(F) CB Lec L1

https://docs.google.com/document/d/1k-nf4XeEDnAtgMWsb7x7ltOUt7Mw_YBOoUrEmk9qhmw/edit?usp=sharing

B

What enzyme is detected when sulfanilic acid and alpha-naphthylamine are added to broth, producing a red color?

• a. Cytochrome c oxidase

• b. Nitrate reductase

• c. Adenylate cyclase

• d. Beta-galactosidase

• e. Phenylalanine deaminase

D

Which of the following organisms is classified as a non-lactose fermenter, producing colorless colonies on MacConkey Agar?

• a. Escherichia

• b. Klebsiella

• c. Enterobacter

• d. Salmonella

• e. Vibrio cholerae

B

All members of the family Enterobacteriaceae are oxidase negative, with the sole exception of which organism?

• a. Escherichia coli

• b. Plesiomonas shigelloides

• c. Shigella dysenteriae

• d. Klebsiella pneumoniae

• e. Serratia marcescens

C

Which group of Enterobacteriaceae is characterized as being non-motile at body temperature?

• a. Escherichia, Klebsiella, and Enterobacter

• b. Salmonella, Shigella, and Proteus

• c. Shigella, Klebsiella, and Yersinia

• d. Proteus, Morganella, and Providencia

• e. Serratia and Citrobacter

A

Which severe upper urinary tract infection involves the kidneys and is differentiated from lower urinary tract cystitis?

• a. Pyelonephritis

• b. Epidemic diarrhea

• c. Septicemia

• d. Meningitis

• e. Hemolytic Uremic Syndrome

E

What specific test utilizes the inoculation of a bacterial strain into the conjunctiva of a guinea pig to prove invasive capabilities? (for Enteroinvasive E. coli)

• a. Oxidase Test

• b. Dienes Phenomenon

• c. Widal's test

• d. ONPG Test

• e. Sereny Test

D

Hemolytic Uremic Syndrome (HUS), characterized by acute renal failure, microangiopathic hemolytic anemia, and thrombocytopenia, is caused by which opportunistic pathogen?

• a. Enterotoxigenic E. coli (ETEC)

• b. Enteroinvasive E. coli (EIEC)

• c. Enteropathogenic E. coli (EPEC)

• d. Enterohemorrhagic E. coli (EHEC)

• e. Enteroadherent E. coli (EAEC)

C

Which highly pathogenic Escherichia coli strain is uniquely Sorbitol-MacConkey (SMAC) negative because it does not ferment sorbitol?

• a. Uropathogenic E. coli

• b. Enterotoxigenic E. coli

• c. Serotype O157:H7

• d. Diffusely Adherent E. coli

• e. Friedlander's bacilli

C

Which adherence pattern on HEp-2 cells is used for the detection of Enteroaggregative E. coli (EAEC)?

• a. Metallic green sheen

• b. Swarming motility

• c. Stacked-brick pattern

• d. Cauliflower appearance

• e. Bull's eye colonies

A

What bacterial enzymes destroy the beta-lactam ring of advanced penicillins and cephalosporins, conferring high-level resistance?

• a. Extended-Spectrum Beta-Lactamases (ESBLs)

• b. Cytochrome c oxidase

• c. Nitrate reductase

• d. Beta-galactosidase

• e. Phenylalanine Deaminase (PAD)

C

Which organism uniquely produces a distinct red pigment called prodigiosin?

• a. Klebsiella pneumoniae

• b. Enterobacter aerogenes

• c. Serratia marcescens

• d. Citrobacter freundii

• e. Proteus mirabilis

D

The ONPG principle tests the ability of an organism to produce beta-galactosidase and hydrolyze ONPG to form which yellow-colored compound? (positive for Serratia marcescens)

• a. Cadaverine

• b. Putrescine

• c. Citrulline

• d. o-nitrophenol

• e. Phenylpyruvic acid

E

The entire PPM group is positive for which specific test, distinguishing them from other Enterobacteriaceae?

• a. Oxidase Test

• b. Sereny Test

• c. Voges-Proskauer (VP)

• d. ONPG Test

• e. Phenylalanine Deaminase (PAD)

B

Which phenomenon occurs when two different strains of P. vulgaris are inoculated on the same plate, forming a visible line of demarcation?

• a. Sereny Test

• b. Dienes Phenomenon

• c. Swarming motility

• d. Oxidation-Fermentation

• e. Hemolytic Uremic Syndrome

D

In the carrier state, asymptomatic individuals harbor Salmonella organisms in which organ?

• a. Kidneys

• b. Lungs

• c. Lymph nodes

• d. Gallbladder

• e. Small intestine

B

What specialized medium yields metallic colonies surrounded by a black ring for the lab diagnosis of enteric fever? (Salmonella)

• a. MacConkey Agar (MAC)

• b. Bismuth Sulfite Agar

• c. Sheep Blood Agar (SBA)

• d. CIN agar

• e. Eosin Methylene Blue (EMB) Agar

D

Which toxin produced by S. dysenteriae deeply inhibits host cell protein production?

• a. Heat-Labile (LT) enterotoxin

• b. Heat-Stable (ST) enterotoxin

• c. Verotoxin I

• d. Shiga Toxin

• e. Prodigiosin

B

What organism is the causative agent of the bubonic and pneumonic plague?

• a. Shigella dysenteriae

• b. Yersinia pestis

• c. Yersinia enterocolitica

• d. Yersinia pseudotuberculosis

• e. Salmonella typhi

A

Which organism forms a distinctive "cauliflower" appearance on Sheep Blood Agar (SBA) at 48 hours and a "stalactite" pattern in broth cultures?

• a. Yersinia pestis

• b. Yersinia enterocolitica

• c. Yersinia pseudotuberculosis

• d. Proteus vulgaris

• e. Serratia marcescens

B

Which organism is known for forming distinct "bull's eye" colonies on CIN agar at 48 hours?

• a. Yersinia pestis

• b. Yersinia enterocolitica

• c. Yersinia pseudotuberculosis

• d. Salmonella typhimurium

• e. Shigella dysenteriae

A

Which heat-stable antigen is located on the outer membrane of the cell envelope and is responsible for endotoxic shock?

• a. O Antigen (Somatic)

• b. K Antigen (Envelope/Capsular)

• c. Vi antigen

• d. H Antigen (Flagellar)

• e. P fimbriae

C

Because the Vi antigen coats the bacteria, the specimen must be inactivated by boiling for 10 minutes to unmask which underlying antigen?

• a. K Antigen

• b. H Antigen

• c. O Antigen

• d. Fimbriae

• e. Pili

D

What systemic epidemiological classification scheme classifies Salmonella serotypes based on their specific O, Vi, and H antigenic formulas?

• a. Sereny Test

• b. Widal's test

• c. Dienes Phenomenon

• d. Kauffman-White Classification

• e. Oxidation-Fermentation (OF) Test

C

On Eosin Methylene Blue (EMB) Agar, E. coli typically presents with which distinctive appearance?

• a. Pink/Red Colonies

• b. Colorless Colonies

• c. Metallic green sheen

• d. Blue-green colonies with black centers

• e. Green/transparent colonies

E

On Hektoen Enteric Agar (HEA), which organism presents as blue-green colonies with black centers due to H2S production?

• a. Escherichia

• b. Klebsiella

• c. Yersinia

• d. Shigella

• e. Salmonella

C

On Xylose Lysine Deoxycholate (XLD) Agar, Shigella presents as what type of colonies?

• a. Yellow colonies

• b. Red colonies with black centers

• c. Red/transparent colonies

• d. Blue-green colonies

• e. Metallic green colonies

B

Which enrichment broth is used for the cultivation of GI pathogens by utilizing high amounts of bile salts to heavily inhibit Gram-positive organisms?

• a. Malonate broth

• b. Selenite & Gram-Negative Broth

• c. Simmon's Citrate Medium

• d. Hugh-Leifson basal medium

• e. MacConkey agar

A

The Methyl Red (MR) test detects mixed acid fermentation of glucose to pyruvate, where a positive result is indicated by what color?

• a. Red

• b. Yellow

• c. Deep magenta

• d. Green

• e. Dark blue/purple

C

In the Deaminase Test (PAD), the conversion of phenylalanine into phenylpyruvic acid yields a distinctive green color upon the addition of which reagent? (PPM group)

• a. Sulfanilic acid

• b. Alpha-naphthylamine

• c. Ferric chloride

• d. Kovac's reagent

• e. Ehrlich's reagent

E

In Amino Acid Utilization testing, lysine is broken down by lysine decarboxylase to form which compound?

• a. Putrescine

• b. Citrulline

• c. Phenylpyruvic acid

• d. Acetoin

• e. Cadaverine

MacConkey Agar (MAC)

What specific agar uses bile salts and crystal violet to selectively inhibit Gram-positive organisms and differentiates bacteria based on lactose fermentation?

Cytochrome c oxidase

What enzyme is responsible for oxidizing a reagent to produce a dark blue/purple color, an enzyme which Enterics uniquely lack?

Cystitis

Which specific lower urinary tract infection is characterized by inflammation of the bladder?

Traveler's diarrhea

What is the alternative term for the epidemic diarrhea known as "Montezuma's revenge" or "turista", caused by Enterotoxigenic E. coli?

Bundle-forming pilus

What virulence factor enables Enteropathogenic E. coli (EPEC) to facilitate attachment to the cells of the small bowel?

Hemolytic Uremic Syndrome (HUS)

What life-threatening condition is clinically defined by a triad of uremia, microangiopathic hemolytic anemia, and thrombocytopenia?

Serotype O157:H7

What highly pathogenic serotype of EHEC is uniquely Sorbitol-MacConkey (SMAC) negative?

Stacked-brick pattern

What distinct adherence pattern to HEp-2 cells characterizes Enteroaggregative E. coli (EAEC)?

Friedlander's bacilli

What is the alternative name for Klebsiella organisms, known for possessing a thick polysaccharide capsule?

Extended-Spectrum Beta-Lactamases (ESBLs)

What specific bacterial enzymes destroy the beta-lactam ring of advanced penicillins and cephalosporins to confer high-level antibiotic resistance? (Klebsiella)

Prodigiosin

What distinct red pigment is produced by Serratia marcescens?

Beta-galactosidase

The o-nitrophenyl-β-D-galactopyranoside (ONPG) principle tests the ability of an organism to produce which specific enzyme to hydrolyze ONPG? (Serratia)

Phenylalanine Deaminase (PAD)

What key biochemical test is universally positive in the PPM group, distinguishing them from other Enterobacteriaceae?

Swarming motility

What fast, wave-like growth spreading across the agar is characteristic of Proteus species?

Dienes Phenomenon

What visible line of demarcation forms when two different strains of P. vulgaris are inoculated on the same plate?

Widal's test

What serological test is used in reference laboratories for the diagnosis of enteric fever? (Salmonella)

A black ring

On Bismuth Sulfite Agar, Salmonella organisms present as metallic colonies surrounded by what specific feature?

Shiga Toxin

What specific toxin produced by S. dysenteriae deeply inhibits host cell protein production?

Yersinia pestis

Which organism is historically responsible for the European plague epidemics and transmitted to humans by flea bites?

Cauliflower appearance

Yersinia pestis forms a "stalactite" pattern in broth cultures and what type of appearance on Sheep Blood Agar (SBA) at 48 hours?

Bull's eye colonies

What distinct colonies are formed by Yersinia enterocolitica on CIN agar at 48 hours?

O Antigen (Somatic)

Which heat-stable antigen constitutes the lipopolysaccharide (LPS) layer and is responsible for endotoxic shock?

Vi antigen

Which Salmonella antigen is categorized as a heat-labile K antigen and must be boiled for 10 minutes to unmask the O antigen?

Kauffman-White Classification

What systemic epidemiological classification scheme groups Salmonella serotypes based on O, Vi, and H antigenic formulas?

Metallic green sheen

What distinctive color morphology does E. coli typically exhibit on Eosin Methylene Blue (EMB) Agar?

Cefsulodin-Irgasan-Novobiocin (CIN) agar

What specific agar acts as a Yersinia Selective Agar to inhibit other organisms?

Voges-Proskauer (VP)

What specific test pathway detects the butylene glycol pathway, resulting in acetoin production?

Putrescine

In amino acid utilization, ornithine is broken down by ornithine decarboxylase to form what compound?

Motility Indole Ornithine (MIO)

What single tube medium specifically tests for three parameters: motility, indole production, and ornithine decarboxylation?

Kovac's or Ehrlich's reagent

In testing for indole production, what reagent is added to the medium to form a positive red ring at the surface?

Shigella dysenteriae type 1

Which specific member of the Enterobacteriaceae family is the sole exception that tests negative for catalase?

P fimbriae

What virulence factor of Uropathogenic E. coli (UPEC) is highly associated with kidney infections by helping the bacteria attach to urinary tract tissues?

Heat-Stable (ST) enterotoxin

Which enterotoxin produced by Enterotoxigenic E. coli (ETEC) increases cGMP by stimulating guanylate cyclase?

White blood cells (WBC)

Unlike typical dysentery, what cellular component is significantly absent in the stool of a patient infected with Enterohemorrhagic E. coli (EHEC)?

Burnt chocolate

What distinct odor is characteristic of Proteus species?

Proteus

Which organism is the strongest and most rapid urease producer among the Enterobacteriaceae, creating a highly alkaline environment?

Bloody and mucoid

In the dysenteric stage of a Shigella infection, the stools are classically characterized as what?

Bipolar "safety pin" staining

What distinct microscopic staining appearance is exhibited by both Yersinia pestis and Yersinia enterocolitica?

18-22C

At what specific temperature range is Yersinia pseudotuberculosis uniquely motile?

H Antigen (Flagellar)

Which heat-labile antigen is found exclusively in motile members of the Enterobacteriaceae family?

Yellow/orange

On Hektoen Enteric Agar (HEA), E. coli ferments sugars and presents as what color colonies?

Xylose

What is the primary differential carbohydrate used in Xylose Lysine Deoxycholate (XLD) Agar?

Citrulline

In amino acid utilization testing, the breakdown of arginine by arginine dihydrolase first forms which compound?

Alcaligenes faecalis

Which specific organism is classified as an asaccharolytic non-oxidizer in the Oxidation-Fermentation (OF) Test?

Gas production

Unlike Triple Sugar Iron (TSI) agar, what specific reaction is uniquely not observed in Lysine Iron Agar (LIA) medium?

Escherichia coli

Indole (+); MR (+); VP (-); Citrate (-)

Klebsiella pneumoniae subsp. pneumoniae & Enterobacter spp.

Indole (-); MR (-); VP (+); Citrate (+)

Klebsiella pneumoniae subsp. oxytoca

Indole (+); MR (-); VP (+); Citrate (+)

Glucose

Triple Sugar Iron (TSI) agar, an acidic (yellow) butt specifically indicates the fermentation of what carbohydrate?

Heat-Labile (LT) enterotoxin

Which enterotoxin produced by Enterotoxigenic E. coli (ETEC) increases cAMP by stimulating adenylate cyclase?

Aerobactin

What specific virulence factor allows Uropathogenic E. coli (UPEC) to chelate iron for bacterial survival?

Mucoid and stringy

Due to its thick polysaccharide capsule, how do Klebsiella colonies physically present when pulled with an inoculating loop?

Peritrichous flagella

What specific structural feature drives the characteristic swarming motility of Proteus vulgaris?

Sodium deoxycholate

What chemical compound acts as the selective inhibitor in Xylose Lysine Deoxycholate (XLD) Agar?

H2S gas (sulfide)

The SIM agar deep specifically tests for indole formation, motility, and the production of what?