In a rather unusual outbreak, public health officials have identified 24 people in 16 states sickened with Salmonella Typhimurium infections linked to teaching and clinical laboratories. Six of those sickened have been hospitalized. No deaths have been reported.
This is the same strain that was associated with infections linked to microbiology lab exposure in 2011 and 2014. This is a public health problem and a reminder that bacteria used in microbiology laboratories can sicken people who work in those labs. [Editor’s note: The first time I was in a microbiology lab the professor warned us against eating or drinking in the room and also walked us through safety steps, including frequent hand washing and the use of gloves, lab coats, and goggles.]
In addition, people who live with those who work in labs are at risk for contracting these infections, even if they never visit the lab. The CDC has issued guidance documents for work with Salmonella and other human pathogens.
PulseNet was used to identify illnesses that may be part of this outbreak. Pulsed-field gel electrophoresis and whole genome sequencing were used to perform DNA fingerprinting on Salmonella bacteria isolated from samples taken from ill persons.
The symptoms of a Salmonella infection include nausea, abdominal cramps, diarrhea, vomiting, and fever. Symptoms usually begin six to 72 hours after exposure to the bacteria. Most people recover without medical treatment, but some do become so ill, either with dehydration or sepsis, that they must be hospitalized.
Patients in this outbreak live in California, Colorado, Florida, Georgia, Iowa, Maine, Michigan, Missouri, North Carolina, New Hampshire, New Jersey, New Mexico, New York, Oklahoma, Texas, and Washington. A new set of guidelines for safety in labs was developed after the 2011 outbreak.
Illnesses started on dates ranging from March 17, 2017 to June 22, 2017. The patient age range is from less than 1 year to 57 years, with a median age of 24. Seventy-five percent of ill persons were female. Nine of the 13 people interviewed by public health officials had laboratory exposures. The patients reported behaviors while working in the lab that could increase the risk of a Salmonella infection, including not wearing gloves or lab coats, not washing hands, and using the same writing utensils and notebooks outside of the laboratory.
The CDC report ends by stating that, “All students and staff in clinical and teaching microbiology laboratories should receive laboratory safety training. Either nonpathogenic or attenuated bacterial strains should be used when possible, especially in teaching laboratories. This practice will help reduce the risk of students and their family members becoming ill.”
