Types of Agar

Question 1

Agar used for growing this organism: aerobic, non-spore forming, non-motile, comma/club shaped G (+) rods arranged in V or L shape; appears like chinese characters with metachromatic granules (Babes-Ernst granules)

Answer 1

Tellurite agar (C. diphtheriae)

Question 2

Agar used for growing this organism: G (+) cocci in chains, gamma-hemolytic, bile and optochin resistant, (+) PYR test, leading cause of Marantic endocarditis in patients with Colorectal malignancy

Answer 2

Bile-Esculin agar (Group D Streptococcus); Hydrolyzes esculin in Bile-Esculin agar

Question 3

Agar used for growing this organism: G (+) with the following virulence factors: PV Leukocidin, hyaluronidase, lipase, exfoliatin, heat-stable enterotoxin, TSST-1, alpha toxin

Answer 3

Mannitol salt agar (S. aureus)

Question 4

Agar used for growing this organism: G (-), oxidase (+), maltose and glucose fermenter with characteristic large polysaccharide capsule

Answer 4

Chocolate agar (N. meningitides from sterile sites)

Question 5

Agar used for growing this organism: G (-) cocco-bacillary rods exhibiting satellite phenomenon around S. aureus colonies; leading cause of Epiglottitis

Answer 5

Chocolate agar + Factors X, V (H. influenzae)

Question 6

Agar used for growing this organism: Non-bloody diarrhea associated with pseudomembranes on colonic mucosa, precipitated by use of antibiotics (Clindamycin, Cephalosporins, Ampicillin) that suppress normal colonic flora

Answer 6

Egg-Yolk agar (C. difficile)

Question 7

Agar used for growing this organism: G (-) organism with insignificant capsule, prominent pili and lipooligosaccharide, implicated in sexually transmitted diseases

Answer 7

Thayer-Martin agar (N. gonorrhea from unsterile sites); oxidase positive and glucose fermenter

Question 8

Agar used for growing this organism: Aerobic bacteria with the ff. virulence factors: cord factor, sulfatides, tuberculin surface protein

Answer 8

Lowenstein-Jensen agar (M. tuberculosis)

Question 9

Agar used for growing this organism: Comma-shaped, motile, oxidase positive organism with high infectious dose, exhibits enterotoxin and mucinase and characteristic shooting-star motility

Answer 9

Thiosulfate Citrate Bile salts Sucrose agar (V. cholera)

Question 10

Agar used for growing this organism: small G (-) rods known for the ff: filamentous hemagglutinin (attachment), false adenylate cyclase (inhibits phagocytic activity), tracheal toxin (damages ciliated cells) and toxin-mediated ADP-ribosylation and lymphocytosis

Answer 10

Bordet-Gengou agar or Regan-Lowe charcoal medium (B. pertussis)

Question 11

Agar used for growing this organism: facultative intracellular bacteria, causing pneumonia accompanied by confusion, nonbloody diarrhea, hyponatremia, proteinuria and hematuria

Answer 11

Charcoal yeast extract agar (L. pneumophila)

Question 12

Agar used for growing this organism: comma shaped, microaerophilic organism, implicated as the most common cause of bacterial gastroenteritis

Answer 12

Skirrows agar (grows well on 42 deg celsius) or Campy medium with antibiotics (C. jejuni)

Question 13

Agar used for growing this organism: weakly staining G (-) spirochete, manifesting as erythema chronicum migrans (Stage 1), Bell’s palsy, myocarditis leading to AV block (Stage 2), autoimmune migratory polyarthritis, acrodermatitis chronica atrophicans

Answer 13

Barbour-Stoenner-Kelly medium (B. burgdorferi, largest medically significant bacteria)

Question 14

Agar used for growing this organism: smallest free-living organisms, known for absence of cell wall, presenting as “walking pneumonia” and implicated as the most common bacterial cause of Stevens-Johnson syndrome

Answer 14

Eaton’s medium (M. pneumoniae)

Question 15

Agar used for growing this organism: G (-) obligate aerobe, non-lactose fermenting, oxidase positive; most common implicated organism in high-risk, ventilator-acquired pneumonia

Answer 15

Cetrimide agar (P. aeruginosa)

Question 16

Agar used for growing this organism: G (-) rod, non-lactose fermenting, H2S producing; known for its Vi capsular antigen

Answer 16

Xylose-lysine-deoxycholate medium (Salmonella spp.)

Question 17

Agar used for growing this organism: G (-) non-lactose fermenting, non H2S producing, non-motile; known to cause the most common and most severe type of bacillary dysentery

Answer 17

Xylose-lysine-deoxycholate (Shigella spp.);
Shigella sonei-Duval’s bacillus (MCC of bacillary dysentery);
Shigella dysenteriae type 1 - Shiga bacillus (most severe form of bacillary dysentery)

Question 18

Agar used for growing this organism: G (-) thin, coiled, obligate aerobe; hooked at one or both pointed ends; multiplies rapidly and primarily affects endothelium of small blood vessels (vasculitis)

Answer 18

Ellinghausen-McCullough-Johnson-Harris medium or Fletcher’s medium (L. interrogans)

Question 19

Organism grown in this agar: Lowenstein-Jensen medium

Answer 19

Mycobacterium tuberculosis

Question 20

Organism grown in this agar: Chocolate agar + Factors X and V

Answer 20

Hemophilus influenzae

Question 21

Organism grown in this agar: Skirrow’s agar

Answer 21

Campylobacter jejuni/Helicobacter pylori

Question 22

Organism grown in this agar: Eaton medium

Answer 22

Mycoplasma pneumoniae

Question 23

Organism grown in this agar: Bile esculin agar

Answer 23

Group D Streptococcus

Question 24

Organism grown in this agar: Tellurite agar

Answer 24

Corynebacterium diphtheriae