growth in O2, but they lack the enzymes to detoxify them
35
What antibiotics are used to treat anaerobic infections?
metronidazole, tindazole
36
Inorganic requirements of certain bacteria
inorganic requirements too high or too low can trigger changes in bacterial phenotypes
37
Low [Fe] induces
C. diptheriae to produce diphtheria toxin
38
Low [Ca] induces
plague bacterium to produce exotoxins
39
Low [Mg] induces
S. aureus to produce toxic shock syndrome toxin TSST-1
40
Heterotrophic metabolism is a __________ pathway
catabolic (oxidation of glucose into simpler carbon compounds)
41
Glycolysis
partially oxidize organic matter to enter other pathways and generate ATP
42
TCA cycle
reducing power to oxidize Carbon into CO2 to generate ATP and intermediates for anabolic pathway
43
fermentation pathway
substrate level phosphorylation to generate ATP, reduces compounds
44
Respiration
proton motive force that occurs in a membrane vesicle for ATP synthesis during the oxidation of NADH
45
Electron Transport Chain
transfer of electrons and hydrogen from NADH2 to terminal electron acceptors (O2)
46
Oxidase test
determines the presence of an ETC component (cytochrome C) by oxidation of phenylenediamine to a colored product
47
Oxidase negative bacteria
Enterobacteria, E. coli, shigella, klebsiella, proteus, yersinia
48
Oxidase positive bacteria
pseudomonas, pasteurella, neisseria
49
ATP Synthase
use of the PMF to synthesize ATP
50
Antibiotics that can collapse the ETC gradient
polymyxin, bacitracin, daptomycin
51
Aerobic respiration
Oxidative phosphorylation, O2 serves as TEA which is reduced by H2O
52
Anaerobic respiration
inorganic compound serves as TEA (nitrate, sulfate)
53
Methemoglobinemia (MetHb) occurs when
elevated levels of NO3 occur in drinking water
54
GI tract normal flora convert NO3 (TEA) to
NO2, in the blood stream could cause MetHb
55
Who is at greatest risk for MetHb?
unborn child
56
Fermentation characteristics
simple, less efficient, incomplete oxidation of carbon substrate, occurs in the cytosol without direct PMF
57
Fermentation mechanism
partially oxidizes carbon compounds which serve as electron acceptors, compounds than released from the cell
58
End product of fermentation in Strep. mutans of dental caries
lactic acid (homolactic fermentation)
59
Acidic pH of the vagina and skin Lactobacillus and Propionibacterium acnes fermentation end products
Lactobacillus: lactic acid (homolactic fermentation)
| Propionibacterium acnes: propionic acid, acetic acid, CO2
60
Abscess are ______ and ________ due to fermentative metabolism of bacteria within
acidic and anaerobic
61
Why is is difficult to treat abscess with antibiotics?
low pH decreases effectiveness of antibiotics, bind free nucleic acids rendering them useless, low pH kills surrounding cells and release compounds for growth
62
Bacteria that only grow fermentatively
may lack ETC/cytochrome, use ferredoxin instead of NAD as electron carrier
63
Streptococcus and Lactobacillus are
aerotolerant anaerobes
64
aerotolerant anaerobes, Streptococcus and Lactobacillus
produce lactic acid and H2O2 from recycling ferredoxin, detoxification occurs by HOST catalase
65
Fermentation by Clostridium results in
H2, CO2, and 4 carbon compounds
66
hydrogen lyase
responsible for the recycling of ferredoxin
67
Clostridium perfringens is an obligate anaerobe, infections can cause
large amounts of H2 to be generated which can cause gas gangrene (myonecrosis)
68
Gas Gangrene due to H2
H2 is insoluble and works its way between tissues, opening up new locations for bacteria to colonize. H2 collapses blood vessels leading to anaerobic condition
69
Proteus spp. in UTI end products
not related to heterotrophic metabolism, rather due to urease which converts urea to ammonia and CO2
70
Proteus spp. releases urease
urease converts urea to ammonia causing urine pH to rise and Ca++ and ammonium form precipitate (renal calculi)
71
Helicobacter pylori in stomach mucosa end products
release urease which cleaves urea to CO2, raising pH so H. pylori can grow, causes duodenal ulcers
72
DNA primase
synthesizes a short ssRNA primer for DNA synthesis
73
DNA gyrase (topoisomerase II)
negative supercoils to relieve torsional stress
74
Topoisomerase IV
decatenation (separation of 2 daughter chromosomes)
75
Topoisomerases II and IV are REQUIRED FOR
DNA synthesis in bacteria
76
DNA synthesis is just like eukaryotes but the partitioning occurs
by membrane attachment in procaryotes, not spindle fibers
77
RNA synthesis is just like eukaryotes, except mRNA in prokaryotes
is short-lived; explains why antimicrobial protein synthesis inhibitors are so effective against bacteria
78
Protein translation is just like eukaryotes, except protein in procaryotes
is short-lived; explains why antibiotics against protein synthesis are so effective
79
Sulfa drugs Sulfonilamides (sulfamethoxazole, trimethoprim) action
directly inhibits nucleotide synthesis to inhibit DNA synthesis/replication, protein synthesis and cell replication
80
Sulfa drugs Sulfonilamides (sulfamethoxazole, trimethoprim) uses
uncomplicated UTI or against pneumocystis carinii in AIDS pt
81
Fluoroquinolones/Quinolones (norfloxacin, ciprofloxacin) action
direct inhibition of DNA synthesis/DNA replication to inhibit cell replication
82
Fluoroquinolones/Quinolones (norfloxacin, ciprofloxacin) uses
UTI and lower respiratory infections
83
Rifampin action
direct inhibition of mRNA synthesis
84
Rifampin uses
treat Hib, meningococcus, and Mycobacterium tuberculosis
85
Chloramphenicol
directly inhibits protein synthesis - used against Hib meningitis, typhoid fever
86
Streptogramins
directly inhibits protein synthesis - vancomycin-resistant enterococci, methicillin-resistant staph, drug-resistant strep
87
Aminoglycosides (streptomycin, tobramycin, gentamicin, amikacin)
directly inhibits protein synthesis - NOT used for INTRAcellular bacteria
88
Tetracyclines
directly inhibits protein synthesis - used against INTRAcellular bacteria
89
Oxazolidinones (linezolid)
directly inhibits protein synthesis - used against VRE, MRSA, DRSP
90
Glycycyclines (tigecycline)
directly inhibits protein synthesis
91
Macrolides (erythromycin, azithromycin)
directly inhibits protein synthesis - used against INTRAcellular bacteria
92
Mupiricin
directly inhibits protein synthesis - used topically for prevention of nasal carriage by S. aureus
93
Penicillins, cephalosporin, carbapenems, monobactams
inhibition of cell wall synthesis
94
Bacitracin
inhibition of cell wall synthesis - topical use only
95
Vancomycin
inhibition of cell wall synthesis - used against MRSA and antibiotic-associated pseudomembranous colitis from clostridium
96
Cycloserine
inhibition of cell wall synthesis - used against Mycobacterium tuberculosis
97
Isoniazid
inhibition of cell wall synthesis - used against Mycobacterium tuberculosis
98
Isoniazid
direct inhibition of fatty acid synthesis
99
Synthesis of peptidoglycan subunits/amino sugars:
UDP: cytoplasmic covalent tag for directed synthesis of NAM and NAG, peptide side chain of NAM is synthesize by enzymes
100
Bactoprenol
binds NAM--NAG complex and translocates it across the CM
101
Peptidoglycan subunit is formed by the sequential
transfer of NAM/NAG from UDP to bactoprenol
102
Transglycolase enzyme
transglycosylation: addition of subunit of NAM/NAG to growing end of peptidoglycan chain
103
Transpeptidases
performs the final cross linking of the peptide stems (an amino acid from each peptide side chain)
104
Bacterial Growth is dependent on
nutrient conditions, cultivation conditions, genotype for catabolic or anabolic pathways
105
4 major phases of a bacteria growth curve
lag phase, log/exponential phase, stationary phase, death/decline
106
Lag Phase
initial phase: cell volume and mass increases, DNA replication occurs, but no cell division
107
Log/Exponential Phase
cell number, mass, volume, and cell component amounts increase exponentially
108
Stationary Phase
no net increase in cell number
109
Death Phase
death occurs at a logarithmic rate, mostly by autolysing
110
Short mean generation time:
Rapidly growing organisms that produce acute disease with rapid onset and rapid progression (high antigenic dose)
111
long mean generation time:
Slowly growing organisms that produce chronic disease with slow onset and progression (low antigenic dose)
112
which antimicrobials are best for short mean generation time microbes
inhibitors of protein and/or peptidoglycan synthesis
113
Gram stain, metabolism, external structures, or spore producing ____________ effect generation time
DO NOT
