As we’ve seen in numerous cases in 2015, food contamination is a real issue for a number of different food types. Vegetable, meat, packaged, fresh – even pet food – we’ve seen too many examples of how bacteria can outsmart our best food safety practices. The Canadian government estimates 1 of every 8 Canadians experiences food-borne illness each year, leading to 11,600 hospitalizations and 238 deaths. As we’ve often discussed on this blog, a common culprit for food contamination is Listeria monocytogenes, in part because of Listeria’s ability to grow in food storage conditions.
Monday, 04 January 2016 10:48

Cyclic-di-GMP takes center stage

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How does a single-celled organism ‘know’ how to respond to its environmental conditions? Understanding microbial cell signaling is one way to determine how bacteria will react in a particular setting. In the past decade, researchers have revealed a significant role for cyclic-di-GMP in bacterial signaling – so much so that the Journal of Bacteriology has devoted its first issue of the year to summarizing a recent conference on cyclic-di-GMP discoveries.
Tuesday, 29 December 2015 10:34

Looking back at 15 top stories from 2015

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In June 2015, mBioblog became mBiosphere, expanding its scope to all of the research journals published by the American Society of Microbiology. To commemorate the end of the year, we’d like to highlight our most popular stories since the switch. The below stories are fifteen of the top stories from 2015 (post-mBiosphere) – how many do you remember?
Regular readers will know that infectious disease issues often land the top billing in microbial news. However, most of our microbial interactions do not negatively impact our health – in fact, some interactions even lead to health improvements. The microbes that lead to these beneficial interactions are called probiotics. These probiotic microbes can be found in many niches of the body, but are most commonly studied with respect the gut microbiome. There, probiotic effects can range from stimulating or regulating the immune system, to promoting healthy division of mammalian cells, to stimulation of nutrient absorption and digestion. Some of the best-studied…
Monday, 14 December 2015 10:31

Albumin enhances antifungal drug activity

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How do we know the effective dose of antibiotics? Despite considering factors such as infection site, body weight, and age, there is a bit of unknown with each administration, since each individual reacts differently through the complexity of so many interacting variables. Additionally, each infection site is unique, with various oxygen levels, antimicrobial peptide production, and immune cell infiltrate affecting the host-microbe interactions. Finally, factors unique to each drug must be considered, including half-life, toxicity, and specificity.
Thursday, 10 December 2015 10:13

Should I stay or should I go: Pseudomonas edition

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The ability of bacterial cells to hunker down as resilient biofilms is an important mechanism used to respond to stress. So is the ability to swim away from a nutrient-poor or stressful environment (for those bacteria lucky enough to be motile). Stay versus go: it’s a primal precursor to fight-or-flight decisions. But as single-celled organisms, bacteria don’t ‘decide’ to initiate biofilm formation versus motility machinery – so how do these cells determine which behavior to commence?
Monday, 07 December 2015 10:12

Advances in antimicrobial peptide applications

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Drug-resistant infections are a problem. Does it even need to be said? International campaigns have done their best to raise awareness, but even if all of humanity agreed to be on their best behavior, it seems the best we might do is slow the inevitable spread of already-identified resistance genes. Microbes have several advantages against our cleverest attempts: they multiply rapidly, they share genes readily, and there are just a dang lot of them. Last month, a gene that confers drug-resistance against the polymyxin colistin, the latest drug of last resort, was found to be widespread in China. How to…
It goes without saying that both patients and their doctors want to treat infections as quickly and successfully as possible. Unfortunately, when it comes to traditional diagnostic methods, culturing a microorganism can take several days – time during which the microbes may be multiplying and the infection spreading. Slower-growing organisms, such as fungi, can take weeks to identify with culture methods. Acquiring the resistance profile of these organisms takes additional precious time, during which the patient caregivers must make their best guess at the infection source and susceptibility.
In the happy afterglow of Thanksgiving, many Americans will have leftovers for reheating and turning into sandwiches. Unfortunately, there might not be as much leftover turkey as in previous years because of the price increase this year. The cause of the recent jump in turkey price talk? Good, old-fashioned supply and demand – while the number of people eating turkey for Thanksgiving remained the same, the supply was decimated this year by avian influenza (although most reports now state that most consumer prices weren’t affected by this epidemic).
Tuesday, 24 November 2015 09:55

Finessing cocoa fermentation

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Food microbiology, the most delicious of all microbiology fields, encompasses many subfields, one of which is fermentation processes. Lots of foodstuffs require microbial metabolic processing to change the chemical composition of food or drink – from fermenting ethanol in alcoholic beverages to lactic acid in cheese and yogurt, microbes contribute a good deal to the everyday foods we eat.
Friday, 20 November 2015 09:54

ICE-ing out antibiotic resistance

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There’s no question antibiotic resistance is one of the major medical issues of our era. The numbers are stark: 23,000 deaths from drug-resistant infections in the United States alone each year (25,000 in the European Union). Hospitals spend billions more on patients who require 8 million days of extra care. These numbers, while striking, are less important than the experience many have had with patients, friends, or family members suffering with an infection not responding to treatment.
Each person’s gut is home to tens of trillions of microorganisms. These organisms can live in the gut and not cause any problems. In some people, however, a microorganism can take up residence in another part of the body and cause disease. Candida albicans is one example.
Tuesday, 17 November 2015 16:38

Tracking a Deadly Fungal Foe in Snakes’ Skin

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It’s never a dull day for Jeffrey Lorch and his colleagues at the U.S. Geological Survey’s National Wildlife Health Center in Madison, Wisconsin who track unexplained mortality and emerging diseases in wild animals. Think of it as a cross between CSI: Animal Kingdom and a zoological CDC.
Earlier today, I wrote about biofilms and the negative consequences they can have on human health during infection. Much discussion of biofilms centers around the interaction of pathogenic microbes and their abilities to form during infection. However, as I alluded to in the introduction, biofilms are important in many nonmedical aspects of life – they contaminate cargo ships, food processing centers (including your kitchen), as well as occur naturally in many environmental settings.
Biofilms – the bane of dentists and cargo ships alike – are a form of surface-attached microbial growth that is especially hardy. The cellular community not only changes its genetic expression patterns to increase resiliency under harsh conditions such as chemical or immunological attack, but the extracellular matrix in which the microbes reside adds a layer of protection. Newly published research support that these two phenomena – the gene expression pattern changes and the physical encasement by the matrix – are related.
Although there has been some movement toward more judicious use of antibiotics, there are still people who take the drugs thinking it will help the common cold, and dentists who regularly prescribe antibiotics for patients prior to some common oral surgeries like third molar extraction.
The relatively new field of extracellular vesicle study (see graph with increasing Pubmed search hits) has found these amazing objects to carry out many different functions for many different cell types. Extracellular vesicles are membrane-bound structures that are released away from cells into the environment. These vesicles carry signaling molecules, nutrient scavenging molecules, immune-modulating molecules – the list goes on and on. Every cell type examined produces vesicles, too: bacterial, protozoan, archaeal, and metazoan extracellular vesicles have been described with many different biological effects.
Wednesday, 28 October 2015 16:18

‘Jazzing up’ the seasonal flu vaccine

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University of Melbourne immunology researchers Brendon Chua and David C. Jackson have been working together for 10 years on how to build a better vaccine.  Their close collaboration sometimes results in them finishing each other’s sentences.  But now, it has also resulted in a multi-tasking, powerhouse of a flu vaccine.  At least in mice, that is.
We discuss the problem of antibiotic resistance a lot on this blog. With increases in the number of infectious diseases that no longer respond to drugs that were once effective, this effort makes sense. However, some diseases have never responded well to antibiotic treatment in the first place. Mucormycosis, also called zygomycosis, is one of these diseases.
Bacteriophage are viruses that target a bacterial host for infection. Their specificity is often constrained not only by a particular species, but can also be restricted to infect only a specific strain of that particular species.