Patient-to-patient transmission not main cause of C. Difficile infections in hospitals

Patient-to-patient transmission not main cause of C. Difficile infections in hospitals

Hospital-Acquired Infections: A Lesson in Bacterium Behavior

In a world where hospital infections are unfortunately all too common, a recent study has shaken things up by suggesting that patients themselves may be the source of deadly infections, rather than hospitals. The research focused on Clostridioides difficile, commonly known as C. diff, a bacterium responsible for causing infections that still plague hospitals despite rigorous infection control measures. So, how did the researchers arrive at this patient-centric hypothesis?

To unravel this conundrum, the study examined over 1,100 patients at a Chicago hospital. Shockingly, it was found that around 9% of the patients were “colonized” with C. diff. However, further analysis of almost 4,000 fecal specimens showed very little evidence of the same strains of C. diff between patients, suggesting that in-hospital transmission was not the primary cause of infection. Instead, the research team discovered that patients who already carried the bacterium in their guts, even without symptoms, were at a significantly higher risk of developing symptomatic infections.

In fact, the study found that patients carrying C. diff had a 24-times greater risk of developing healthcare-onset C. difficile infections compared to those who were non-carriers. This indicates that the infection control measures in place at the Chicago hospital, such as regular hand hygiene, environmental disinfection, and single patient rooms, were effective in preventing C. diff transmission between patients.

Lead researcher Evan Snitkin, an associate professor at the University of Michigan Medical School, noted that these findings underline the importance of understanding the triggers that cause patients with asymptomatic C. diff to transition into having infections. This would contribute to further progress in protecting patients from developing C. diff infections.

C. diff, the culprit behind all this trouble, is responsible for nearly half a million infections each year in the United States, with 13,000 to 16,000 deaths reported annually. Hospitalized patients have often been blamed for transmitting the bacterium to one another, but past research has consistently shown that the majority of C. diff infections in hospitals couldn’t be explained by patient-to-patient transmission. The recent study at the Chicago hospital came to the same conclusion.

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However, this doesn’t mean that hospital infection prevention measures aren’t necessary. On the contrary, these measures are likely responsible for the low transmission rate observed in the study. Yet, it is clear that additional steps are required to identify patients who carry C. diff in order to prevent infection.

Hannah Newman, senior director of infection prevention at Lenox Hill Hospital in New York City, emphasizes the challenge of identifying asymptomatic carriers. When individuals show symptoms, it becomes easier to identify and implement necessary infection prevention strategies to prevent the spread of C. diff. However, when patients carry the bacterium in their gut without experiencing symptoms, they are referred to as being colonized.

The exact triggers that lead to a transition from being a carrier to an actively infected state are still unclear, but the use of antibiotics is suspected to play a role. Newman suggests that attention should be given to reducing the risk of developing an infection in asymptomatic carriers by carefully optimizing antibiotic usage and recognizing other risk factors.

Snitkin also believes that antibiotic usage alone may not be the primary cause, stating that while antibiotic disruption of the microbiota is one possible trigger, it does not guarantee infection development in every patient who carries C. diff and receives antibiotics. This suggests that multiple factors may be at play.

According to Donna Armellino, senior vice president of infection prevention at Northwell Health in Manhasset, N.Y., older patients and those who have been previously hospitalized are at the highest risk of carrying C. diff. These patients often experience alterations in their gastrointestinal tract due to surgery, antibiotics, or other mechanisms, leading to symptoms that are then treated with antibiotics.

Interestingly, the study highlighted a significant contrast between the prevalence of C. diff in healthcare settings and the general population. Approximately 5% of individuals outside of healthcare environments have C. diff in their guts, where it typically causes no issues.

Armellino emphasizes that while hospitals can control the environment, they cannot control whether patients are carrying C. diff. It is not typical practice to administer antibiotics to prevent C. diff infections before they occur, although this approach deserves further research.

One possible reason for the low patient-to-patient transmission rate observed in this study is that the ICU where the research took place had private rooms. In many hospitals, patients share bathrooms and are in close proximity to one another, making transmission more likely.

This eye-opening research sheds new light on the complexities of hospital-acquired infections. It challenges the conventional belief that transmission between patients is the primary cause and highlights the importance of understanding the behavior of bacterium within patients themselves. While infection control measures have undoubtedly had a positive impact on reducing transmission rates, further efforts should focus on identifying asymptomatic carriers and minimizing their risk through optimized antibiotic use and other preventive strategies.

The study, published in the journal Nature Medicine, serves as a reminder of the ongoing battle against hospital-acquired infections and the need for continued research and improvements in infection prevention to protect vulnerable patients.