AFI study identifies possible new transmission factor in hospital-acquired infections

The ADA Forsyth Institute published a new study that has identified a possible contributing factor to the spread of hospital-acquired infections, offering new insights into the transmission of these infections and why they’re so hard to combat.

A news release reveals that the dangerous multidrug resistant pathogen, Klebsiella species, thrives under nutrient-deprived polymicrobial community conditions that could be found in infected hospital environments. Scientists discovered that Klebsiella colonizing a healthy human oral cavity not only has natural multidrug resistant capability but also dominates the bacterial community when starved of nutrients. 

Klebsiella, more specifically K. pneumoniae, is one of the top three pathogens responsible for hospital-acquired infections. Klebsiella can naturally inhabit the oral and nasal cavities of healthy individuals asymptomatically but can become pathogenic under certain conditions.

Batbileg Bor, Ph.D., associate professor at AFI and principal investigator of the study, noted that the current study took place in a laboratory, and that a thorough clinical study is needed to confirm their results. 

“However, what we’re finding gives insight into what could be happening in the clinic, and these results are concerning. Healthy oral and nasal cavities can be carriers of Klebsiella species, and oral and nasal fluids can easily be released from the body through coughing, sneezing and even just talking.”

Hospital environments provide ideal conditions for Klebsiella to spread to susceptible patients, Dr. Bor explained, because nasal or saliva droplets on hospital surfaces, sink drains and the mouths and throats of patients on ventilators are all starvation environments for polymicrobial communities. 

Dr. Bor concluded that two important discoveries came out of this study.

“First, if a person sneezes on a surface, for instance, and if there is Klebsiella present, Klebsiella will use the other microbes in this starvation condition as a nutrient to outcompete others, and this could lead to higher chances of infection. That’s the transmission mechanism that could be happening, at least for Klebsiella from the oral and nasal cavity,” Dr. Bor said. “Secondly, the healthy oral microbiome itself has some kind of control mechanism to keep these Klebsiella in check. That's very important, and nobody's really thinking about it. Somehow, Klebsiella is staying in low numbers and low prevalence in the oral cavity.”

For more information, visit the full study, published in Microbiome.