Table 2. Prevention of Dysbiosis.

Intervention	Mechanism of action/Application	Advantages	Disadvantages	References
Control measures	-Screening via nasal or rectal swabs for multidrug-resistant organisms. -Good hygiene, environmental cleaning, contact precautions etc.	-Easy to apply.	-Difficult to measure its direct effectiveness.	[103,128-130]
Antimicrobial stewardship programs	-Wise choice of antibiotics (e.g. avoidance of anti-anaerobic antimicrobials) and use of narrow-spectrum agents help to preserve gut microbiota. -Shorter courses of antibiotics lead to fewer microbiota disruptions and easier restoration. -Lower doses of antibiotics result in a lower risk of resistant genes. -Use of antibiotics that are not faecally and/or biliary excreted prevents the development of gut resistance.	-Good rates of preventing infections with multidrug-resistant organisms. -Applicable in every healthcare facility. -No need for adjuvant equipment/substances.	-No many directly focused studies on the colonization of the gut microbiota. -In some cases, it is inevitable to avoid some antibiotics. -Needs coordinated action between many specialties.	[102,103,129,131,136,137,139,140,143,144]
Chelating/degradating agents	-Use of substances such as beta-lactamase enzymes and charcoal-based substances that absorb the remaining amount of antibiotic before reaching the colon protecting this way the gut microbiota without affecting the serum levels of the antibiotic.	-Promising preliminary results. -No serious adverse events.	-Need for more clinical trials. -Difficult to measure their long-term clinical benefit.	[102,145,147,150-153,156,158,159,161,163]