Reactive arthritis is defined as joint inflammation caused by a sterile inflammatory reaction following a recent infection. Of the following, the LEAST likely micro-organism that may cause reactive arthritis is

Correct Answer: A

Rationale: Clostridium difficile is less commonly associated with reactive arthritis.

Correct Answer: A

Rationale: HLA-B27 is strongly associated with ankylosing spondylitis, an inflammatory condition affecting the spine.

Correct Answer: A

Rationale: HLA-B27 is strongly associated with ankylosing spondylitis, an inflammatory condition affecting the spine.

Correct Answer: D

Rationale: Infectious rhinitis is the most common cause of nonallergic rhinitis in children.

Correct Answer: D

Rationale: Irritability is an early sign of hypoxia in infants, as oxygen deprivation initially affects neurological function before progressing to more severe signs like cyanosis.