Constipation itself can be a cause of UTI in children. Having said that, I hope that the urine sample taken for testing was a clean catch , midstream sample, so that a false report was avoided. There is significant bacterial growth in the sample that was tested, hence requires antibiotics as culture was positive. Do not worry. Hb also is low for age , iron supplementation shall be enough. Continue supplementation for atleast 3 months. The photo of culture report attached here does not have the sensitivity report for all the first line oral antibiotics , hence cannot recommend a safer one here.

According to blood reports of your child there are other better option to be given in this case. As there are other drug which are shown sensitive that can be used . Orpenam safety is not established in children but neither it’s considered unsafe so it’s use depend on clinical . But whatever antibiotics is given should be continued for 14 days even if child is symptom free. Iron can be continued