Spyware.Agent is the generic detection for malware that gathers information about a person or organization the affected system belongs to.
Spyware.Zbot is the detection for a family of spyware that specializes in stealing confidential information from affected systems, especially banking details.
Spyware.Zbot is mostly spread via email with links that the victims would have to click, but they have also been seen as being spread by exploit kits.
Malwarebytes protects users from Spyware.Zbot by using real-time protection.
Malwarebytes can remove Spyware.Agent without further user interaction. However, it is recommended that users determine what information was stolen so they can mitigate further losses due to the security breach.