MICRO Flashcards
(154 cards)
1
Q
Specimen that requires Staphylococcus streak?
A
Conjunctiva
2
Q
Specimen for Whooping cough?
A
Nasopharyngeal (caused by B. pertussis)
3
Q
Blood required to prepare 750mL of Blood agar?
A
37.5 mL (Multiply by .05)
4
Q
Human bite infection can be caused by?
A
- Streptococcus anginosus: a-hemolytic, GPC in chains (52%)
- Staphylococcus aureus: B- hemolytic, GPC in clusters (30%)
- Eikenella, corrodens: Non-hemolytic, small GN Bacilli (30%)
5
Q
Differentiates bacteria from dust?
A
Acridine Orange stain (binds with DNA)
6
Q
How to see an organism that is low in concentration in a specimen?
A
Acridine Orange stain
7
Q
What to do if slide coagulase is negative?
A
Do tube coagulase
8
Q
Selenite broth was cultured and processed using MALDI. E.coli was detected, what would you report?
A
No shigella or salmonella isolated
9
Q
P. aeruginosa causes?
A
Cystic fibrosis
10
Q
Media used to isolate organism causing cystic fibrosis?
A
- Rogen loye with CO2
- MSA
11
Q
C. difficile causes?
A
Pseudomembranous colitis
12
Q
Causative agent of subacute endocarditis?
A
Streptococcus viridans
13
Q
Burned patient infection?
A
P. aeruginosa (reverse isolation needed for patients that are immune compromised)
14
Q
Best stain for acid fast bacteria?
A
ZN
15
Q
Color of M. tuberculosis after methylene blue counterstain?
A
Red
16
Q
Color of M. leprae?
A
Red
17
Q
Kinyoun stain?
A
Red mycobacteria (cold ZN, no flame required)
18
Q
Non-hemolytic, slide coagulase negative staphylococcus from female urine specimen?
A
S. saprophyticus
19
Q
Gram positive cocci, catalase positive, slide coag pos (organism is variable), non hemolytic organism isolated from a urine specimen. What’s the next step?
A
Do Novobiocin/ Report as Staphylococcus saprophyticus
20
Q
Atmospheric environment for B. fragilis?
A
Anaerobic
21
Q
INNER EAR INFECTION vs SINUS INFECTION for specimen importance?
A
- S. pneumoniae: 1 VS 2
- H. influenzae: 2 VS 1
- M. catarrhalis: 3 VS 3
22
Q
Metallic sheen colony seen. What to do next?
A
Oxidase (Pseudomonas is positive)
23
Q
Cost effective method for throat swab?
A
Gram stain
24
Q
Causes bacterial vaginosis?
A
G. vaginalis (vaginitis- inflammation)
25
Differentiates E. coli 0157 vs Shigella spp?
Motility
26
Fisherman with wound infection?
Aeromonas Malaria sp seen in Wright stain: Do parasitemia
27
After ID of P. falciparum in blood smear, what to do?
Call the physician (choose parasitemia if given as choice. Thick smear doesn’t need to be done because question said it is already identified)
28
Ineffective antiseptic against fungus?
Ethanol
29
K. oxytoca (+) vs. K. pneumoniae (-), where to get colonies from?
BAP/SBA (indole test)
30
A fungal culture negative after 5 days, what to do?
Incubate for 7 days
31
Blood culture positive for gram negative bacilli, what to do?
Call Dr or ward
32
Women diagnosed with S. saprophyticus, organism is?
Novobiocin resistant
33
What’s next if slide coag neg, tube coag pos?
Report as S. aureus (if tube neg and PYR pos- S. lugduniensis)
34
Which organism is slide coag positive, tube negative, and PYR positive?
S. lugduniensis
35
Gram pos cocci, cat -ve, optochin resistant, Bile soluble positive, PYR negative?
S. pneumoniae
36
Heavy inoculum?
Smaller zones
37
Light inoculum?
Bigger zones
38
0.5 Macfarland: 1-3 x 108 CFU/mL. What’s used to make it?
Barium sulfide
39
Antibiotic used to treat Enterococcus faecalis in CSF?
Ampicillin (3rd gen cephalosporin)
40
E. faecium- R to ampicillin, what to use?
Vancomycin
41
Antibiotic for E. coli in CSF?
Ceftriaxone (3rd gen cephalosporin, can cross BBB)
42
Which is the drug of choice when treating sepsis caused by E. coli?
Ceftriaxone
43
A KB in S. pneumoniae using oxacillin was 20 mm after 16 hrs of incubation?
Incubate for 4 more hours (needs 20-24 hrs)
44
Which organisms are resistant to Nitrofurantoin?
All Proteus (PPM)
45
B lactamase positive H. influenzae, how to report?
Report as ampicillin resistant
46
B lactamase positive N. gonorrhoeae, how to report?
Report as penicillin resistant
47
Non-motile, citrate negative, what ID?
Shigella sonnei
48
Function of antibiotic in MTM?
Reduce normal flora
49
Bacterial vaginosis, most appropriate test?
Wet mount and GS
50
Anaerobic organisms are often isolated in?
Mixed culture
51
Negative culture from neonatal sepsis, most common cause?
Inadequate blood volume
52
Color of M. TB after addition of Methylene blue?
Blue
53
Insect vector for Malaria?
Anopheles
54
Urine sample for Culture and Sensitivity, 4 different colonies found, what to do next?
Mixed growth, assume contamination
55
S. typhi don’t react with antisera, what to do?
Boil and repeat
56
Organism that causes impetigo?
Streptococcus pyogenes
57
Organism used for negative control for PYR?
Streptococcus agalactiae (S. pyogenes is PYR positive, Enterococcus is always PYR positive)
58
What might be the gram pos bacilli seen in urine culture?
Corynebacterium
59
Economic method to ID Group A Beta hemolytic streptococcus?
Subculture/isolation and ID
60
Gram negative intracellular diplo isolated from sputum?
M. catarrhalis
61
Which organism is unsuitable for anaerobic control?
Bacteroides fragilis
62
Clostridium novii (strict anaerobe) Pseudomonas aeruginosa (strict aerobe), what to do?
Do tube coag at 22C for 24 hr (negative tube coag on 37C needs to be left at RT for 24 hrs= if pos, report as pos)
63
Color of methylene blue when anaerobic conditions are met?
White
64
Most critical step in gram stain?
Differentiation, why?
65
Pink cocci in chains
Over decolorized
66
FIRST Priority to process? CSF vs synovial vs. suprapubic urine?
CSF
67
Shipment method for N. meningitidis?
RT with CO2
68
How many sets of blood culture for 24 hours?
< 2 sets
69
False positive in oxidase test, what is indication?
Using nichrome wires/loops
70
False positive in catalase test, what is indication?
Culture from BAP
71
When to measure the pH of media?
Before pouring and solidification (pH changes after autoclaving)
72
Vibrio difference from Aeromonas and Plesiomonas?
Salt tolerance
73
Endogenous type of infection in mouth and gut?
Bacteroides fragilis (they are inside the body, but can cause infection)
74
Where will you use anaerobic culture? (surgical tissue, urine or bronchial washing)
Surgical tissue (vs Urine, bronchial washings)
75
Anaerobic blood culture with suspected organism is negative after 5 days, what to do?
Do an aerobic culture (vs increasing blood volume, incubating for 5 more days)
76
Which should be reported first? Eye keratitis or Gas gangrene?
Gas Gangrene
77
Lacto 2+, Gardnerella v 3+ what is the result? Normal or B. Vaginosis?
Normal (vaginosis has no lacto)
78
MIC?
Last tube/well where bacteria did not grow
79
CSF low glucose, what is the bacteria?
Bacterial meningitis (high CHON and WBC)
80
Bipolar stains, what is the bacteria?
Yersinia pestis (G&S)
81
You are encountering erroneous bacterial controls for catalase test, what to do?
Perform controls with clinical isolates
82
An ANAEROBIC bottle suspected with C. albicans and incubated yielded no growth in 5 days. What’s the next step?
Prepare an aerobic culture bottle
83
Long beaded branching gram pos isolated in sputum?
Nocardia
84
GS in pos BD culture bottle yielded GP cocci. What is the first thing the technologist should do?
Call the physician to report the finding
85
2 consecutive days with small zone in KB test what is the probably the reason?
Antibiotic is expired
86
Additional precaution for B. anthracis?
Inform the receiving lab
87
You identified a C. diff in the hospital what is the next step?
Call infection control
88
Identified S. aureus on floor?
Call infection control
89
GPC, catalase neg, non-hemolytic organism found, what to do next?
PYR (Enterococcus)
90
Optochin R, BILE SOLUBLE, mucoid organism alpha hemolytic, what is next step?
Report S. pneumoniae
91
Cause of Otitis media?
S. pneumoniae
92
Otitis media with alpha hemolytic mucoid colonies?
S. pneumoniae
93
Gram positive rods, catalase pos, Non-hemolytic, non-motile, box-endings and aerobic, what ID?
B. anthracis
94
BSC to use for suspected B. anthracis?
Use BSC II
95
Causes of Bordetella Pertussis?
Whooping cough
96
Best specimen for B. Pertussis?
NPS
97
Abundant cell for B. Pertussis?
Lymphocytes
98
What is the MOST important info required for detection of C. Diff?
Date of admission (Commonly ordered once admitted, useless to ask for another sample within 8 days)
99
What is the most appropriate test for C. Diff?
Toxin detection (stool)
100
Best specimen for T. spiralis?
Muscle biopsy
101
Mode of transmission of T. Spiralis?
Eating undercooked pork
102
Which of the following results is expected when a yeast produces blastoconidia, pseudohyphae and chlamydospores on corn meal agar?
Germ tube positive
103
What is the appropriate action given the control results below? (PYR for E. faecalis is Positive and PYR for S. agalactiae is Negative)
Record and report patient results
104
Reptiles and poultry serve as reservoir of this organism?
Salmonella
105
Cause of human bite? ID?
Alpha-hemolytic Strep (Streptococcus anginosus)
106
Warm and presence of small water droplets is found in an anaerobic jar, but the indicator is still blue. What probably is the reason?
Leak in the gasket
107
Presence of Malaria in thin smear? What is the next thing to do?
Do thick smear
108
False Resistant in Kirby Bauer Test?
Didn’t surplus the swab around the tube
109
No bacteria present in a heat-fixed gram stain from blood culture bottle specimen, what to do next?
Fix using methanol
110
What situation needs to be reported in hospital’s infection control? (Maltose positive in cerebrospinal fluid vs Gram stain with Gram positive bacilli)
Maltose positive in cerebrospinal fluid
111
Patient with whooping cough, what cell is the most prominent? (Lymphocytes vs Atypical lymphocytes)
Lymphocytes
112
Sample from a cervical specimen with the following test results: Cytochrome Oxidase is NEG, Glucose POS, Maltose NEG, Lactose NEG. What’s the next thing to do? (Report as N. gonorrhea OR Repeat Cytochrome oxidase)
Repeat Cytochrome oxidase
113
How to differentiate an organism most likely to be Aeromonas / Pleisiomonas / Vibrio?
By using a Salt Broth
114
To confirm, what is the most common urine contamination?
* FIRST is Viridians strep.
* SECOND is Coryne.
* THIRD is CONs
115
VANCOMYCIN: E. Coli <=6 , S. Aureus 10 , E. Aerogenes <=6. AMPICILLIN: E. Coli 32 , S. Aureus 28 , E. Aerogenes 30. HOW TO INTERPRET? OPTION A) E aerogenes resistant to Vanc and susceptible to Amp, OPTION B) E aerogenes susceptible to Vanco and resistant to Amp, OPTION C) Use other organism for same antibiotics, OPTION D) Repeat control with same organism?
Option B
116
All Gram negatives are resistant to Vancomycin?
True
117
E. aerogenes is a spice group organism?
True
118
So whether zone size is large or small, for this spice group organism, ampicillin is reported as Resistant?
True
119
In Molecular, PCR, no product after 20 cycles, what to do?
Increase to 45 cycles
120
In Molecular, PCR, no product after 25 cycles, what to do?
Increase to 45 cycles
121
In Molecular, PCR, no product after 30 cycles, what to do?
Increase to 45 cycles
122
What is the result of all Gram negatives with respect to Vancomycin?
All Gram negatives are resistant to Vancomycin
123
What is reported as Resistant for E. aerogenes regardless of zone size?
Ampicillin
124
In Molecular, what should be done if there is no product after 20 cycles of PCR?
Increase to 45 cycles
125
In Molecular, what decontaminates the PCR work area?
Uracil DNA glycosylase
126
True or False: G-C has a higher melting point than A-T.
TRUE
127
What are the correct temperatures and durations for Denaturation, Annealing, and Extension in PCR?
DENATURATION: 95-98/94-95 C for 30s-1m
ANNEALING: 40-60/50-68 C for 30s-1m
EXTENSION: 72 C for 1 min
128
If PCR was performed at 72C-94C-55C with 20 cycles, what should be done?
Reset test to 94—55—72
129
What could cause DNA to fail to hybridize in Molecular PCR?
Reverse primer not used
130
What enzyme is used to convert RNA to DNA for replication?
Reverse transcriptase
131
What happens if the temperature fails to reach 94C in PCR?
DNA will remain Double stranded
132
How can it be determined if PCR is done?
Fluorescent signal threshold reached
133
What is the PCR arrangement for the sequence G-A-C-T-G-A-C-T?
DNA: A-T and G-C
RNA: A-U and G-C
134
Which part of the eukaryotic cell contains DNA and RNA?
DNA: Nucleus
RNA: Cytoplasm
135
If PCR control is positive but the target is not detected, what is the likely cause?
Incorrect primer is used
136
What method is used to identify the presence and number of a gene in a genome?
Southern blot
137
Where is nucleic acid produced in a gene?
DNA in nucleus, RNA in cytoplasm
138
How much volume of 50 mmol MgCl2 is required for a 2.4mm master mix for ten 50 microliter PCR?
25 microliter
139
Which condition may be associated with increased phagocytes?
Septicemia
140
What should be done if PCR yields no product after 25 cycles?
Increase to 45 cycles
141
What is the role of Uracil DNA glycosylase (UDG)?
Decontamination
142
Why did DNA fail to hybridize?
Didn't use reverse primer
143
Which product has a higher melting point: one with more A-T bonds or more G-C bonds?
The higher more G-C bonds
144
What type of bacteria is characterized as gram-positive, rods, non-motile, non-hemolytic, box-endings, aerobic?
Anthracis
145
What should be done first when culturing a urine specimen?
Mix the urine FIRST
146
What should be reported for non-hemolytic, slide-coagulase negative Staph from a female urine specimen?
Report S. Saprophyticus
147
If the oxacillin sensitivity test for P. pneumonia has a zone of 20mm after 16 hours of incubation, what action should be taken?
Report as Sensitive and need to incubate for 4 more hours
148
What is the best stain for acid-fast bacteria?
ZN
149
Which organism most likely causes impetigo?
Streptococcus Pyogenes
150
Which organisms could be used as the negative control for the PYR test?
Enterococcus Spp.
151
At what temperature are stool cultures for Campylobacter incubated?
42 degree Celsius
152
What is the growing condition of Bacteroides fragilis?
Anaerobic
153
What specimen requires Staph streaks?
BAL or Conjunctiva
154
How much blood is required to prepare 750 ml of Blood agar?
37.5ml
