Display Last Tweet function – search results

I haven’t been able to find an answer to this question and thought I may get some good answers here….

I have this solution in place for displaying my latest tweets, but my Twitter ID is not being found. I have tried using other Twitter user names and it works – why wouldn’t I be showing up in the search results?

This code is in my functions.php file:

function displayLatestTweet($twitterID){
     include_once(ABSPATH.WPINC.'/rss.php');
     $latest_tweet = fetch_rss("https://search.twitter.com/search.atom?q=from:" . $twitterID . "&rpp=1");
     echo $latest_tweet->items[0]['atom_content'];
}

And this in my template file:
<p><?php displayLatestTweet('twitter_name'); ?></p>

Thanks