Lower Urinary Tract
Is there a direct antimicrobial effect of botulinum neurotoxin type A?
Article first published online: 9 AUG 2012
© 2012 THE AUTHORS. BJU INTERNATIONAL © 2012 BJU INTERNATIONAL
Volume 110, Issue 11c, pages E886–E890, December 2012
How to Cite
Wöllner, J., Schmidig, K., Gregorini, F., Kessler, T. M., Zbinden, R. and Mehnert, U. (2012), Is there a direct antimicrobial effect of botulinum neurotoxin type A?. BJU International, 110: E886–E890. doi: 10.1111/j.1464-410X.2012.11414.x
- Issue published online: 21 DEC 2012
- Article first published online: 9 AUG 2012
- Accepted for publication 10 May 2012
- onabotulinumtoxin A;
- abobotulinumtoxin A;
- agar diffusion assay;
- microdilution assay;
- minimum inhibitory concentration;
- antimicrobial effect
Study Type – Therapy (case series)
Level of Evidence 4
What's known on the subject? and What does the study add?
Several studies describe a reduction of symptomatic urinary tract infections in patients with neurogenic detrusor overactivity after intradetrusor injections of botulinum neurotoxin A (BoNT/A). It was, however, unclear if a direct antibacterial effect of BoNT/A plays a role in this clinical observation.
This is the first study to investigate a potential antibacterial effect of two frequently used BoNT/A formulations (i.e. Botox® and Dysport®), providing evidence that BoNT/A does not exert an antibacterial effect on lower urinary tract pathogens.
- • To determine a potential direct antimicrobial effect of botulinum neurotoxin type A (BoNT/A).
MATERIALS AND METHODS
- • A prospective study was carried out using onabotulinumtoxin A (Botox®) and abobotulinumtoxin A (Dypsort®) in agar diffusion and broth microdilution assays with various clinical urinary tract isolates (Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Acinetobacter baumannii, Citrobacter freundii, Klebsiella oxytoca and Bacillus subtilis).
- • Inhibition zones (mm) of bacteria around a disc containing 20 µL saline with 4 IU of Botox® were measured in the agar diffusion assay.
- • Minimal inhibitory concentrations (MICs, IU/mL) of both toxins for all bacteria were determined in the broth microdilution assay after overnight incubation at 35 °C.
- • There was no inhibition zone in the agar diffusion assays with any bacterial strain.
- • The microdilution test using Botox® and Dysport® showed bacterial growth in all dilutions, i.e. MICs > 20 and >100 IU/mL for Botox® and Dysport®, respectively.
- • BoNT/A has no direct antimicrobial effect.
- • The reduced frequency of symptomatic urinary tract infections (sUTIs) in patients with neurogenic detrusor overactivity (NDO) after BoNT/A intradetrusor injections seems to be caused by different indirect mechanisms, which are still not completely understood.