32-year-old Woman with Severe Pelvic Pain

Presented by:

Dr. Michael T. Kelly, MDS Metro

Clinical Case:

A 32 year old woman was seen in a family medicine clinic with a 24h history of severe pelvic pain described by the patient as "worse than having a baby." She also complained of right lower quadrant pain, low back pain, and constant lower abdominal cramping. Physical examination revealed a "toxic appearing" patient with fever and normal blood pressure. Upon pelvic examination, a purulent cervical discharge was noted. An intrauterine device that had been in place for one year was removed. The purulent cervical discharge was sent to the laboratory for gram stain and culture. The gram stain showed abundant PMNs and gram negative bacilli. Cultures yielded heavy growth of an oxidase positive, fermentative, gram negative bacillus.

Questions:

• What type of infection does this patient have?
• Based on the characteristics described, what group of organisms is most likely involved in this infection?
• What are the key biochemical reactions for identification of this isolate?

Discussion:

The clinical diagnosis in this patient was endometritis, an infection of the lining of the uterus. Most cases of endometritis occur after delivery and are referred to as postpartum endometritis. The etiology of postpartum endometritis is thought to be ascending infection involving vulvovaginal flora. Cultures of endometrial specimens, collected at surgery or using protected swabs that avoid the normal vaginal flora, often yield mixed organisms, including anaerobic bacteria, in cases of endometritis. Severe, life-threatening endometritis (puerperal sepsis) is caused by group A streptococcal infection. These infections have historical significance because they led to the discoveries of Semmelweiss and others that laid the ground work for modern infection control techniques. Today, group A strep puerperal sepsis still occurs, and when cases are found, investigation of health care workers who may be carriers of the organism is indicated. Group B streptococci can also cause significant postpartum endometritis. Chlamydia trachomatis is another cause of postpartum endometritis, but these infections are usually less severe than those described above. Endometrial infections that do not follow delivery or surgery are relatively rare. Accordingly, this case represents an unusual infection.

The characteristics of the organism isolated from this patient suggest that it is a member of the Vibrionaceae. Positive oxidase, negative gram reaction and fermentation of glucose are the basic characteristics of members of this group. Members of the Vibrionaceae may or may not exhibit curved morphology, and the curved morphology is more often seen in initial gram stains of clinical material rather than gram stains of cultures. Vibrios may also show pleomorphic gram stain morphology. Critical biochemical tests for speciation of the organism include salt requirement, decarboxylase reactions, and carbohydrate fermentation pattern. The organism was identified as Vibrio vulnificus. It did not grow in nutrient broth without supplemental salt (halophilic or salt requiring). The key biochemical characteristics of the organism were: positive lysine and ornithine; negative arginine, and fermentation of cellobiose and salicin but not arabinose or sucrose.

The isolation of Vibrio vulnificus from this patient was unexpected, and additional information was solicited from the patient in order to ascertain the possible source of the infection. The patient indicated that she had been swimming in the Gulf of Mexico and engaged in sexual intercourse while in the water the day before onset of her symptoms. The presence of an intrauterine device may also have increased the susceptibility of this patient to infection with a marine vibrio. Vibrio vulnificus is commonly found in the waters of the Gulf of Mexico and other warm seawater environments, and it is a naturally occurring marine microorganism that occasionally infects humans. Therefore, it appears that this patient acquired her infection from exposure to the organism in seawater. Most V. vulnificus infections present as primary septicemia that occurs after consumption of raw shellfish, especially oysters harvested from waters where the organism is endemic. Other manifestations include seawater-associated wound infections. V. vulnificus is a highly virulent organism, and infections caused by the organism have up to a 50% mortality rate, especially in patients with certain underlying diseases such as cirrhosis, hemochromatosis or thalasemia. The treatment of choice is doxycycline plus ceftazidime; this patient was treated with tetracycline, and recovered within a few days.

References:

• Tison DL and Kelly MT. 1983. Vibrio vulnificus endometritis. J Clin Microbiol 20: 185-186.
• Tison DL. 1999. Vibrio. In Manual of Clinical Microbiology, 7th Edition, p. 501-502.
• Mead PB. 2000. Infections of the female pelvis. In Principles and Practice of Infectious Diseases, 5th Edition, p. 1236-1237.