Do i really need to iron every clothing my baby has to wear to kill microorganisms in it?

No: Not really. A normal good washing should be sufficient unless there is an unusaul problem.Remember that not all microorganisms are bad.

I agree: Healthy babies adapt to bacteria in the home pretty well. As new organisms colonize their intestines, their stools change color. Ask your dentist if you have bacteria in your mouth that can make your infant's erupting teeth prone to cavities (e.g., if you lick pacifiers). Family & visitors should wash their hands or use alcohol-based cleansers before handling baby. But ironing? No need.