Despite the risk of developing catheter-associated urinary tract infections (CAUTI), catheter reuse is common among people with spinal cord injury (SCI). This study examined the microbiological burden and catheter surface changes associated with short-term reuse. Ten individuals with chronic SCI reused their catheters over 3 days. Urine and catheter swab cultures were collected daily for analysis. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses were used to assess catheter surface changes. Catheter swab cultures showed no growth after 48 h (47.8%), skin flora (28.9%), mixed flora (17.8%), or bacterial growth (5.5%). Asymptomatic bacteriuria was found for most participants at baseline (n = 9) and all at follow-up (n = 10). Urine samples contained Escherichia coli (58%), Klebsiella pneumoniae (30%), Enterococcus faecalis (26%), Acinetobacter calcoaceticus–baumannii (10%), Pseudomonas aeruginosa (6%) or Proteus vulgaris (2%). Most urine cultures showed resistance to one or more antibiotics (62%). SEM images demonstrated structural damage, biofilm and/or bacteria on all reused catheter surfaces. XPS analyses also confirmed the deposition of bacterial biofilm on reused catheters. Catheter surface changes and the presence of antibiotic-resistant bacteria were evident following short-term reuse, which may increase susceptibility to CAUTI in individuals with SCI despite asymptomatic bacteriuria.