This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
Most common causative agent for meningitis after spinal subarachnoid block is 
Select and explain. 
A. Staphylococcus epidermidis, B. Staphylococcus aureus, C. Pseudomonas, D. Streptococcus
A: Staphylococcus epidermidis
Answer: A: Staphylococcus epidermidis 
Explanation: Infective meningitis is mainly due to Staphylococcus epidermidis carried along with needle from skin. Spinal epidural abscess (SEA) in children is a rare infectious emergency warranting prompt intervention. Predisposing factors include immunosuppression, spinal procedures, and local site infections such as veebral osteomyelitis and paraspinal abscess. Staphylococcus aureus is the most common isolate. Iatrogenic meningitis is a rare, but potentially fatal condition. We repo four cases of meningitis after spinal anesthesia and review the possible etiological factors of post spinal meningitis Ref Robbins 9/e pg 345