Scientists from the ADA Forsyth Institute (AFI) have identified a key factor that may contribute to the spread of hospital-acquired infections (HAI), providing new insights into the challenges of combating them. Their research reveals that the dangerous multi-drug resistant (MDR) pathogen, Klebsiella, thrives in nutrient-poor conditions found in hospital environments.

The significance of hospital infections
According to the World Health Organization, hospital infections pose a significant risk to patients, often resulting in prolonged hospital stays, serious health complications, and high mortality rates. One of the most challenging aspects of treating HAI is the pathogens' resistance to multiple drugs. In a recent study published in the journal Microbiome, AFI scientists found that Klebsiella, which colonizes healthy individuals, not only has an inherent MDR capability but also dominates the bacterial community when deprived of nutrients.

Klebsiella in starvation conditions
“Our research shows that Klebsiella can outcompete other microorganisms in its community when deprived of nutrients,” said Batbileg Bor, Ph.D., associate professor at AFI and lead researcher of the study. “We analyzed samples of saliva and nasal fluids to observe Klebsiella’s reaction to starvation conditions. Astonishingly, under such conditions, Klebsiella quickly spreads, dominating the entire microbial community as other bacteria die off.”

Klebsiella is one of the three main pathogens responsible for HAI, including pneumonia and irritable bowel syndrome. As colonizing opportunistic pathogens, they naturally inhabit the oral and nasal cavities of healthy individuals but can become pathogenic under certain conditions. “Hospital environments provide ideal conditions for Klebsiella to spread,” explained Dr. Bor. “Nasal or saliva droplets on hospital surfaces, sink drains, and the mouths and throats of ventilated patients are all starvation conditions.”

Survival and spread of Klebsiella
Dr. Bor further explained: “When a patient is put on a ventilator, they stop receiving food orally, causing the bacteria in their mouth to be deprived of nutrients, allowing Klebsiella to outcompete other oral bacteria. The oral and nasal cavities can thus serve as reservoirs for multiple opportunistic pathogens.”

Long-term presence of the pathogen
Additionally, Klebsiella can derive nutrients from dead bacteria, enabling it to survive for extended periods in starvation conditions. Researchers found that Klebsiella present in oral or nasal samples remained for over 120 days after being deprived of food.

Other significant findings from the study include the observation that Klebsiella from the oral cavity, which contains a diverse microbial community, was less prevalent and abundant than those from the nasal cavity, which is less diverse. These findings suggest that microbial diversity and specific commensal (non-pathogenic) saliva bacteria may play a crucial role in limiting the overgrowth of Klebsiella species.

Association with hospital infections
Revolutionary research conducted by AFI scientists offers new insights into the transmission and spread of hospital infections, paving the way for more effective prevention and treatment strategies. A clear link was found between oral and nasal colonization by Klebsiella and serious hospital infections, highlighting the need for improved hygiene practices and infection control in hospital settings.

Collaborators and funding
Additional collaborators on the project include: Xuesong He, Alex S. Grossman, Jett Liu, Nell Spencer, Wenyuan Shi, and Hatice Hasturk from ADA Forsyth; Daniel R. Utter from the California Institute of Technology; Lei Lei from Sichuan University; Nidia Castro dos Santos from Guarulhos University; and Jonathon L. Baker from the Oregon Health & Science University.

Funding
This research was partially supported by funds from the National Institute of Dental and Craniofacial Research of the National Institutes of Health under grant T90 fellowship (Alex S. Grossman); 1K99DE027719 (Batbileg Bor), 1R01DE031274-01 (Batbileg Bor), and 1R01DE023810 (Xuesong He).

Further research
Continued research is crucial for understanding the mechanisms by which Klebsiella survives and spreads in hospital conditions. Further studies are planned to identify specific genes and proteins responsible for drug resistance and survival in starvation conditions. These results could lead to the development of new therapeutic strategies targeting these key factors and reducing the incidence of hospital infections.

The importance of hygiene
The research emphasizes the importance of strict hygiene measures in hospitals to reduce the spread of Klebsiella and other MDR pathogens. Regular cleaning and disinfection of surfaces, proper sterilization of medical equipment, and educating medical staff on best practices for infection prevention can significantly reduce the risk of HAI. Additionally, the use of protective equipment, such as gloves and masks, is crucial in preventing the transmission of pathogens among patients and medical staff.

Research conclusions
AFI scientists continue to work on research and development of new methods to combat hospital infections. Their work provides a foundation for future research and innovations in the field of medical microbiology, aiming to improve patient health and reduce the incidence of serious infections in hospital environments. Given the resistance of Klebsiella and other MDR pathogens, ongoing collaboration among scientists, medical staff, and healthcare institutions is needed to develop effective strategies to combat these threats.

Source: Forsyth Institute