Case report on a swift shift in uropathogens from Shigella flexneri to Escherichia coli: a thin line between bacterial persistence and reinfection.

Background: Urinary tract infections (UTI) are mostly caused by bacteria. Urine cultures are usually a definitive measure to select the appropriate antibiotics for the elimination of a uropathogen and subsequent recovery from the infection. However, the preferred antibiotics as determined by urine culture and sensitivity may still not eliminate the infection and would require further examination to ascertain the cause of treatment failure which could be unresolved bacteriuria, bacterial persistence, immediate reinfection with a different uropathogen or misdiagnosis.