diff --git a/lib/pg_ldap_sync/application.rb b/lib/pg_ldap_sync/application.rb
index c984730..f512e81 100644
--- a/lib/pg_ldap_sync/application.rb
+++ b/lib/pg_ldap_sync/application.rb
@@ -149,7 +149,7 @@ class Application
     groups = []
     res = pg_exec "SELECT rolname, oid FROM pg_roles WHERE #{pg_groups_conf[:filter]}"
     res.each do |tuple|
-      res2 = pg_exec "SELECT pr.rolname FROM pg_auth_members pam JOIN pg_roles pr ON pr.oid=pam.member WHERE pam.roleid=#{PG.escape(tuple[1])}"
+      res2 = pg_exec "SELECT pr.rolname FROM pg_auth_members pam JOIN pg_roles pr ON pr.oid=pam.member WHERE pam.roleid=#{@pgconn.escape_string(tuple[1])}"
       member_names = res2.map{|row| row[0] }
       group = PgRole.new tuple[0], member_names
       log.info{ "found pg-group: #{group.name.inspect} with members: #{member_names.inspect}"}