compress reference.bib by leaving only one author on the list

Shrink reference.bib

import os, sys
import re

in_fd = open('reference.bib', 'r')
out_fd = open('test.bib', 'a')

p = '\{(.*)\}'

for line in in_fd.readlines():
  if line.find('author') > -1 or line.find('AUTHOR') > -1:
    nl = "\tauthor = {"+ re.search(p, line).group(1).split(" and ")[0]+"{\,}et.al},\n"
    out_fd.write(nl)
  else:
    out_fd.write(line)