What Causes Yellowish White Vaginal Discharge?

female 23 years old,gave birth via c.section a month ago,2 weeks ago had her c.section with pus.7 days prior to gram stain noted vaginal discharge with yellowish-whitish discharge.no itchy feeling or pain.with previous medications:cefuroxime 500mg tablet twice a day,clindamycin 300mg capsule every 8 hours,ciprofloxacin 500mg tablet every 8 hours.her ob-gyne has no say about this.she also had pap smear yestersay june 13,2011