Which organism is a Gram-positive bacillus with boxcar shape and positive for reverse CAMP test?

Prepare for the CAMLPR Microbiology Test. Utilize flashcards and engaging multiple-choice questions, each equipped with descriptions and explanations. Ready yourself for an excellent performance!

Multiple Choice

Which organism is a Gram-positive bacillus with boxcar shape and positive for reverse CAMP test?

A Gram-positive bacillus with a boxcar shape that is positive for the reverse CAMP test points to Listeria monocytogenes. The short, straight rods with blunt ends can appear boxcar-like under the microscope, and the reverse CAMP reaction is a distinctive diagnostic clue for Listeria, setting it apart from other Gram-positive rods. In the CAMP test, while the classic CAMP effect occurs with Streptococcus agalactiae and Staphylococcus aureus, Listeria shows a reversed pattern, helping to confirm its identity. This combination of morphology and the reverse CAMP result is not seen with Clostridium perfringens (an anaerobic, spore-forming rod) or with the other listed organisms, so the described features best fit Listeria monocytogenes.

A Gram-positive bacillus with a boxcar shape that is positive for the reverse CAMP test points to Listeria monocytogenes. The short, straight rods with blunt ends can appear boxcar-like under the microscope, and the reverse CAMP reaction is a distinctive diagnostic clue for Listeria, setting it apart from other Gram-positive rods. In the CAMP test, while the classic CAMP effect occurs with Streptococcus agalactiae and Staphylococcus aureus, Listeria shows a reversed pattern, helping to confirm its identity. This combination of morphology and the reverse CAMP result is not seen with Clostridium perfringens (an anaerobic, spore-forming rod) or with the other listed organisms, so the described features best fit Listeria monocytogenes.

More practice questions