The HEALTH | March-April. 2026

Researchers from the Singapore- MIT Alliance for Research & Technology( SMART) worked with collaborators from Nanyang Technological University( NTU Singapore), Massachusetts Institute of Technology( MIT), and the University of Geneva( UNIGE). They found that Enterococcus faecalis( E. faecalis), a bacterium commonly found in the human gut, plays a key role in prolonging infections by altering the wound environment.

The team found that the bacterium produces lactic acid, lowering tissue pH. This acidity disrupts immune function, especially in macrophages- cells that detect and clear infections. As a result, the body’ s early warning system is suppressed, allowing infections to persist or worsen.

DISRUPTED CELL SIGNALS

Chronic wounds, such as diabetic foot ulcers and post-surgical infections, are highly susceptible to these mechanisms. These wounds often heal slowly and can lead to complications, including amputation, increasing strain on patients and healthcare systems.

The findings were published in Cell Host & Microbe in a paper titled“ Enterococcus faecalis-derived lactic acid suppresses macrophage activation to facilitate persistent and polymicrobial wound infections.” The research also explains why multi-bacterial infections are common in chronic wounds. By weakening immune defences, E. faecalis creates favourable conditions for other microbes such as Escherichia coli( E. coli) to thrive.

A mouse wound model supported the findings. Strains of E. faecalis that produce lactic acid elicited weaker immune responses and slower recovery. In contrast, strains unable to produce lactic acid were cleared more efficiently, and stronger immune responses were observed.

“ Chronic wound infections often fail not because antibiotics are powerless, but because the immune system has effectively been‘ switched off’ at the infection site. We found that E. faecalis floods the wound with lactic acid, lowering pH and muting the NF-κB alarm inside macrophages – the very cells that should be calling for help.

“ By pinpointing how acidity rewires immune signalling, we now have clear targets to reactivate the immune response,” said the first author of the paper, Dr Ronni da Silva, who is also the Research Scientist at SMART AMR, SCELSE-NTU Visiting Researcher.

Furthermore, the corresponding author of the paper and Principal Investigator at SMART AMR, SCELSE- NTU Visiting Academic and Professor at UNIGE, Prof Kimberly Kline, explained that:“ This discovery strengthens our understanding of host-pathogen interactions and offers new directions for developing treatments and wound care that target the bacteria’ s immunosuppressive strategies.

“ By revealing how the immune response is shut down, this research may help improve infection management and support better recovery outcomes for patients, especially those

DELAYED HEALING: A mouse wound infection model demonstrated that wounds infected with E. faecalis had dampened immunity, allowing E. faecalis to persist and even enabling co-infecting bacteria like E. coli to thrive. The model allowed researchers to study how lactic acid- driven immune suppression promotes persistent, polymicrobial infections.( Photo: SMART AMR)

with chronic wounds or weakened immunity.”

The study points to treatment strategies that restore immune function. These include reducing wound acidity or blocking lactic acid pathways. Such approaches offer new hope for faster, more effective healing.

DISEASE ERADICATED: Leprosy, a long-standing infectious disease brought under control through sustained health efforts in Chile.

HIDDEN WOUND THREAT: Mouse wound infection model showing a circular punchbiopsy wound used to study how bacterial infections progress over time. Researchers tracked how E. faecalis persists in these wounds and how immune responses change during infection.( Photo: SMART AMR)

CHILE has become the first country in the Americas to eliminate leprosy. The World Health Organisation( WHO) verified this after more than three decades without local transmission.

The last locally acquired case was recorded in 1993. Imported cases have been detected occasionally. Despite this, the disease remained under close watch through mandatory reporting, integrated surveillance, and sustained clinical readiness.

An independent expert panel convened in 2025 reviewed national data, surveillance systems, and response capacity. The panel confirmed the absence of local transmission and Chile’ s ability to manage future cases.

Between 2012 and 2023, 47 cases were reported nationwide, none locally acquired.

“ Chile’ s elimination of leprosy sends a clear message to the world: with sustained commitment, inclusive health services, integrated public health strategies, early detection and universal access to care, we can consign ancient diseases to history,” said WHO Director- General Dr Tedros Adhanom Ghebreyesus.

Authorities said continued vigilance will be key to sustaining the achievement.- The HEALTH