Battles Between Bacteria and Viruses May Improve Personalized Care

Battles Between Bacteria and Viruses May Improve Personalized Care

Highly personalized oral health care may be achievable based on recent findings about the human oral microbiome in a broad analysis of the human bacterial immune system. Results of the study published in Genome Research explain the defense mechanisms of microbes in the oral cavity are unique and traceable, and offer the potential to provide information to construct effective, individualized treatment for oral diseases. The report illuminates how speedy communication and adaptability make bacteria resilient, and hints at better understanding of how they might be overcome as causes of harmful disease.

When viruses attack bacteria the attack triggers changes in the bacterial communities. Inside a single bacteria, strands of DNA reserve space where they can hold data about foreign matter that has attacked them. Bacteria use the information stored in this space to recognize and respond to future attacks by the same foreign matter, which in some cases may be a virus. “We knew that bacteria developed specific resistance to viruses, but before this study we had no idea of the extent to which certain oral bacteria in humans have utilized these resistance mechanisms against viruses,” notes David Pride, MD, PhD of the University of California, San Diego (UCSD).

Viruses can determine which bacteria are present in a bacterial community by the strains of microbes they kill off and the strains they leave behind. Pride says he thinks viruses are the primary mechanisms by which new genes come in and out of the bacterial community.

In the study saliva samples were collected from four human subjects considered periodontally healthy. The subjects were studied from an 11-month to 17-month period and had their genetic sequences analyzed to determine the dominant ways in which the immune repertoires of oral streptococcal microbes would behave. Researchers found that the genetic sequences of the streptococcal bacteria changed “a remarkable amount” even when measured over short periods. Pride observed that DNA sequences inside the genes of microbes appeared to change on nearly a daily basis.

“Each time we sampled our human subjects, approximately one-third of the immune repertoire in the bacterial community was new,” Pride says.

The study helped reveal that in humans the features of the bacterial immune response can be used to track bacteria and their viruses. Being able to trace the lineages of microbes, Pride emphasizes, will possibly increase the level of personalization that can be applied to oral health care.

Pride told GenomeWeb.com his future research efforts would explore how the genetic sequences, viruses and bacteria interact in the oral microbiome, and seek to learn more about how they “differ between oral health and folks who have periodontal diseases or gingivitis.”

Source: Genome Research; University of California, San Diego; GenomeWeb.com