The microbiologic diagnosis of endometritis is difficult. Anaerobes play an important role in this infection. However, most cases of endometritis follow childbirth, and it has been demonstrated that in the postpartum period, whether or not there is endometrial infection, significant numbers of anaerobes and other organisms from the cervical and vaginal flora may be found in the uterine cavity.
Although many organisms can cause infection of the placenta and upper genital tract, the most common organisms include S. aureus, beta-hemolytic streptococci, E. coli, Neisseria gonorrhoeae(GC) and Chlamydia trachomatis (CT). Listeria monocytogenes is associated with infections of the placenta.
Pontential specimens include: Endometrial Swabs, Biopsies and Curettings, Placenta Swab/Tissue, Products of Conception, Endometrial/Uterine, Cul de sac/Transvaginal, Fallopian Tube, Tubo-Ovarian Swabs or Aspirates.
Direct examination
Gram stain
Culture
| Media | Incubation |
| Blood Agar (BA) | CO2, 35°C x 48 hours |
| Chocolate Agar (CHOC) | CO2, 35°C x 48 hours |
| Vancomycin-Colistin-Nystatin Agar (VCN) | CO2, 35°C x 72 hours |
| MacConkey Agar (MAC) | O2, 35°C x 48 hours |
| Wilkins Chalgren Agar (WC) | AnO2, 35°C x 48 hours |
| WC Nalidixic acid – Tween 80 (NAT) | AnO2, 35°C x 48 hours |
| WC Nalidixic acid – Vancomycin (NAV) | AnO2, 35°C x 48 hours |
| Thioglycolate broth (THIO) | O2, 35°C x 7 days |
- If tissue/aspirate is received, add WC, NAT, NAV and THIO. For tissues and biopsies, freeze remaining tissue in the -70ºC freezer for minimum of 3 months.
- If Actinomyces is specifically requested set up 2 sets of anaerobic plates to allow 7 days undisturbed incubation for one set.
Work-up any organism(s) that is predominant (heavier than vaginal flora). All potential pathogens should be identified. In particular, examine for any growth of S. aureus, beta hemolytic streptococci, Listeria monocytogenes and N. gonorrhoeae.
Examine the WC, NAT and NAV plates after 48 hours incubation. Work-up up to 2 types of anaerobes.
If there is growth in THIO but no evident growth on plates inoculate CHOC (CO2 at 35°C x 48 hours) and WC (AnO2 at 35°C x 48 hours).
If Actinomyces is requested, keep plates for 7 days.
Gram stain
Report with quantitation the presence of the WBCs and organisms.
Culture
Negative Report
“No significant growth” or “No growth.”
“No Neisseria gonorrhoeae isolated.”
If VCN plate is overgrown by swarming Proteus or yeast, report ONLY as “Unable to rule out Neisseria gonorrhoeae due to bacterial/yeast overgrowth.”
Positive Report
Quantitate and report all significant isolates with appropriate susceptibility results.
“Neisseria gonorrhoeae” isolated (do not quantitate) “Report has been copied to Medical Officer of Health”.
Telephone all positive GC cultures to floor/ordering Physician.
For all positive GC cultures, send a Communicable Disease Report to the Medical Officer of Health and record in significant isolates log book.
Bailey & Scott’s Diagnostic Microbiology. Finegold & Baron: 7th Ed. C. V. Mosby Co., p. 59.