Since August 2010, a commercial strain of Salmonella Typhimurium has caused 73 confirmed illnesses, including one death, according to a report released on April 28th by CDC. The illnesses are spread over 35 states. Pennsylvania is hardest hit, with six confirmed illnesses.
The median age of infected individuals is 24 years; their ages range from less than 1 year to 91 years old. Nearly two-thirds (63%) of the victims are female.
Ten (14%) of the 73 outbreak victims were hospitalized. While illness onset dates range from August 20, 2010 to March 8, 2011, the number of new cases appears to have peaked in the first half of November 2010.
Investigators found that outbreak victims were significantly more likely than a control group to have been exposed to a microbiology lab environment – some of the victims worked with Salmonella – in the week before becoming ill. Several children of individuals who worked in or studied in a microbiology lab were among the outbreak victims.
The CDC Investigation Report credits the New Mexico Department of Health with the discovery that the outbreak strain “. . .was indistinguishable from a commercially available Salmonella Typhimurium strain used in laboratory settings.” According to CDC, this strain was “. . .known to be present in several teaching or clinical laboratories associated with ill students or employees. . .”
This Salmonella outbreak has nothing to do with contaminated food, poor food handling practices, dirty water, or African Dwarf Frogs. It was caused, purely and simply, by careless handling of infectious bacteria, by sloppy lab practices, and by inattention to basic biosafety procedures.
I was trained as a clinical microbiologist, a clinical mycologist and a food safety microbiologist. I have spent most of my professional life working with food-borne and water-borne pathogens, including Salmonella, E. coli O157:H7 and Clostridium botulinum. And I am here to tell you that a sloppy lab is an unreliable lab.
The first responsibility of a teaching lab is to teach its students how to handle themselves safety in a microbiology lab. Only then can students be trusted to handle infectious bacteria with proper respect for the risks involved.
The first responsibility of a clinical lab manager is to ensure that all of the lab personnel – and any visitors to the lab – are aware of, and follow, all lab safety and bio-containment practices. Only then can the results issuing from that lab be considered reliable. Only then can lab personnel – and their families and friends – be protected from lab-acquired illnesses.
This Salmonella Typhimurium outbreak should not have happened. It would not have happened if lab managers and teaching personnel had been paying attention to their first responsibilities.
This outbreak is inexcusable!