Effectiveness of neomycin/polymyxin bladder irrigation to treat resistant urinary pathogens in those with spinal cord injury

Abstract

Individuals with spinal cord injury (SCI) will sometimes develop bacterial organisms in the bladder that are resistant to oral antibiotics. This study evaluated the effectiveness of a 5-day course of intermittent neomycin/polymyxin bladder irrigation at eradicating or changing the bacterial sensitivity from parenteral to oral antibiotics. A chart review of individuals with SCI who were treated with neomycin/polymyxin bladder irrigations was performed. Inclusion criteria included the use of an indwelling catheter and the presence of asymptomatic bacteria resistant to oral antibiotics. The most common reason for treatment was eradication of resistant organisms prior to urologic testing. Bladder irrigation consisted of 3 rinses with 30 ml 3 times a day for 5 days. Pre- and post-urine samples were compared for white blood cells (WBCs), colony count and culture, and sensitivity. Chi-square tests were used to determine whether the proportion of changes in resistance or sensitivities was different from zero. The Wilcoxon Signed Rank Test was used to determine differences in bacteria, colony counts, and WBCs. Ten individuals were identified. A total of 12 neomycin/polymyxin irrigation treatments were evaluated because 2 individuals had a second series of irrigations at least 6 months apart. Nine of the 12 (75%) were considered to have successful irrigations because there was a change in culture sensitivity so that oral antibiotics would be effective post irrigation. This was statistically significant. There were no significant changes in colony counts or the number of WBCs. The authors concluded that while neomycin/polymyxin bladder irrigation did not change the type of organism, it was effective in changing resistance of most organisms. Individuals could then be treated with oral rather than intravenous or intramuscular antibiotics. Further work is needed to determine whether other variables, such as increased length of time of irrigation or increased frequency of irrigations, may actually eradicate the organisms.