Serratia flowers

Serratia marcescens can form brilliant red colonies on LB agar due to the synthesis of the secondary metabolite prodigiosin. In the Microbiology teachinglab, we had students create pigment mutants of S. marcescens and these lovely shades of pink and white were collected for analysis.

This photo was taken from our Submitted by: Phages_for_all_ages Thanks to the author(s): UIUC

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We are what we eat: Contributions to the microbial zoo within our guts

We celebrated International Pathology Day 2015 a couple of days back (18 Nov 2015). One of the activities at our booth was the chance to streak an agar plate with some familiar food and drink items-namely chicken rice chili sauce, sugar cane juice and carrot juice. There were 199 participants and they will get to see the results of their efforts on our Facebook page today (20 Nov 2015) around  1300 local time (0500 GMT).

The purpose of this exercise was two-fold. First it gave participants the opportunity to try their hand at one of the most fundamental techniques in microbiology. Second (after they see the results), it hopefully will provoke them to think about how we sometimes unwittingly acquire the bacteria that inhabit our innards. 

If you think about it, when we are formed in the womb, our guts are sterile. We usually acquire our first dose of bacteria while travelling down our mother’s birth canal. We continue to add to this initial stock of bacteria for the remainder of our lives. So every time you go to the toilet for a poop, consider that the smelly deposit you leave behind represents an incomplete record of

1. times you played in the playground as a kid and failed to wash your hands afterwards before snacking.
2. items you ate or drank that weren’t thoroughly cooked
3. etc…you get the idea

So what were the bacteria that grew out of our samples?

The chicken rice chili sauce had the lowest colony counts and least variety, which is not surprising since some of the ingredients (chili, ginger, garlic and vinegar) inhibit bacterial growth. Bacilis subtilis is a Gram positive rod commonly found in the environment that is non-pathogenic for humans.

In carrot juice, Enterobacter ludwigii has been associated with urinary tract, respiratory tract, and blood infections. Rahnella aquatilis as its name suggests is an environmental Gram negative rod associated with water and is of no clinical significance. Pantoea spp. are plant pathogens that occasionally cause human infections.

In sugar cane juice, both Klebsiella pneumoniae and Serratia marcescens are associated with human infections.

What are we to make of this? Well clearly most of us (myself included) drink fresh fruit juice regularly with no ill effects. These bacteria probably do not directly cause disease as a result of ingestion and therefore do not pose a problem to healthy people. However if you are a patient with a problem with your immune system you may want to avoid that sugar cane juice you left overnight in the fridge.

Ryan Returns Home from ICU

Ryan Returns Home from ICU

Ryan was discharged — directly from the ICU — and is now at home. We were fortunate to get out when we did because our area is getting quite the progression of precipitation: freezing rain, sleet, ice, and then snow.

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Ryan gets his IV antibiotic this morning.

Over the next 14 days I must give him a strong (and somewhat uncommon) antibiotic intravenously. It is for the bacteria, serratia, that…

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Никогда не заходите в дом в обуви! И вот почему!

Ряд научных исследований подтверждает, что носить уличную обувь по дому – плохая идея. И причины эти довольно просты.

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It all began in late September of 1950, when over a few days, a Navy vessel used giant hoses to spray a fog of two kinds of bacteria, Serratia marcescens and Bacillus globigii — both believed at the time to be harmless — out into the fog, where they disappeared and spread over the city.

The unsuspecting residents of San Francisco certainly could not consent to the military’s germ warfare test, and there’s good evidence that it could have caused the death of at least one resident of the city, Edward Nevin, and hospitalized 10 others.

Over the next 20 years, the military would conduct 239 “germ warfare” tests over populated areas, according to news reports from the 1970s.

These tests included the large-scale releases of bacteria in the New York City subway system, on the Pennsylvania Turnpike, and in National Airport just outside Washington, D.C.

– From the MSN article: ‘One of the Largest Human Experiments in History’ was Conducted on the Unsuspecting Residents of San Francisco



Spaceflight Causes Increased Virulence of Serratia Marcescens on a Drosophila Melanogaster Host

Abstract: Drosophila melanogaster, or the fruit fly, has long been an important organism for Earth-based research, and is now increasingly utilized as a model system to understand the biological effects of spaceflight. Studies in Drosophila melanogaster have shown altered immune responses in 3rd instar larvae and adult males following spaceflight, changes similar to those observed in astronauts. In addition, spaceflight has also been shown to affect bacterial physiology, as evidenced by studies describ…
from New NASA STI