Coupled Gentamicin-Lactobacillus Rhamnosus in NLUTD

People with spinal cord injury/disease (SCI/D) experience, on average, 2.5 episodes of UTI annually. Since repeated exposures of bacteria to antibiotics leads to multi-drug resistant organisms (MDROs), it is likely that the frequent use of antibiotics for UTI is a driver of the increasing prevalence of infections with MDROs in the SCI/D population. This prevalence of MDROs among people with SCI/D represents a microcosm of the world-wide public health crisis of antibiotic resistance. As stated by the CDC, "antibiotic resistance is one of the biggest public health challenges of our time." In the US alone, 2.8M people annually develop infections with resistant microbes; of whom 35,000 die as a direct result. Infections with resistant organisms are associated with longer hospital lengths of stay, increased mortality, and higher health care costs. With UTI persistently being the leading reason for rehospitalizations among people with SCI/D, infections with resistant organisms represent a contributor to elevated health care costs as well as mortality risk. Additionally, the cost to treat a UTI due to an extended-spectrum beta-lactamase (ESBL) organism is estimated to be 1.5 times greater than treating a non-ESBL pathogen. Thus, not only are people with SCI/D and UTI at greater risk of mortality due to MDROs, they are also likely to have higher costs as a result of UTI. These costs can only be expected to increase, as the rate of antibiotic resistant UTIs increases. Moreover, individuals with SCI/D and NLUTD experience lower urinary tract symptoms (LUTS) frequently, and these may be treated with antibiotics whether they represent UTI or not.

As noted earlier, the standard of care for UTI treatment (systemic antibiotics, guided by standard urine culture (SUC)) is flawed and contributes to overtreatment and antimicrobial resistance. Use of intravesical therapeutics have been a part of clinical practice since the 1960's and intravesical antibiotics have been studied for nearly 30 years; however, use of intravesical antibiotics for UTI is typically only considered as a "last resort" (such as for recurrent UTI). Agents used include gentamicin, tobramycin, colistin, and neomycin/polymyxin. Gentamicin is the most commonly studied intravesical antibiotic and when administered intravesicularly, it has been shown to have little to no systemic absorption, nor nephro- or oto-toxicity (as with intravenous administration). Intravesical gentamicin has been shown to be safe, tolerated, and effective for recurrent UTI in people with NLUTD.

Our team was first to compare the urobiomes of people with SCI/D and NLUTD to those of neurologically intact controls. This work verified the existence of the urobiome, showing that most control female urobiomes are predominated by Lactobacillus and some control male urobiomes contain Lactobacillus, but most do not. We also showed that NLUTD urobiomes are dysbiotic, depleted in beneficial bacteria as most NLUTD females lacked or had reduced Lactobacillus levels, while most NLUTD males lacked the Streptococcus and/or Corynebacterium that was commonly observed in control males. These results support our hypothesis that NLUTD bladders of most females and at least some males could be colonized by LGG, and that LGG in the urobiome could improve urinary symptoms.