Micro, Ass 1, Renee’s Questions

1.     What is the flagellum of prokaryotes powered by?
1.     Proton motive force (proton gradient)
2.     How does the flagellum of prokaryotes move?
2.     Rotates (like a propeller)
3.     How does the flagellum of the eukaryote move? How is it powered?
3.     Whip-like; ATP hydrolysis
4.     What are the cilia-like structures in prokaryotes called that are involved in adherence or exchange of genetic material?
4.     Fimbriae/Pili
5.     What are bacterial cell walls composed of?
5.     Peptidoglycan
6.     What do antibiotics target in bacteria?
6.     Peptidoglycan
7.     T/F Bacteria cell membranes contain cholesterol.
7.     F
8.     T/F Prokaryotes usually have single, circular chromosomes without histones or introns.
8.     T
9.     T/F Shape cannot be used as a diagnostic tool for determining bacteria.
9.     F – Shape is an important diagnostic tool.
10.  What are the six shapes or Bacteria?
10.  Coccus– Sphere; Coccobacillus – elongated sphere; Bacillus – rod; Vibrio – “comma”; Spirillum – rigid corkscrew shape; Spirochete – flexible corkscrew shape
11.  What are some problems associated with diagnosis based on shape?
11.  bacteria change shape during growth – especially during stationary phase; Pleomorphic organisms don’t have a specific shape
12.  What arrangement do streptococci take?
12. Long chain of cells
13.  What bacterium is described as a “bunch of grapes”?
13.  Staphylococci
14.  Do all bacteria contain a capsule?
14.  No, but gram + or – can have capsules
15.  What regulates capsule production?
15.  Growth phase and growth environment
16.  What layer is directly inside the capsule of a gram + cell?
16.  Fibrillar layer (protein layer)
17.  T/F All gram + cells have this layer.
17.  F
18.  What is characteristic of the peptidoglycan layer in a gram + cell?
18.  Thick, >40 layers, Highly cross-linked
19.  What is characteristic of the peptidoglycan layer in a gram – cell?
19.  Thin, 1-2 layers, not highly cross-linked
20.  What layer is inside the peptidoglycan layer?
20.  Cytoplasmic membrane
21.  What cell type has an outer membrane? Where is it found?
21.  Gram – ; directly inside the capsule (if present)
22.  What are 2 features of the outer membrane?
22.  Lipopolysaccharide, Unique Proteins
23.  What are the proteins called and what do they do in the outer membrane?
23.  Porins; Diffusion channels, adhesions, antibiotic resistance
24.  In Gram – what is the region called between the outer membrane and the cytoplasmic membrane?
24.  Periplasmic space
25.  What are 2 features of the Periplasmic space?
25.  Contains the peptidoglycan layer, enzymes involved in cell wall biosynthesis
26.  T/F The cytoplasmic membrane and cytoplasm are very similar in Gram + and – bacteria.
26.  T
27.  What is the extracellular, carbohydrate rich coating on some bacteria called?
27.  Glycocalyx
28.  Where is the glycocalyx made?
28.  In the cell then exported to exterior
29.  What are the 2 types of glycocalyx?
29.  Capsule and Slime layer
30.  What is the capsule composed of?
30.  Repeating carbohydrate subunits
31.  What are 2 roles of the Capsule?
31.  Prevent cell from drying out, act as an energy source.
32.  How does the capsule act as a virulence factor? Why is this good?
32.  Prevents bacterium from recognition by hiding its antigenic components, antipagocytic – blocks complement deposition; Targets for vaccines.
33.  What is another name for the Slime layer?
33.  Exopolysaccharide, EPS
34.  What is the major distinguishing factor between a capsule and slime layer?
34.  Capsules are more firmly attached to cell
35.  T/F Capsules are easily stained.
35.  F – difficult to stain because they are mostly carbohydrate
36.  What kind of stain can be used to stain capsules?
36.  India Ink – leaves a halo around the cell
37.  What is movement based on chemical sensing called?
37.  Chemotaxis
38.  What are Flagella composed of?
38.  Flagellin protein
39.  Why is Flagellin a major antigenic target?
39.  Its high copy number
40.  What recognizes Flagellin?
40.  TLR5 (Toll-Like Receptor 5)
41.  What can Flagellin be used for in verifying the organism?
41.  Used for Strain Typing
42.  What provides the energy for rotation?
42.  Proton Motive Force
43.  T/F Flagella arrangement is diagnostic for some species of bacteria.
43.  T
44.  What is a single flagellum at one pole of the cell called? Example?
44.  Monotrichous; Vibrio
45.  How is a Lophotrichous cell organized?
45.  One pole with several flagella.
46.  How are Peritrichous cells organized? Example?
46.  Flagella all over the cell; Salmonella, Escherichia
47.  What is a cell called that has flagella at both poles?
47.  Amphitrichous
48.  What is characteristic of a Spirochete?
48.  Endoflagella
49.  How do Endoflagella work?
49.  Wound around cell not exposed to external environment, forms an axial filament, Rotation of Flagella causes bacterium to move like a corkscrew.
50.  What is an example of a bacterium with Endoflagella?
50.  Syphilis
51.  What projections are used for adherence?
51.  Fimbriae
52.  What projections are used for transfer of genetic material between bacteria?
52.  Pili
53.  What protein are Pili made up of?
53.  Pilin
54.  T/F Pili can be found on ALL gram + and – cells.
54.  F – not all cells produce pili, but they can be found on Gram + or –
55.  How are Pili involved in Motility?
55.  Extension of pili, adhering to surface, then retracting
56.  What is a Biofilm? What is essential for this?
56.  Organized system of bacteria formed on surfaces; Adherence by Pili
57.  What is a Mesosome?
57.  Invaginations of the plasma membrane that can form vesicles in Gram + or –
58.  What is the Gram + cell envelope made from?
58.  > 40 peptidoglycan layer, Contains teichoic and lipoteichoic acids
59.  What substance in Gram +, are not found in Gram – cells?
59.  Teichoic acids
60.  How are teichoic acids linked to peptidoglycan?
60.  Covalently
61.  How are lipoteichoic acids anchored to the cytoplasmic membrane?
61.  Lipid Tail
62.  What is used to aid in identification of the bacteria?
62.  Teichoic and lipoteichoic acids
63.  T/F Both Gram + and – can form spores.
63.  F – Only some Gram + can form spores
64.  What is a Spore?
64.  Dormant Bacterial form that resists heat, desiccation, and many chemicals
65.  When do spores develop and how long do they live?
65.  In response to nutrient limitations or stress; Long-Lived!
66.  What is present in a Gram – cell that Gram + cells do not have?
66.  Outer Membrane
67.  What does this membrane function as?
67.  Permeability barrier
68.  What is inbetween the inner and outer membrane?
68.  Periplasmic Space
69.  T/F the peptidoglycan layers in Gram + and – are the same.
69.  F – the peptidoglycan layer in Gram – cells is thin 1-2 layers.
70.  Why is the peptidoglycan layer a good drug target?
70.  Unique to bacteria and essential in most bacteria.
71.  T/F All Bacteria have a peptidoglycan cell wall
71.  F – Mycoplasm and Chlamydiae do not
72.  What makes up the “Glycan” portion of the cell wall?
72.  NAM-NAG, linked disaccharide chain repeated
73.  What can cleave this linkage?
73.  Lysozyme – found in human tears and mucus membranes
74.  What makes up the “peptide” portion?
74.  Pentapeptide composed of D- And L- amino acids
75.  What portion of the peptidoglycan are crosslinked?
75.  Pentapeptides
76.  What is the 3 step process of peptidoglycan synthesis?
76.  1. Single disaccharide linked to a pentapeptide are synthesized in the cytoplasm. 2. Translocated across cytoplasmic membrane. 3. Disaccharide chain links to growing chain, and cross linking occurs between glycan chains
77.  What step is targeted by bacitracin?
77.  Step 1
78.  What catalyzes crosslinking b/w glycan chains?
78.  Transpeptidase activity of penicillin-binding proteins
79.  What step is the target of B-Lactam Antibiotics?
79.  Cross linking step, Step 3
80.  What is similar about the peptidoglycan structure among Gram + and -?
80.  NAM-NAG, pentapeptides bound to disaccharide.
81.  What is different about the structure?
81.  Gram + have a L-lysine at the 3rd position, Gram – have a DAP
82.  T/F DAP is only found in prokaryotes
82.  T
83.  What extra feature do some Gram + cells have?
83.  Interpeptide bridge, 5 glycines attache to the 3rd position L-lysine
84.  Where does cross-linking occur in Gram – cells?
84.  Between DAP on one and 4th D-Ala of another, (5th D-Ala released)
85.  Where does cross-linking occure in Gram + cells?
85.  Interpeptide and 4th D-ala, or L-lys and 4th D-ala (if no interpeptide) (5th D-ala is released)
86.  How many distinct forms of peptidoglycan have been found in gram positive bacteria?
86.  8
87.  Where are these differences found?
87.  Pentapeptide and interpeptide bridges
88.  What is necessary for cellular rigidity?
88.  Peptidoglycan cross-linking
89.  What are PBPs?
89.  Penicillin binding proteins, secreted proteins that are anchored to the outer surface of the cytoplasmic membrane
90.  What are the 2 categories of PBPs?
90.  High molecular weight and Low molecular weight
91.  What do High Molecular weight PBPs do?
91.  Essential for growth, encode transpeptidase and transglycosylase activities
92.  What do Low Molecular weight PBPs do?
92.  NOT essential for growth, Encode ONLY carboxypeptidase activity
93.  What does B-Lactam antibiotics (penicillin) inhibit?
93.  Transpeptidase and Caraboxypeptidase activities, Cant’s Grow!
94.  What percentage of pentapeptides are cross-linked in Gram -? Gram +?
94.  20-30%; 80-90%
95.  What is the glycosidase called that hydrolyses the NAM-NAG bond?
95.  Lysozyme
96.  What type of cells is this an important antibacterial defense against?
96.  Gram +
97.  Why is lysozyme less important in defense against Gram -?
97.  Presence of the Outer Membrane prevents lysozyme access to the peptidoglycan layer.
98.  Which type of cell has extensive cross-linking?
98.  Gram +
99.  What is the main function of the Outer Membrane?
99.  Permeability barrier
100.        What does the Outer Membrane protect the cell against?
100.        Antibiotics, lysozymes, toxins, etc.
101.        What are 4 functions of proteins in the outer membrane?
101.        Autoagregation, Adhesins, Flagella/Pili, Phage recognition
102.        Where are Lipopolysaccharides located?
102.        Outer leaflet of outer membrane
103.        What is responsible for the permeability barrier properties of the Outer Membrane?
103.        Lipoplysaccharide
104.        What is essential for viability?
104.        Lipopolysaccharide
105.        How is the O-antigen attached to the Lipid A?
105.        Core polysaccharide
106.        What is the O-antigen composed of?
106.        Repeating oligosaccharides
107.        T/F The O-antigen is Highly variable and can be quite long.
107.        T
108.        T/F The O-antigen is essential.
108.        F – it is not essential
109.        What is the morphology of an O-Ag +? O-Ag – ?
109.        Smooth colonies; rough or dry on agar plates.
110.        T/F The core polysaccharide is not essential for growth.
110.        F – it is essential for growth
111.        What makes up the core polysaccharide?
111.        7 Conserved carbohydrates
112.        What unique carbohydrates does the core polysaccharide have?
112.        2-keto-3-deoxyoctonoic acid (KDO), Heptose
113.        What type of cell is Lipid A unique to?
113.        Gram –
114.        What is Lipid A commonly referred to as?
114.        Endotoxin
115.        What is Lipid A recognized by?
115.        TLR4
116.        What part of the LPS is responsible for the barrier properties of the outer membrane?
116.        Lipid A
117.        How do some pathogens alter the structure of LPS?
117.        Enzymatic reactions
118.        What can an altered LPS cause?
118.        Altered interactions with innate immune response
119.        What can a Reduction of negative charge of the LPS result in?
119.        Altered interaction with TOL receptors and resistance to cationic antimicrobial peptides. (RESISTANCE!)
120.        T/F Alterations in Acylation results in altered interaction with TLR
120.        T
121.        T/F Lipid A is not essential for Growth
121.        F
122.        What is Lipid A made up of?
122.        Acylated glucosamine disaccharide
123.        What imparts negative charges to LPS?
123.        Phosphorylation
124.        What adaptive responses do some organisms have to affect interaction with the innate immune system?
124.        Cap the phosphorylated part, or enzymatically remove the phosphate group.
125.        What is the inside leaflet of the outer membrane made up of?
125.        Phospholipids
126.        What makes up the outer leaflet?
126.        LPS
127.        What can lead to resistance to antimicrobial peptides?
127.        Reduction of negative charges of LPS
128.        What stabilizes the LPS?
128.        Salt bridges
129.        How are the Salt Bridges formed?
129.        Magnesium ions bound to phosphates of adjacent LPS molecules
130.        T/F Some antibiotics target Salt bridges to destabilize the outer membrane?
130.        T
131.        What stimulates pro-inflammatory signal transduction pathways?
131.        LPS via TLR4
132.        How can endotoxic shock become life-threatening?
132.        IL-1 induction causes fever, macro & PMN activation causes oxidative damage , increased hypotension from increased permeability, thrombosis, tissue necrosis
133.        T/F cytoplasmic membrane is a target for antibiotics.
133.        F
134.        What is the difference between Gram + and – in secretion of proteins?
134.        Gram +: secreted across 1 membrane Gram -: secreted through 2 membranes; many proteins first secreted into periplasm, further processed then secreted into environment.
135.        How many different mechanisms for protein secretion in bacteria are there?
135.        6
136.        What is Type 1 and where are they found?
136.        ATP binding cassette (ABC) transporter; in prokaryotes and eukaryotes
137.        What type of substrates to ABC transporters secrete?
137.        Drugs, carbohydrates, peptides, proteins
138.        What type is the General Secretory pathway?
138.        Type II
139.        What are Type II pathways unique to and what do they involve?
139.        Bacteria; chaperones, and signal peptides
140.        What type is associated with pathogenic strains?
140.        Type III “contact dependent secretion systems”
141.        How do Type III mechanisms work?
141.        Directly inject effector proteins into the host cell cytoplasm
142.        What type is associated with conjugation?
142.        Type IV
143.        What is an example of Type IV?
143.        Helicobacter, Pertussis Toxin
144.        What Type is related to Porin Proteins?
144.        Type V, Autotransporters
145.        How do Autotransporter work?
145.        Exports proteins to the cell surface where they are released by proteolytic cleavage into the extracellular environment
146.        What Type was discovered most recent?
146.        Type VI
147.        How do bacteria divide?
147.        Binary fission
148.        What kind of growth does this result in?
148.        Exponential growth. Cell number = 2n, where n = number of divisions
149.        What does division by binary fission require?
149.        1) Extension of cell wall; 2) Replication of the genome; 3) Segregation of Chromosomes by membrane attachment; 4) Septum formation
150.        How is Growth Rate equated?
150.        Growth Rate = ? in #cells / unit time
151.        What is the generation time?
151.        The time required for one cell to grow and divide into two cells.
152.        What is the generation time dependent on?
152.        Growth conditions – pH, temp, salinity, nutrients, etc.
153.        What are the four phase of the bacterial growth curve?
153.        Lag Phase, Esponential (log) Phase, Stationary Phase, Death Phase
154.        What phase is associated with adapting to a new environment?
154.        Lag Phase
155.        What phase has a great death rate than growth rate in culture?
155.        Death Phase
156.        What phase corresponds with a maximal DNA and protein synthesis?
156.        Log Phase
157.        In what phase do bacteria have an elevated resistance to antibiotics?
157.        Stationary phase
158.        What phase may cells need to synthesize enzymes?
158.        Lag Phase
159.        Why might cells need to synthesize enzymes?
159.        To utilize nutrients in the medium or for adaptive responses to changes in osmolarity, pH, temperature, etc.
160.        In what phase are bacteria most susceptible to drugs?
160.        Log Phase
161.        What phase is the best time to do differential staining?
161.        Log Phase
162.        What phase do cells become metabolically inactive?
162.        Stationary phase
163.        What phase do gram + bacteria produce spores?
163.        Stationary phase
164.        What phase is the growth rate equal to the death rate?
164.        Stationary phase
165.        What is a complex aggregation of microorganisms encased in a protective, adhesive carbohydrate matrix?
165.        Biofilm
166.        What are Biofilms characterized by?
166.        1) Surface attachment; 2) structural heterogeneity; 3) genetic diversity; 4) complex community interactions
167.        What percentage of all infections are estimated to be caused by Biofilms?
167.        80%
168.        T/F Biofilm associated bacteria are resistant to antibiotics.
168.        T
169.        How do biofilms protect against the immune system?
169.        Antiphagocytic; Brovide barrier against immune system
170.        During energy production in eukaryotes what is the ultimate electron acceptor?
170.        Oxygen
171.        What toxic products are produced as a result of metabolism in the presence of oxygen?
171.        Hydrogen peroxide and Superoxide anion
172.        What type of bacteria require oxygen for growth?
172.        Obligate aerobe
173.        What are the oxygen requirements of Microaerophiles?
173.        Oxygen levels form 2-10%
174.        What type of bacteria cannot tolerate oxygen?
174.        Obligate anaerobes
175.        How do Aerotolerant anaerobes deal with oxygen?
175.        Do not use aerobic metabolism, but have enzymes that detoxify the poisonous forms of oxygen.
176.        What type of bacteria can grow in the presense of absence of oxygen?
176.        Facultative anaerobes
177.        What type of metabolism occurs in the absence of oxygen?
177.        Fermentation
178.        Why are obligate anaerobes killed in the presence of oxygen?
178.        Lack enzymes required to detoxify toxic forms of oxygen
179.        What specific enzyme do obligate anaerobes lack to detoxify superoxide?
179.        Superoxide dismutase
180.        What other enzymes do they lack to get rid of the product of superoxide dismutase?
180.        Catalase and peroxidase
181.        What is formed by superoxide dismutase?
181.        Peroxide, H2O2
182.        What type of oxygen requirement do most bacteria have?
182.        Facultative anaerobes; they grow in the presence or absence of oxygen.
183.        What enzyme do all Facultative anaerobes have?
183.        Superoxide Dismutase
184.        How do low temperatures affect bacterial growth?
184.        Affects membrane fluidity and enzyme kinetics
185.        How do Maximal temperatures affect bacterial growth?
185.        Reduced growth due to protein denaturation, thermal lysis and membrane collapse.
186.        What category of growth temperatures are most human pathogens in? What is the temperature range?
186.        Mesophiles; ~15-45 C
187.        What are the bacteria called that grow at temperatures between -5-20C?
187.        Psychrophiles
188.        What temperatures do Hyperthermophiles grow at?
188.        ~65 – 105 C
189.        What bacteria grow best at temperatures between ~45 – 80 C?
189.        Thermophiles
190.        How do pH levels in the body inhibit microbial growth?
190.        Certain regions of the body have lower pH which prevents microbial growth. Ex. Vaginal secretions
191.        What is an example of a pathogen that has adapted to an acidic environment?
191.        Helicobacter pylori
192.        What is an organism that is capable of synthesizing ALL its metabolites called? Example?
192.        Prototroph; E. coli, Salmonella, Pseudomonas
193.        What is an Auxotroph? Example?
193.        An organism that has lost the ability to synthesize certain substances required for its growth and metabolism as the result of mutational changes; Chlamydia, Lactobacilli, Haemophilus, Neisseriae, Francisella
194.        What are essential nutrients that bacteria can’t produce on their own called?
194.        Growth Factor
195.        What is commonly used to identify and differentiate bacteria?
195.        Nutrient requirements
196.        What mineral is essential from growth?
196.        Iron
197.        What proteins are used as a host defense to protect iron?
197.        Lactoferrin and transferrin
198.        How have pathogenic bacteria evolved to get the iron they need?
198.        1) Transporter for lactoferrin and transferrin; 2) Production of siderophores 3) production of iron releasing cytotoxins
199.        What are Siderophores?
199.        Iron binding compounds that can ‘steal’ iron from lactoferrin
200.        What two groups do microbial metabolism fall into?
200.        Anabolism and Catabolism
201.        What type of reactions make new cell components and require energy?
201.        Anabolism
202.        What happens in Catabolism?
202.        Breakdown of compounds for building blocks, creation of energy
203.        What common intermediate is made in metabolism?
203.        Pyruvate
204.        What determines the fate of pyruvate?
204.        Oxygen
205.        In the presence of oxygen how is pyruvate utilized?
205.        Funneled through Krebs Cycle.
206.        What are the electrons removed from pyruvate used for?
206.        Reduce NAD+ a NADH and FAD+ a FADH2
207.        Where are these coenzymes used? Where are the electrons transferred to?
207.        ECT; oxygen – the final electron acceptor of aerobic respiration.
208.        What occurs in the absence of oxygen?
208.        Anaerobic respiration – fermentation
209.        How is Pyruvate used in fermentation?
209.        Degraded to various organic end products; lactic acid, ethanol
210.        What can be used in fermentation to identify and classify bacteria?
210.        The end products
211.        Which is more efficient in energy production, Aerobic or anaerobic respiration?
211.        Aerobic
212.        How many ATP can Aerobic respiration produce? Anaerobic?
212.        38; 2
213.        How are bacteria classified?
213.        Phenotype and/or genotype
214.        What phenotypic traits can be observed in bacteria?
214.        1) Staining characteristics; 2) Shape; 3) biotype differentiation; 4) colony appearance; 5) antigen-specific tests
215.        What are RFLP patterns?
215.        Restriction Fragment Length Polymorphism – technique used to differentiate bacteria based on the sizes of chromosomal fragments generated following digestion with a restriction enzyme.
216.        What is the taxonomic category ranking below a family and above a species?
216.        Genus
217.        What are individual organisms displaying similar characteristics?
217.        Species
218.        How do subspecies usually arise?
218.        From geographic separation
219.        How can different strains be defined?
219.        Serotype and biotype
220.        What is an Isolate?
220.        A pure culture of organism isolated from heterogeneous population of microorganism
221.        What are the bacterial taxonomy relevant to the clinical setting?
221.        Genus a Species a Strain a Subspecies a Biovar/Biotype a Serovar/Serotype
222.        What is the most deadly subspecies of Francisella tularensis?
222.        Francisella tularensis ssp. tularensis
223.        How do the two different species of Salmonella differ?
223.        Salmonella typhi – typhoid fever Salmonella typhimurium – gastroenteritis
224.        What bacteria is a Gram + Cocci, catalase+?
224.        Staphylococcus
225.        How is streptococcus classified?
225.        Gram+ cocci, catalase –
226.        What color do gram + stain?
226.        Purple
227.        What color do gram – stain?
227.        Pink
228.        What color are gram – after decolorize?
228.        Unstained
229.        What are the steps for Gram staining?
229.        1) Fix the bacteria of a slide 2) flood slide with crystal violet 3) Rinse add Iodine 4) Rinse and decolorize 5) Add Safranin and Rinse 6) pat dry
230.        What are 3 exceptions to the gram stain and why?
230.        Mycoplasma – lack cell wall; Chlamydiae – disulfide linked proteins not peptidoglycan; Mycobacteria – waxy lipids in cell wall
231.        What type of stain is used for Mycobacterium and Nocardia?
231.        Acid-fast Stain
232.        What is used for a dye in Acid-fast stains? What color does it stain?
232.        Carbolfuchsin; red
233.        What is added to Acid-fast stains to visualize other cells present?
233.        Methylene blue
234.        What diseases do Mycobacterium and Nocardia cause?
234.        Tuberculosis, leprosy, other skin/lung infections
235.        Where can Transient Flora be found?
235.        Environment – door handles, desks, people
236.        What is the population of organisms called that are regularly found at any anatomical site?
236.        Resident Flora
237.        T/F Internal tissues contain Resident Flora.
237.        F – Internal tissues are free of microorganisms
238.        What type of organisms are found in the Resident Flora?
238.        Bacteria (most), Fungi (few), Protozoa (rare)
239.        What region of the body is most poplulated?
239.        GI tract
240.        Do the blood, brain, and muscle have normal flora?
240.        No – Internal tissues are free of microorganisms
241.        What are 3 examples of bacteria that occupy multiple niches of the body?
241.        Staphylococcus epidermidis, Staphylococcus aureus, Corynebactrium spp.
242.        What is Tissue Tropism?
242.        Favoring growth in one tissue more than another.
243.        What factors can influence flora diversity?
243.        1) Age and sex 2) Diet and nutrition 3) Sanitation and hygiene
244.        How does normal flora prevent colonization of pathogenic bacteria?
244.        1) competing for attachement sites and nutrients. 2) Antagonize bacterial growth
245.        What is another benefit of Normal Flora?
245.        Synthesize and excrete vitamins – K, B12
246.        How can the Normal Flora contribute to disease? Examples?
246.        Bacteria from one site infect a new site; E. Coli from GI pathogenic in lung or urinary tract; Streptococci to Blood stream from oral surgery
247.        What happens in antibiotic induced diarrhea?
247.        Antibiotics destroy normal flora allowing opportunistic pathogens to grow.
248.        What are Nosocomial Infections?
248.        Infections that result from staying in a hospital
249.        Where does Corynebacterium diphtheriae occupy?
249.        Throat
250.        What bacterium only occupies the urogenital epithelium?
250.        Neisseria Gonorrhoeae
251.        What are most Nosocomial infections due to?
251.        Antibiotic-resistant organisms
252.        What 3 factors result in Nosocomial infections?
252.        1) High prevalence of pathogens 2) Compromised hosts 3) efficient mechanisms of transmission from patient to patient
253.        Where do 25% of Nosocomial infections develop?
253.        ICU
254.        What is the single most important method to limit cross transmission?
254.        Hand Hygiene
255.        What is used on the skin or other tissue to reduce microorganisms?
255.        Antiseptics; Iodine, Alcohol
256.        What is used on inanimate objects to reduce microorganisms?
256.        Disinfectants; alcohols, phenols, aldehydes, surfactants
257.        The suffix –stasis/-static refers to?
257.        Inhibition; no complete destruction (stuck like static)
258.        –cide/cidal refers to?
258.        Destruction or inactivation (homicide)
259.        What 3 environmental conditions affect treatment?
259.        1) Temperature and pH 2) Composition and Quantity 3) Contact time
260.        How does high temperature control bacterial growth?
260.        Denaturation of proteins
261.        Why is moist heat more effective then Dry heat?
261.        Water is a better conductor
262.        T/F Pasteurization sterilizes dairy products and fruit juices.
262.        F – Not sterilization, heat resistant microbes survive
263.        Is Boiling complete sterilization?
263.        No
264.        How do you achieve true sterilization?
264.        121C at 15 psi for 15min
265.        What can survive with boiling?
265.        Endospores, protozoan cysts, some viruses
266.        What is a very effective dry heat treatment?
266.        Incineration (inoculating loop)
267.        Why is slow freezing better then quick freezing?
267.        Crystals form and puncture membranes
268.        How do HEPA filters work?
268.        Filters microbes out of air and gas
269.        What are the 2 categories of radiation?
269.        Ionizing and nonionizing
270.        How does ionizing radiation work?
270.        Creates ions by ejecting electrons from the atoms they strike
271.        What are 3 examples of Ionizing radiation?
271.        Electron Beams, Gamma Rays, X-rays
272.        What form is used to sterilize food products?
272.        Gamma Rays
273.        Which has Rapid cell death, but poor tissue penetration?
273.        Electron beams
274.        What is non-ionizing radiation suitable for?
274.        Disinfection air, transparent fluids, surfaces
275.        What is the symbol used to label irradiated foods?
275.        Radura
276.        What is an example of non-ionizing?
276.        UV radiation
277.        How does it work?
277.        Excites electrons, making new covalent bonds
278.        What Causes Thymine Dimers?
278.        UV radiation
279.        What type of chemical control is best for blood, vomit, feces?
279.        Phenols, Phenolics
280.        What type of organisms are Alcohols not effective against?
280.        Fungal spores and endospores
281.        What are Tinctures?
281.        Solutions of other antimicrobial agents in alcohol.
282.        What chemical agent is effective against vegetative bacterial and fungal cells, fungal spores, bacterial endospores, and protozoan cysts, as well as many viruses?
282.        Halogens
283.        What is used in the treatment of drinking water?
283.        Ozone
284.        What is an effective sporocide used to sterilize equipment?
284.        Peracetic acid
285.        What are Quats?
285.        Antimicrobial surfactants
286.        What can be used to prevent blindness by N. gonorrhoeae?
286.        1% silver nitrate
287.        What is Thimerosal used for?
287.        Preserve vaccines
288.        How do heavy metals control bacterial growth?
288.        Ions precipitate proteins and react with sulfhydryl groups on enzymes
289.        What type of disinfecting agent is Formalin?
289.        Aldehyde
290.        T/F You’re glad this is the last question.
290.        T – you’re sane F – you might be a gunner
Categories: Microbiology