Catheterization of mice triggers resurgent urinary tract infection seeded by a bladder reservoir of<i>Acinetobacter baumannii</i>

Abstract

The antibiotic-resistant bacterium <i>Acinetobacter baumannii</i> is a leading cause of hospital-associated infections. Despite surveillance and infection control efforts, new <i>A. baumannii</i> strains are regularly isolated from health care facilities worldwide. In a mouse model of urinary tract infection, we found that mice infected with <i>A. baumannii</i> displayed high bacterial burdens in urine for several weeks. Two months after the resolution of <i>A. baumannii</i> infection, inserting a catheter into the bladder of mice with resolved infection led to the resurgence of a same-strain urinary tract infection in ~53% of the mice within 24 hours. We identified intracellular <i>A. baumannii</i> bacteria in the bladder epithelial cells of mice with resolved infection, which we propose could act as a host reservoir that was activated upon insertion of a catheter, leading to a resurgent secondary infection.