According to the Centers for Disease Control and Prevention, a foodborne disease occurs in one in six persons (48 million), resulting in 128,000 hospitalizations and 3,000 deaths annually in the United States. The Foodborne Active Surveillance Network () of the CDC’s Emerging Infections Program monitors cases of eight laboratory diagnosed infections from 10 U.S. sites (covering 15% of the U.S. population). Monitored organisms include Campylobacter, Cyclospora, Listeria, Salmonella, Shiga toxin–producing Escherichia coli (STEC), Shigella, Vibrio, and Yersinia. In 2018, FoodNet identified 25,606 cases of infection, 5,893 hospitalizations, and 120 deaths. The incidence of infection (cases/100,000) was highest for Campylobacter (20), Salmonella (18), STEC (6), Shigella (5), Vibrio (1), Yersinia (0.9), Cyclospora (0.7), and Listeria (0.3). How might these pathogens affect your patients? First, a quick review about the four more common infections. Treatment is beyond the scope of our discussion and you are referred to the for assistance. The goal of this column is to prevent your patients from becoming a statistic this holiday season.
It has been the most common infection reported in FoodNet since 2013. Clinically, patients present with fever, abdominal pain, and nonbloody diarrhea. However, bloody diarrhea maybe the only symptom in neonates and young infants. Abdominal pain can mimic acute appendicitis or intussusception. Bacteremia is rare but has been reported in the elderly and in some patients with underlying conditions. During convalescence, immunoreactive complications including Guillain-Barré syndrome, reactive arthritis, and erythema nodosum may occur. In patients with diarrhea, Campylobacter jejuni and C. coli are the most frequently isolated species.
Campylobacter is present in the intestinal tract of both domestic and wild birds and animals. Transmission is via consumption of contaminated food or water. Undercooked poultry, untreated water, and unpasteurized milk are the three main vehicles of transmission. Campylobacter can be isolated in stool and blood, however isolation from stool requires special media. Rehydration is the primary therapy. Use of azithromycin or erythromycin can shorten both the duration of symptoms and bacterial shedding.
Nontyphoidal salmonella (NTS) are responsible for a variety of infections including asymptomatic carriage, gastroenteritis, bacteremia, and serious focal infections. Gastroenteritis is the most common illness and is manifested as diarrhea, abdominal pain, and fever. If bacteremia occurs, up to 10% of patients will develop focal infections. Invasive disease occurs most frequently in infants, persons with hemoglobinopathies, immunosuppressive disorders, and malignancies. The genus Salmonella is divided into two species, S. enterica and S. bongori with S. enterica subspecies accounting for about half of culture-confirmed Salmonella isolates reported by public health laboratories.
Although infections are more common in the summer, infections can occur year-round. In 2018, the CDC investigated at least 15 food-related NTS outbreaks and 6 have been investigated so far in 2019. In industrialized countries, acquisition usually occurs from ingestion of poultry, eggs, and milk products. Infection also has been reported after animal contact and consumption of fresh produce, meats, and contaminated water. Ground beef is the source of the November 2019 outbreak of S. dublin. Diarrhea develops within 12-72 hours. Salmonella can be isolated from stool, blood, and urine. Treatment usually is not indicated for uncomplicated gastroenteritis. While benefit has not been proven, it is recommended for those at increased risk for developing invasive disease.