Yet Another Call to Arms

My fiancé and I have worked side-by-side in the science lab for years now, and yet he still has to lovingly remind me to be cautious of where I set my backpack down in the laboratory, to leave IN the lab anything that has touched the lab bench (like pens and notebooks), to take my ‘lab’ shoes off at the door to our apartment, and to be extremely careful of when I handle my phone on the job. I am extremely thankful for his reminders, which to me are not always second nature. Especially in light of recent events… Follow FromTheLabBench on Twitter

Salmonella Typhi.jpgA recent Salmonella outbreak hit 35 states, causing 73 infections and 1 death according to the Centers for Disease Control and Prevention (CDC), reporting on incidents this April. Unfortunately this type of outbreak is not uncommon, typically stemming from batches of contaminated meat, peanut butter, meals from unfortunate fast food restaurant chains, or even handling of pet frogs. However, the recent outbreak is cause for special concern, because it was discovered to have originated in clinical and teaching microbiology laboratories, controlled environments where appropriate safety regulations are supposedly enforced. “The fact that cases seem to be happening all over the country has raised the question of whether there are issues with laboratory safety and appropriate training techniques,” – Mack Sewell, state epidemiologist at the New Mexico Department of Health in Santa Fe.

The strain of Salmonella that caused the outbreak is Salmonella typhinurium, a relatively common strain of the rod-shaped, Gram-negative bacterium (Hayden, Nature) that uses molecular ‘needle-like’ appendages to initiate infection in eukaryotic ‘host’ cells via secretion of toxins that suppress immune response (Schraidt et al). The microbe causes gastroenteritis (inflammation of the gastrointestinal tract) and symptoms characteristic of typhoid fever.

Needle complex.jpg

The outbreak hardly reflects well on those in charge of laboratory safety practices, who had been warned by several late articles in Nature calling for improvements in safety measures and safety training programs following the death of a research assistant in 2009 and an undergraduate student in a Yale University workshop in 2011. The secondary Salmonella infection of children in contact with laboratory members raises tremendous concerns, and warrants a re-evaluation of safety practices in these microbiology laboratories, and in hazardous material containing chemical or biological laboratories in general. The Centers for Disease Control and Prevention (CDC) is currently conducting investigations of laboratory officials and faculty involved with clinical and teaching microbiology laboratories ‘to identify areas where improvements in biosafety and laboratory safety training can be made to prevent future illnesses’ CDC cautions those working in microbiology laboratories to never eat or drink on or near contaminated surfaces, and to be aware that pathogenic bacteria can hitch a ride home on pens, notebooks, and other personal items. Lab personnel should be trained in proper safety practices and sterile techniques BEFORE ever handling pathogenic agents.

Mack Sewell, New Mexico state epidemiologist, quotes his own professor in saying “anyone who catches something they’re working with gets an automatic ‘F’.” While a good motivation to be cautious, proficiency in safety procedures should far predate working with pathogenic bacteria for either course credit or research applications. As I mention in a previous Call to Arms for lab safety, an excellent grade in Microbiology 101, an entire at the bench course on microbe biosafety practices, should be a prerequisite for working with any type of pathogenic organism. “We need a more institutionalized, hands-on lab safety education, treating safety as a first priority, not as an afterthought to avoid costly fines due to failed inspections or accidents.” I hope we learn our lesson on the importance of lab safety soon than later. Infections stemming from an expert-supervised science laboratory are, I believe, completely unacceptable and avoidable.


1. Salmonella hits US teaching labs – Published online 10 May 2011 | Nature 473, 132 (2011) | doi:10.1038/473132a

Image 1 – Color-enhanced scanning electron micrograph showing Salmonella typhimurium (red) invading cultured human cells. _Public Domain under National Institutes of Health, part of the United States Department of Health and Human Services. _

Image 2 – Left: A transmission electron-microscope image of isolated T3SS needle complexes from Salmonella typhimurium (Schraidt et al). Right: Schematic of the type III secretion-system needle-complex (Wiki Commons).
Hayden EC (2011). Salmonella hits US teaching labs. Nature, 473 (7346) PMID: 21562531