**10. Future directions of gut microbiota diagnostics**

There is currently a major focus on exploring the gut microbiota. This is mainly done through the application of explorative techniques such as next generation sequencing. The next phase will be the validation where the discoveries are validated using targeted techniques such as microarray analyses or quantitative PCR. The final phase will be to identify correlations between microbiota and disease that will give some added value

Gut Microbiota in Disease Diagnostics 117

could also act as a general help for physicians in determining the best treatment for

Understanding how different bacteria in the gut influences the metabolism of drugs and foodstuff, leads to a more personalized, tailor-made drug treatment regime. Since it is generally recognized that the composition of the gut microbiota has a profound effect on health as well as how foodstuff and drugs are metabolized, a profiling of the gut microbiota would constitute an important aspect of the personalized medicine approach. It is expected that personal medicine would lead to more effective treatments, as well as cost-saving on

The search for a common core gut microbiota has revealed that each individual has a unique and fairly stable microbiota, at least in adults. Therefore, each individual's own microbiota may be the best control for that person. This calls for routine checks where deviations from its own "normal" core microbiota will be evaluated. Such a test would also include other genetic and physical markers, which combined would give a status of the individual's

With future technical development we believe the next generation gut microbiota diagnostic will integrate phylogeny and functionality of the gut microbiota. A functionality that is particularly relevant is antibiotic resistance. There is currently a major fear for the development of multi-resistant pathogens, and that the current treatment regimes with broad-spectrum antibiotics will eradicate beneficial bacteria. In this regard targeted narrow spectrum antibiotics could be the solution. Narrow-spectrum antibiotics, however, would require better diagnostics of the actual disease causing organisms. Therefore, a profiling of the gut microbiota may be essential prior to administration of such narrow antibiotics to

Another aim in treatment of gut microbiota disorders is to restore the diseased gut microbiota towards the healthy state. This could be done either through tailor-made administration of probiotics, prebiotics and antibiotics, or a combination of these substances. Another approach would be to transplant the gut microbiota from close relatives or samples from the same individual collected before disease occurs. Such an approach would resemble what is currently done for treatment of *Clostridium difficile* infections where the gut

As more data are being generated, the importance of the gut microbiota on health will become more recognized. The advancement in characterizing the composition of the gut microbiota in humans paves the way for new and better health treatments. The techniques used for exploring the gut microbiota and characterizing the functions of the microbiota, may not necessarily be the same techniques used to diagnose and monitor treatment of gut health related diseases. The GA-map assay is a promising tool for the development of gut microbiota diagnostics in routine applications. Such assays has the potential to be set up as a high through-put service, and can also be incorporated into smaller Point-of-Care devices,

healthcare budget due to optimizing the drug treatment for each person.

3. **Deviations from each individuals normal flora** 

patients.

health condition.

ensure optimal treatment.

**11. Conclusions** 

microbiota is transplanted from relatives.

2. **Personalized medicine** 

Fig. 8. Illustration of the GA-map diagnostic procedure. The GA-map assay will initially be offered through centralized service labs. A database covering relationships between profiles and disease will constantly be updated based on accumulated information, and a web-based interface with the customers will be available.

through diagnostics. This would open up for various applications of tests for profiling the gut microbiota in disease management.

As the importance of the gut microbiota on health becomes more established and recognized, profiling the composition of the gut microbiota will become an important diagnostic and prognostic tool in the future. This will give an additional window for health professionals to assess the conditions of the patient.

As technology advances and miniaturization and sophisticated Point-of-Care devises are being developed, such comprehensive tests will become easier to perform and more affordable. We see at least three areas where such a test would be applied in health care in the future:

#### 1. **Disease specific diagnostics**

As discussed in this paper, certain health conditions are related to imbalance in the gut microbiota. A test that can correlate imbalances in the gut microbiota to specific health conditions will have a value as a diagnostic and prognostic tool. Furthermore, such tests could also act as a general help for physicians in determining the best treatment for patients.

#### 2. **Personalized medicine**

116 New Advances in the Basic and Clinical Gastroenterology

SERVICE LAB

Updating of Database

• Sample received • DNA purification

• Analysis of results

• PCR • Labeling • Hybridization • Scanning

Fig. 8. Illustration of the GA-map diagnostic procedure. The GA-map assay will initially be offered through centralized service labs. A database covering relationships between profiles and disease will constantly be updated based on accumulated information, and a web-based

through diagnostics. This would open up for various applications of tests for profiling the

As the importance of the gut microbiota on health becomes more established and recognized, profiling the composition of the gut microbiota will become an important diagnostic and prognostic tool in the future. This will give an additional window for health

As technology advances and miniaturization and sophisticated Point-of-Care devises are being developed, such comprehensive tests will become easier to perform and more affordable. We see at least three areas where such a test would be applied in health care in

As discussed in this paper, certain health conditions are related to imbalance in the gut microbiota. A test that can correlate imbalances in the gut microbiota to specific health conditions will have a value as a diagnostic and prognostic tool. Furthermore, such tests

CUSTOMER

Sample collection

Reply back to MD

the future:

interface with the customers will be available.

professionals to assess the conditions of the patient.

gut microbiota in disease management.

1. **Disease specific diagnostics** 

Questionnaire

Understanding how different bacteria in the gut influences the metabolism of drugs and foodstuff, leads to a more personalized, tailor-made drug treatment regime. Since it is generally recognized that the composition of the gut microbiota has a profound effect on health as well as how foodstuff and drugs are metabolized, a profiling of the gut microbiota would constitute an important aspect of the personalized medicine approach. It is expected that personal medicine would lead to more effective treatments, as well as cost-saving on healthcare budget due to optimizing the drug treatment for each person.

#### 3. **Deviations from each individuals normal flora**

The search for a common core gut microbiota has revealed that each individual has a unique and fairly stable microbiota, at least in adults. Therefore, each individual's own microbiota may be the best control for that person. This calls for routine checks where deviations from its own "normal" core microbiota will be evaluated. Such a test would also include other genetic and physical markers, which combined would give a status of the individual's health condition.

With future technical development we believe the next generation gut microbiota diagnostic will integrate phylogeny and functionality of the gut microbiota. A functionality that is particularly relevant is antibiotic resistance. There is currently a major fear for the development of multi-resistant pathogens, and that the current treatment regimes with broad-spectrum antibiotics will eradicate beneficial bacteria. In this regard targeted narrow spectrum antibiotics could be the solution. Narrow-spectrum antibiotics, however, would require better diagnostics of the actual disease causing organisms. Therefore, a profiling of the gut microbiota may be essential prior to administration of such narrow antibiotics to ensure optimal treatment.

Another aim in treatment of gut microbiota disorders is to restore the diseased gut microbiota towards the healthy state. This could be done either through tailor-made administration of probiotics, prebiotics and antibiotics, or a combination of these substances. Another approach would be to transplant the gut microbiota from close relatives or samples from the same individual collected before disease occurs. Such an approach would resemble what is currently done for treatment of *Clostridium difficile* infections where the gut microbiota is transplanted from relatives.
