People who move houses bring along with them most of their belongings. Findings of a new research, however, have revealed that it isn't just kitchen utensils, furniture, tools and other household items that people bring with them when they move from one house to another or stay in a hotel room. They also take along with them the household bacteria.

For the new study which was published in Science on Thursday, Aug. 28, Jack Gilbert, from the Institute for Genomic and Systems Biology of the Argonne National Laboratory in Argonne, Illinois, and colleagues followed seven families comprised of 18 individuals, four dogs and a cat for a period of six weeks. Three of these families moved to new homes during the course of the study.

The researchers asked the participants to take microbial samples daily from parts of their body as well as from household items such as light switches, door knobs and floors. After conducting a DNA analysis of the samples and identifying the different bacteria, the researchers were able to characterize the different species of bacteria for each household and how these microbes change over time.

Gilbert and colleagues also compared the surfaces of the participants' old and new homes and found them to have nearly identical bacterial makeup, which suggests that the household germs travel with family members and can take over new homes.

"The microbiota in each home were identifiable by family," the researchers wrote. "After a house move, the microbial community in the new house rapidly converged on the microbial community of the occupants' former house, suggesting rapid colonization by the family's microbiota."

The researchers have likewise found that each home has a distinct community of bacteria that is unique enough they could identify from which of the seven families an unidentified sample came from and because bacterial signatures are as unique as fingerprints, these could be potentially used in forensic investigations. Bacterial samples, for instance can be used as evidence on who has inhabited a particular home and how recently the home dwellers have left.

The findings of the study may also contribute to a better understanding of how the environment influences a child's development.

"Let's say a kid grows up in an apartment block, without going outside much," Gilbert said. "They're just getting this same human bacteria fed back to them, day after day. This study has made a sort of road map, showing how bacteria move through the home, so you can expose your child to a greater microbial community by hijacking those routes."