Micro-Koneman-Kd

Front 1

Lowenstein-Jensen medium

Back 1

dry, heaped-up yellow to buff-colored colonies of Mycobacterium tuberculosis.

Front 2

Back 2

M marinum is characterized by broad bacilli with cross banding.

Front 3

Back 3

Escherichia coli : Good growth, green metallic sheen.
Klebsiella pneumoniae : Good growth, purple colonies, no sheen.
Shigella flexneri : Good growth, transparent colonies (lactose negative)

Front 4

Lowenstein-Jensen agar , rapid grower, arylsulfatase +, nitrate+

Back 4

M. fortuitum

Front 5

Lowenstein-Jensen agar , rapid grower, arylsulfatase +, nitrate=

Back 5

M. chelonae

Front 6

Lowenstein-Jensen agar , niacin+

Back 6

M. tuberculosis

Front 7

Lowenstein-Jensen agar , niacin=

Back 7

MAI (( resemble whipple disease)), M.bovis

Front 8

M. abscessus
M. chelonae
M. fortuitum

Back 8

Rapidly Growing Mycobacteria

Front 9

list the other photos?

Back 9

Group I - photochromogens, develop yellow or orange pigment when exposed to light;
Mycobacterium marinum,
Mycobacterium asiaticum
Mycobacterium kansasii,
Mycobacterium simiae.

Front 10

other scotos?

Back 10

Group II - scotochromogens, form orange-yellow pigment in the dark;
Mycobacterium gordonae,
Mycobacterium szulgai
Mycobacterium scrofulaceum

Front 11

scoto at 37C
photo at room temp 22C

Back 11

Mycobacterium szulgai

Front 12

M. malmoense
M. avium complex (MAC)
M. xenopi

Back 12

Group III - nonchromogens, are unpigmented

Front 13

M. chelonae
M. abscessus
M. fortuitum

Back 13

Group IV - rapid growers

Front 14

3rd leading cause of blindness worldwide

Back 14

M.leprae(Hansen disease); in US - HAWAII,TEXAS,LOUSIANA; armadillos

Front 15

Back 15

The vertical streak is a beta-hemolysin-producing strain of Staphylococcus aureus, and at right angles to it are streaks of (1)Enterococcus faecalis, (2)Streptococcus salivarius, (3)S. agalactiae, and (4)E. durans. Note the large area of complete lysis where the extracellular compound of S. agalactiae encounters the beta-lysin of S. aureus.

Front 16

Catalase positive reaction

Back 16

S. aureus infection

Front 17

MacConkey agar

Back 17

Red colonies: Escherichia, Klebsiella, Enterobacter (strong lactose fermenters)
Pink colonies: Citrobacter, Providencia, Serratia, Hafnia
Colorless colonies: Proteus, Edwardsiella, Salmonella, Shigella

Front 18

Eosin methylene blue (EMB) agar

Back 18

Green-black-purple colonies: Escherichia, Klebsiella, Enterobacter, Serratia, Hafnia, Citrobacter, Providencia
Colorless colonies: Proteus, Edwardsiella, Salmonella, Shigella

Front 19

Back 19

Triple Sugar Iron agar slant (TSI slant)
Escherichia coli : A/A (G) (+lactose)
Shigella flexneri : K/A (+glucose,-lactose)
Proteus vugaris : K/A, H2S (+glucose,-lactose, +H2S)
Pseudomonas aeruginosa : K/N

Hint 19

K = alkaline = Red; A = acid = Yellow; NC = No change; G = gas produced; H2S = hydrogen sulfide produced

Front 20

nematode

Back 20

infection via ingestion of eggs; heavy infestations=rectal prolapse in young kids; dual infection with Ascaris lumbricoides

Front 21

trematode

Back 21

schistosoma mansoni
Africa, Nile delta
infect hepatic portal vasculature and inferior mesenteric vessels
pipestem fibrosis----cirrrhosis

Front 22

trematode

Back 22

schistosoma japonicum
Philippines,China, SE asia
infect the liver

Front 23

trematode

Back 23

Schistosoma haematobium
Africa , Middle east
infect veins of bladder
long term=squamous cell ca. of bladder
detected in terminal urine specimen, midday;S.INTERCALATUM INTESTINE

Front 24

trematode

Back 24

Fasciola hepatica
large
ingestion feshwater plants
infestation of bile ducts with eventual biliary fibrosis

Front 25

Back 25

Chinese liver fluke, or oriental liver fluke
ingestion of undercooked freshwater fish; biliary fibrosis; cholangiocarcinoma
clonochis sinensis

Front 26

Back 26

Chinese liver fluke, or oriental liver fluke
ingestion of undercooked freshwater fish; biliary fibrosis; cholangiocarcinoma

Front 27

Regan Lowe Charcoal agar

Back 27

Bordetella pertussis
PCR useful for partially treated cases
detect or confirm with FA stain

Front 28

Mueller Hinton II Broth with Lysed Horse Blood is for use
in broth dilution antimicrobial susceptibility testing of

Back 28

Streptococcus
pneumoniae with 11 antimicrobial agents

Front 29

dimorphic

Back 29

H. capsulatum
granuloma/necrotizing
organism within histiocytes

Front 30

Back 30

Cyclospora cayetanensisGastroenteritis

Front 31

CHROM agar

Back 31

Methicillin Resistant Staphylococcus aureus - mauve
Other bacterial colonies - inhibited, blue or colourless

Front 32

Back 32

A: Stages of P. falciparum in thin blood smears. Fig. 1: Normal red cell; Figs. 2-18: Trophozoites (among these, Figs. 2-10 correspond to ring-stage trophozoites); Figs. 19-26: Schizonts (Fig. 26 is a ruptured schizont); Figs.27, 28: Mature macrogametocytes (female); Figs. 29, 30: Mature microgametocytes (male).

Front 33

Back 33

Ring-form trophozoites of P. falciparum in a thin blood smear.

Front 34

Back 34

Ring-form trophozoites in a thin blood smear, exhibiting Maurer's clefts./falciparum

Front 35

Back 35

Schizont of P. falciparum in a thin blood smear.

Front 36

Back 36

Trophozoites of P. vivax in a thin blood smear. Note the amoeboid appearance and Schüffner's dots.

Front 37

Back 37

schizont of P. vivax in a thin blood smear.

Front 38

Back 38

Trophozoites of P. ovale in thin blood smears. Note the fimbriation and Schüffner's dots.

Front 39

Back 39

Enterobius vermicularis
The incidence of D. fragilis is nine times higher in patients
with pinworm infections, suggesting that E. vermicularis eggs may be infected with the flagellate and serve as the chief
vector for transfer to humans.

Front 40

The parasite egg in image 1 was identified. What parasite has a high incidence of being found in association with
the one in the image?
a) Isospora belli
b) Entamoeba histolytica
c) Giardia lamblia
d) Dientamoeba fragilis

Back 40

d is correct. The parasite egg in the image is that of Enterobius vermicularis. Note the shape resembling a
football, the smooth, thin wall, and the absence of opercula. The incidence of D. fragilis is nine times higher in patients
with pinworm infections, suggesting that E. vermicularis eggs may be infected with the flagellate and serve as the chief
vector for transfer to humans.

Front 41

The organism in image 2 (Sabouraud dextrose plate) was cultured from lung tissue obtained from an organ
transplant patient. What is the organism?
a) Mucor spp.
b) Histoplasma capsulatum
c) Aspergillus fumigatus
d) Aspergillus terreus

Back 41

c is correct. The image is that of a mold with a central blue-green zone and a
white peripheral apron which is characteristic of A. fumigatus. The other choices don't have this characteristic
appearance. Mucor spp. (choice a) grows rapidly so that it will quickly cover the entire surface of the plate and may lift
the lid of the plate. H. capsulatum (choice b) usually appears as delicate cobweblike, gray-white mycelium. A. terreus
(choice d) has some sort of yellow or brown pigmentation.

Front 42

Image 4 is that of a test used to presumptively identify a catalase-negative streptococcus with characteristic
hemolysis. Which organism is streaked perpendicular (identified by arrow) to the presumptive organism (presumptive -
the unknown organism being tested)?
a) S. aureus
b) Group A Streptococcus (S. pyogenes)
c) Group D Streptococcus
d) Enterococcus spp.

Back 42

a is correct. The image is that of the CAMP test used to identify group B streptococcus. S. aureus is streaked
along almost the entire diameter of the blood agar plate, and the presumptive GBS is streaked perpendicular to this.
Most strains of S. aureus produce a β-hemolysin. These β-hemolysins diffuse out into the agar, and the extracellular
protein produced by GBS (CAMP factor) diffuses out into the agar. Where these two substances intersect, you
observe synergistic hemolysis.

Front 43

The organism seen in image 5 is that of mycobacterium growing on a plate. Which of following mycobacteria show
this morphology?
a) M. simiae
b) M. marinum
c) M. szulgai
d) M. tuberculosis

Back 43

d is correct. The mycobacterium in the image is showing cording. Of the choices, only M. tuberculosis can
have this appearance, which is due to production of "cording factor." As a matter of fact, all the organisms of the MTB
complex can have this appearance.

Front 44

See image 6 of a peripheral blood smear. You obtain the history that this patient lives on the Northeast Coast with
her family, and none of them have strayed far from that area. She recently developed fever, malaise, anorexia, and
fatigue. What is the most likely diagnosis?
a) Ehrlichia chaffeensis
b) Babesia microti
c) Plasmodium falciparum
d) Borrelia recurrentis

Back 44

b is correct. It may be very difficult to distinguish B. microti from the early ring forms of P. falciparum on a
peripheral smear if the characteristic Maltese cross (indicating the mature form of B. microti) is not identified. While P.
falciparum (choice c) is certainly a consideration, the fact that this patient hasn't really travelled makes it less likely.
Neither E. chaffeensis (choice a) nor B. recurrentis (choice d) infect red blood cells. With E. chaffeensis, a
rickettsia-like bacteria, you see organisms (morula) in the cytoplasm of macrophages. B. recurrentis, the cause of
relapsing fever, is a spirochete that, if seen in blood, is present outside of the red blood cells.

Front 45

Mycobacterium szulgai has an interesting characteristic. The organism is a _____ @ 25°C and a _____ @ 37°C.
a) non-photochromagen; photochromagen
b) photochromagen; non-photochromagen
c) scotochromagen; photochromagen
d) photochromagen; scotochromagen

Back 45

d is correct. In the Runyon Classification Scheme, M. szulgai is classified as a scotochromagen (at 37°C).
Scotochromagens produce pigment in the dark and in the light. Photochromagens produce pigment only in the light
and not in the dark.

Front 46

You get a call from a clinician who insists on ordering a “Legionella pneumophila antigen” on a urine specimen
because the team highly suspects this organism, has already started the patient on treatment, and would like to rapidly
confirm their clinical diagnosis; however, you find out that no other microbiology test was ordered. What do you tell the
clinician?
a) The urine antigen test is a tedious test that takes several days to perform. Same-day results are not possible.
Culture should also be considered.
b) The Legionella pneumophila antigen test only detects serogroup 1. A negative urine antigen test does not
mean that the patient does not have Legionella. Culture should also be considered.
c) The results of the urine antigen test are affected by therapy; therefore, since the patient has already started
treatment, a negative result does not necessarily mean the patient did not have Legionella. Culture should also be
considered.
d) The urine antigen test is not really a specific test. There is a lot of cross-positivity with Streptococcus pneumoniae
in patients who are bacteremic. Culture should also be considered.

Back 46

Choice b is correct. The Legionella pneumophila antigen test only detects serogroup 1.

Front 47

What obvious morphologic characteristic distinguishes Bacillus anthracis from Bacillus cereus?
a) B. anthracis is non-motile.
b) B. cereus is non-motile.
c) The spores of B. anthracis are present on the terminal ends of the organism.
d) The spores of B. cereus are present on the terminal ends of the organism.

Back 47

Choice a is correct. The Bacillus genera are spore-forming, gram positive rods. Most of these organisms are motile
(choice b incorrect), with one notable exception being Bacillus anthracis. Neither B. anthracis nor B. cereus has spore
present at the terminal ends of the organism (choices c and d). The spores are either subterminal (B. anthracis) or
subterminal or central (B. cereus).

Front 48

Which of the following viruses are non-enveloped?
a) Parvovirus
b) Hepatitis A
c) Papovavirus
d) all of the above

Back 48

Choice d is correct. Parvovirus and Papovavirus (choice a and c) are DNA viruses while hepatitis A (choice b) is an
RNA virus

Front 49

Which of the following features are associated with lepromatous leprosy?
widespread skin infections
superinfection with Strongyloides
non-caseating granulomas with few AFB
A & B
A, B, C

Back 49

D. A & B.
Lepromatous leprosy is associated with anergy and therefore a more widespread involvement with the presence of large numbers of acid-fast bacilli and foamy macrophages. The tuberculoid form is associated with a robust granulomatous reaction to infection. In tuberculoid form, there is a small number of organisms present. Two leprosy factoids: Mycobacterium leprae grows on armadillo footpads and the most consistent signs are anesthetic skin lesions with palpable prominent peripheral nerves.

Front 50

Which of the following mycobacterial species is the cause of the Buruli ulcer?
M. leprae
M. ulcerans
M. fortuitum
M. marinum
M. chelonei

Back 50

B. M.
The necrotizing ulcerative cutaneous Buruli ulcer is caused by infection with M. ulcerans. All the choices are notable for causing skin disease without pulmonary disease. Most are associated with penetrating trauma - M. marinum with fresh water fish tanks.

Front 51

What condition particularly predisposes toward M. kansasii pulmonary disease?
pneumoconiosis
pre-existing M. tuberculosis
squamous cell carcinoma of the lung
diabetes mellitus
congenital pulmonary adenomatoid malformation

Back 51

A. PNEUMOCONIOSIS.
Behind Mybacterium tuberculosis and M. avium-intracellulare, M. kansasii is one of the most common causes of mycobacterial pulmonary disease.

Front 52

Which of the following coinfections often lead to smear-negative TB and PPD anergic false-negative results?
HCV
Borrelia burgdorfei
Ascaris lumbricoides
HIV
methicillin-resistant Staphylococcus aureus

Back 52

D. HIV.
TB is a difficult disease to diagnose - screening tests like PPC and sputum smears have high false-negative rates and culture often takes weeks. Nucleic acid amplification tests may be more sensitive and rapid, but long-term validation is lacking. HIV makes diagnosis even more difficult.

Front 53

What percentage of immunocompetent people infected with primary TB infection develop active TB?
0%
10%
50%
90%
100%

Back 53

B. 10%.
Actually, 10% is on the high side of estimates as the vast majority of people (90%) infected with respiratory TB resolve the infection. The remaining 5-10% (higher in the immunocompromised) go on to develop active disease, which most often is pulmonary, but can also be extrapulmonary.
QCCP2, M. tuberculosis

Front 54

Staphylococci
Streptococci
Enterococcus

Back 54

Gram + cocci

Front 55

Bacillus
Clostridium
Corynebacterium
Listeria
Actinomyces
Nocardia
Mycobacterium

Back 55

Gram + bacilli

Front 56

Mycoplasma
Ureaplasma

Back 56

Mycoplasma

Front 57

Neisseria
Moraxella

Back 57

Gram -- cocci

Front 58

Pseudomonas
Legionella
Boertella
Francisella
Brucella

Back 58

Gram -- bacilli (AEROBIC)

Front 59

Campylobacter
Helicobacter

Back 59

Gram -- curved bacteria (Microaerophilic)

Front 60

Escherichia
Klebsiella
Shigella
Salmonella
Proteus
Yersinia

Back 60

Gram -- bacilli (anAerobic, facultative)

Front 61

Citrobacter
Enterobacter
Escherichia
Klebsiella

Back 61

C E E K
lactose fermenters; enterobacteriacae

Front 62

Shigella
Yersinia

Proteus
Salmonella
ShY: nonmotile, no H2S
PS : motile; yes H2S

Back 62

Sh Y P S
lactose nonfermenter
enterobacteriacae

Front 63

All ferment glucose,
oxidase negative,
catalase positive
reduce nitrates to nitrites

Back 63

Enterobacteriaceae

Front 64

Vibro
Haemophilus
Pasteurella

Back 64

Gram -- bacilli (anAEROBIC, facultative)
non-Enterobacteriaceae

Front 65

Treponema
Borrelia
Leptospira

Back 65

Gram --- envelope, spirochetes)

Front 66

VDRL( venereal disease research laboratory test)
RPR( rapid plasma reagin test)
ART (automated reagin test)

Back 66

Nontreponemal (reaginic) tests;
Appears one week later, non specific, may also be positive in autoimmune disease....lupus, viral hepatitis

Front 67

FTAB-ABS (fluorescent treponemal antibody absorption test)
MHA-TP (microhemagglutination-Treponema pallidum)

Back 67

Treponemal Ab test
used to confirm; specific

Front 68

Rickettsia
Ehrlichia
Bartenella
Coxiella

Back 68

Rickettsiaceae

Front 69

Chlamydiae

Back 69

Obligate intracellular bacteria

Front 70

Back 70

Staph epidermidis:endocarditis
Staph saprophyticus: UTI

Front 71

Bile esculin - positive

6.5% NaCl - negative(Enterococcus = +)

PYR - negative
. When found in blood associated with Bowel
carcinoma. Increased % in bowel due to higher
levels of bile or underlying colonic disease
. Always susceptible to Penicillinbcd5c8

Back 71

Streptococcus Group D not
enterococcus
Streptococcus bovis

Front 72

A urine specimen from a middle aged female is received in the lab and grows small white colonies on sheep blood
agar that are coagulase negative and positive for catalase. The Gram stain reveals Gram-positive cocci in clusters.
The organism is plated onto a Mueller-Hinton agar and a Novobiocin disc is placed onto the plate. The next
morning, the plate is examined and shows no zone of inhibition. What is the MOST LIKELY organism growing on
this plate?
a. Staphylococcus epidermidis
b. Staphylococcus aureus
c. Staphylococcus saprophyticus
d. Staphylococcus lugdunensis
e. Staphylococcus haemolyticus

Back 72

C. Many of the different species of Staphylococcus can be differentiated by simple testing. The coagulase
negative Staphylococcus organisms include S. epidermidis and S. saprophyticus. While both organisms are catalase
positive, differentiation can be made using Novobiocin. S. saprophyticus is resistant while S. epidermidis is sensitive½Ò¬u

Front 73

You receive plates from a respiratory specimen that exhibit no growth on a blood agar plate and growth of small
gray colonies on a chocolate plate. You perform a gram stain, which reveals small, pleomorphic gram-negative rods.
Based on these results you conclude that this organism is a Haemophilus species. To further subtype the organism,
you test for factor requirements and hemolysis. The next day, you examine the plate and based on the growth, you
determine the organism is H. influenzae. What growth pattern most closely resembles the expected findings for this
organism?
a. Growth and hemolysis, does not require factor X, does not require factor V
b. Growth and hemolysis, requires both factors X and V
c. Growth and hemolysis, does not require factor X, requires factor V
d. Growth but no hemolysis, requires both factors X and V
e. Growth but no hemolysis, does not require factor X, requires factor V

Back 73

D. Haemophilus influenza type b is one of the leading causes of bacterial meningitis worldwide, especially in
young unvaccinated children. Infection with Haemophilus can also cause cellulitis, pericarditis and pneumonia.
Pneumonia is typically caused by non-type b strains, most commonly serotype f. Haemophilus is a gram negative rod.
Differentiating species can be accomplished by testing for factor requirements and observing hemolysis. All
Haemophilus species isolated from humans require factor V. H. influenzae does not show hemolysis on blood agar
and requires factor X. An alternate method for testing for factor X requirement is the porphyrin test. In addition,
Haemophilus is one of the few organisms that show satellite growth around a streak of Staphylococcus aureus.or V

Front 74

In preparation for an upcoming laboratory inspection, you are reviewing your quality control procedures in the
microbiology department. You have a list of atypical bacteria-antibiotic resistance profiles that are posted and should
alert the technicians to perform confirmatory testing. Which of the following bacteria-antibiotic resistance combinations
is INCORRECT and should prompt retesting by another method to confirm resistance?
a. Proteus resistant to cefazolin
b. Klebsiella resistant to ampicillin
c. Enterobacter resistant to ampicillin and cefazolin
d. E. coli resistant to no antibiotics
e. Serratia resistant to ampicillin, cefazolin and cefuroxime

Back 74

A. Strains of Proteus are resistant to nitrofurantoin but are susceptible to the remainder of the drugs that are
commonly tested. The other microorganism-drug combinations are expected patterns of resistance.

Front 75

Which spiral bacterium has hooks at both ends?
a. Leptospira
b. Borrelia
c. Treponema
d. Brachyspira
e. Helicobacter­¬«4

Back 75

A. All of the choices are spiral bacteria, but only Leptospira has hooked ends. Leptospira is a tightly coiled,
right-hand spiraled bacteria. Infection of humans occurs most commonly via direct contact with infected animals
through cuts on the skin or via the conjunctiva. Most infections have a mild clinical course and resolve while
recognized infections present with sudden onset of fever, chills and myalgia. The minority of cases present with
jaundice, acute renal failure, pulmonary hemorrhage and cardiac arrhythmias, known as Weil's disease.

Front 76

You finalize a report from a skin wound as no growth after 5 days. The clinician calls and he is concerned that the
specimen was not cultured correctly, as he was certain there was adequate material upon collection. He states that
the patient had an abscess on the thigh and upon drainage, there was 25ml of purulent fluid expressed from the
lesion. Following the drainage, a swab culture was taken for microbiology. The clinician sent the swab for gram
stain, aerobic and anaerobic cultures. Your BEST response to address the clinician's concern is:
a. Occasionally organisms just do not grow and we cannot explain why. Ask the clinician to send another
swab and the lab will repeat the cultures.
b. A swab should only be used if no other type of specimen can be submitted and in that case, one swab
should be submitted for each type of culture
c. Swabs never contain adequate material and should not be used for culturing specimens in the
microbiology laboratory
d. Occasionally organisms just do not culture and we cannot explain why. Tell the clinician you will reculture
the specimen from the original swab
e. Tell the clinician you will allow the plates to incubate for another 3 days to see if there will be delayed
growth and then issue an amended report at that timeBntãBnt

Back 76

B. Preferred specimens for microbiologic culture include fresh tissue, fluid, exudates and instrumentation (i.e.
screws, plates, catheter tips). A specimen should be submitted to microbiology on a swab only when there is no
availability of other types of specimens. Material submitted on a swab often yields an inadequate amount of material
for culture. To increase the likelihood of having enough material for culture on a swab, one swab should be submitted
for each type of culture the clinician desires. For example, one swab should be submitted for each of the following:
Gram stain, aerobic culture and anaerobic culture, for a total of three swabs.cefur

Front 77

You receive a respiratory specimen in the laboratory that is labeled bronchial washing and has been obtained by
bronchoscopy. As standard procedure in your lab, you culture the specimen to a blood and buffered charcoal yeast
extract plate. On the third day, you examine the plates and notice colonies growing that you would describe as
having a ground-glass appearance. You perform a Gram stain and see tiny gram-negative rods. There is no
growth on the blood plate. What is the MOST LIKELY organism growing on the BCYE plate?
a. Neisseria gonorrhoeae
b. Mycoplasma pneumoniae
c. Moraxella catarrhalis
d. Burkholderia cepacia
e. Legionella pneumophiliafur

Back 77

E. Legionella is a fastidious, slow growing organism. Buffered charcoal yeast extract should be used to allow
for the growth of the Legionella organism. The cultures must be observed for 7 days due to the slow rate of growth of
this organism. L. pneumophilia is the most common organism and colonies have a ground-glass appearance with
iridescent edges. Gram stain of the organism reveals tiny gram-negative rods. Hospital acquired Legionella most often
originates in the water distribution system and environmental studies should be performed in these cases.copla

Front 78

You receive a proficiency test unknown in your microbiology lab. You are told the specimen is from a wound, so you
plate the specimen onto your four standard agars. Pictured are the colonies on MacConkey agar. Based on these
findings, you perform an indole test and find that it is positive. What is the MOST LIKELY organism?
a. Citrobacter freundii
b. Klebsiella pneumoniae
c. Pseudomonas aeruginosa
d. Klebsiella oxytoca
e. Proteus

Back 78

D. The colonies pictured are growing on MacConkey agar and are pink, which indicates that they are lactose
positive. Of the choices, only the Klebsiella and C. freundii are lactose positive. The colonies are mucoid, which is most
characteristic of Klebsiella species due to their capsule. Differentiation between K. pneumoniae and K. oxytoca can be
made by testing for indole. K. pneumoniae is negative for indole while K. oxytoca is positive. Klebsiella are gramnegative
rods carried in the nasopharynx and the bowel and are a frequent cause of urinary tract infections.

Front 79

You isolate a Staphylococcus aureus on a specimen from a wound. You test for Erythromycin susceptibility and find
that the organism is resistant. You perform a D-test disk diffusion test to evaluate clindamycin inducible resistance.
Based on the results pictured, can you treat this patientʼs infection with clindamycin?
a. No. The discs are too close together and therefore the test is not valid
b. No. The zone of resistance around the clindamycin disc indicates that the bacteria is resistant
to clindamycin
c. No. Because there is no zone of inhibition around the erythromycin disc, the test is not
applicable
d. No. The flattening of the clindimycin zone of inhibition near the erythromycin disc indicates the
organism is resistant to clindamycin
e. Yes. The size of the zone of inhibition surrounding the clindamycin disc indicates that the
bacteria is susceptible to clindamycin

Back 79

D. D Zone Test for Inducible Clindamycin Resistance in Methicillin Resistant Staphylococcus Aureus (MRSA)Clindamycin is an excellent antibiotic for the treatment of methicillin sensitive Staphylococcal infections. For the test to
be valid, there must be a zone of inhibition around the clindamycin and no zone around the erythromycin. For the test
to be positive, inferring that the organism is resistant to clindamycin, there must be flattening of the zone of inhibition
around the clindamycin, nearest the erythromycin disc.

Front 80

You receive a cultured specimen on a MacConkey plate. Based on the growth pictured, you perform an oxidase
test, which is positive. What is the BEST organism identification for this specimen?
a. Proteus mirabalis
b. Enterobacter cloacae
c. Pseudomonas aeruginosa
d. Klebsiella pneumoniae
e. Escherichia coli

Back 80

C. Based on the picture, the organism growing on the plate is lactose negative. Of the choices, the only
organisms that fall into this category are Pseudomonas and Proteus. Differentiation can be made by an oxidase test,
which is positive with Pseudomonas and negative with Proteus. Pseudomonas is a Gram-negative rod that is slightly
curved and has one or more flagella. The organisms are lactose non-fermenters on MacConkey agar, oxidase positive
and catalase positive. Pseudomonas aeruginosa is known to cause folliculitis in association with swimming pools and
whirlpools, “swimmers ear”, as well as infections in patients with cystic fibrosis.

Front 81

A clinician calls for a preliminary report on a wound specimen. As the resident on microbiology, you are asked to
review the Gram stain made from the specimen. Based on the image, what is the MOST APPROPRIATE interpretation
of this stain?
a. Gram positive rods in chains are present, issue a preliminary report
b. The specimen is under-decolorized and should be repeated before giving the clinician an interpretation
c. The specimen was inappropriately collected, ask the clinician to recollect the specimen
d. The Gram stain was over-decolorized and should be repeated before giving the clinician any information
e. In preparation of the Gram stain, saffarin was never placed onto the slide

Back 81

B. In evaluating a Gram stain, epithelial cells and/or white blood cells are built in controls that will help you
discern that the process was performed appropriately. In a Gram stain, epithelial cells/ WBCʼs should stain pink. If the
stain is under-decolorized, as in this case, the epithelial cells are blue. These cells are not as useful in interpreting
over-decolorization, as they will be pink in both appropriately decolorized and over-decolorized specimens. If saffarin
was not used, there would be no evidence of pink coloration and the epithelial/ WBCʼs would be colorless.

Front 82

While examining the plates from a wound specimen that came from the operating room, you identify tiny, white
creamy colonies that appear to be yeast, mixed with some larger white colonies. You notice that the plates were
cultured late the previous evening, but you do not want to delay your identification and susceptibility another day.
You decide to carefully isolate only the larger colonies and perform disc diffusion susceptibility testing on a
Mueller-Hinton plate. Based on the image, what is the BEST interpretation of this test?
a. Based on the growth of small colonies within the zone of inhibition, the organism is susceptible to TE
b. Based on the growth of small colonies within the zone of inhibition, the organism is resistant to TE
c. The growth of small colonies within the zone of inhibition indicates that there is mixed growth
d. The growth of small colonies within the zone of inhibition indicates that the organism has a delayed
resistance to TE
e. The growth of small colonies within the zone of inhibition indicates that the organism has delayed
susceptibility to TE

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C.This picture is an example of mixed growth. A report should not be finalized when mixed growth is seen.
Growth of colonies within the clear zone typically indicates mixed growth, and colonies showing mixed growth should
be subcultured, reidentified and retested. Occasionally, this picture can indicate mutant organisms growing in the clear
zone, which will eventually become resistant to the antibiotic. For staphylococci and enterococci only, growth within the
zone of inhibition around an oxacillin or vancomycin disc is indicative of resistance.

Front 83

A urine specimen from a middle aged female in received in the microbiology laboratory. You notice on the patientʼs
history that her chief complaint is urinary tract infection symptoms with alkaline urine. You examine the blood agar
plate and see >100 k/ml of pinpoint smooth whitish-gray colonies growing on the aerobic blood agar plate. There is
no growth on the MacConkey plate. You decide to make a Gram stain and notice that as you try to pick a colony
from the plate, the colony is very sticky and difficult to sample. While you wait for the Gram stain to dry, you
perform a catalase, which is positive. Examination of the Gram stain reveals small slightly curved Gram positive
rods. Based on the Gram stain and other findings, what is the MOST LIKELY diagnosis?
a. Staphylococcus saprophyticus
b. Corynebacterium urealyticum
c. Escherichia coli
d. Enterococcus fecalis
e. Stenotrophomonas maltophilia

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Answer 7a: B.

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Based on the image and the diagnosis, what type of crystals are commonly found in the urine of these patients?
a. Calcium oxalate
b. Tyrosine
c. Urate
d. Struvite (triple phosphate)
e. Cystine

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D. C. urealyticum is one of the more frequently isolated clinically significant Corynebacterium species in
clinical specimens, often responsible for urinary tract infections. Gram stain reveals Gram positive, slightly curved rods.
C. urealyticum is catalase positive and strongly urease positive. C. urealyticum urine splitting capability results in
alkaline urine and the formation of struvite crystals, which have the easily identifiably “coffin-lid” appearance. Colonies
tend to be sticky when sampling from agar and are therefore difficult to remove.
Cystine crystals are hexagonal. Tyrosine crystals are needle like. Calcium oxalate crystals are square with a three
dimensional point and resemble envelopes. Urate crystals are small, clear, rounded circular objects often with
striations radiating from the center.

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the probability that the test will be negative among patients who do not have the disease

Back 85

Sp = TN / (TN + FP)
A large specificity means that a positive test can rule in the disease. David Sackett coined the acronym "SpPIn"

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Back 86

Front 87

A patient is admitted to the hospital and the clinician orders a nasal swab to screen for methicillin resistant
Staphylococcus aureus (MRSA). The swab is received in the microbiology laboratory and is plated onto a
CHROMagar MRSA plate. Based on the growth you see in the image, you perform a latex agglutination test, which
is positive. The BEST interpretation of this specimen is:
a. The growth indicates that the organism is a methicillin resistant Staphylococcus aureus
b. The growth, not the color, indicates that the organism is Staphylococcus aureus and that it is sensitive
to methicillin
c. The color of the organisms indicate that the organisms growing on the plate are methicillin resistant
Staphylococcus aureus
d. The color of the organisms indicate that the organisms growing on the plate are methicillin sensitive
Staphylococcus aureus
e. The color of the organism growing on the plate is suggestive of growth of a red pigmented Serratia
species

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Answer: C. CHROMagar MRSA is a qualitative method to detect nasal colonization by methicillin resistant S. aureus.
This test is only a screening test that is performed on anterior nares swab specimens. CHROMagar is a selective and
differential medium that incorporates cefoxitin and specific chromogenic substances to detect MRSA. Growth alone
does not confirm that the organism is methicillin resistant S. aureus. The mauve-colored colonies confirm methicillin
resistant S. aureus. If the organisms are not pink, the growth is not methicillin resistant S. aureus. Organisms other
than MRSA can grow and produce a blue or green color, white or no color at all. Coagulase positivity can then be
confirmed. Serratia should not grow on this selective media.

Front 88

You identify a Klebsiella pneumoniae on a plate from a respiratory specimen. To test the sensitivities for the
organism you use an automated minimum inhibitory concentration (MIC) device. The sensitivity results are ready
the next morning and you review the report before sending out the final results. The report shows that the
organism is sensitive to all antibiotics. What is your MOST APPROPRIATE next step?
a. Finalize the report with the given sensitivities and send the report to the clinician
b. Leave the sample on the automated MIC device for another 24 hours to give the machine more time to
evaluate the sensitivities
c. Finalize the report, stating that the organism is resistant to Ampicillin, despite the MIC results, since
you know that all Klebsiella are intrinsically resistant
d. Replate, incubate and repeat you initial tests that were used to identify the organism as Klebsiella
pneumonia
e. Repeat sensitivities with an alternate method, such as Kirby Bauer disc diffusion

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E. Ampicillin is a β-lactam antibiotic, for which Klebsiella species are intrinsically resistant. Klebsiella
organisms are typically sensitive to all other antibiotics. This result is most likely inaccurate, and should not be reported
without rechecking the results. Leaving the specimen on the automated MIC device is not effective and will not yield
correct results. The best approach for an automated MIC result of a Klebsiella organism that does not show resistance
to Ampicillin is to manually check the sensitivity, by a method such as Kirby Bauer disc diffusion. Some labs will also
repeat the sensitivities on the automated MIC device.

Front 89

All of the following are required to activate Factor X in vivo, except:
Ca++
ATP
platelet surface
Factor VIIIa
Factor IXa

Back 89

B. ATP.
The activation of Factor X is central coagulation because active Factor X is responsible for activating thrombin with Factor V as a cofactor. The platelets are involved with coagulation through increased phosphatidyl inositol on their surfaces, thus facilitating factor interaction.

Front 90

How does tissue factor pathway inhibitor inhibit coagulation?
inhibition of tissue factor-Factor VIIa-Factor Xa complex
conversion of thrombin to prothrombin
uncoupling Factor XII-dependent crosslinking of fibrin
binding and hiding tissue factor on the endothelial surface
consumption of activating ATP

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A. INHIBITION OF TISSUE FACTOR-FACTOR VIIA-FACTOR XA COMPLEX.
TFP1, also know as lipoprotein-associated coagulation inhibitor, anticonvertin, or extrinsic pathway inhibitor, depending who you ask, functions predominantly by inhibiting the critical first step of coagulation, the formation of the tissue factor-Factor VIIa-Factor Xa complex.

Front 91

S. bovis

Back 91

associated with colon CA

Front 92

60-80% of all vWD cases; quantitative defect
decreased levels of vWF are detected (10-45% of normal, i.e. 10-45 IU).

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Type 1 vWD

Front 93

20-30%; qualitative defect
normal levels of vWF, but the multimers are structurally abnormal, or subgroups of large or small multimers are absent.
Four subtypes exist: 2A, 2B, 2M and 2N.

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Type 2 vWD

Front 94

abnormality of the synthesis or proteolysis of the vWF
small multimer units in circulation.
Factor VIII binding is normal.
low ristocetin co-factor activity compared to the von Willebrand's antigen.

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Type 2A

Front 95

"gain of function" defect leading to spontaneous binding to platelets and subsequent rapid clearance of the platelets and the large vWF multimers. A mild thrombocytopenia may occur.
The large vWF multimers are absent in the circulation and the factor VIII binding is normal.
Like type 2A, the RiCof:vWF antigen assay is low when the patient's platelet-poor plasma is assayed against formalin-fixed, normal donor platelets.
However, when the assay is performed with the patient's own platelets ("platelet-rich plasma"), a lower-than-normal amount of ristocetin causes aggregation to occur.
This is due to the large vWF multimers remaining bound to the patient's platelets.
Patients with this sub-type are unable to use desmopressin as a treatment for bleeding, because it can lead to unwanted platelet aggregation.

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Type 2B

Front 96

This is caused by decreased or absent binding to GPIb on the platelets. Factor VIII binding is normal.

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Type 2M

Front 97

deficiency of the binding of vWF to factor VIII.
normal vWF antigen level and normal functional test results but has a low factor VIII.
some 2N patients may have been misdiagnosed in the past as having hemophilia A, and should be suspected if the patient has the clinical findings of hemophilia A but a pedigree suggesting autosomal, rather than X-linked, inheritance.

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Type 2N (Normandy)