Pathogenic bacteria are routinely isolated from samples collected as a part of the national surveillance program initiated by the Japanese Society of Chemotherapy (JSC), Japanese Association for Infectious Disease (JAID), and Japanese Society of Clinical Microbiology (JSCM), with the goal of investigating infection trends and the emergence of antimicrobial resistance [[1], [2], [3]]. The first survey under this program was conducted by the JSC in 2008. The second survey was then conducted by the JAID and JSCM in 2011, and the third and fourth were jointly conducted by the three groups in 2015 and 2020, respectively. Notably, during the second survey of the surveillance program, bacteria from eight species were collected.

Uncomplicated urinary tract infections (UTIs) are defined as those affecting premenopausal, non-pregnant adult females with no prior history of UTI, whereas any cases that do not adhere to this description are considered complicated UTIs (cUTIs). In particular, UTIs in males are typically considered complicated since they rarely affect young healthy males unless there are specific risk factors involved (such as presence of foreskin). Therefore, when managing male patients with UTIs, it is necessary to consider the presence of underlying urinary tract diseases. Adding to this complexity, a wide variety of bacteria are usually isolated from cUTIs, including both gram-negative and gram-positive bacteria, with increasing proportions of drug-resistant organisms. As with other infections, cUTIs must be treated with empirical antimicrobial therapy. In severe cUTI cases, broad-spectrum antimicrobial agents are often started, while milder cases may be treated with narrow-spectrum agents or with oral agents. To that end, urine- and blood-based testing are essential for pathogen identification, and drug sensitivity profiles created from surveillance data may help in treatment guidance. In this study, we aimed to assess the latest data from a 2020–21 survey regarding the susceptibility of the causative agents of cUTIs to antimicrobial agents.