The purpose of this study is to assess the efficacy of 3 days of azithromycin (AZI) compared to 3 days of ciprofloxacin (CIP) (standard-of-care) for the treatment of children hospitalised with dysentery in Ho Chi Minh City.

Antimicrobial resistance is a well-established international healthcare crisis and children with diarrhoeal infections represent a significant proportion of the global infectious disease burden. With the increasing rates of antimicrobial resistance observed in the organisms associated with children presenting with dysentery in Vietnam and the investigator's capacity to demonstrate international transmission events, new data regarding alternative treatment options such as azithromycin, in particular for the new highly-antimicrobial resistant S. sonnei, are urgently needed.

The study team will perform a phase IV open label randomised controlled trial to compare the efficacy of AZI to CIP (standard-of-care) for the treatment of children hospitalised with dysentery in Ho Chi Minh City, Vietnam. Children aged 6 to 60 months presenting to the participating hospital with symptoms/signs of dysentery (diarrhoea with blood and/or mucus accompanied by 1 or more of: fever ≥37.8°C, abdominal pain and /or tenesmus) within the previous 72 hours will be enrolled to the study.

After enrolment, participants will be managed according to WHO and local algorithms for children with bloody diarrhoea. In addition, after providing a stool sample, children will be randomly allocated to receive CIP 15mg/kg body weight/ twice daily or AZI 10mg/kg body weight/ daily for 3 days. After enrolment, children will be reviewed for clinical and microbiological response to treatment.

Inclusion Criteria:

1. Male or female aged 6 months to 60 months at time of hospital presentation.
2. Have symptoms and/or signs of dysentery, specifically passing stools containing mucus and/or blood with/without abdominal pain, tenesmus or fever (≥37.8˚C).
3. Be eligible for treatment with oral medication in the opinion of the admitting physician (i.e. no clinical requirement for parenteral treatment on admission).
4. Be within 72 hours of the onset of signs/symptoms.
5. Have a parent/guardian present at admission who can provide written informed consent.

Exclusion Criteria:

1. Those known to have specific medical (patients with known prolongation of the QT interval, congenital long QT syndrome)/surgical conditions which may affect disease severity/presentation or response to treatment (e.g. affecting antimicrobial absorption), including:

   1. gastrointestinal abnormalities, including short bowel syndrome, chronic (inflammatory or irritable) bowel disease.
   2. inherited or acquired immune system deficiency rendering the patient immunocompromised, including chronic/long-term steroid treatment or other immunosuppressive treatment

2. Presentation with severe infection requiring parenteral antimicrobial treatment, including shock jaundice, extensive gastrointestinal bleeding, convulsion , drowsiness or coma, reduced or less movement when stimulated, tachypnea > 60 times per minute, grunting, chest retraction, refuse to suck.

3. Known hypersensitivity to any of the trial drugs (CIP or AZI).

4. Coexisting infection requiring other or additional antimicrobials to be prescribed/ administered.