Viruses help form biofilms

Inoviridae virionBacteria frequently grow in communities called biofilms, which are aggregates of cells and polymers. An example of a biofilm is the dental plaque on your teeth. Biofilms are medically important as they can allow bacteria to persist in host tissues and on catheters, and confer increased resistance to antibiotics and dessication. Therefore understanding how biofilms form is crucial for controlling microbial infections. An advance in our understanding of biofilms formation is the observation that filamentous phages help them assemble, and contribute to their fundamental properties.

Pseudomonas aeruginosa is an important human pathogen which is a particular problem in patients with cystic fibrosis. The ability of this bacterium to form biofilms in the lung is linked to its ability to cause chronic infections. Pseudomonas aeruginosa biofilms contain large numbers of filamentous Pf bacteriophages (pictured; image credit). These viruses lyse cells and release DNA, which becomes one component of the biofilm matrix.

Mixing supernatants of P. aeruginosa cultures with hyaluronan, which is present in airways of cystic fibrosis patients, resulted in the formation of a biofilm – in the absence of bacteria. A major component of P. aeruginosa biofilms was found to be Pf bacteriophages. When purifed Pf bacteriophages were mixed with hyaluronan, biofilms formed. Similar biofilms also formed when the filamentous bacteriophage fd of E. coli was mixed with hyaluronan. Mixtures of Pf bacteriophages and various polymers (alginate, DNA, hyaluronan, polyethylene glycol) formed liquid crystals (matter in a state between a liquid and a solid crystal).

Pf phages were detected in sputum from patients with cystic fibrosis, but not in uninfected patients. Addition of Pf phage to sputum from patients infected with P. aeruginosa made the samples more birefringent, a property of liquid crystals. Compared with a strain of P. aeruginosa that does not produce Pf phage, colonies of virus-producing strains formed liquid crystals. These observations indicate that Pf phage help organize the bacteria into a biofilm matrix.

Some features of biofilms include their ability to adhere to surfaces, to protect bacteria from dessication, and to increase resistance to antibiotics. Addition of phage Pf increased biofilm adhesion and tolerance against dessication. Such addition also made the biofilm more resistant to aminoglycoside antibiotics, because these were sequestered in the biofilm. No phage-mediated increased resistance to ciprofloxacin was observed, probably because this antimicrobial does not interact with polyanions of the biofilm as do aminoglycosides.

These results show that presence of bacteriophage in a biofilm of P. aeruginosa helps organize the matrix while contributing to some of its fundamental properties. It seems likely that filamentous phages of other bacteria will play roles in biofilm formation, suggesting that targeting the phages in these matrices could be effectie strategies for treating biofilm infections.

TWiV 352: Science art with Michele Banks

On episode #352 of the science show This Week in Virology, Vincent meets up with Michele Banks in Washington, DC to discuss her career as a creator of science-themed art.

You can find TWiV #352 at

TWiM 90: Think globally, act locally

I usually don’t post TWiM episodes here, but #90 has a lot of virology. In this episode, recorded in La Jolla, CA at the annual meeting of the Southern California Branch of the American Society for Microbiology, I first speak with Laurene Mascola, Chief of Acute Communicable Diseases at the Los Angeles County Department of Public Health. Dr. Mascola talks about how Los Angeles county has prepared for an outbreak of Ebola virus. Next up is David Persing, Executive Vice President and Chief Medical and Technology Officer at Cepheid. His company has developed an amazing, modular PCR machine that is brining rapid diagnosis everywhere, including the United States Post Office. And it might even be available on your refrigerator one day.

Watch TWiM #90 below, or listen at or iTunes.


Scientists for Science

Scientists for Science are confident that biomedical research on potentially dangerous pathogens can be performed safely and is essential for a comprehensive understanding of microbial disease pathogenesis, prevention and treatment. The results of such research are often unanticipated and accrue over time; therefore, risk-benefit analyses are difficult to assess accurately.

If we expect to continue to improve our understanding of how microorganisms cause disease we cannot avoid working with potentially dangerous pathogens. In recognition of this need, significant resources have been invested globally to build and operate BSL-3 and BSL-4 facilities, and to mitigate risk in a variety of ways, involving regulatory requirements, facility engineering and training. Ensuring that these facilities operate safely and are staffed effectively so that risk is minimized is our most important line of defense, as opposed to limiting the types of experiments that are done.

In contrast to recombinant DNA research at the time of Asilomar in 1975, studies on dangerous pathogens are already subject to extensive regulations. In addition to regulations associated with Select Agent research, experimental plans on other pathogens are peer reviewed by scientists and funding agencies, and the associated risk assessments are considered by biosafety experts and safety committees. Risk mitigation plans are proposed and then considered and either approved or improved by safety committees.

If there is going to be further discussion about these issues, we must have input from outside experts with the background and skills to conduct actual risk assessments based on specific experiments and existing laboratories. Such conversations are best facilitated under the auspices of a neutral party, such as the International Union of Microbiological Societies or the American Society for Microbiology, or national academies, such as the National Academy of Sciences, USA. We suggest they should organize a meeting to discuss these issues.

Scientists for Science have a range of opinions on how risk is best assessed. However, maintaining dogmatic positions serves no good purpose; only by engaging in open constructive debate can we learn from one another’s experience. Most importantly, we are united as experts committed to ensuring public health is not compromised and the reputation of science in general, and microbiology in particular, is defended.

Please visit the Scientists for Science website to view the supporters of this initiative.

Viral fiber art

dengue virus pillowViruses inspire many different types of art, but I was unaware of the number of people who make viruses out of fiber!

On This Week in Virology #266 we heard from Emily who had knitted a dengue virus pillow (photograph at left).

The next week on TWiV #267 we heard from Carolyn who had knitted a picornavirus (photo below).

knit picornavirus

The following week (TWiV #268) we heard from Jessica who has also knitted two different icosahedral structures.

knit icoshadedron

This made me wonder how many people knit viruses, so I searched Ravelry for ‘virus’. Here are some of the interesting creations I found.

Cold virus by Krista:

Cold virus

Dawn’s cold virus (rhinovirus):


Melini’s phage hat:

phage hat

Two H1N1 influenza viruses:

h1n1 knit

And Susan’s bacteriophage:

knit bacteriophage

There are also bacteria, such as this collection (with some viruses) from Clare:

knit microbes

You can find more by searching for ‘microbe’ at Ravelry (login required), where you’ll also find the patterns to reproduce these wonderful creations. Microbes are clearly inspiring and fascinating to fiber artists!

Do you make fiber viruses? If so let me know and we can include a photograph here.

Michael Schmidt on copper at TEDx

On TWiM #55 we discussed the remarkable ability of copper to reduce hospital acquired infections. Now you can watch Michael Schmidt, TWiM co-host and a co-author on this work, discuss the findings at a recent TEDx talk in Charleston, South Carolina.

The science-themed art of Deb Sklut

During my visit to Berkeley, CA to record TWiV #228, I met Deb Sklut, an artist who is inspired by the power of science. I recorded a brief conversation with Deb which you can view below. Her work can be found at Screenology (formerly SqueakySqueegeeArt).


TWiM 53: Live in Manchester

On episode #53 of the science show This Week in Microbiology, Vincent, Laura, David, Kalin and Paul get together at the Society for General Microbiology meeting in Manchester, England to talk about next-generation approaches to antimicrobial therapy.

You can find the audio for TWiM #53, along with show notes, at Watch video of the episode below.

Behind the scenes in Manchester

TWiM 41: ICAAC live in San Francisco

On episode #41 of the science show This Week in Microbiology, Vincent and Michael travel to San Francisco for the 52nd Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), where they meet with Bill, John, and Victor to discuss tuberculosis, monitoring infectious disease outbreaks with online data, and outside-the-box approaches to antibacterial therapy.

You can view video of this episode below, or download audio or video files at


Viruses at Artomatic 2012

While on a business trip to Washington DC I took time to visit Artomatic 2012 in Arlington, Virginia. Artomatic is a month-long festival of over 1,000 artists who create visual art, music, performance, film, fashion, and more. I went because Forrest McCluer was showing his work there – he makes models of viruses from computer parts. We have featured his work on the science show This Week in Virology, most recently on episode 184. Forrest alerted us to the exhibit of another artist working with microbe themes, Michele Banks, and I went to see her work as well.

Forrest was showing AdenoCD virus, a model of adenovirus built from compact discs. Below are some photographs of the showing. Clicking them will load a much larger version.

adenoCD virus

AdenoCD virus at Artomatic 2012

adenoCD virus

adenoCD virus

In the image below you can see how Forrest distinguishes the subunits around the five-fold icosahedral axis (pentons) from the other capsid subunits (hexons).

adenoCD virus

Forrest has made a number of virus constructions from computer parts, as described on this poster which is part of the exhibit.

adenoCD virus

Below is the computer virus transport module – a crate used to carry the sculpture to the exhibition.

adenoCD virus crate

I signed the guestbook – but there were no more virus cookies left.

Visit Forrest’s website to learn more about why and how he makes sculptures of viruses. A gallery of his sculptures can be found here.

adenoCD virus

Michele Banks‘ work was exhibited on the same floor. Michele is a painter and collage artist based in Washington, DC. Her pieces are based on scientific and medical themes. She is not a scientist, but loves and is fascinated by the natural world, especially at the microscopic level.

These photographs do not do her work justice; there are much better images on her website.

Petri dishes 7

Petri dishes 7 by Michele Banks


Love and Death: Viruses

Love and Death: Viruses by Michele Banks

Portrait of a human

Portrait of a human by Michele Banks

The next day I purchased ‘Beautiful But Deadly 4’, a watercolor painting of viruses (image below). Michele brought the painting to ASM headquarters where I was working, so I was able to bring it home. It’s a wonderful collage of viruses that would look great in the TWiV Studio (my office at Columbia University Medical Center).

Beautiful But Deadly 4 by Michele Banks

Beautiful But Deadly 4 by Michele Banks

Do you know other artists who create art based on microbes? Please add a comment so we can develop a list of these individuals here at virology blog.