Impact of Type and Duration of Antibiotic Prophylaxis on UTI Rates After Botox

Objectives: To compare the effect of various oral antibiotic prophylaxis on urinary tract infection (UTI) treatment following onabotulinumtoxin A injections in women with idiopathic and neurogenic overactive bladder (OAB).

Methods: This was a single center retrospective cohort study of women >18 who underwent onabotulinumtoxin A injection for OAB between June 2018 and June 2023. Our primary outcome was defined as any treatment for UTI based on either symptoms or positive urine culture. UTI incidence was compared by duration (1 day, 3 days, 5 days, and ≥ 7 days of antibiotic prophylaxis) and type of antibiotic. A sub analysis of UTI rate in patients with neurogenic bladder was performed.

Results: A total of 1,250 subjects were included. The subjects had an average age of 65±14 years were 50% white, 43% Black/African American, and 2% Asian. The majority were obese (mean BMI 30.8 +/- 9.1 kg/m2), non-smokers (66%), and post-menopausal (81%). About one third of the patients had neurogenic bladder.

The overall UTI rate within 30 days was 10.2%. There was no difference between 1 day, 3 days, 5 days, or ≥ 7 days of treatment (p=0.42). Retreatment rate for UTI was low at 1.9% and only 1.8% of urine cultures showed resistance to the prophylactic antibiotic, with no differences in these two outcomes between different durations of prophylactic antibiotics (p>0.05 for both). There was no difference in adverse events including ER visits, Urgent Care Visits, urinary retention, or need for clean intermittent catheterization (Table 1).

When examining type of antibiotic used, treatment with Nitrofurantoin had the lowest UTI rate at 8.7% (p < 0.01) compared to Trimethoprim/Sulfamethoxazole, Cefalexin, Ciprofloxacin, and Amoxicillin/clavulanic acid (Table 2). Urine cultures did have a higher rate of resistance to the prophylactic antibiotic of choice in the Trimethoprim/ Sulfamethoxazole category (p=0.0086), however, overall resistance was low with a rate of 4.6%.

In subjects with neurogenic OAB, duration of prophylactic antibiotic therapy did not affect UTI rates (p=0.10). Subjects with neurogenic OAB did have higher rates of ER visits with a 3 day prophylactic course compared to the other lengths (p=0.03). However, there was no difference in any of the other adverse events by duration of antibiotic prophylaxis (p>0.05 for all).

Conclusions: There is no difference in the length of prophylactic antibiotic use and the UTI rate after onabotulinumtoxin A injections for the general population or for those with a neurogenic bladder. UTI rates were higher when an antibiotic other than Nitrofurantoin or Trimethoprim/ Sulfamethoxazole were used as prophylaxis. Cultures are more likely to have resistance to the prophylactic antibiotic when using Trimethoprim/ Sulfamethoxazole, however, the resistance rates were overall low.