Tag Archives: bacteria

Bacteria Can Change Shape to Avoid Antibiotics?!

Posted on October 7, 2019 by | 1 comment

Can bacteria now consciously make the decision to change its’ shape to avoid being targeted by antibiotics? This article titled “Bacteria caught changing shape to evade antibiotics” seems to think so. However, upon reading this article, I discovered that it’s not that the bacteria makes the conscious decision to change its’ shape in order to avoid being targeted by antibiotics, but rather, the environment that the bacteria is in allows it to shed its’ cell wall. The title of the article is extremely misleading, and can cause undeserved panic because it is implying that bacterial organisms that are damaging to humans have evolved to the point where humans can no longer control them.

TEM of L-form bacteria from Mark Leaver of Newcastle University

If you continue to read the article, you’ll also discover that this certain strain of bacteria can’t evade all antibiotics. It can only make antibiotics that target the cell wall of the bacteria ineffective. There are antibiotics specifically made for targeting cell walls because there aren’t any human cells with cell walls, which makes it easier for the antibiotics to target the right cell. However, bacteria can shed its’ cell wall under non-hostile conditions such as an environment with high sugar concentration. By shedding that wall, the bacteria makes itself harder to detect by the antibiotics and our own immune system. That means that there is one less thing to differentiate the bacteria cell from our own human cell.

With a strong and healthy immune system, the L-form bacteria can eventually be destroyed. It is a little bit more complicated for people with weaker immune systems because they need help from antibiotics, but the antibiotics are ineffective because bacteria will stay in their L-form until the antibiotics leave the system, in which case the cell wall forms again.

Ultimately, there is no need to be worried that bacteria have evolved to consciously change its’ shape to avoid being targeted by our immune system or by antibiotics because it doesn’t. All the bacteria is doing is performing the functions it is programmed to do, like setting up protection against a hostile environment whether it is with a cell wall or without one.

-Sharon Li

 

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Posted in Biological Sciences, Science Communication, Science in the News

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Making a Difference with Recycling..?

Posted on September 29, 2019 by | Leave a comment

Recycling plastic here in B.C. is straightforward and easy. Simply sort your items into those blue bins and leave them out on weekly collection days. No headache, no hassle and no hidden conspiracy, right?

CBC’s Marketplace found out exactly otherwise. In an investigative report released this past weekend, by placing trackers in bales of plastic commissioned to be recycled, they found that only one out of three waste collection businesses with links to B.C.’s municipal recycling programs ended up recycling the plastic. What did the other two businesses do with their plastic? One dumped it in a landfill. The other brought it to a waste-to-energy facility, where it was incinerated, and what remained was then dumped in a landfill.

What was established instead, was that only 9% of Canadian plastic ended up being recycled. Which begs the question, what happens to the rest? In Canada, 2.8 million tonnes were thrown away as garbage. Ending up in landfills or oceans. On a global scale, 8 million tonnes go into the oceans annually. In the ocean, plastics are then weathered under the influence of solar UV radiation into miniscule fragments called, “microplastics”.

Microplastics are either consumed by marine life or wash up along the shores of beaches. On beaches, they become a habitat in which bacteria can proliferate. With a recent study finding a vast array of bacterial communities thriving on the surfaces of microplastics sampled from beaches and coastal regions in Singapore. Some of the bacteria found were harmful, being linked to the bleaching of corals or infection of open wounds. But some bacteria species identified were able biodegrade plastic, offering a potential solution towards solving the plastic pollution issue.

It should be clear by now that the accumulation of plastic pollution in the oceans is bad. Further compounding this is the ineffectiveness of recycling. So, what does that leave residents of B.C. to do? Reduce and Reuse. The onus once again falls on the individual to be ever more vigilant, and more responsible for minimizing their part in the use of plastic.

– Ryan Chew

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Posted in Science in the News

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Dogs: more than just cute!

Posted on September 23, 2019 by | 1 comment

Angus, one of two “super sniffer” dogs trained to alert their handler when they detect C. difficile. Source: Vancouver Coastal Health

We’ve all seen (or heard of) drug-sniffing dogs, but what about bacteria-sniffing ones?

Since 2016, a team from Vancouver Coastal Health has been tweaking a program that trains dogs to alert their handlers when they detect the scent of C. difficile. Over an 18-month period, the two dogs (Angus and Dodger) that have been trained for this role have detected 391 areas at Vancouver General Hospital where this bacteria was found.

Clostridioides difficile, more commonly referred to by its shorthand C. difficile or simply C. diff, are the leading cause of nosocomial (or hospital-originating) infectious diarrhea. Formerly known as Clostridium difficile, the bacterium was renamed late last year to more accurately portray the genus it falls in.

Angus and Dodger were trained with scent training kits from the Scientific Working Group on Dog and Orthogonal detector Guidelines (SWGDOG), which allowed them to identify the distinct odour of C. difficile. Microorganisms smell due to the variety of volatile chemicals they produce in response to various external factors. In the specific case of C. difficile, it is often described as having a sickly sweet or particularly foul smell.

The symptoms of a C. difficile infection can range from mild abdominal cramping to life-threatening sepsis and inflammation of the colon. The full range of symptoms can be found here. Most cases occur after taking antibiotics, which may kill both the good and bad bacteria in your gut – these are known as your gut microbiota. 

Without your normal gut microbiota, C. difficile can take advantage of this “clean slate” and proliferate in your intestine, throwing off the balance of good and bad bacteria. Within a period of several days to a few weeks, infected patients will start to show symptoms – the most common being diarrhea. Ideally, somebody with symptoms of infection will have tests done by a doctor and undergo treatment if necessary.

The progression of infection and the post-infection considerations are shown below in this graphic published by the Centre for Disease Control:

The progression of a C. diff infection. Source: Centre for Disease Control

In a study published by the Canadian Journal of Infection Control, it was found that 82% of contaminated surfaces were found in common areas. These included washrooms, hallways, and waiting rooms. Even with the most stringent sanitization procedures, it was relatively easy to find in areas that are commonly overlooked! 

One of the areas that tested positive for C. difficile contamination was inside a toilet paper dispenser – something that I personally would never think to sanitize. 

While there’s still a lot of work that needs to be done before we can train dogs to safely detect all sorts of infectious bacteria, the developments of the canine scent detection program are notable steps in the right direction. 

For more information about canine scent detection of C. difficile in Vancouver-area hospitals, you can learn more here and through this page.

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Posted in Issues in Science, Science Communication, Science in the News

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