This week's Morbidity and Mortality Weekly Report, a CDC publication, discusses a May 2012 outbreak of shigellosis, an illness caused by Shigella bacteria. The outbreak, which was associated with a private bridge club, is significant because it is the first outbreak involving Shigella sonnei resistant to azithromycin, one of the world's best-selling antibiotics in the United States.
"As foodborne pathogens like Shigella become more resistant to antibiotic treatment, it is critical that restaurants, daycare centers and other venues where food is served make sure that food handlers wash their hands thoroughly," said Fred Pritzker, an attorney who represents victims of shigellosis outbreaks throughout the United States. "When an outbreak does occur, victims and their families have the legal right to hold those responsible accountable." You can contact Fred for a free consultation here.
Outbreak investigators interviewed bridge club workers and members who had visited the bridge club during the week of May 22, 2012. They collected stool specimens from workers who handled food and from workers and members with diarrhea. Thirty-nine outbreak victims were identified among club members with diarrhea and four among club workers.
Most of the outbreak victims were sick for about 6 days. One was sick for 14 days. Common shigellosis symptoms included diarrhea in 95% of patients, abdominal cramps in 70%, and fever in 56%. 10 people were hospitalized.
Investigators tested stool samples of those sickened. 10 of the Shigella isolates underwent pulsed-field gel electrophoresis (PFGE), yielding indistinguishable patterns. Four isolates has some resistance to streptomycin, sulfisoxazole, tetracycline, and trimethoprim-sulfamethoxazole. Unlike most Shigella isolates tested by NARMS, these isolates also showed some resistance to azithromycin.
Although there have been cases of shigellosis caused by Shigella strains with some indication of resistance to azithromycin, this is the first outbreak documented in the United States and might indicate increasing circulation of such strains. Because azithromycin currently is recommended for treatment of infections caused by multidrug-resistant Shigella, these azithromycin-resistant strains will be difficult to treat and cause greater risk of serious illness and death. Shigella infections can cause hemolytic uremic syndrome (HUS), a leading cause of kidney failure in the United States.
The CDC is asking health professionals to report azithromycin treatment failure among shigellosis patients to public health authorities and to retain Shigella isolates from such cases for further analysis.