Trimethoprim-sulfamethoxazole prophylaxis against urinary tract infection in the chronic spinal cord injury patient

Suppressive therapy with antibiotics has long been thought to decrease the number of complications from the neuropathic bladder in spinal cord injury patients, but it may also induce resistance to antibiotics which subsequently causes difficulties in treating symptomatic urinary tract infections. Forty-three chronic spinal cord injury patients were randomized to continue to receive daily trimethoprim-sulfamethoxazole (TMP-SMX) urinary tract prophylaxis versus discontinuing antibiotic prophylaxis. Patients were all at least 6 months after spinal cord injury. Patients were followed for a minimum of 3 months, with weekly catheter urine cultures. The difference in the colonization rate at onset and after 3 months (percent of cultures with asymptomatic bacteriuria) between the control and prophylaxis group was not statistically significant (P > 0.1). There was a significant decrease in the percentage of TMP-SMX resistant asymptomatic bacteriuria in the control group, 78.8%, compared to 94.1% in the suppressive group (P < 0.05). There was no significant difference in the number of symptomatic urinary tract infections following the withdrawal of suppressive therapy between the control group, 0.035/week, and the prophylaxis group, 0.043/week (P > 0.5). There was a larger percentage of TMP-SMX resistant symptomatic urinary tract infections in the treated group, 42.5% versus 37.5% in the control group, but the difference was not significant (P > 0.5). Irrespective of the method of bladder management, suppressive therapy with TMP-SMX did not reduce the incidence of symptomatic bacteriuria and did increase the percentage of cultures resistant to TMP-SMX in asymptomatic patients.