A colleague recently pointed me to a Center’s For Disease Control and Prevention (CDC) account of a multi-state outbreak of human Salmonella Typhimurium infections linked to various clinical, commercial, and teaching microbiology laboratories (linked below) from July 2017. Twenty-four people were infected across sixteen states. Six of the ill were hospitalized but fortunately no deaths reported. Surprisingly, or perhaps not, this same strain had been previously associated with infections linked to microbiology laboratory exposure in 2011 and 2014. The CDC had this to say about the outbreak “Laboratory-associated salmonellosis continues to be a public health problem. This outbreak is a reminder that bacteria used in microbiology laboratories can sicken people who work in labs. Others who live in their households can also get sick, even if the household members never visited the laboratory.” I have also linked some common sense safety advice provided by the CDC for students and employees working in microbiology laboratories.
I share this not to frighten but as a reminder/warning to any wanna be or current DIY microbiologists out there that microbiological safety is not to be taken lightly. I am not aware of any outbreaks yet linked to a home/basement micro lab, but I can virtually guarantee one or more will come. As one can see from this example, laboratory associated infections do happen, and they happen from exposures that occur in fully equipped and properly certified professional microbiology labs. The exposure risks of a home lab are obviously much higher. Of course the home microbiologist should not be working with, or have access to, infectious disease causing microorganisms in the first place. These organisms, designated as biosafety level (bsl) 2 or higher, are capable of causing human or animal disease in non-immunocompromised hosts (the biosafety level classification scheme runs from 1 to 4 — safe to very, very not safe). Salmonella are classified as bsl-2 along with other common foodborne disease causing organisms such as pathogenic E. coli (E. coli O157:H7 being the most well known of these though there are many others) and Listeria monocytogenes. There are purchasing and shipping restrictions on bsl-2 and higher microbes that are intended to ensure they remain in the hands of laboratories trained to handle them appropriately. That said they can be isolated from the environment, foods, and feces fairly readily if one has the appropriate knowledge and access to the needed culture media. Media can also be made at home and a clever enough DIYer could hit upon a recipe that would allow recovery of any of these pathogens or others. I am not saying it would be easy, for it would not, but it could most certainly be done, and done at very low cost. In any event, my advice to the DIY microbiologist, stick to working with the non pathogens. Plenty of interesting work can be done with the unfathomably high number of microbes out there that are not pathogenic (the the vast, vast majority actually). There is no need to take unnecessary risks with your own and your friends and families health.