Unit 1 Flashcards
(392 cards)
0
Q
natural selection (can/cannot) be observed while it is happening
A
can
1
Q
generation of diversity (can/cannot) be seen while it is happening
A
cannot
2
Q
diseases in which genetic changes lead to increased pathogenicity
A
syphilis, Spanish flu
3
Q
diseases that have lost pathogenicity
A
syphilis, scarlet fever
4
Q
diseases in which genetic changes lead to changes in host range
A
AIDS, SARS
5
Q
diseases in which genetic changes can lead to drug resistance
A
Staph, HIV is developing resistance to anti virals
6
Q
clean water is associated with rarity of ___
A
cholera
7
Q
clean air is associated with reduction in ___
A
tb
8
Q
vaccines have helped ____ (six diseases)
A
measles, mumps, rubella
smallpox
polio
diptheria
9
Q
recently discovered to be infectious diseases
A
stomach ulcers, cervical cancer
10
Q
what sequence is used to determine generation of diversity
A
16s RNA
11
Q
what is the rate of change in bacterial DNA
A
1% every 50 million years
12
Q
bacterial DNA has this shape
A
circular
13
Q
circles of DNA containing small numbers of genes that are not essential to the bacterium, extrachromosomal
A
plasmid
14
Q
viruses that infect bacteria and carry a small number of genes (3 or 4) that are not essential to the bacterium, may be extrachromosomal or integrated
A
bacteriophages
15
Q
(a lot/not a lot) of the bacterial genome has a known function
A
a lot
16
Q
pyr- gal- amp
A
cannot make pyrimidine (lacks pyr gene)
cannot digest galactose (lacks galactose synthesis gene)
resists ampicillin (has a gene that digests ampicilin)
17
Q
genetic basis for ID and classification of bacteria: ___ gene
A
16sRNA
18
Q
bacterial genes with related functions all share the same regulatory elements, known as ____
A
operon
19
Q
how is bacterial transcription regulated
A
by metabolic products or deficiencies directly (unlike eukaryotes which use a promoter)
can be positive or negative regulation
20
Q
_____ is when bacteria in a large group express different genes than when only a small number are present
A
quorum sensing
21
Q
Ames test
A
bacteria are used to predict if an agent could be a carcinogen
22
Q
antibiotic resistance is usually due to:
A
acquisition of genes from some other bacteria
23
Q
how does transformation gene exchange work
A
DNA released from a dead bacteria may be taken up non specifically by live bacteria. Could be chromosomal or plasmid DNA. May be incorporated into recipient genome by homologous recombination.
24
transformation allows the ____ gene to be transferred in S. penumonii
capsule
25
____ enzymes are used in genetic engineering for cutting and splicing DNA for production of new plasmids or viruses
restriction
26
practical uses of transformation in bacteria
recombinant Hep B vaccine, recombinant insulin, virus vectors for gene therapy
27
how does conjugation gene exchange work
F factor plasmid is injected through the male's sex pilus, both bacteria must be alive.
28
conjugation is used to transfer ____ genes among intestinal bacteria
anti biotic resistance
29
F- bacteria
female
30
F+ bacteria
male, without integration
31
Hfr bacteria
male with integrated plasmid due to H Frequency Recombination
32
how does gene exchange occur via transduction
some bacteriophage (lytic phage) can infect bacteria and cause lysis, releasing DNA which can then be taken up by the bacteriophage and carried into another bacterium
33
a bacteriophage that can insert itself into the bacterial chromosome producing a prophage in the chromosome
lysogenic phage
34
what does a prophage do and what kind of transduction is it involved in
it excises itself with some adjacent bacterial DNA and which is carried out to another bacterium, specialized transduction
35
specialized transduction transfers toxins of ____ (four diseases)
diptheria, botulism, scarlet fever, cholera
36
non chromosomal DNA that carry genes for antibiotic resistance
R factors
37
regions of a bacterial chromosome that have several adjacent genes that contribute to pathogenesis of a disease
pathogenicity islands
38
how are pathogenicity islands transferred between bacteria
transformation, transduction, conjugation
39
where the bacterial genome is localized
nucleoid
40
what kind of ribosomes do bacteria have
70S
41
what is the bacteria cell wall made of
peptidoglycan
42
how to bacteria reproduce
binary fission
43
difference between gram + and -
- has an LOS/LPS layer, and + has a thicker cell wall
44
steps of the gram stain
fix, crystal violet, iodine, decolorize, counterstain. gram + binds crystal violet permanently while gram - releases the crystal violet.
45
why do acid fast bacteria resist gram staining
mycolic acid layer
46
Gram - endotoxin
LPS
47
Gram + surface structure that occasionally causes septic shock
teichoic acids
48
slime layer for attachment, biofilms
glycocalyx
49
capsule achieves what for the bacteria
immune evasion
50
vaccines are raised against
the capsule
51
gram + pili
simple and newly discovered
52
gram - pili
complex, Type I attachment, variants Type 4 propulsion, Types 3 and 4 secretion
53
porin proteins are found in __ bacteria
gram -
54
what cleaves the peptidoglycan cell wall
lysozyme
55
mycobacter is acid fast ___
+
56
E. coli is acid fast ___
- (appears blue)
57
what part of the LPS/LOS is toxic
the Lipid A chains
58
two types of glycocalyx
slime layer and capsule
59
motion of bacteria flagella
corkscrews, not whiplike
60
how are bacteria flagella powered
transmbembrane electron gradients
61
difference between eukaryotic and prokaryotic bacteria ribosomes
bacterial ribosomes are smaller and sediment less readily under ultracentrifugation (70S/80S)
62
chemical differences between eukaryotic and prokaryotic ribosomes are capitalized on for
drug targets
63
when some bacteria are nutrient depleted, they go through a multi step process to become
spores
64
spores can resist all cleaning except
autoclaving
65
with unlimited nutrients and waste removal, bacteria undergo ___ growth
exponential
66
pattern of bacterial growth in culture vessel
lag, log, stationary, death
67
facultative aerobes, obligate aerobes, and aerotolerant anaerobes have these enzymes
protective enzymes like catalase, oxidase, superoxide dismutase
68
how obligate anaerobes get their ATP
fermentation
69
bacteria that cannot ferment are ____ _____
obligate aerobes
70
bacteria that encode pathways for both fermentation and respiration are __ ___
facultative anaerobes
71
the ability of some bacteria to sense their population density and alter their genetic expression accordingly
quorum sensing
72
what does quorum sensing require
an inducer, a receptor for the inducer, and a transcriptional activator that responds to high intracellular levels of the inducer
73
examples of when bacteria use quorum sensing (two examples)
biofilms and coordinated expression of toxins
74
common structure of exotoxins
AB subunit structure. B delivers A to site of A's toxic activity.
75
common activity for A subunit in exotoxin
ADP-ribosylation
76
inactivated toxoids are used for
vaccines
77
steps of koch's postulates
1. observe pathogen in sick animal
2. grow pure culture of pathogen
3. infect new animal from pure culture
4. observe same disease in new animal
5. obtain pure culture of same pathogen from new animal
78
```
normal flora examples and where they are located
skin:
skin:
throat:
throat:
gut:
```
S. epidermidis
C. albicans
staph and strep in throat
coliforms in gut
79
normal flora can become ___ when assumptions of commensal relationship are violated
opportunistic pathogens
80
normal flora that act as symbiotes and where they are found
lactobacillus in vagina, nutrient generating bacteria in gut
81
assumptions of commensal relationship
containment in appropriate compartment, immunocompetent host, balance among commensal organisms
82
commensals participate in this process that is an element of innate immunity
colonialization resistance
83
non pathogen ID and LD
very high ID and LD
84
profound toxicity may result from (3 ways)
superantigenicity, interference with signal transduction, depolymerization of actin
85
enterobacteriaceae is a phylogenetic grouping including foodborne members (four) and opportunistic pathogens (six)
Shigella, E. coli, Salmonella, Yersinia
| Klebsiella, Enterobacter, Serratia, Proteus, Providencia, and Morganella
86
enterobacteriaceae are gram __ by definition
(-)
87
enterobacteriaceae are (sporulating/non sporulating) by definition
non sportulating
88
enterobacteriaceae are shaped like
straight rods
89
enterobacteriaceae are (aerobes, anaerobes, facultative anaerobes)
facultative anaerobes
90
enterobacteriaceae are catalase (+/-)
(+)
91
enterobacteriaceae are oxidase (+/-)
(-)
92
enterobacteriaceae (can/cannot) ferment glucose
can
93
virulence concern for enterobacteriaceae
promiscuous, extreme antibiotic resistance is a huge problem for the whole group
94
how to do antimicrobial sensitivity testing
smear an agar plate with a liquid culture of the patient isolate, place disks of various antibiotics on the plate before overnight incubation
95
results of antimicrobial sensitivity testing
successful plating produces a lawn of bacteria interrupted by zones of clearing around effective antibiotics. zones of clearing must be measured and compared to a table to determine which antibiotic is the most effective
96
enterobacteriaceae virulence factors in the gut
pili for attachment (GI and urinary tract continuously push stuff out otherwise), and T3SS (for adhesion, enterotoxins, subverting gut macrophage)
97
how enterobacteriaceae get into the gut
allow themselves to be sampled by M cells in Peyer's patches, then alter local macrophages for bacterial survival and spread to the exterior surface of the gut (T3SS) OR use macrophages as Trojan Horses to gain access into the whole system (Typhoid fever) via lymph nodes
98
prevention of foodborne enterobacteriaceae
water treatment, handwashing, food pasteurization, cooking
99
a primarily pediatric complication caused by release of shiga toxin into the bloodstream
hemolytic uremic syndrome
100
patients positive for this antigen may develop reactive arthritis after an infection by Shigella, Salmonella, Yersinia, campylobacter, or chlamydia
Human Leukocyte Antigen
101
major opportunistic nosocomial pathogens that rarely cause symptoms in previously healthy people
ICU bugs: Klebsiella, Enterobacter, Serratia, Proteus, Providencia, Morganella
102
how to prevent spread of ICU bugs
switching of IV lines and catheters, ICU and patient scrubdowns, minimization of hospital stays
103
obligate anaerobes derive all their ATP from ____
fermentation
104
products of fermentation
organic acids, alcohols, solvents
105
enzymes necessary to grow in an oxygen atmosphere
catalase, superoxide dismutase, peroxidase
106
two sources of anaerobic pathogens
normal flora that escape their proper compartment and form an abscess at a new site OR soil organisms that enter the body through wounds or consumption
107
consumption of vacuum packed food causes ingestion of
anaerobic pathogens
108
culture of anaerobes requires:
anoxic conditions-growth and handling
reducing agents and tightly stoppered in fully filled container-liquid
agar plates incubated in an anaerobic jar
anaerobic glovebox
109
how to identify unknown anaerobes
gram stain, gas chromatography of fermentation products
110
major pathogenic anaerobes (three)
Clostridium, GNAB, actinomyces
111
Gram + anaerobic pathogens
Clostridium and Actinomyces
112
normal flora anaerobic pathogens
GNAB, actinomyces, C. difficile
113
type of anaerobic pathogen from soil
Clostridium (minus C. difficile)
114
anaerobic pathogens from the soil use ___ ability to jump into humans
spore forming
115
how is anaerobic virulence determined
exotoxin expression
116
anaerobic pathogen diseases that result from neurotoxin expression
tetanus and botulism
117
anaerobic pathogen diseases that depend on tissue-degrading enzymes
gas gangrene and abscess formation
118
abscess disease treatment begins with ______
surgery (draining, debriding)
119
toxigenic disease treatment begins with ___
antitoxin
120
anaerobic infection treatment concludes with ____
antibiotics
121
there are cases of C. difficile infections being passed between two hospital patients who were both examined by the same colonoscope--how?
C. difficile forms spores and colonoscopes cannot be auto claved
122
some foodborne Clostridium infections can be treated without antibiotics--how?
because exotoxins. Botulism can be caused by ingestion of C. botulinum toxin without any live Clostridia being present (or not able to colonize gut). These intoxications can be treated with antitoxin and do not require antibiotics.
123
why do anaerobes grow slowly in culture
their metabolism is inefficient
124
abscesses fill with:
bacteria and dead neutrophils
125
what does a test tube culture look like if it is growing a strict aerobe
growth just at top
126
what does a test tube culture look like if it is growing a strict anaerobe
growth only at bottom
127
what does a test tube culture look like if it is growing facultative anaerobe
growth throughout
128
how does gas chromatography work to identify anaerobes
either extracts from culture or pus sample are run against control mixes of several acids
129
penicillin G, cefoxitin, chloramphenicol, clindamycin, metronidazole
antibiotics for anaerobic bacteria
130
shape of pathogenic anaerobes
rods
131
anaerobic bacteria that form spores
clostridium and some GNAB
132
TB has been a major human disease for ___ years
5000
133
eradication of TB seemed possible until__
AIDS
134
implications of slow growing mycobacteria
delays in vitro culture results, defeats some antibiotics
135
mycobacteria gram stain result
poor gram staining because of mycolic acid cell wall structure
136
acid fast result for mycobacteria
(+)
137
how does TB get to the CNS
hematogenous spread
138
how does TB get to the GI tract
swallowing infected sputum
139
how does an immunocompetent person react to TB infection
strong CMI response, can hold infection latent for decades
140
how does hematogenous spread of infection occur
intracellular infection of naive macrophages (Trojan Horse)
141
response in immunocompetent host to TB in macrophages
CD8 cells kill infected macrophages and establish granulomas in which infection is contained
142
extrapulmonary manifestations of TB are ___ and are usually a sign of ___
scrofula in neck, genitourinary, CNS (meningitis or abscess), skeletal
reactivation
143
response to pediatric TB
trace source (it was recently acquired) and watch for miliary and meningitis (lethal pediatric infections)
144
TB infection protocol: determine exposure by __ and/or __, perform __ ___ ___ as soon as cultures grow
TST and/or IGRA, antibiotic resistance testing
145
directly observed therapy for TB
4+ drug therapy featuring isoniazid, isolate patient for first two weeks
146
TB vaccine
BCG, used abroad, not cost effective here
147
best way to reduce TB
good diet and housing
148
atypical mycobacteria are ____ acquired and do not cause ___
environmentally, leprosy/TB
149
atypical mycobacteria infection in an immunocompetent adult is usually _____
cutaneous
150
atypical mycobacteria infection in a child is usually ___
scrofula
151
immunosuppressed hosts of atypical mycobacteria may exhibit:
TB like symptoms (particularly from M. kansasii or MAI/C
152
atypical mycobacteria infections are (easy/difficult) to treat
difficult, require multiple antibiotics
153
M. leprae challenge
no in vitro culture system
154
M. leprae has a (long/short) incubation period
long, doesn't transmit easily
155
Tuberculoid leprosy
PPD+, paucibacillary, vigorous CMI both contains infection and damages nerves
156
Lepromatous Leprosy
multibacillary, weak CMI, extensive cutaneous symptoms, PPD-
157
Lepromin PPD tests:
anti-leprosy response and position on the tuberculoid-lepromatous spectrum, does NOT test exposure
158
treatment for leprosy
2 years dapsone+rifampin
159
CMI stands for
cell mediated immune response
160
CMI response to TB infection
terminates the unimpeded growth of the M. tuberculosis 2-3 weeks after initial infection
161
miliary TB
more likely to develop right after primary infection, less likely as a reactivation. hematogenous spread of TB through body, many tiny noncalcified foci of infection appear like millet seeds in lung on chest x ray
162
M tuberculosis diagnosis-TB meningitis
Brudzinski's neck sign (lay child flat, pull up head, knees come up as well)
163
MAI, MAC
M avium and M intracellulare, very difficult to distinguish
164
result of MAI/MAC
pulmonary disease indistinguishable from TB in severely immunocompromised patients, environmentally widespread, found in soil and water
highly drug resistant
165
transmission methods of spirochetes
sexual, vector-borne, environmental
166
action of spirochetes
cross quickly into bloodstream causing immediate bacterermia and eventual multi-organ infections. some cross the blood-brain barrier leading to meningitis and other CNS symptoms
167
why no vaccines for spirochetes?
virulence factors are primarily for immune evasion, not very antigenic to start with and may immunomodulate the host to further decrease the response.
168
why is diagnosis of spirochete infection challenging?
disease proceeds in phases which may be separate by months or years (need for meticulous history!), treponema are too small to see by standard microscopy, Lyme has no clear and quick lab test
169
eye exams can be useful to diagnosis of ___ infections
spirochete
170
antibiotic resistance is/is not a problem for spirochete infections
is not
171
spirochete reaction to treatment
Jarisch-Herxheimer
172
stages of syphilis
painless chancre, rash with flu (meningitis possible), latency or dangerous cardiac or CNS involvement (gummas possible)
173
congenital syphilis
devastating but preventable with prenatal care
174
Lyme disease requires ___ ___ to transmit (amount of time)
24 hours
175
prevention of lyme
prompt removal of ticks with gloves, tweezers, possible doxycycline
176
three phases of Lyme disease
skin infection, immune/neurological issues, chronic lyme with more severe immune, neuro-, fibromyalgia
177
antibiotic treatment for lyme
may take a month but no more than that
| Jarisch-Herxheimer reaction may help to confirm diagnosis
178
vibrio shape
curved rods
179
vibrio gram stain
gram -
180
where do vibrios reside
oceans
181
what disease do vibrios cause
fecal-oral gastroenteritis
182
H pylori causes
peptic ulcers
183
vibrios may infect wounds contaminated by
seawater, ocean debris
184
gastroenteritis and peptic ulcers require that the vibrios have __ ___ factors
GI virulence factors
185
most pathogenic strains of V cholerae
contain O1 genetic marker of colonization by lysogenic bacteriophage that carries virulence factors
186
how is V cholerae transmitted
fecal oral
187
how does V cholerae infect the host
usually killed by stomach acid
| if it survives, secretes mucinase to attach to and colonize the intestine
188
after colonizing the intestine, V cholerae secretes
choleragen
189
choleragen is
an AB subunit enterotoxin that interferes with signal transduction
190
choleragen causes
massive watery diarrhea
191
main problems to treat with cholera
dehydration and electrolyte imbalance
192
Campylobacter jejuni carries:
GI virulence factors like pili that allow it to establish a locus of infection in the intestine
193
characteristics of syphilitic meningitis
low inflammation, may not express Brudzinski's signs
194
gummas
gummatous syphilis: granulomatous lesions with rubbery, necrotic center (primarily liver, bones, testes)
195
cardiovascular syphilis
aneurysm of ascending aorta caused by chronic inflammation of vasa vasorum
196
Argyll Robertson pupil
hallmark of neurosyphilis
| one or both pupils fail to respond to light but does constrict to focus on a near object
197
major intracellular pathogens (there are a lot, like ten)
Neisseria, Enterics (Shigella, E. coli, Salmonella, Yersinia), Mycobacter, some bacilli, Legionella, Listeria, Rickettsial, Chlamydia, some fungal infections (Histoplasma, Cryptococcus), ALL viruses
198
strategies for intracellular survival
escape the endosome, subvert the endosome, survive endolysosomal fusion
199
facultative intracellular pathogens
can divide independently on agar plates but enter host cells as part of their pathogenesis (Neisseria, Enterics, Mycobacter, bacilli, Legionella)
200
obligate intracellular pathogens
Rickettsial, Chlamydia--require host cell resources to multiply
201
how are obligate intracellular pathogens grown in lab
tissue cultures like viruses
202
how intracellular pathogens use human macrophages
for transport around the body and to evade humoral and surface-innate immunity (actin based cell-cell spread)
203
how intracellular pathogens use T3SS
enhance phagocytosis by the target cell type or alter the endosome so lysosomes fail to fuse it
204
antibiotics used to treat intracellular infections
tetracyclines (contraindicated in pregnancy)
| must cross human cell membrane easily and remain active or activatable after doing so
205
facultative intracellular bacterium that causes gastroenteritis when it contaminates cold-stored pre-prepared foods
Listeria monocytogenes
206
how does Listeria monocytogenes infect its host
after endocytosis, it escapes the endosome and uses actin-based motility to spread between cells (ActA virulence factor)
207
Listeria monocytogenes can cause what in immunosuppressed? and will complicate what?
dangerous disease such as meningitis
| pregnancy (no deli meat or cheese)
208
Chlamydia obligate intracellular replication strategy and how they enter cells
tiny, infectious, rugged elementary bodies which "unpack" into larger, delicate reticulate bodies after cell penetration. They carry a T3SS for entry
209
Chlamydia infection carries a risk of:
Reactive Arthritis sequel
210
difficulties in diagnosing chlamydia
may hide behind other STD on exam
211
common problem with chlamydia
reinfection from partner
212
chlamydia ____ bodies are small, infectious, have a rigid outer membrane, are rugged, bind to receptors on epithelium of lung or mucous membrane
elementary
213
chlamydia ____ bodies are the non infectious intracellular form, metabolically active, replicating, synthesizes own DNA RNA and proteins, requires ATP from host cell, fragile Gram - membrane
reticulate
214
Listeria shape and gram stain
small gram + rod
215
Listeria motility
tumbling by temperature sensitive flagella
216
Listeria hemolysis
beta hemolytic
217
structural virulence factors for Staph
Protein A, capsule, coagulase
218
a basic component of understanding the prevention and control of infection
Chain of Infection
219
how HAI's (hospital acquired infections) occur
direct contact with infecting agent from an infected or colonized individual carried from one person to another by health care workers
indirect contact via contaminated equipment or other inanimate objects
respiratory transmission (airborne or droplet)
220
how the infecting agent leaves the reservoir host
portal of exit
221
isolation/cohorting of infected individuals in the hospital (does/does not) help to eliminate the source of the infectious agent
does help
222
standard precautions for healthcare workers
clean hands when entering and leaving the patient's room, cover mouth and nose with arm or tissue when coughing or sneezing, wear gown and glove if soiling is likely, wear mask and eye protection if splashing with body fluids likely
223
diseases that can be suspended in the air and travel via air currents
TB, chickenpox, shingles, measles, pandemic influenza
224
airborne infection precautions
N95 mask and gown, private negative pressure room, patients wear surgical masks if leaving room
225
examples of diseases spread by droplets
bacterial meningitis, seasonal flu, pertussis, mumps
226
precautions used for droplet diseases
surgical mask and gown, frequent hand washing
227
used for patients known or suspected to be infected or colonized with epidemiologically important microorganisms (MRSA, VRE, resistant acinetobacter, ESBL gram negatives)
contact precautions
228
examples of contact precautions
gowns, alcohol based hand washing products
229
diseases for which you should use Contact PLUS Precautions
C diff, acute diarrhea with a likely infectious cause or in adult with recent history of antibiotic use, Norovirus/Rotavirus, enteric infections (including Campylobacter, Cryptosporidium, Salmonella, Shigella, Escherichia coli)
230
what are the Contact PLUS Precautions
hand washing with soap and water, room disinfected with bleach
231
a method to prevent a patient in a compromised health situation (patient in chemo) from being contaminated by other people or objects
Reverse (Protective) Isolation
232
what to wear for reverse isolation
gown, surgical mask, gloves
233
most resistant infectious agent to antiseptics and disinfectants
bacterial spores
234
infectious agents with low resistance to disinfection and antisepsis
HIV- lipid viruses
235
describes process that destroys or eliminates all forms of microbial life and is carried out in healthcare facilities by physical or chemical methods
sterilization
236
living tissues (can/cannot) be sterilized
cannot
237
describes a process that eliminates many or all pathogenic microorganisms except bacterial spores on inanimate objects
disinfection
238
the reduction of microorganisms on living tissue/skin
antisepsis
239
antiseptics (do/do not) kill spores
do not
240
critical items require what level of cleaning
sterilization via physical methods
241
examples of critical items
items that enter normally sterile parts of the body such as surgical instruments, implants, and invasive monitoring device
242
level of cleaning used for semicritical items
high level disinfectant
243
examples of semi critical items
items that come into contact with mucous membranes or nonintact skin (respiratory therapy and anesthesia equipment, some endoscopes, laryngoscope blades, diaphragm fitting rings)
244
how non critical items should be cleaned
alcohols, phenolics, halogens, quaternary ammonium compounds
245
examples of non critical items
bedpans, blood pressure cuffs, crutches, computers
246
most widely used method for sterilizing inanimate objects
auto claving
247
benefits of auto claving
short processing time, highly effective
248
sterilization method used for products that contain petroleum based liquids
dry heat sterilization
249
used for products that may rust or corrode with moisture
dry heat sterilization
250
how irradiation sterilization works
high energy gamma rays penetrate throughout product resulting in damage to nucleic acid
251
items for which irradiation sterilization is used
single use medical supplies-syringes, implants, catheters, IV sets, surgical gloves, gauze
252
when would filtration be used for sterilization
liquids that contain protein or other delicate compounds that may be destroyed by heat or radiation
253
disadvantage of ethylene oxide gas sterilization
highly flammable and potentially explosive
254
plasma sterilization is often used for items such as
endoscopes (high penetration of medical lumens)
255
benefits of plasma sterilization
rapid turnaround, small enough to place next to where procedure is being performed
256
compounds active against viruses (hepatitis, HIV)
chlorine
257
compounds with broad antimicrobial spectra including, at higher concentrations, bacterial spores and M tuberculosis
chlorine
258
used for antisepsis of skin, mucous membranes, wound sites
iodophores (complexes of iodine with detergents)
259
used as a surgical scrub and for the treatment and prevention of infections in wounds, ulcers, cuts, and burns
betadine (iodine compound)
260
used for general skin cleansing, surgical scrub, pre operative skin prep, can be used for showering before surgery
chlorhexidine
261
compound with a strong bacteriostatic action against many gram positive organisms (including staph)
phenolics/phisohex
262
powerful surfactants with built in detergent activity (do not work on endospores, M tuberculosis, non enveloped viruses)
Quaternary ammonium compounds
263
metals used to control bacterial growth
silver and copper
264
five strep species
Group A, Group B, pneumococci, viridans strep, enterococci
265
three staph species
S aureus, S epidermidis, S saphrophyticus
266
two Neisseria species
N meningitidis, N gonnorhoeae
267
gram - cocci
Neisseria
268
gram + cocci
staph and strep
269
maltose fermenters in Neisseria
N meningitidis
270
Neisseria that do not ferment maltose
N gonnorrhoeae
271
catalase positive, gram + cocci
staph
272
catalase -, gram + cocci
strep
273
coagulase + staph
S aureus
274
two species of coagulase - staph
S epidermidis and S saprophyticus
275
Novobiocin sensitive, coagulase - staph
S epidermidis
276
Novobiocin resistant, coagulase - staph
S saprophyticus
277
two species of alpha hemolytic strep
S pneumoniae, Viridans group
278
two species of Beta hemolytic strep
Group A, Group B
279
two species of Gamma hemolytic strep
Group D: E faecalis, S bovis
280
alpha hemolytic strep sensitive to optochin (bile salts)
S pneumoniae
281
alpha hemolytic strep resistant to bile salt optochin
Viridans group
282
members of the Viridans group
S sanguis, S mutans
283
beta hemolytic strep sensitive to bacitracin
Group A (S pyrogenes)
284
beta hemolytic strep resistant to bacitracin
Group B (S agalactiae)
285
gamma hemolytic strep that grows in NaCl
E faecalis
286
gamma hemolytic strep that does not grow in NaCl
S bovis
287
appearance of Staph growths
grow in clumps, cocci
288
hemolysis of S aureus
Beta
289
color of S aureus colonies
gold
290
what allows subtyping of S aureus
different bacteriophages affect different strains
291
what does Protein A do (S aureus virulence factor)
binds immunoglobins
292
what does the capsule do
inhibits phagocytosis
293
S aureus toxins
coagulase, Protein A, enterotoxin, exfoliatin, Leukocidin, TSS toxin
294
common S aureus presentation
abscesses
295
reservoir and transmission of S aureus
30% of ppl carry S aureus in nose/skin
| transmission by direct contact or by fomites
296
hemolysis of S epidermidis
non hemolytic
297
where is S epidermidis found
normal flora of skin and mucous membrane of many people
298
typical infection sites for S epidermidis
piercings, catheters, IV lines, shunts
| because it attaches to nylon and plastic readily
299
hemolysis of S saprophyticus
non hemolytic
300
what infection does S saprophyticus cause
UTIs in women (but not main cause)
301
a method based on antisera to carbohydrate antigens of the cell wall used to classify strep
Lancefield group
302
appearance of pneumococci
diplococci
303
Lancefield classification of pneumococci
no Lancefield group
304
pneumococci virulence factors
no toxins. polysaccharide capsule is both antigen and virulence factor which prevents phagocytosis and stimulates the opsonizing antibody
305
reservoir of pneumococci
found in throat of 5-50% of people
306
Lancefield classification of Viridans group
none
307
viridans group virulence factors
enzymes that metabolize extracellular polysaccharides, acids
308
reservoir of viridans group
normal flora of mouth in all people
309
Group A strep virulence factors
pili encoded by a pathogenicity island, numerous toxins
310
diagnostically useful hemolysin for Group A strep
IgM antibody from Streptolysin O
311
reservoir of Group A strep
found in pharynx and skin of 10% of ppl
312
beta hemolytic strep, resistant to bacitrain, positive in CAMP test
Group B strep
313
main virulence factor of Group B strep
capsule
314
reservoir and transmission of Group B strep
found in genital tract of 25% of women
| can be transmitted to baby at or before birth
315
non hemolytic strep, bile resistant
Group D
316
non hemolytic strep, no Lancefield group, obligate anaerobes, found in abscesses that contain a complex mix of microorganisms, not primary pathogens
Peptostreptococcus
317
reservoir or peptostreptococcus
normal flora of mouth, respiratory tract, female genital tract, bowel
318
gram -, diplococci, require chocolate agar
Neisseria
319
what does heating the chocolate agar achieve
inactivates fatty acids
320
endotoxin in Neisseria
LOS membrane
321
helps Neisseria attach to surfaces
IgA protease
322
transmission of N meningitidis
droplets
323
virulence factor of N meningitidis
polysaccharide capsule
324
N gonorrhoeae virulence factor
pili allow attachment
325
transmission of N gonorrhoeae
sexual or neonatal
326
The application of knowledge of the organisms most likely to cause infection in a given clinical setting and its most likely susceptible antibiotic
empiric therapy
327
what should you perform on recovered isolates of microorganisms before treating someone with an infection and why
antimicrobial susceptibility testing (AST) because different organisms vary in their susceptibility to antimicrobial agents
328
vancomycin should be used for treatment of gram (+/-) bacterial infections
gram +, because it cannot penetrate the outer membrane of gram - bacteria
329
Group A strep (S pyogenes) remain universally susceptible to what antibiotic
penicillin
330
series of factors to consider for optimal choice of antimicrobial agent
age, history of previous adverse reactions to antimicrobial agent, pregnancy, renal and hepatic function, site of infection
331
stomach pH varies with age. The pH of gastric secretions is (higher/lower) in young children.
higher pH, less acidic. Also less acidic in older people.
332
implication of a longer half life for an antibiotic
increase the time between doses
333
______: encompasses all the ways that the body manipulates a drug, including absorption, distribution, metabolism, and excretion
pharmacokinetics
334
_____: describes the biochemical and physiologic effects of the drug and its mechanism of action on the bacteria
pharmacodynamics
335
antimicrobial agents that inhibit the growth and/or reproduction of the infecting agent but fail to actually kill the agent
bacteriostatic
336
examples of bacteriostatics
macrolids (erythromycin), clindamycin, sulfamethoxazole, trimethoprim, tetracyclines, and chloramphenicol
337
examples of bacteriocidals
Beta lactam antibiotics (penicillins and cephalosporins), vancomycin, aminoglycosides (gentamycin), and fluoroquinolones (ciprofloxacin)
338
antimicrobials may be ___ at low concentrations but ____at high concentrations
bacteriostatic, bacteriocidal
339
the inhibitory concentration used to quantitate the activity of an agent against an organism
Minimum Inhibitory Concentration (MIC)
340
examples of broad spectrum antibiotics
carbapenems, extended spectrum cephalosporins, beta lactam/beta lactam inhibitor combinations, newer fluoroquinolones
341
examples of narrow spectrum antibiotics
older penicillins, macrolides, vancomycin (only gram +)
342
natural antibiotics have ___ toxicity and ___ effectiveness
high, low
343
synthetic antibiotics have __ toxicity and __ effectiveness
low, high
344
five main mechanisms of antibiotics
```
interfere with cell wall synthesis
interfere with protein synthesis
interfere with cytoplasmic membrane function
interfere with nucleic acid synthesis
interfere with metabolic pathway
```
345
why use cell wall synthesis as a target of antibiotics
because humans don't have a cell wall
346
why use protein synthesis as a target of antibiotic action
because humans and bacteria have different ribosomes
347
the beta lactams
penicillins, cephalosporins, carbapenems, monobactams
348
antibiotics that interfere with cell wall synthesis
beta lactams, vancomycin, bacitracin
349
antibiotics that act on the cell membrane
polymyxins
350
antibiotics that interfere with folate synthesis
sulfonamides, trimethoprim
351
antibiotics that interfere with nucleic acid synthesis
DNA Gyrase-quinolones
| RNA Polymerase-Rifampin
352
antibiotics that interfere with ribosomes
macrolides, clindamycin, linezolid, chlamphenicol, strepogramins, tetracyclines, aminoglycosides
353
mechanism of action of antibiotics that inhibit cell wall synthesis
inhibit cross linking between peptide chains
354
the cross linking of peptide chains in the cell wall is catalyzed by a series of transpeptidase enzymes referred to as:
penicillin binding proteins (PBPs)
355
features of beta lactams
house with attached garage, can give very high doses, binds at the active site of the transpeptidase enzyme, bacteriocidal, irreversible
356
four main beta lactam classes:
penicillins, cephalosporins, monobactams, carbapenems
357
how does MRSA become resistant to beta lactams
by modifying the PBP
358
how does the beta lactam bind to the PBP
it is a structural analog for the catalytic site
359
as you increase from 1st generation to 4th generation of cephalosporins, what increases?
resistance to enzymes that destroy that antibiotic
360
monobactams are active against gram (+/-) bacilli
gram -
361
use carbapenems for:
bacteria that won't be affected by penicillin or cephalosporin
362
glycopeptides (vancomycin) are effective against gram (+/-) and have this mechanism of action
gram +
| (not gram - because of LPS)bind to aa residues thus preventing the cross linking of the peptidoglycan sheets
363
how does fosfomycin work
inhibits phosphoenel pyruvate, halting muramic acid synthesis
364
when should you use fosfomycin
treating UTIs, one megadose
365
three mechanisms of action when inhibiting protein synthesis
act on large ribosomal subunit
act on small ribosomal subunit
block elongation process of assembling polypeptide
366
risk with using aminoglycosides
very close therapeutic to toxic index
367
the innate ability of a bacterial species to resist activity of a particular antimicrobial agent through its inherent functional or structural characteristics
intrinsic/natural resistance
368
gram negative bacteria have intrinsic resistance to what type of antibiotics
vancomycin
369
enterococci have intrinsic resistance to all
cephalosporins
370
antibiotic resistance that occurs due to chromosomal mutation
mutational resistance
371
resistance that occurs when a particular microorganism obtains the ability to resist the activity of a particular antimicrobial agent to which it was previously suscepitible. this occurs through _______
acquired, horizontal gene transfer
372
four major mechanisms of antibiotic resistance
enzymatic inactivation, decreased permeability, efflux, alteration of target site (this is what MRSA uses, alters PBP)
373
what is an ESBL and what are the most common producers of ESBLs
extended spectrum B-lactamases: enzymes that mediate resistance to extended spectrum cephalosporins but do not affect carbepenems
produced by Gram (-)
374
the action of a beta lactamase inhibitor
irreversibly bind to enzyme so the enzyme is taken out of the system, allowing the antibiotic to work
375
example of a beta lactamase inhibitor
clavulanate (used with amoxicillin)
376
what do beta lactamases do
they inactivate beta lactam antibiotics by splitting the amide bond of the beta lactam (attached garage) ring
377
three types of beta lactamases
1. ESBLs (cephalosporins are useless, use carbepenems, produced by Gram -)
2. amp c beta lactamases (resistance to penicillin)
3. carbepenemases (largest antibiotic resistance spectrum-super bugs)
378
what antibiotic do you use against MRSA
vancomycin
379
producing decoy D-ala residues at the cell surface confer resistance to which antiobiotic
vancomycin
380
advantages of Gram staining
simple, reliable, gives preliminary information
381
advantages of culture methods to determine cause of infection
can identify bacteria more specifically
382
disadvantages of culture method to identify bacterial cause of infection
slower turnaround
383
advantages of bacterial antigen testing
rapidly performed, relatively inexpensive
384
disadvantages of bacterial antigen testing
some assays have poor sensitivity and there is limited availability of some assays
385
direct antigen testing and detection from clinical specimens have which advantages
relatively inexpensive, easy to perform, rapid turnaround time
386
the gram stain does not differentiate between:
normal flora from pathogenic bacteria
387
an advantage of the molecular methods of infectious agent detection over the traditional methods
more rapid identification of fastidious or slow growing organisms is possible
388
disadvantage of the molecular methods used to identify an infectious agent
detect live AND dead nucleic acids
389
IgM response is:
immediate
390
IgG response is:
long lasting
391
higher dilution is consistent with ____ level (higher/lower) level of antibody in patient serum
higher
