Hartmann lab undergrad gets Argonne internship

Mia Tran, a sophomore in the Hartmann lab, was recently granted admission to the Science Undergraduate Laboratory Internship (SULI) program. Congrats, Mia! Here’s what she has to say about it:

Mia Tran in the lab

I’ve been offered the opportunity to intern at Argonne National Laboratory this summer, under the SULI program supported by the Department of Energy, which I’m very very excited about. I will be doing research on contaminant cycling and transformations in wetland environments, which aligns well with my current interest in water, chemistry, and ecosystems. It feels surreal to me still, and I could not have gained the experience and connections that were important in my application process without the time I’ve spent with this lab!

Stressed-out dust is sharing antibiotic resistance genes

  • Bacteria can swap their genes with neighboring bacteria
  • Study finds that antibiotic resistance genes can be transferred
  • Nonpathogens could give antibiotic resistance genes to pathogens

EVANSTON, Ill. — Indoor dust is evolving — and not in a good way.

A new Northwestern University study is the first to find that bacteria living in household dust can spread antibiotic resistance genes. Although most bacteria are harmless, the researchers believe these genes could potentially spread to pathogens, making infections more difficult to treat.

“This evidence, in and of itself, doesn’t mean that antibiotic resistance is getting worse,” said Northwestern’s Erica Hartmann, who led the study. “It’s just one more risk factor. It’s one more thing that we need to be careful about.”

The study will be published on Jan. 23 in the journal PLOS Pathogens. Hartmann is an assistant professor of environmental engineering in Northwestern’s McCormick School of Engineering.

A bacterium can share its genes by using either of two methods: dividing, which is the equivalent to having a baby, or horizontal gene transfer. The primary method for spreading antibiotic resistance genes among species, horizontal gene transfer occurs when a bacterium makes a copy of its genes and swaps them with a neighbor.

Bacteria can share many different types of genes — as long as the genes have mobile segments of DNA. Hartmann and her team were the first to find that antibiotic resistance genes in dust microbes have mobile capabilities.

“We observed living bacteria have transferrable antibiotic resistance genes,” Hartmann said. “People thought this might be the case, but no one had actually shown that microbes in dust contain these transferrable genes.”

Although it is rare for pathogens to live in indoor dust, they can hitchhike into homes and mingle with existing bacteria.

“A nonpathogen can use horizontal gene transfer to give antibiotic resistance genes to a pathogen,” Hartmann explained. “Then the pathogen becomes antibiotic resistant.”

Why do bacteria share genes? Hartmann says they can’t handle the stress of being indoors. The indoor environment might be too dry and cold without enough food, for example, or it might be occasionally spritzed with antimicrobial solutions. (Hartmann, by the way, recommends dusting with a damp cloth instead of using antimicrobial solutions, which can make bacteria more resistant to antibiotics.)

“Microbes share genes when they get stressed out,” Hartmann said. “They aren’t equipped to handle the stress, so they share genetic elements with a microbe that might be better equipped.”

The study, “Mobilization antibiotic resistance genes are present in dust microbial communities,” was supported by the Alfred P. Sloan Foundation and the Biology & the Built Environment Center at the University of Oregon.

This story was originally published by Northwestern University.

The image is reproduced from Ben Maamar et al. JESEE 30:1-15 (2020).

Spreading awareness about antibiotic resistance with SPOT

PhD student Alexander McFarland recently did some outreach with senior citizens. He talks about the experience here.

I recently had the opportunity to go to the Levy Center with the Science Policy Outreach Task Force (SPOT), a Northwestern University science advocacy group, to speak with senior citizens about bacterial antibiotic resistance. When I first signed up for this event, I was told to give a presentation about any important scientific problem that voting-aged citizens should be aware of. Naturally, I picked antibiotic resistance due to its increasing clinical prevalence and the need for policy-level actions to reverse the trend.

In my mind, the battle between scientists developing antibiotics and bacteria evolving resistances to them is similar to arms races in human history. Using this metaphor, I hoped to communicate that you can help stop the arms race by:

  • Listening to your doctor
  • Not taking antibiotics when you have a cold
  • Taking all antibiotics for their prescribed length

At the conclusion of my talk the audience had many more specific and detailed questions and comments that went beyond my simple presentation on the antibiotic arms race. We ended up having an informative discussion on topics such as antibiotic use in farm animals and the pros and cons of antibacterial vaccines. Overall, I had a great time and look forward to future outreach events with SPOT.

People Still Learning win big at the Up-Goer Five Thing

During ASM Microbe 2019 in San Francisco (the Amer. Soc. For Microbiology Annual Conference), postdoc Ryan Blaustein presented some Hartmann Lab research in the popular science communication session “The Up-Goer Five Thing: Simple Words for Tiny-Life Studies.” The UG5 objective is to share your work in a simple and entertaining way by using only the ten hundred most commonly used words. Here are some examples and a handy text editor to test for the approved language.

The ASM session was set up as a competition between “People Running Things” (PIs) and “People Still Learning” (trainees). Each presentation was treated like a normal 5-minute powerpoint pitch, but with a UG5 twist on things…well, there was a surprise guitar sing-a-long led by one of the participants. At the end, the audience voted on the best team overall (best hypothesis, methods, results), team MVPs, and best word/phrase substitution. Team “People Still Learning” won – congrats team! Here’s what twitter had to say about the event.

Here’s Ryan’s reaction to the event:

“Participating in the UG5, from preparing the abstract to giving the formal presentation, was a fun learning experience. It helped me think about new and better ways to communicate my everyday work. All scientists can certainly benefit from knowing how to share their work in lay terms. Now, along with Erica and Jim, I would like to help bring this type of event to our department at Northwestern University to challenge student’s science communication skills in a creative arena.”

Hartmann lab at the Microbiome Center Symposium

On April 16th, the Hartmann lab group took a day trip down to the University of Chicago for the 2019 Microbiome Symposium.

Hartmann lab members Erica Hartmann, Jiaxian Shen, Alex McFarland, Clayton Johnson, and Ryan Blaustein at the 2019 Microbiome Research Symposium.

We listened to some lovely talks from researchers in various fields, but all of the talks highlighted emerging methods in microbiome research. The day served as a great opportunity to network with scientists from around the Chicagoland area. Three of our members (Ryan Blaustein, Alex McFarland, and Jiaxian Shen) used the symposium as an opportunity to share their research in poster form.

Antimicrobial paints have a blind spot

Spore-forming bacteria survive on surfaces coated with antimicrobial, latex paints

  • Antimicrobial paints kill most bacteria within 24 hours, but some survive
  • Such products are typically tested on pathogens but not common bacteria like Bacillus
  • Antimicrobial paints could favor antibiotic resistance — making harmless bacteria like Bacillus harmful

SEM image of Bacillus timonensis spores with vegetative cells in the background. Image credit: Jinglin Hu

EVANSTON, Ill. — Antimicrobial paints offer the promise of extra protection against bacteria. But Northwestern University researchers caution that these paints might be doing more harm than good.

In a new study, the researchers tested bacteria commonly found inside homes on samples of drywall coated with antimicrobial, synthetic latex paints. Within 24 hours, all bacteria died except for Bacillus timonensis, a spore-forming bacterium. Most bacilli are commonly found in soil, and many are also found in indoor environments.

“If you attack bacteria with antimicrobial chemicals, then they will mount a defense,” said Northwestern’s Erica Hartmann, who led the study. “Bacillus is typically innocuous, but by attacking it, you might prompt it to develop more antibiotic resistance.”

Bacteria thrive in warm, moist environments, so most die on indoor surfaces, which are dry and cold, anyway. This makes Hartmann question the need to use antimicrobial paints, which may only be causing bacteria to become stronger.

A painted surface that we perceive as smooth is actually quite mountainous on the micro-scale. Image credit: Daniela Ruiz

Spore-forming bacteria, such as Bacillus, protect themselves by falling dormant for a period of time. While dormant, they are highly resistant to even the harshest conditions. After those conditions improve, they reactivate.

“When it’s in spore form, you can hit it with everything you’ve got, and it’s still going to survive,” said Hartmann, assistant professor of civil and environmental engineering in Northwestern’s McCormick School of Engineering. “We should be judicious in our use of antimicrobial products to make sure that we’re not exposing the more harmless bacteria to something that could make them harmful.”

The study was published online on April 13 in the journal Indoor Air.

One problem with antimicrobial products — such as these paints — is that they are not tested against more common bacteria. Manufacturers test how well more pathogenic bacteria, such as E. coli or Staphylococcus, survive but largely ignore the bacteria that people would more plausibly encounter.

E. coli is like the ‘lab rat’ of the microbial world,” Hartmann said. “It is way less abundant in the environment than people think. We wanted to see how the authentic indoor bacteria would respond to antimicrobial surfaces because they don’t behave the same way as E. coli.”

The study, “Impacts of indoor surface finishes on bacterial viability,” was supported by the Alfred P. Sloan Foundation (award number G-2016-7291) and the Searle Leadership Fund.

This story was originally published by Northwestern University.

What we can learn from ISS microbes

PhD student Alex McFarland and postdoc Ryan Blaustein review data comparing ISS and Earth-based microbes

Our latest publication, led by postdoc Ryan Blaustein, is an Editor’s pick in the journal mSystems! He used pangenomics to see if there was anything special about microbes in a very special built environment: the International Space Station. Luckily for astronauts, while there are some particular features of ISS microbes, they don’t look like they’re going to do humans any harm. Peruse some of the popular media pieces covering this work below.

Good news: space bacteria (probably) aren’t evolving to destroy us in Popular Science

Study on Microbes Found on International Space Station Is “Quite a Relief” on inverse.com

New paper on antimicrobials and antibiotic resistance out

Dust with higher levels of triclosan, represented by orange triangles, contain more antibiotic-resistant bacteria. Graphic by Vlad Tchompalov.

Our latest work, in collaboration with the Biology and the Built Environment Center, is out in mSystems! Read it for yourself, and check then out some of the media coverage:

Your dust bunnies are alive but fighting them with antibacterials is a bad idea on CBC Radio’s Quirks & Quarks

Your gym mats may be breeding antibiotic-resistant germs in PBS NewsHour

Microbes that live at the gym are pumped up on antibiotic resistance in CBC News