Brief Answer:
The decision depends on clinical symptoms and its correlation with reports

Detailed Answer:
Hello

Thanks for asking on this platform

I can understand your concern.There are so many organsims that are part of normal healthy skin,intestine,oral cavity and genitourinary tract and merely presence of these organisms(mixed enteric and skin flora) in rectal swab dose not indicates that there is infection.Even thousands of anerobes can be there in healthy intestine.It is the correlation of clinical symptoms with the investigation result that matters.
I would like to know the condition for which this test was recommended for your baby(is there any history of foul smelling loose stool or any wound in perianal area).

Metronidazole as a treatment may be needed in the presence of clinical symptoms.

I hope this helps.
Please let me know if you have any more query.
Regards

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