Paul Wilson admitted two counts of oral rape of a girl aged two or three years old.
He also pleaded guilty to a further 45 charges of making and distributing indecent images and inciting youngsters to engage in sexual activity on the internet.
The 20-year-old, of Newbold Croft, Nechells, Birmingham, was charged with rape in January after his arrest on suspicion of child abuse prompted an investigation into his employment at the nearby Little Stars Nursery.
During an earlier hearing at Birmingham Magistrates' Court on April 7, a district judge was told the grooming charges related to a total of 22 girls aged between 12 and 15.
Marni Chimba, prosecuting, told the lower court Wilson used multiple identities to befriend the girls on chatlogs and social networking sites, even pretending sometimes to be a previous victim.
The prosecutor said: 'Some of the aliases were female names and he also pretended to be the complainants, encouraging others to send their movies to him.'
Miss Chimba said some of the victims were directed to expose themselves using webcams. Others were filmed and recorded performing and taking part in sexual acts.
Wilson also distributed indecent images and threatened some of the children that he would show images he had already captured to their friends or parents.
One victim said she felt shocked, violated and ashamed.
The girl, who cannot be named, also disclosed her 'pure hatred' for Wilson who, after pressuring her into exposing herself via a webcam, threatened to distribute the images if she refused to follow his orders.
Her mother warned other parents to monitor their children's internet use more closely, saying: 'You think they are on sites, safe, just talking to their friends, but there are outsiders who will latch on and pretend to be their friends and take them for what they want.'
Wilson was warned today by a judge at Birmingham Crown Court that he was facing an indeterminate jail sentence. Read More