diff --git a/sphinx/directives.py b/sphinx/directives.py
index 16680c6bd..3d17d0a10 100644
--- a/sphinx/directives.py
+++ b/sphinx/directives.py
@@ -38,12 +38,16 @@ def index_directive(name, arguments, options, content, lineno,
     indexnode = addnodes.index()
     indexnode['entries'] = arguments
     for entry in arguments:
-        try:
-            type, string = entry.split(':', 1)
-            env.note_index_entry(type.strip(), string.strip(),
-                                 targetid, string.strip())
-        except ValueError:
-            continue
+        entry = entry.strip()
+        for type in entrytypes:
+            if entry.startswith(type+':'):
+                value = entry[len(type)+1:].strip()
+                env.note_index_entry(type, value, targetid, value)
+                break
+        # shorthand notation for single entries
+        else:
+            for value in entry.split(','):
+                env.note_index_entry('single', value.strip(), targetid, value.strip())
     return [indexnode, targetnode]
 
 index_directive.arguments = (1, 0, 1)