Ampicillin for the treatment of complicated urinary tract infections caused by vancomycin-resistant Enterococcus spp (VRE): a single-center university hospital experience.

Vancomycin-resistant enterococci (VRE) are a common cause of urinary tract infections (UTIs) and are typically multidrug resistant, including ampicillin. This retrospective study evaluated outcomes of 84 adult patients hospitalized between January 2007 and December 2015 with ampicillin- and vancomycin-resistant enterococcus isolates causing UTI and treated with ampicillin. Treatment response was classified as clinical cure and microbiological eradication. Clinical cure was achieved in 88.1% (74/84) of patients. In patients with follow-up cultures, microbiological eradication was achieved in 86% (50/58) of patients. Cure rates were similar in patients with indwelling urinary catheters (n = 45) receiving catheter exchange/removal (90.47%; 19/21) versus catheter retention (87.5%; 21/24). Presence of co-morbidities, such as diabetes and chronic kidney disease, were not associated with increased risk of treatment failure. Immunocompromised patients achieved lower cure rates of 78.1% (25/32) compared with 94.2% (49/52) among those without immune impairment (P = 0.038). Presence of an underlying urinary tract abnormality was also associated with a lower cure rate of 71.4% (15/21) compared with 93.7% (59/63) in those without urinary tract abnormalities (P = 0.0135). Overall cure rates remained high in all groups providing good evidence to support ampicillin for the treatment of complicated UTI caused by ampicillin- and vancomycin-resistant enterococci.