micro final Flashcards
(167 cards)
1
Q
A relationship where one organism (the parasite) benefits at the expense of the host, often causing harm.
A
Parasitism
2
Q
A close and long-term biological interaction between two different biological organisms, which can be mutualistic, commensal, or parasitic.
A
Symbiosis
3
Q
The degree of pathogenicity or the ability of a microorganism to cause disease.
A
Virulence
4
Q
Infections caused by organisms that typically don’t cause disease in a healthy host but can cause illness in someone with a weakened immune system
A
Opportunistic infections
5
Q
Infections acquired in a hospital setting; also known as hospital-acquired infections (HAIs).
A
Nosocomial infections
6
Q
Toxin that lyses red blood cells.
A
Hemolysin
7
Q
Toxin that targets and kills white blood cells
A
Leukocidin
8
Q
General term for a toxin that kills or damages host cells.
A
Cytotoxin
9
Q
An enzyme produced by some bacteria (e.g., Staphylococcus aureus) that clots plasma. also used as a bench test
A
Coagulase
10
Q
Detects cell bound coagulase (clumping factor).
A
Slide test
11
Q
Detects extracellular coagulase (secreted enzyme that causes clotting).
A
Tube test
12
Q
Items worn to minimize exposure to hazards, such as gloves, masks, gowns, and face shields.
A
PPE (Personal Protective Equipment)
13
Q
Best virulence factor to prevent phagocytosis?
A
Capsule (helps bacteria evade the host immune system by preventing engulfment by phagocytes).
14
Q
Capsule
Enzymes (coagulase, hyaluronidase, proteases)
Toxins (hemolysin, leukocidin, enterotoxins)
Adhesins. these are all examples of what?
A
Examples of virulence factors:
15
Q
Partial hemolysis → greenish discoloration (e.g., Strep pneumoniae)
A
Alpha
16
Q
Complete hemolysis → clear zone (e.g., Strep pyogenes)
A
Beta
17
Q
No hemolysis → no change (e.g., Enterococcus faecalis)
A
Gamma
18
Q
Collect specimens before or after antibiotic therapy to avoid false negatives?
A
before
19
Q
media selection is based on what?
A
Specimen source/
Expected pathogens
20
Q
when you have a liquid specimen what should you do to increase recovery of pathogens?
A
centrifuge
21
Q
CSF should be what to concentrate cells/pathogens.
A
cytocentrifuged
22
Q
Technique to isolate bacterial colonies:
A
Isolation streaking (quadrant method)
23
Q
CSF, blood, urine, lungs, Synovial fluids are examples of what type of body site?
A
sterile body sites
24
Q
Unacceptable sputum criteria
A
25 squamous epithelial cells/low power field = rejected (indicates mouth contamination)
25
Reporting unacceptable sputum
“Specimen not acceptable for culture due to oropharyngeal contamination”
26
Chronic vs. Acute inflammation (on gram stain):
Acute: Numerous neutrophils (active infection)
Chronic: Mostly mononuclear cells (lymphocytes, macrophages)
27
Requires oxygen to grow.
Aerobic
28
Grows without oxygen; oxygen is toxic.
Anaerobic
29
Grows best in increased CO₂ (5–10%).
Capnophilic
30
Requires special nutrients or conditions (e.g., Haemophilus, Neisseria).
Fastidious
31
Can grow with or without oxygen, but may prefer one.
Facultative anaerobe/aerobe
32
Must have a certain condition (e.g., obligate anaerobes can't survive in oxygen).
Obligate
33
what media type Inhibits some organisms while allowing others to grow.
Selective
34
Supports the growth of most organisms, especially fastidious ones
Nutrient/Enriched
35
Shows differences in bacterial metabolism (color change).
differential
36
which media is selective for Gram-negative rods (enterics)
MAC
37
which media is selective for Gram-positive cocci
CNA
38
which media is selective for Neisseria gonorrhoeae & N. meningitidis
MTM
39
CHOC media is a nutrient for what 2 bacteria species?
Haemophilus
Neisseria (Provides X and V factors through lysed RBCs
40
Enriched broth used to support aerobes, anaerobes, and microaerophiles
THIO
41
Where do aerobes grow in a THIO broth?
top
42
Where do anaerobes grow in a THIO broth?
bottom
43
if there is groth throughout the thio broth what does that mean
facultative anaerobes
44
What grows on Mannitol Salt Agar? what color is positive
staphylococcus/ yellow
45
What does positive growth on a Bile Esculin plate/slant look like? (suggestive for what bacteria?)
black/ group D or enterococcus
46
What is LIM broth media selective for?
GBS
47
what is another name for lim broth?
Todd Hewitt broth
48
what is observing and interpreting the growth of microorganisms on agar plates to identify, classify, and enumerate them
plate reading
49
Primary cultures should incubate for how long?
18-24 hours
50
at what temp should primary cultures be incubated at?
37 degrees C
51
What is Quadrant streaking good for?
to isolate single colonies from a mixed specimen
52
how do you grade quadrant streaking?
1+,2+,3+,4+
53
What is the most common specimen for a urine culture?
mid stream clean catch
54
how do you streak out a urine?
treak straight down the middle, then zigzag across the plate
55
1 µL loop: Each colony = how many CFU/mL?
1,000 CFU/mL
56
using a 10 uL calibrated loop = how many mL
0.01mL
57
10 µL loop: Each colony = how many CFU/mL?
100 CFU/mL
58
using a 1 uL calibrated loop = how many mL
0.001 mL
59
1 µL loop: Each colony = how many CFU/mL
1,000 CFU/mL
60
which bacteria lack an outer membrane?
gram positive
61
which bacteria respond to antibiotics better?
gram positive
62
this bacteria has an outer membrane and does not respond to antibiotics well
gram negative
63
cell wall contains thick layer of peptidoglycan and teichoic acid which holds on to crystal violet
gram positive
64
this bacteria only produces exotoxins
gram pos
65
cell wall contains thin layer of peptidoglycan and doesn't hold on to crystal violet
gram neg
66
this bacteria produces endotoxins and exotoxins and other virulence factors
gram neg
67
which toxins produce fever, hypotensive shock, elevated wbc's, and possible DIC
endotoxins
68
What does positive Bile Esculin look like?
black in tube
69
strep app that are positive for BE?
Group D and Enterococcus
70
What does positive 6.5% NaCL test look like?
turbid or cloudy in broth
71
which strep is pos for 6.5% NaCL?
Enterococcus
72
What is an “A” disk?
Bacitracin disk
73
What organisms are sensitive/resistant to it?
S=Group A Strep
R=Other β-hemolytic streps
74
What is a “P” disk?
Optochin disk
75
What is the chemical name for optochin?
Ethylhydrocupreine hydrochloride
76
What organisms are sensitive/resistant to optochin?
S=Strep pneumo
R=Strep viridans
77
What 2 bugs used in CAMP test?
staph aureus and GBS
78
What does a positive Oxidase test look like?
purple
79
Small, grayish-white colonies, β-hemolytic, virulence factors include streptolysin O, hyaluronidase, Protein M, streptokinase
strep pyo
80
this virulence factor is O2 labile, causes lysis of RBCs.
Streptolycin O
81
this virulence factor breaks down connective tissue.
Hyaluronidase
82
which virulence factor inhibits phagocytosis
M protein
83
which virulence factor breaks down fibrin (promotes spreading).
Streptokinase
84
Pharyngitis (strep throat) is a disease state of what spp of bacteria
strep pyo
85
impetigo and Scarlett fever is caused by which bacteria
strep pyo
86
sequelae infections that are associated with strep pyo
Glomerulonephritis and Rheumatic fever
87
S. pyogenes produces what in an anaerobic environment
streptolysin o
88
what drug of choice is used to treat strep pyo
penicillin
89
when there is a depression in the center of the colony
umbilicate
90
when there is a raised center in the middle of the colony
umbonate
91
Large, grayish-white colonies, β-hemolytic
GBS
92
Umbilicate (dented), α-hemolytic
Strep Pneumoniae
93
what does MOPS stand for and what disease is it related to?
strep pneumo and meningitis, otitis media, pneumonia, sinusitis
94
gram stain morphology of strep pneumonia
lancet shape diplococci
95
bile solubility of strep pneumonia
positive/clear
96
drug of choice to treat strep pneumonia
Penicillin or Ceftriaxone (if resistant)
97
BE negative
Group D
98
BE positive
enterococcus
99
Small, grayish-white, may be beta, α-hemolytic or non-hemolytic colonies and pyr/nacl negative
group d
100
Small, grayish-white colonies, beta, α-hemolytic or non-hemolytic colonies and pyr/nacl positive
enterococcus
101
which strep sp can cause a pseudocatalase Reaction and can grow under extreme conditions
enterococcus
102
which strep spp causes nosocomial infections mainly UTI's from catheters and peritonitis
enterococcus
103
drug of choice to treat enterococcus
synergistic therapy
Cell wall-active agent (such as ampicillin or vancomycin)
and Aminoglycoside
104
Nutritionally variant streptococci
(NVS) is known as what
abiotrophia
105
abiotrophia(NVS) may satelite around what bacteria
staph aureus
106
which bacteria needs nutrients from another organism, like Staph aureus in order to grow
Abiotrophia (NVS)
107
staph aureus is coagulase pos or neg
positive
108
staph spp is catalase what
positive
109
coag pos- b-hemolytic creamy, white, or, rarely, light gold colonies
staph aureus
110
which virulence factor of staph aureus binds to Fc region of antibodies, preventing opsonization.
protein A
111
most important staph pathogen that lives in the nares
staph aureus
112
which virulence factor of staph aureus causes food poisoning
enterotoxin A
113
enzymes of staph aureus
Coagulase
Hyaluronidase
Lipase
Penicillinase
114
enterotoxin in staph aureus that is associated with contaminated milk products
enterotoxin C and D
115
cytolytic toxins of staph aureus
hemolysis and leukocidins
116
staph aureus produces which four hemolysins?
alpha, beta, delta, gamma
117
Extracellular proteins that are toxic for many cells: RBCs, WBCs,
fibroblasts, macrophages and platelets
cytolic toxins
118
(SSSS) Scalded Skin Syndrome or Ritter’s disease -Causes the
epidermal layer of the skin to slough off
exfoliative toxin
119
infections caused by staph aureus that the Abscess is filled with pus and
surrounded by necrotic tissues and damaged leukocytes
SUPPURATIVE
(boil, carbuncle, furuncle, impetigo, osteomyelitis)
120
infection caused by staph aureus and is also known as Ritters disease
SSSS (Staphylococcal Scalded skin syndrome)
121
infection caused by staph aureus and is associated with super-absorbent tampons and surgical packing
Toxic Shock Syndrome (TSS)1
122
drug of choice for staph aureus
Methicillin (for MSSA)
123
drug of choice for MRSA
Vancomycin (for MRSA)
124
Resistance due to mecA gene
MRSA
125
Exotoxin kills PMN leukocytes and helps prevent phagocytosis; often associated with community-acquired infections
P-V leukocidin
126
enzyme in staph aureus that is very diagnostic and importance in virulence but is not completely understood
coagulase enzyme
127
this staph enzyme hydrolyzes the hyaluronic
acid present in connective tissues, helping spread of infection
Hyaluronidase Enzyme
128
this enzyme in staph aureus breaks down fats and oil created by the sebaceous
glands on skin surfaces
lipase enzyme
129
enzyme of staph aureus that hydrolyzes the β-lactam ring of penicillin making penicillin –resistant staphylococci
penicillinase
130
staph spp; colonies are white or off-white and non-hemolytic and mainly a contaminant of blood cultures
staph epi
131
CoNS, sensitivity to Novobiocin >17 mm
staph epi
132
disease states of staph epi are
Prosthetic valve infections
Catheter-related infections
133
CoNS; white or yellowish colonies, non-hemolytic; commonly causes UTIs in sexually active young women.
staph sapro
134
novobiocin resistant
staph sapro
135
Lemon-yellow colonies (distinct, dry appearance) often considered a containment
micrococcus
136
how to differentiate micrococcus from staph
Modified Oxidase/ bacitracin (S)
137
what are X and V factor
heme and NAD
138
which media are X and V found in?
CHOC agar
139
which two organisms does satellitism show up
hemophilus sateliting staph aureus
140
GNCB or GNB
Haemophilus influenzae
141
what is called when growth of fastidious organisms around other bacteria that release the
necessary growth factors or break down toxic products
satellitism
142
special media or growth requirements for H. influenza
X and V
143
this species causes meningitis, epiglottis, pneumonia, cellulitis and bacterimia
H influenza
144
which vaccine is given for H. influenza
Hib vaccine
145
GNCB or GNB that only requires V factor to grow
H. parainfluenza
146
this spp has no hemolysis and is normal flora of the oral cavity
H. parainfluenza
147
GNCB or GNB; gram stain looks like school of fish; causes chancroid
H. ducreyi
148
Fastidious spp that is normal flora of Oral and URT and Genital tract; GNDC
Neisseria
149
GNDC ox+ cat+ and ferments only glucose
Neisseria gonorrhoeae
150
special media used for Neisseria gonorrhoeae
MTM and CHOC
151
GNDC, Ox+, Cat+ and ferments glucose and maltose
Neisseria meningitidis
152
media used for Neisseria meningitidis
BAP and CHOC also TM
153
Differentiate N. lactamica and N. sicca from the other Neisseria based on CTA fermentation tests
N. lactamica ferments lactose and N. sicca ferments sucrose
154
What are the ingredients in MTM
vancomycin, colistin, nystatin, and trimethoprim.
155
what does vancomycin do in MTM media
Inhibits Gram-positive bacteria
156
what does colistin do in MTM media
Inhibits Gram-negative bacteria
157
what does nystatin do in MTM media?
inhibits fungi
158
what does trimethoprim do in MTM media
inhibits proteus
159
GNDC; DNAase+, Catarrhalis Disk +
Moraxella catarrhalis
160
differentiate moraxella from Neisseria with CTA
fermentation test;
does not ferment any sugars
161
Hockey Puck’ colonies; opportunistic infections in elderly
Moraxella catarrhalis
162
Bronchitis, Pneumonia, Sinusitis and Otitis media are diseases caused by which bacteria
Moraxella catarrhalis
163
3rd most common in
Otitis media infections, what bacteria?
Moraxella catarrhalis
164
GNCB; normal flora of oral cavity; isolated in human bite wounds and closed
fist wounds;
Eikenella corrodens
165
member of the HACEK group that causes endocarditis
Eikenella corrodens
166
‘pit’ or corrodes media agar
and has bleach like odor
Eikenella corrodens
167
