microbiology an introduction 13th edition test bank

Correct Answer: C

Rationale: Neonatal meningitis is commonly caused by E. coli K1 and group B streptococci due to their ability to cross the blood-brain barrier in newborns. E. coli K1 is a frequent cause in early-onset cases, while group B streptococci are common in late-onset cases. Neisseria meningitidis and streptococcus agalactiae are not as likely to cause neonatal meningitis. Listeria and shigella are also uncommon causes in neonates. Therefore, choice C is the most likely pair of organisms responsible for neonatal meningitis.

Correct Answer: C

Rationale: The correct answer is C: mesophiles. Mesophiles are microorganisms that thrive in moderate temperatures, typically between 25�C and 40�C. This temperature range is ideal for their growth and reproduction. Thermophiles (A) prefer high temperatures, psychrophiles (B) thrive in cold temperatures, and psychrotrophs (D) can grow at refrigeration temperatures but have an optimal range above 20�C. Therefore, the mesophiles are the best fit for organisms that show optimal growth in moderate temperatures.

Correct Answer: C

Rationale: The correct answer is C: leg swelling. Endocarditis is an infection of the inner lining of the heart chambers and valves. Symptoms typically include fever, chills, weight loss, and muscle aches due to the body's immune response to the infection. Leg swelling is not a common symptom of endocarditis. It may occur in conditions like heart failure but is not directly associated with endocarditis. Therefore, choice C is the correct answer. Choices A, B, and D are incorrect because fever and chills, weight loss, and muscle aches are commonly seen in endocarditis due to the systemic inflammatory response to the infection.

Correct Answer: A

Rationale: The correct answer is A: The pyocyanin released by Pseudomonas aeruginosa. Pyocyanin is a blue-green pigment produced by Pseudomonas aeruginosa, a common cause of nosocomial infections in burn patients. The presence of blue-green pus and gram-negative rods in the wound along with fever suggests an infection with Pseudomonas aeruginosa. The other choices are incorrect because E. Coli typically causes gastrointestinal infections and releases enterotoxins, Staphylococcus aureus releases hemolysins causing hemolysis of red blood cells, and Shigella dysenteriae releases shigatoxin causing bloody diarrhea, none of which match the clinical presentation described in the question.

Correct Answer: A

Rationale: The correct answer is A: Pseudomonas aeruginosa. This is because Pseudomonas is a Gram-negative rod, oxidase-positive, and a lactose non-fermenter. The presence of fever and chills suggests a systemic infection, which is common with Pseudomonas. Salmonella typhi, Shigella dysenteriae, and Escherimalia coli are all Gram-negative rods but are typically lactose fermenters and do not match the characteristics described in the question.