Tracing the start of COVID-19 in GA

At a time when COVID-19 appears to be receding in much of Georgia, it’s worth revisiting the start of the pandemic in early 2020. Emory virologist Anne Piantadosi and colleagues have a paper in Viral Evolution on the earliest SARS-CoV-2 genetic sequences detected in Georgia. Analyzing relationships between those virus sequences and samples from other states and countries can give us an idea about where the first COVID-19 infections in Georgia came from. We can draw Read more

Reddit as window into opioid withdrawal strategies

Drug abuse researchers are using the social media site Reddit as a window into the experiences of people living with opioid addiction. Abeed Sarker in Emory's Department of Biomedical Informatics has a paper in Clinical Toxicology focusing on the phenomenon of “precipitated withdrawal,” in collaboration with emergency medicine specialists from Penn, Rutgers and Mt Sinai. Precipitated withdrawal is a more intense form of withdrawal that can occur when someone who was using opioids starts medication-assisted treatment Read more

CROI: HIV cure report and ongoing research

The big news out of CROI (Conference on Retroviruses and Opportunistic Infections) was a report of a third person being cured of HIV infection, this time using umbilical cord blood for a hematopoetic stem cell transplant. Emory’s Carlos del Rio gave a nice overview of the achievement for NPR this morning. As del Rio explains, the field of HIV cure research took off over the last decade after Timothy Brown, known as “the Berlin patient,” Read more

microbiology

New animal model for elimination of latent TB

The significance of a recent Tulane/Yerkes study on eradicating latent tuberculosis in non-human primates may not be apparent at first glance. After all, it used the same antibiotic regimen (isoniazid + rifapentine) that is recommended by the CDC for human use.

But consider whether someone who was exposed to TB in childhood might still have it in their lungs somewhere. It’s difficult to know if treatments get rid of the bacteria completely.

“The antibiotic treatment we used for this study is a new, shorter regimen the CDC recommends for treating humans with latent tuberculosis, but we did not have direct evidence for whether it completely clears latent infection,” says Yerkes/Emory Vaccine Center researcher Jyothi Rengarajan, who was co-principal investigator along with Deepak Kaushal of Tulane. “Our experimental study in macaques showing almost complete sterilization of bacteria after treatment suggests this three-month regimen sterilizes humans as well.”

In an editorial in the same journal, CDC and Johns Hopkins experts call the results “dramatic” and say application of the drug regimen “could presage a major step forward in TB prevention and control.” Read more

Posted on by Quinn Eastman in Immunology Leave a comment

Antibiotic resistance enzyme caught in the act

Resistance to an entire class of antibiotics – aminoglycosides — has the potential to spread to many types of bacteria, according to new biochemistry research.

A mobile gene called NpmA was discovered in E. coli bacteria isolated from a Japanese patient several years ago. Global spread of NpmA and related antibiotic resistance enzymes could disable an entire class of tools doctors use to fight serious or life-threatening infections.

Using X-ray crystallography, researchers at Emory made an atomic-scale snapshot of how the enzyme encoded by NpmA interacts with part of the ribosome, protein factories essential for all cells to function. NpmA imparts a tiny chemical change that makes the ribosome, and the bacteria, resistant to the drugs’ effects.

The results, published in PNAS, provide clues to the threat NpmA poses, but also reveal potential targets to develop drugs that could overcome resistance from this group of enzymes.

First author of the paper is postdoctoral fellow Jack Dunkle, PhD. Co-senior authors are assistant professor of biochemistry Christine Dunham, PhD and associate professor of biochemistry Graeme Conn, PhD. Read more

Posted on by Quinn Eastman in Uncategorized 1 Comment

C. difficile: its name says what it is

If you’re looking for an expert on the “notorious” bacterium Clostridium difficile, consider Emory microbiologist Shonna McBride.

C. difficile is a prominent threat to public health, causing potential fatal cases of diarrheal disease. C. difficile can take over in someone’s intestines after antibiotics clear away other bacteria, making it dangerous for vulnerable patients in health care facilities. Healthcare-associated infections caused by other types of bacteria such as MRSA have been declining, leaving C. difficile as the most common cause, according to recently released data from the CDC.

Shonna McBride, PhD

McBride’s work focuses on how C. difficile is able to resist antimicrobial peptides produced by our bodies that keep other varieties of bacteria in check.

A 2013 paper from her lab defines genes that control C. difficile’s process for sequestering these peptides. It appears that its ability to resist host antimicrobial peptides evolved out of a system for resisting weapons other bacteria use against each other.

Since C. difficile requires an oxygen-free environment to grow, studying it can be more difficult than other bacteria. The McBride lab has a recent “video article” in the Journal of Visualized Experiments explaining how to do so using specialized equipment.

McBride explains in a recent Microbe magazine cover article that C. difficile’s ability to form spores is connected to the threat it poses:

Without the ability to form spores, the strict anaerobe C. diffıcile would quickly die in the presence of atmospheric oxygen. However, the intrinsic resilience of these spores makes them diffıcult to eradicate, facilitating the spread of this pathogen to new hosts, particularly in health care settings where they withstand many of the most potent disinfectants.

Yet the process of sporulation is markedly different in C. difficile compared with other kinds of bacteria, she says in the review.

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