Thank you for your query,
As your child is having loose stools since 10 days and not showing improvement with 5 day course of antibiotic,better to give stool for culture and sensitivity as the causative organism may grow and the antibiotic sensitivity can be know to start appropriate antibiotic.
Continue to give sips of oral rehydrating solutions to prevent dehydration
and consult your Pediatrician
for stool investigation and the to know the need for probiotic
and zinc supplementation.
Hope i have answered your query.