No studies have evaluated the ultrasound features of the male sex accessory glands in infertile patients with bacterial male accessory gland infection (MAGI) according to the microbiological outcomes of bacterial cultures (absent, partial or complete) following antibiotic therapy administration. Therefore, the aim of this study was to evaluate the ultrasound characteristics of the prostate, seminal vesicles, and epididymal tracts after treatment with levofloxacin (a common quinolone antibiotic), in patients with infections caused by Escherichia coli (a Gram-negative bacterium) according to the Naber's classification, which includes the following categories: eradication, eradication with superinfection, persistence and persistence with superinfection. The study was conducted in 100 patients aged 25±8 years (range: 20-40 years) with bacterial MAGI and bacterial cultures positive only for E. coli (colony forming units ≥10(6) per ml). Retrospective analysis was conducted only on patients treated with oral levofloxacin (500 mg) administered once daily for 28 days who were recruited over the last 5 years. Following antibiotic treatment, patients with microbiological persistence or persistence with superinfection had a significantly higher percentage of ultrasound abnormalities suggestive of prostato-vesiculitis (PV) (30.2% and 36.0%, respectively) or prostato-vesiculo-epididymitis (PVE) (60.2% and 70.0%, respectively) compared with patients with microbiological eradication (PV=10.2% and PVE=8.2%, respectively) or eradication with superinfection (PV=18.8% and PVE=21.2%, respectively). In conclusion, patients with microbiological persistence or persistence plus superinfection showed the highest prevalence of complicated forms of MAGI (PV and PVE), compared with patients with microbiological eradication or eradication with superinfection.