This is the outcome of a study into the effects of probiotics on healthy people, not those immunocompromised!
“Relying on faecal samples as an indicator of what goes on inside the gut is inaccurate and wrong” says immunologist Elinav Eran Elinav of the Weizmann Institute of Science in Israel after he and colleagues studied the microbiome of healthy volunteers directly using endoscopies and colonoscopies. The study "found that the probiotic colonisation patterns were highly dependent on the individual. That tells us that the concept that everyone can benefit from a universal probiotic bought from the supermarket is empirically wrong, he says."
The study investigated what happened to the microbiome of three groups. 'The microbiome of the first group was allowed to recover by itself, whereas the second group was given probiotics. The third group was treated with a dose of their own original pre-antibiotic microbiome by a faecal microbiota transplant.' and found surprising results:
"The take-home message is that probiotics don’t always live up to their harmless reputation, and to be effective, their formula needs to be tailored to the individual." and for us if we are neutropenic, probably best avoided.