I already have US esl certification

[bushbruc]

Hi, I already teach ESL in the Maryland public schools and have ESL certification here. What would it take for me to get international TEFL certification? Can I just transfer it? Thanks. Bruce

[systematic]

There is no such thing as an international TESOL certificate - it's just a word the course providers use. However, if your current certificate is issued by a well known TESOL course provider, you should have no problem in getting it accepted worldwide.
Even better would be a certificate issued by a state authority. A state teacher licence would be excellent, but some countries may require a certified translation of it for visa and/or work permit applications.