As soon as they are notified that you have filed. It takes the Court about two weeks to notify the creditors after you have filed. Creditors will also stop calling if you inform them that you filed the bankruptcy petition, and supply them with the docket number. After the bankruptcy petition is filed, the court mails a notice to all the creditors. Usually, your attorney deals with all creditors.
Bankruptcy petitions are public records.
However, it is not the practice of newspapers in this area to run stories of who filed bankruptcy. Under normal circumstances, only your creditors know that your have filed. 525 prohibits employers from discriminating against you because you filed a bankruptcy petition or because you failed to pay a dischargeable debt. Under some circumstances you may be able to keep some credit cards if the creditor agrees. Generally I recommend against this.