microbiology

Last reviewed 07/2021

Chlamydia trachomatis and Neisseria gonorrhoea account for the majority of cases.

• in UK, chlamydia trachomatis is the most important cause of PID, being responsible for at least 50% of identified cases
• Neisseria gonorrhoea and chlamydia trachomatis co-infection can occur

Less commonly, PID may result from:

• Mycoplasma hominis
• Mycoplasma genitalium
• anaerobes such as Bacteroides
• G. vaginalis
• Haemophilus influenzae
• Cytomegalovirus
• U. urealyticum (2)
• Actinomyces israelii - especially with long term IUCD; may cause unilateral infection
• Herpes simplex virus type II - very rarely

No microbiological cause can be found in 20%.

Routes of infection include:

• ascending from the vagina - endogenous infection, for example, Bacteroides; or sexually transmitted infection, especially Chlamydia and Neiserria

• direct inoculation - for example, during dilatation and curettage, termination of pregnancy, insertion of a intrauterine contraceptive device

• transperitoneal - for example, following appendicitis or diverticulitis

• haematogenous - classically tuberculosis, usually at the time of puberty, but theoretically, any bacteraemia may produce pelvic foci of infection

Reference:

• (1) Prescribers' Journal (1998), 38(2), 65-72
• (2) Center for disease control 2006. Morbidity and mortalty weekly report - Sexually Transmitted Diseases Treatment Guidelines