Resistance genes in the hand microbiome

Background

There are major socio-economic gains to be made from reducing the spread of disease-causing viruses and microorganisms in the home and public environment. In addition, reducing the spread of infection is a strategic priority area in the WHO's work to limit unnecessary antibiotic use and the development of resistance in society. Effective hygiene products and disinfectants for professional and private use are crucial in this work.

In order to be long-term effective against the spread of infection in society, it is of great importance that repeated use of these products does not harm the natural microbiota present on our skin, as the skin's normal microbiota is an important protection against infections. These products should also not cause resistance selection, as resistance to disinfectants may also give rise to increased resistance to antibiotics.

Challenge

Given the extensive societal challenges we face globally linked to increased problems with antibiotic and biocide resistance, there is today a great need for broader knowledge regarding the development of resistance. As a result of the rapid development that is now taking place in microbiology and virology in terms of tools for whole-genome sequencing and bioinformatics, there are today great opportunities to build new crucial knowledge and actively work to reduce the spread of resistance in society.

Methods

The project further develops and adapts a methodology for whole genome sequencing that is suitable for mapping resistance genes to antibiotics and biocides in microorganisms. This methodology was adapted for studies of the microflora on both hands, surfaces and in complex biological samples. In a study consisting of twelve subjects, the presence of resistance genes in the normal flora of the hands was mapped and quantified before, during and after a long-term use of long-acting disinfectants. 

Culture-based methodology was established and applied for studies of links between biocide resistance and antibiotic resistance, so-called cross-resistance. Specifically, in vitro studies were performed on how skin bacteria's resistance to the biocide benzalkonium chloride can arise, and how the cross-resistance to certain antibiotics then increases. To evaluate the societal relevance of the induced resistance, the most resistant bacteria were completely sequenced and the DNA code was compared with resistance genes identified in hospital samples.