Erythema Nodosum and Bilateral Breast Abscesses Due to Salmonella enterica Serotype Poona

CASE REPORT

In September 2009, a 23-year-old, married, nonlactating Ethiopian woman returning from a vacation in Ethiopia was admitted to Al-Amiri Hospital, Kuwait, with swelling of both legs of 3 days' duration. She had no history of systemic illnesses, immune disorders, or intake of immunosuppressant drugs. On examination, the swellings on the legs were symmetrical, tender, and erythematous, with warm nodules and raised plaques on the shins of both legs. Systemic examination was unremarkable. Her serum C-reactive protein (IMMAGE 800 immunochemistry system; Beckman, Brea, CA) was 48.1 mg/liter (reference, <1.0 mg/liter). An initial diagnosis of erythema nodosum was made, and no antibiotics were prescribed. On the eighth day of hospitalization, the patient developed painful swellings in both breasts, fever (38.2°C), and tachycardia (108 beats/min). An empirical treatment with intravenous clindamycin (600 mg every 8 h) was immediately initiated after blood was collected for culture. The left breast was swollen and tender, with a hard mass of around 7 cm by 4 cm located in the left lower quadrant. The right breast had a swelling of about 5 cm by 4 cm in size in the upper outer quadrant. The nipples of breasts were not retracted, and there was no discharge. There were palpable axillary lymph nodes of 1 to 2 cm on both sides. Blood examination (LH 750 analyzer; Coulter, Miami, FL) showed leukocytosis, with a white blood cell count of 17.8 × 10⁹ cells/liter (reference, 4 × 10⁹ to 11 × 10⁹/liter). The abscesses of both breasts were then drained surgically under general anesthesia. Pus specimens from both breasts were sent to the microbiology laboratory in a tightly capped, sterile universal container for investigations. Gram staining of both specimens showed numerous pus cells, but no microorganism was seen. Ziehl-Neelsen staining of smears and mycobacterial culture on Lowenstein-Jensen medium were negative for mycobacteria (5). Cultures of both specimens on MacConkey agar and blood agar (Oxoid, Basingstoke, United Kingdom) grew a Salmonella species, which was identified by an automated system (Vitek; bioMérieux, Marcy l'Etoile, France) and API 20E tests (bioMerieux, Marcy l'Etoile, France), while blood culture (Bactec blood culture system; BD Diagnostic Systems, Sparks, MD) was negative after 7 days of incubation. The organism was identified as Salmonella enterica serotype Poona (antigens 1,13,22:z: 1,6) according to the Kauffmann-White scheme by using commercial (Murex, Dartford, United Kingdom; Statens Serum Institut, Copenhagen, Denmark; and Denka Seiken, Tokyo, Japan) and in-house antisera. The organism was susceptible to ampicillin, ceftriaxone, chloramphenicol, trimethoprim-sulfamethoxazole, and ciprofloxacin by disk susceptibility testing (Oxoid). Clindamycin was discontinued and ciprofloxacin given (400 mg every 12 h) for 9 days. The stool and urine cultures done on the day when Salmonella was identified were negative for pathogens (1). The pus culture for anaerobic bacteria on blood agar did not yield any growth. The patient's blood was tested for hemoglobin electrophoresis by high-pressure liquid chromatography (10), and the values were normal (HbA, 98.8%; HbA2, 2.3%). She was also negative for human immunodeficiency virus, hepatitis B virus surface antigen, and hepatitis C virus by enzyme-linked immunosorbent assay (ELISA) (AxSYM; Abbott, Wiesbaden, Germany). Four weeks after admission, the patient was discharged and recovered fully.

The clinical presentations of nontyphoidal Salmonella infection are protean and include gastroenteritis (most common), bacteremia, septic arthritis, osteomyelitis, and endovascular infection (9). When associated with Salmonella infections, erythema nodosum is usually accompanied by intestinal Salmonella infections (6). Breast infection due to nontyphoidal Salmonella isolates is extremely rare (3). Breast abscess is commonly caused by Salmonella enterica serovar Typhi and Salmonella enterica serovar Paratyphi organisms (9). Thus, our case is novel in two respects: erythema nodosum occurred without a gastrointestinal illness, and breast abscesses were due to a rare serotype of nontyphoid Salmonella (serotype Poona). Risk factors for breast abscesses caused by salmonellae include extremes of age, immunosuppression, intravenous drug abuse, hemoglobinopathies, and previous trauma (4). This patient did not have any of these risk factors. This suggests that S. Poona may cause breast abscesses in immunocompetent individuals.

S. Poona has been isolated from many foods, animals, and water. Even though it is a rare human pathogen, it has recently caused several cantaloupe-associated outbreaks of salmonellosis in North America (2). A case of meningitis in a neonate in association with maternal mastitis due to S. Poona has also been reported recently (8).

S. Poona infection has been reported in food animals in Ethiopia (7). The patient gave a history of eating meat while in Ethiopia. It is likely that the breasts became infected during a transient bacteremic episode originating from the patient's bowel. To our knowledge, this is the first reported case of erythema nodosum that is associated with an extraintestinal nontyphoidal Salmonella infection. While complete serotyping of Salmonella is not possible in routine clinical laboratories, laboratories should undertake this task with the help of reference laboratories, as has been done in our case, to identify rare serotypes of Salmonella causing unusual disease manifestations.