Introductory address: microbial etiology of pelvic inflammatory disease.

The etiology of acute pelvic inflammatory disease is multifactorial, and the pattern of organisms most frequently causing the condition fluctuates. For example, tuberculous salpingitis has gradually become a rarity in many areas, and cases of nongonococcal salpingitis have started to outnumber those of gonococcal salpingitis. Chlamydia trachomatis now causes more cases than Neisseria gonorrhoeae in many regions. Mycoplasma hominis is another (often overlooked) etiologic agent infection in the upper genital tract of women. Pelvic inflammatory disease due to anaerobic microorganisms seems to occur more frequently in some areas (i.e., the United States) than in others (i.e., Europe).