Physicians performing a surgery. Image credit: sasint (CC0)
Many bacteria thrive in moist hospital environments, such as sinks, drains and medical equipment, and pose a significant infection risk. For example, the bacterium Pseudomonas aeruginosa can cause severe infections in patients with burns, wounds or weakened immune systems. This species can further develop resistance to many antibiotics, making infections more difficult to treat and control.
Hospitals use infection prevention programs to detect and limit bacterial spread. But identifying how and where the bacteria persist remains a challenge. To reveal hidden outbreaks and identify environmental sources, scientists have started using genome sequencing – the process of reading a bacterium’s complete genetic code – to monitor how hospital infections begin and propagate.
To underscore the value of this method, Stribling et al. investigated a decades-long Pseudomonas aeruginosa outbreak in a hospital in the United States, despite ongoing infection control efforts. By sequencing the genomes of more than 250 bacterial samples collected over ten years, the team traced the outbreak’s origin to the late 1990s, soon after the hospital opened.
The same strain spread across multiple wards and evolved into two related subgroups. Genetic and environmental analyses revealed that contaminated sink drains acted as long-term reservoirs, repeatedly infecting patients even years apart. The bacteria gradually became resistant to several major antibiotics. Guided by these genomic insights, targeted infection control actions – such as sink decontamination and routine genomic monitoring –finally reduced new infections and helped contain the outbreak.
The findings of Stribling et al. demonstrate how routine genome sequencing can uncover hidden infection routes and guide more effective hospital control measures. Public health systems could use similar approaches to detect outbreaks earlier and prevent prolonged hospital contamination. Before this can become routine, hospitals will need access to affordable sequencing technologies, trained personnel and real-time data sharing. In the long run, such integrated genomic surveillance could protect patients and reduce the global burden of antibiotic-resistant infections.
