Hospital-Acquired Lung Infection May Travel to Gut, Result in Sepsis: Study

Researchers warn that the bacterium likely reaches other parts of the body when patients swallow saliva and mucus carrying the organism.

New research indicates that lung infections acquired during hospitalization can spread to other parts of the body, potentially leading to life-threatening complications.

According to findings published in the journal Nature Communications on November 25, a bacterium known as Pseudomonas aeruginosa can spread from a patient’s lungs to their gut, causing sepsis, which may eventually lead to death.

Hospital-Acquired Infection Risks

Hospital-acquired infections are illnesses patients contract while receiving treatment for another condition. They can arise in many ways, including surgical site infections, catheter-associated urinary tract infections, bloodstream infections, contaminated medical devices, improperly cleaned equipment, ventilator-related infections and exposure to common bacteria present in healthcare settings.

Recent research has shown just how easily these pathogens can circulate within hospitals. A study published earlier this year indicated hospital sinks are home to dozens of harmful bacteria that can cause hospital-acquired infections and pose serious risks to patients. 

Among the most dangerous outcomes of these infections is sepsis, a life-threatening condition that can quickly spread through the bloodstream and damage multiple organs. According to the U.S. Centers for Disease Control and Prevention, more than 350,000 people die every year in the U.S. from sepsis.

Despite this risk, data suggests that mandated sepsis protocols from the Centers for Medicare & Medicaid Services have not significantly reduced sepsis-related mortality. However, other research indicates that hospitals using systems designed to detect early signs of sepsis can lower deaths from severe infections by as much as 20%.

For the new study, researchers from the Wellcome Sanger Institute in Cambridge, U.K. analyzed DNA taken from hospital patients to understand how bacteria move through the body. The team, led by Dr. Lewis W.S. Fisher, sampled the respiratory systems and gut bacteria of 256 hospital patients.

According to the findings, 84 patients tested positive for the bacteria P. aeruginosa, a common bacterium that can cause serious infections in several body locations, including pneumonia, ear infections, urinary tract infections and wound infections. Among those, 27 patients had the same strain of bacteria in another part of the body.

Researchers found that the same bacteria present in the lungs also appeared in the gut, indicating the infection had spread rather than coming from a new source. They suggested that swallowing saliva and mucus containing the bacteria may be a likely “route of gut colonization.”

“Our data suggests that pervasive P. aeruginosa multi-body site colonisation, particularly within ICUs, likely starts with respiratory colonisation before moving to the gut.”

— Dr. Lewis W.S. Fisher, High frequency body site translocation of nosocomial Pseudomonas aeruginosa

The team recommended that patients infected with P. aeruginosa be viewed as at risk for sepsis that begins in the gut, particularly those already vulnerable to life-threatening complications. This includes older adults and patients who are seriously ill with other conditions.

Researchers warned that their findings highlight how lung infection may cause the spread of major disease by sharing bacteria between multiple body parts. They said the findings should inform future strategies for hospitals to track and prevent sepsis-related deaths.

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