What is the most appropriate action for an infant with a fever and decreased urine output, accompanied by prolonged membrane rupture at birth?

In the scenario described, where an infant presents with fever, decreased urine output, and a history of prolonged rupture of membranes at birth, the most appropriate action is to send samples for culture and begin parenteral antibiotic treatment.

This is critical because the combination of fever and prolonged rupture of membranes raises concerns for possible early-onset sepsis, which is a life-threatening condition in neonates. The risk of infection is particularly high in infants who have been exposed to prolonged rupture of membranes, as the protective barrier provided by the amniotic sac is compromised, potentially allowing pathogens to enter the infant's system.

Sending samples for culture is essential to identify the causative organism and guide appropriate antibiotic therapy. Starting parenteral antibiotics immediately is crucial in this case to manage any potential infection promptly, as delays in treatment in a febrile infant can lead to rapid deterioration and increased morbidity and mortality.

The other options—initiating oral hydration, performing immediate surgery, or scheduling an outpatient follow-up—would not address the urgent need for identification and treatment of a possible serious infection in this vulnerable population. Oral hydration is insufficient in a scenario potentially involving sepsis, immediate surgery is not indicated without evidence of an abdominal condition, and outpatient follow-up would delay necessary