espressioni regolari: parole separate da virgola

[andr3a]

<?php
$test = "dfdf fds dfsdf,fdfd,fsdf";


echo preg_replace(
	"/(?i)([a-z]+\s{1}|[a-z]+|,[a-z]+)/e", 
	'"[".preg_replace("/\s|,/", "", "\\1")."]"', 
	$test
);

// risultato:
// [dfdf][fds][dfsdf][fdfd][fsdf]
?>