What Legionnaires' and Cyclospora Reveal about a Warming World

As New York City investigates new cases of Legionnaires' disease and health officials continue responding to Cyclospora outbreaks linked to contaminated produce across the US, there's another story that's getting little attention:

Climate change is becoming one of the defining public health challenges of our time.

Dr. Tyler Evans, infectious disease physician, CEO of Wellness Equity Alliance, and author of Pandemics, Poverty, and Politics, can discuss why recent outbreaks are reminders that climate change is increasingly a public health crisis.

Key Discussion Points:

• Extreme heat creates the conditions for disease. Hotter summers warm building water systems, making it easier for Legionella bacteria to multiply in cooling towers and plumbing if maintenance falls behind. At the same time, heavier rainfall and flooding increase the chances that produce becomes contaminated with pathogens like Cyclospora.

• Infrastructure is becoming a climate vulnerability. Legionnaires' disease and Cyclospora are often described as isolated outbreaks, but both expose aging water, sanitation, and food systems that are struggling to withstand more frequent heat extremes and severe weather.

• Climate change magnifies existing inequities. The same neighborhoods that experience the hottest temperatures because of decades-old redlining often have older housing, aging infrastructure, higher rates of asthma and chronic disease, and fewer resources to recover from environmental health threats. Climate doesn't create these disparities—it amplifies them.

• Environmental policy is infectious disease policy. Conversations about clean water, resilient infrastructure, urban cooling, and emissions reduction are also conversations about preventing future outbreaks. Public health and climate resilience are no longer separate issues.

• The Fourth of July heat dome showed what comes next. More than 185 million Americans were under extreme heat warnings, and dozens died from heat-related illness. Heat is the most visible climate health threat, but it's also quietly increasing risks for waterborne and environmentally driven infections that receive far less attention.

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)

Anthrax‑causing bacteria have dwelled in soil for centuries

 

Throughout history, humans and animals have seeded new lands with Bacillus anthracis spores. The spores are hardy travelers: They can survive for over 50 years and are resilient to dehydration, radiation, toxic chemicals and enzymatic degradation.

Anthrax in early Egypt may have been one of the plagues described in the Bible. Animal husbandry texts in China have described anthrax for millennia. French explorers brought Bacillus anthracis spores to American soil in the early 1700s.

While people usually spread anthrax accidentally, there are infamous examples of anthrax spread on purpose.

In the 1930s and ’40s, Japanese military leaders released anthrax spores in Chinese villages, killing thousands of people. On Sept. 18, 2001, envelopes of spores were mailed to American media and congressional leaders, killing five people.

The weaponized use of Bacillus anthracis spores brings to mind white powder rather than the brown earth where they naturally lie.

This is an article extract by Hannah Kinzer (Ph.D. Candidate in Public Health, Washington University in St. Louis). The full article can be found here. 

 

Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)

On oral fecal microbiota transplantation

 

Could fecal microbiota transplantation help patients heal after stem cell transplantation?

A new study published in Nature Communications shows that oral fecal microbiota transplantation (FMT) is a safe addition to preventing graft-versus-host disease in patients undergoing stem cell transplantation for blood cancers. This research is part of a phase 2 clinical trial led by Armin Rashidi, MD, PhD, a medical oncologist at Fred Hutch. 

The randomized phase of the trial will study whether FMT improves health outcomes for patients undergoing stem cell transplantation, such as less acute graft-versus-host disease, fewer hospitalizations, fewer infections, better quality of life and longer survival. 

 Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)

Tattoo inks and microbial contamination

This week's article looks at microbial contamination risks associated with tattoo inks and the tattoo process and assesses recently published US FDA guidance: 

https://www.linkedin.com/pulse/tattoos-microbial-infection-risks-tim-sandle-ph-d-cbiol-fisct-eqiue/

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Many tattoo inks are contaminated, although different rounds of laboratory analysis show a degree of variation according to locale and ink source. However, there has been a commonality over the past decade for ~50% of inks found to contain microorganisms (10–80% of unopened commercial tattoo inks are contaminated with microorganisms according to my review of the literature. The populations recovered are up to 3·6 × 10^8 CFU per gram. It should be noted that studies tend to pinpoint higher rates of contamination in North America compared with Europe.

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)

New dual therapeutic strategy shows promise against multidrug-resistant Salmonella

Antibiotic-resistant bacterial infections stand as one of the critical biological threats to human health on a global scale. One example is with multidrug-resistant (MDR) Salmonella enterica. The rise of MDR strains, coupled with the constrained array of treatment options, requires continuous innovation of therapeutic approaches.

 

According to Pharmaceutical Microbiology Resources: “Salmonella enterica serovar Typhimurium bacteria (S. Typhimurium) commonly cause human gastroenteritis, inflammation of the lining of the intestines. The bacteria live inside the gut and can infect the epithelial cells that line its surface.”

 

Image: NIAID, Public Domain, https://commons.wikimedia.org/w/index.php?curid=450281
 

A new study charts the discovery and application of a new therapeutic strategy to target the multidrug-resistant bacterium Salmonella enterica, with promising results.

 

The research was carried out at the University of Eastern Finland, as well as from the Rosario National University, Argentina, and the University of the Republic, Uruguay. The research introduces a strategy to enhance the efficacy of colistin, a last-resort antibiotic.

 

Commenting on this, Senior Researcher Christopher Asquith states: “Through the utilisation of a non-antibiotic anti-virulence quinazoline compound, we investigated a dual-pronged therapeutic methodology.”

 

The combined treatment with the quinazoline and colistin targets Salmonella by simultaneously inhibiting its resistance mechanisms against colistin and disrupting the bacterium’s envelope electrochemical equilibrium.

 

This synergistic interplay not only introduces a new route to counter MDR bacteria but also lays the groundwork for potentially addressing resistance challenges associated with other antibiotics.

 

The quinazoline compound specifically affects the key regulatory pathway used by the bacterium for both the advancement of infection and the development of resistance. The outcomes presented within this study underscore the potential of leveraging this pathway to target bacterial disease.

 

This should also provide a blueprint for tailored interventions beyond Salmonella to a spectrum of bacterial infections.

 

The efficacy of the dual treatment in mitigating mortality was demonstrated using an in vivo insect infection model, presenting promise in terms of future therapeutic applications.

 

The research has been published in the journal Scientific Reports, titled “Enhancing colistin efficacy against Salmonella infections with a quinazoline-based dual therapeutic strategy”.

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)

Respiratory bacteria can 'turn off' our immune system to survive

Image:  Chest radiograph of an 88 year old man, about one week after onset of fever, fatigue and mild coughing. Lab tests detected both Influenza A virus and Haemophilus influenzae. It shows multifocal, patchy consolidation, mainly in the right upper lobe. By Mikael Häggström.

Scientists based at The University of Queensland have identified how a common bacterium is able to manipulate the human immune system during respiratory infections and cause persistent illness.

 

The research studied the virulence mechanisms of Haemophilus influenzae, a bacterium that plays a significant role in worsening respiratory tract infections. These bacteria are especially damaging to vulnerable groups, such as those with cystic fibrosis, asthma, the elderly, and Indigenous communities.

H. influenzae is a Gram-negative, non-motile, coccobacillary, facultatively anaerobic, capnophilic pathogenic bacterium of the family Pasteurellaceae. The bacteria are mesophilic and grow best at temperatures between 35 and 37 °C.

 

The bacterium persists by essentially turning off the body's immune responses, inducing a state of tolerance in human respiratory tissues. To draw on an analogy, the bacterium has a unique ability to 'talk' to and deactivate the immune system, convincing it there was no threat.

 

To demonstrate this, the researchers prepared human nasal tissue in the lab, growing it to resemble the surfaces of the human respiratory tract, then monitored gene expression changes over a 14-day 'infection'. They found very limited production of inflammation molecules over time, which normally would be produced within hours of bacteria infecting human cells.

 

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The researcher next applied both live and dead Haemophilus influenzae, showing the dead bacteria caused a fast production of the inflammation makers, while live bacteria prevented this. This proved that the bacteria can actively reduce the human immune response.

 

The consequence is that in cases where local immunity drops, for example during a viral infection, the bacteria may be able to 'take over' and cause a more severe infection.

 

These findings will lead to future work towards new treatments to prevent these infections by helping the immune system to recognise and kill these bacteria.

 

The research paper is: “Tolerance to Haemophilus influenzae infection in human epithelial cells: Insights from a primary cell-based model”. PLOS Pathogens, 2024; 20 (7): e1012282 DOI: 10.1371/journal.ppat.1012282

 

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)