Vol

DEPARTMENT OF PATHOLOGY
The Johns Hopkins Medical Institutions

Vol. 18, No. 1
THE JOHNS HOPKINS MICROBIOLOGY NEWSLETTER
Monday, January 4, 1999

Provided by Leslie Edwards Reger, Division of Outbreak Investigation, Maryland Department of Health and Mental Hygiene.

Oubreaks reported to DHMH Monday, 12/28/98 - Friday, 1/1/99:
8 outbreaks reported:
1 foodborne gastroenteritis in a food-service facility
6 gastroenteritis (all presumed viral) in nursing homes
1 influenza-like illness reported in a nursing home

The Johns Hopkins Hospital. Information provided by Dr. Ann Smith, Department of Pathology.

Case Report: A previously healthy four-month-old African American female was evaluated at an outside hospital during the first days of December because of vomiting and diarrhea for one week. The patient was given intravenous fluids and discharged to home. Despite this therapy, she continued to have diarrhea and fever. She was brought to The Johns Hopkins Hospital, evaluated, and admitted for observation. At that time, mucous and flecks of blood were noted in her stool. The infant’s mother stated that she was the primary caregiver for several foster children in addition to the infant and that she had been feeding the patient homemade baby foods and cereals. Physical exam revealed an irritable baby with a temperature of 39^oC. No other abnormal or focal findings were noted. The patient’s white blood cell count was 22,700 with 11% bands and 43% polymorphonuclear cells. Stool and blood cultures were sent to the microbiology lab and the patient was given an intramuscular dose of Ceftriaxone.

Laboratory Diagnosis and Clinical Course: Stool cultures revealed normal fecal flora. Blood cultures, however, were positive for Yersinia enterocolitica which was sensitive to Piperacillin, Cefuroxime, and Gentamicin. The patient became afebrile and was eating well after her first dose of Ceftriaxone. She was continued on antibiotics and within a week she was discharged home. The patient’s mother was educated about foodborne diseases and how to prevent food contamination.

Epidemiology: Yersinia enterocolitica is a relatively rare cause of foodborne disease in the United States. However, among invasive bacterial pathogens such as Salmonella, Shigella, and Campylobacter, it is no longer an uncommon cause of inflammatory diarrheal syndromes. Lee et al found that during January 1990, Yersinia was isolated from stool specimens from patients with gastroenteritis in Baltimore as often as Campylobacter and more often than Shigella. Y. enterocolitica has large natural reservoirs in pigs and cows and most foodborne cases have been linked to meat and dairy products. Because the pathogen can multiply at temperatures as low as 4^oC, the consumption of raw meat, even if properly refrigerated, can cause infection. In Lee’s study, the patients’ diarrheal illnesses were clustered around the Thanksgiving, Christmas, and New Year’s holidays. Furthermore, patients gave a history of exposure to raw pork intestines (chitterlings). Few of the patients, however, had direct contact with raw chitterlings which emphasizes the importance of indirect transmission of Yersinia to infants by caretakers who handle contaminated foods.

Clinical Manifestations: Yersinia enterocolitis is characterized by fever, diarrhea, and abdominal pain of one to three weeks duration. In patients less than five years of age, blood or mucus may be present in the stool. Older children and adults can present with terminal ileitis and leukocytosis which can be clinically indistinguishable from acute appendicitis. Yersinia enterocolitica septicemia is less common and is most often reported in patients with an additional underlying illness, the very young, or the elderly. Patients with iron overload, such as those with hemochromatosis or who receive frequent transfusions, are also at risk for septicemia. Patients with sepsis are at increased risk for developing splenic or hepatic abscesses, wound infections, or meningitis. Approximately 30% of adults with Yersinia gastroenteritis can develop reactive polyarthritis and/or erythema nodosum which typically begins a few days to a month after the acute diarrheal illness. Sacroiliitis and Reiter syndrome have also been reported as complications and develop more frequently in individuals with the HLA-B27 haplotype.

Diagnosis and Treatment: Y. enterocolitica is a gram-negative, non-lactose-fermenting, urease-positive bacillus. It grows on blood and MacConkey agars at room temperature and at 37^oC and in buffered saline at 4^oC. Colonies appear very small after 24 hours of incubation and are readily apparent at 48 hours. Isolation of the pathogen from stool cultures is difficult because of the slow growth of the organism and the overgrowth of normal fecal flora. The yield can be increased by using selective CIN agar. Although many labs do not consider this cost effective for routine diagnostic cultures, the microbiology lab at JHU routinely cultures all stool specimens for Y. enterocolitica. More than fifty serotypes of the organism have been identified with serotypes O3, O8, and O9 most frequently isolated from clinical specimens. Because Yersinia enterocolitis is usually a self-limited illness, antibiotic therapy is generally not warranted. However, because the morality of septicemia approaches 50%, antibiotic therapy with aminoglycosides, piperacillin, tetracycline, or third-generation cephalosporins is recommended.

References:

Bishai WR, Sears CL. Food poisoning syndromes. Gastroenterology Clinics of North America. 22(3): 579-608, 1993 September.
Lee LA, Taylor J, Carter GP et al. Yersinia enterocolitica O:3: An emerging cause of pediatric gastroenteritis in the United States. Journal of Infectious Diseases. 163: 660-663, 1991.