Which antibiotic is considered safe for use in neonates?

Ampicillin is the correct answer as it is a commonly used antibiotic in neonates due to its safety profile and effectiveness against a range of infections. It is a penicillin antibiotic that is well-tolerated in newborns and can treat various bacterial infections, including those caused by susceptible strains of Streptococcus and E. coli, which are particularly relevant in the neonatal population.

In contrast, the other antibiotics listed are associated with potential risks in neonates. Chloramphenicol can cause "Gray Baby Syndrome," a serious condition due to the immature liver function in neonates, leading to the accumulation of the drug. Sulfamethoxazole/trimethoprim is not recommended for neonates due to the risk of kernicterus, which is a type of brain damage resulting from excessive bilirubin. Tetracycline is contraindicated in all pediatric populations, including neonates, because it can cause permanent discoloration of teeth and affect bone growth due to its ability to chelate calcium. Thus, ampicillin stands out as the safe and effective choice for treating infections in newborns.