Question 1

Which of the following criteria is NOT used in Bergey’s classification of bacteria?

Accepted Answer

Antibiotic resistance profile

Question 2

A patient presents with fever, headache, and a rash on the palms and soles after a tick bite. Which organism is most likely responsible, and what is the recommended treatment?

Accepted Answer

Rickettsia rickettsii; Doxycycline

Question 3

Which diagnostic method is most appropriate for confirming Chlamydia trachomatis infection?

Accepted Answer

DNA probes

Question 4

A patient with a history of sexual activity presents with urethritis. Which organism is most likely, and what is a common treatment?

Accepted Answer

Chlamydia trachomatis; Azithromycin

Question 5

Which bacterium is associated with peptic ulcers and is diagnosed using the urea breath test?

Accepted Answer

Helicobacter pylori

Question 6

A child presents with whooping cough. Which diagnostic method and prevention strategy are most appropriate?

Accepted Answer

Bordet-Gengou agar; DTaP vaccine

Question 7

Which Gram negative rod is a non-lactose fermenter, produces a blue-green pigment, and is an opportunistic pathogen?

Accepted Answer

Pseudomonas aeruginosa

Question 8

A patient develops hemolytic uremic syndrome after eating undercooked beef. Which strain of E. coli is most likely responsible?

Accepted Answer

EHEC O157:H7

Question 9

Which bacterium causes swarming growth on agar, is urease positive, and is associated with kidney stones?

Accepted Answer

Proteus mirabilis

Question 10

A patient presents with bloody diarrhea after fecal-oral transmission. Which organism is most likely responsible?

Accepted Answer

Shigella

Question 11

Which bacterium requires both X and V factors for growth and is prevented by the Hib vaccine?

Accepted Answer

Haemophilus influenzae

Question 12

A patient presents with meningitis. Which Gram negative diplococcus is most likely, and what is the recommended treatment?

Accepted Answer

Neisseria meningitidis; Penicillin

Question 13

Which bacterium is diagnosed using ELISA and Western blot, and is transmitted by deer ticks?

Accepted Answer

Borrelia burgdorferi

Question 14

A patient with a history of travel to an area with poor sanitation presents with rice-water stools and severe dehydration. Which organism is responsible, and what is the primary treatment?

Accepted Answer

Vibrio cholerae; Fluid and electrolyte replacement

Question 15

Which bacterium is grown on Thayer-Martin agar and is treated with cephalosporins?

Accepted Answer

Neisseria gonorrhoeae

Question 16

A patient presents with systemic infection after consuming contaminated food. Which organism is most likely responsible for typhoid fever?

Accepted Answer

Salmonella typhi

Question 17

Which bacterium is diagnosed using charcoal yeast extract agar and urine antigen, and is transmitted via water aerosols?

Accepted Answer

Legionella pneumophila

Question 18

A patient presents with bubonic plague after a flea bite. Which organism is responsible, and what is the recommended treatment?

Accepted Answer

Yersinia pestis; Tetracycline

Question 19

Which of the following equations best represents the calculation of bacterial doubling time ($t_d$) given the growth rate constant ($k$)?

Accepted Answer

$t_d = \frac{\ln 2}{k}$

Question 20

A patient presents with peptic ulcers. Which test would you use to confirm the diagnosis, and what property of the bacterium does it exploit?

Accepted Answer

Urea breath test; Urease positive

Gram Negative Bacteria: Classification, Pathogens, and Clinical Relevance

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