Investigating ‘underground’ habitat of Listeria bacteria

The literature describes Listeria as ubiquitous bacteria with widespread occurrence. Yet they only become a problem for humans and animals when they contaminate food processing facilities, multiply, and enter the food chain in high concentrations. An infection with Listeria monocytogenes can even be fatal for humans or animals with weakened immune systems. Listeria in soil or water represent a relatively low risk to humans,” explains study director Beatrix Stessl. “The concentrations are too low. The aim of our study was to ascertain where Listeria occur and which species and genotypes were prevalent there.” Martin Wagner, head of the Institute of Milk Hygiene, adds: “This information can help us to better understand the mechanisms through which these bacteria are spread.” Over a period from 2007 to 2009, first author Kristina Linke and her colleagues collected nearly 500 soil and 70 water samples from three Austrian regions: the eastern Alps, the Donauen National Park adjacent to the river Danube, and Lake Neusiedl. The study regions involved natural, non-agricultural areas. Of all samples, 30 percent were detected positive for Listeria. Of these, 6 percent were contaminated with Listeria monocytogenes, the only species that is potentially dangerous for both humans and animals. L. monocytogenes was detected especially near the rivers Schwarza and Danube. Particularly high rates of the bacteria in soil and water samples were registered in September 2007 during extensive flooding in the region. In most regions, the researchers found only Listeria that are non-pathogenic to humans. The species Listeria ivanovii, which is potentially dangerous for animals, was found mainly in mountainous regions where the bacteria are presumably excreted by wildlife species. The non-pathogenic Listeria seeligeri was most frequently isolated in the region around Lake Neusiedl, which is likely explained by the waterfowl population in this area. No Listeria were isolated in high-altitude mountain regions. The researchers explain the greater contamination at lower altitudes with the proximity to farms, agricultural land and the urban environment. Although Listeria that contaminate food are generally not considered to be resistant to antibiotics, Stessl and her team found several Listeria strains in soil samples which resisted treatment with antibiotics. The bacteria have developed resistance. Stessl sees the possible causes as follows: “A number of soil microorganisms, such as fungi, naturally produce antibiotics. Listeria which are constantly exposed to these substances in the soil probably develop resistance. We believe, however, that the development of particularly high-resistant strains of Listeria can be explained by the proximity to agricultural land and the urban environment.”  Science Daily  Original web page at Science Daily


Obituary Dr. Fritz Huchzermeyer

Dr. Fritz Huchzermeyer Dr. Fritz Huchzermeyer

(12 January 1930 – 3 March 2014)

It is with great sadness that I announce the passing of Dr. Fritz Huchzermeyer, Pretoria, South Africa – a prominent veterinary scientist, a creative mind and a good friend; you will remember: he was the author of our last Editorial, the linguistic analysis of the word Nandu.

To talk about Fritz only in veterinary terms is impossible, and the Nandu editorial proves what I mean. He was the most colorful character I have met in the science arena, an ever curious personality, a thoughtful individual who merits to be remembered for many reasons. Rather than trying to picture my own experiences with him since early students’ times in Hannover, Germany, I quote from an account of his vita compiled by his wife Hildegard and children David, Philippa and Marie.

“Fritz loved science and knowledge, but also enjoyed painting, sketching, sculpting, cooking, blowing the trumpet, writing and running. Beside his contribution to veterinary science, he has left many rich memories plus an archive ranging from Comrades Marathon silver medals to poetry collections and colorful abstract paintings.

During studies in theology in Vienna, he fell in love with Hildegard back home, whom he had asked to type up an assignment. A change in academic direction was followed by marriage, and soon Hildegard joined him in the study of veterinary science at the University of Hannover.
Here they were surrounded by a circle of family and of individualistic, open-minded and international friends and fellow students. These have remained close to the family ever since. Both Fritz and Hildegard completed one year of their studies at the Ecole Veterinaire Maisons Alfort, France.

Open to adventure, Fritz accepted a posting to the then Rhodesia as field veterinarian. In 1975 he took up a senior lecturer post in poultry diseases at the Veterinary Faculty in Onderstepoort. Hildegard became his colleague across the road at the Institute. Refuge from segregated and regulated South African society was found on a thornveld smallholding in Buffeldrift with many unconventional pets and in a growing collection of books in the various languages mastered by Fritz. Through a technical exchange, Fritz took the family to Paraguay for the year 1980. While working at the Veterinary Faculty in Asuncion, he immersed them in Spanish and Guarani and in friendships with diverse Paraguayans met while out jogging. He later moved to the Onderstepoort Veterinary Institute working in poultry and then in pathology, branching into specializations in ostrich and crocodile diseases. This work continued until two months before his death, when he handed his accumulated collections over to colleagues whom he had mentored.

After retirement, Fritz completed his PhD. He remained much sought after as crocodile and ostrich specialist, writing and publishing authoritative texts and being invited by farmers and associations around the world (particularly as chair of the Veterinary Group in the Crocodile Specialist Group, IUCN). One of several trips involved an 11-day crossing, by foot, of the unmapped Likouala swamp in a remote region of the Congo, in search of dwarf crocodiles. Tortoises and other interesting animals were part of his home life, and these featured in his most pleasant dreams.”

In collaboration with paleontologists in China, Dr. Huchzermeyer co-authored an article published last year in Nature. The paper reported the preservation of ovarian follicles in Mesozoic birds and the early evolution of avian reproductive behavior. Crocodilians and birds are closely related to dinosaurs and have served as models to explore the reproductive behavior of the theropods.

It would have been in Fritz’ spirit to conclude this obituary with one of his poems:

To the Sacred Crocodiles of Burkina Faso
(Montélimar, July 2006)

Feared and ferocious predator, what is it
That you can live in harmony with man
When you are sacred and revered,
And when you are accepted as an equal
That – even when your lake is dry –
The villagers will share their home with you?
We know already that you are a gentle parent,
And yet it is so difficult to understand
Your very motions and emotions.
We cannot read expressions in your face
And only barely in your voice;
In our ignorance we will behave
So much more brutally than you.

It is my dream that all of us
Could live in harmony with all the crocodiles
As is the case
In a small part
Of Africa.

Marian C. Horzinek


Long-acting shot prevents infection with HIV analogue

A study in macaques has raised hopes that preventing HIV infection in humans will soon be as easy as a shot in the arm four times a year. In a proof-of-concept study, researchers have shown that an antiviral drug injected into the muscle protects monkeys from infection for weeks afterward. “We believe it’s a very practical, feasible approach to HIV prevention,” says David Ho, a virologist at the Aaron Diamond AIDS Research Center in New York and a co-author of the study, which is published online today in Science. In the absence of a proven vaccine, ‘pre-exposure prophylaxis’ with drugs used to treat the infection has become one of the most promising strategies to cut down HIV infection rates among high-risk populations, including people living in sub-Saharan Africa, intravenous-drug users and men who have sex with men. A 2010 study found that among men who have sex with men, those who took a combination of tenofovir and emtricitabine daily reduced their risk of contracting HIV by more than 90%. However, not everyone in the trial — which lasted for several months — took the medication every day, and among all participants who received the pill, HIV infection rates dropped by only 44%. Ho and his colleagues, who include researchers from drug-maker GlaxoSmithKline in Research Triangle Park, North Carolina, studied an experimental drug called GSK744. GSK744 is a highly potent analogue of dolutegravir (sold as Tivicay), which was approved by the US Food and Drug Administration for HIV treatment last year.

GSK744 works by interfering with the enzyme that HIV uses to insert its DNA into the human genome. This blocks the key step needed for the AIDS virus to replicate itself, and the viral DNA simply degrades inside the cell. Turning the drug into an injection depended on its chemical properties. Because GSK744 is not soluble in water, the researchers melted it and crystallized it into nanoparticles, which they suspended in solution. When this fluid is injected into muscle, Ho explains, it forms a ‘depot’ and slowly seeps into the blood and tissues, including the rectum, where HIV exposure can occur. “The depot allows the agent to be around for three to four months,” says Ho. To test the drug’s effectiveness, Ho and his team squirted a solution containing a hybrid of the simian and human AIDS-causing viruses into the rectums of 16 macaque monkeys once a week for eight weeks. Half of the macaques received two injections of GSK744 during that period. The other half, which served as the control group, did not. All the macaques in the control group became infected, typically within two weeks. All of the macaques receiving GSK744 were protected.

A follow-up experiment showed that a single dose of GSK744 protected monkeys for 5–10 weeks on average. Because humans metabolize the drug much more slowly than macaques do, Ho thinks it will remain effective in humans for up to three months. Jonathan Mermin, director of the US National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention at the US Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, says that the CDC is presenting data from a similar study in macaques this week at the Conference on Retroviruses and Opportunistic Infections in Boston, Massachusetts. He says that those results show that the shot is also effective warding off infections after exposure through the vagina, and that it is now time to start testing the strategy in humans. “It’s hard to get healthy people to take a pill or put on a salve every day,” notes Robert Schooley, an infectious-disease specialist at the University of California in San Diego, who was not involved in the study. An injection strategy, he says, is “a very important avenue to pursue”.  Nature

March 18, 2014 Original web page at Nature