CFS patients have been reported to be dominantly “Type A” personalities, that is:
- “The theory describes Type A individuals as ambitious, rigidly organized, highly status-conscious, sensitive, impatient, take on more than they can handle, want other people to get to the point, anxious, proactive, and concerned with time management. People with Type A personalities are often high-achieving “workaholics“, push themselves with deadlines, and hate both delays and ambivalence.“
Later this wikipedia article states
- “An analysis of the literature suggests the possible role of Mg deficiency in the susceptibility to cardiovascular diseases, observed among subjects displaying a type A behavior pattern. Experimental data which support this hypothesis are reviewed. Type A subjects are more sensitive to stress and produce more catecholamines than type B subjects. This, in turn, seems to induce an intracellular Mg loss. In the long run, type A individuals would develop a state of Mg deficiency, which may promote a greater sensitivity to stress and, ultimately, lead to the development of cardiovascular problems.“
Looking at the literature for CFS we find 48 articles on PubMed dealing with Magnesium and CFS. As far back as 1991 (25 years ago), magnesium supplementation was found to have significant impact on CFS patients.
- “20 patients with CFS had lower red cell magnesium concentrations than did 20 healthy control subjects matched for age, sex, and social class (difference 0.1 mmol/l, 95% confidence interval [CI] 0.05 to 0.15). In the clinical trial, 32 patients with CFS were randomly allocated either to intramuscular magnesium sulphate every week for 6 weeks (15 patients) or to placebo (17). Patients treated with magnesium claimed to have improved energy levels, better emotional state, and less pain, as judged by changes in the Nottingham health profile. 12 of the 15 treated patients said that they had benefited from treatment, and in 7 patients energy score improved” 
There has been two studies
- “Type A behaviour, coping strategies …between chronic fatigue and irritable bowel syndrome patients prior to illness and between these groups and healthy controls.”
- “CFS patients’ mean score on the JAS[A test for Type A Personality] was 5 points higher than that of the general population (healthy controls)” 
As well as similar results:
- “For 57 Chinese American individuals initially diagnosed with CFS, those who recovered after one year reported lower levels of life stress than those who did not recover.” 
Hypothesis: Stress behavior is Microbiome Related
This includes Type A Personality. There is actually some literature that seems to support it:
- Gut microbiome composition is associated with temperament during early childhood.
- “Understanding microbiota-brain interactions is an exciting area of research which may contribute new insights into individual variations in cognition, personality, mood, sleep, and eating behavior, and how they contribute to a range of neuropsychiatric diseases ranging from affective disorders to autism and schizophrenia.” 
- “there is now expanding evidence for the view that commensal organisms within the gut play a role in early programming and later responsivity of the stress system.” 
- “suggest a role for the gut microbiota in the regulation of anxiety, mood, cognition and pain.” 
Treating Stress And Anxiety
If we assume that the above hypothesis is true, then we should find studies where taking probiotics etc. measurably reduces stress. We do.
- “these results suggest that consumption of fermented foods that contain probiotics may serve as a low-risk intervention for reducing social anxiety.” 
- Yakult – 4 bottles/day – “Decrease in Anxiety symptoms [Score reduced by 50%] for CFS patients 
- “These results suggest that chronic ingestion of L. Plantarum PS128 could ameliorate anxiety– and depression-like behaviors and modulate neurochemicals related to affective disorders.”
- “Lactobacillus rhamnosus (JB-1) … promotes consistent changes in GABA-A and -B receptor sub-types in specific brain regions, accompanied by reductions in anxiety and depression-related behaviors.” 
Similarly, supplements that are known to reduce stress would also exhibit some antibacterial impacts. The most common ones are the Adaptogens:
- An alternative treatment for anxiety: a systematic review of human trial results reported for the Ayurvedic herb ashwagandha (Withania somnifera).
- Plant-based medicines for anxiety disorders, part 2: a review of clinical studies with supporting preclinical evidence.
- A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults.
- “W. somnifera exhibited significant antibacterial activities against Gram-negative bacteria, particularly S. typhi.”
- Rhodiola Rosea Root (Rosavin)
- Decrease in the level of psychic fatigue and situational anxiety, [The effect of the preparation rodakson on the psychophysiological and physical adaptation of students to an academic load]. 
- “concluded that repeated administration of R. ROSEA extract SHR-5 exerts an anti-fatigue effect that increases mental performance, particularly the ability to concentrate, and decreases cortisol response to awakening stress in burnout patients with fatigue syndrome.” A randomised, double-blind, placebo-controlled, parallel-group study of the standardised extract shr-5 of the roots of Rhodiola rosea in the treatment of subjects with stress-related fatigue.
- Magnolia Bark [honokiol]
- “It has therapeutic potential in anxiety, pain, cerebrovascular injury, epilepsy, and cognitive disorders including Alzheimer’s disease.”
- Antimicrobial effect of Magnolia officinalis extract against Staphylococcus aureus.
- Antifungal activity of magnolol and honokiol
- Jujube Fruit
Personal observation: Clostridium butyricum(Miyarisan probiotic) has been reported to reduce stress levels considerably. While there are no studies on it and anxiety, I would advocate it in addition to the above. This effect may be unique to CFS patients because of their specific dysfunctions.
- “Benzodiazepines (BZDs) are a class of drug that is presumed to indirectly promote gamma-amino butyric acid (GABA) activity and rapidly control the core symptoms associated with Generalized Anxiety Disorder.”
“Recently, an increased intake of highly processed, low-fibre food products rich in simple sugars has been observed, resulting in low levels of butyrate production in the intestinal lumen.”  This shift may account for multiple increases of conditions and also suggests that high-fibre food is essential.
It is well known that stress and anxiety triggers CFS flares. Reducing anxiety with probiotics and selected herbs is beneficial and may contribute towards a microbiome shift that could lead to remission.