Investigation Details

October 22, 2019

CDC and public health officials in several states investigated 13 multistate outbreaks of Salmonella infections with serotypes Agona, Alachua, Altona, Anatum, Braenderup, Enteritidis, Infantis, Manhattan, Montevideo, Muenchen, Newport, and Oranienburg. Epidemiologic, laboratory, and traceback evidence indicated that contact with backyard poultry, such as chicks and ducklings, from multiple hatcheries was the likely source of these outbreaks.

Public health investigators used the PulseNet system to identify illnesses that were part of these outbreaks. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA fingerprinting is performed on Salmonella bacteria isolated from ill people by using a standardized laboratory and data analysis method called whole genome sequencing (WGS). CDC PulseNet manages a national database of these sequences that are used to identify possible outbreaks. WGS gives investigators detailed information about the bacteria causing illness. In these outbreaks, WGS showed that bacteria isolated from ill people were closely related genetically. This means that people in these outbreaks were more likely to share a common source of infection.

A total of 1,134 people infected with the outbreak strains of Salmonella were reported from 49 states and the District of Columbia. A list of the states and the number of cases in each is on the map of reported cases page.

Illnesses started on dates from January 1, 2019, to October 9, 2019. Ill people ranged in age from less than 1 year to 99 years, with a median age of 34. Of 988 ill people with age information available, 212 (21%) were children younger than 5. Fifty-six percent were female. Of 740 people with information available, 219 (30%) were hospitalized. Two deaths were reported from Ohio and Texas.

Whole genome sequencing (WGS) was conducted to identify any predicted antibiotic resistance in 814 isolates from ill people and 38 isolates from food, animals, or the environment. A total of 187 isolates had predicted antibiotic resistance or decreased susceptibility to one or more of the following antibiotics: amoxicillin-clavulanic acid (5% of 187 isolates), ampicillin (6%), cefoxitin (5%), ceftriaxone (5%), chloramphenicol (4%), ciprofloxacin (<1%), fosfomycin (7%), gentamicin (2%), kanamycin (1%), nalidixic acid (<1%), streptomycin (6%), sulfamethoxazole (6%), tetracycline (4%), and trimethoprim-sulfamethoxazole (<1%). There was no antibiotic resistance predicted for 665 (78%) isolates. Testing of 52 clinical isolates using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory provided comparable results (fosfomycin and kanamycin were not tested by this method). If antibiotics are needed, some infections related to these outbreaks may be difficult to treat with some commonly recommended antibiotics and may require a different antibiotic choice.

In interviews, ill people answered questions about animal contact in the week before they became ill. Of 619 people interviewed, 392 (63%) reported contact with backyard poultry before becoming ill. Ill people reported buying poultry from various sources, including agricultural stores, websites, and hatcheries. Six of the outbreak strains that made people sick were identified in samples collected from poultry.

As of October 22, 2019, these outbreak investigations are over.