Posts

Lactobacillis-Bacteria

Does ZIP code factor into genitourinary system health?

Lactobacillis-Bacteria

Clinicians suspect that taking probiotics, such as lactobacillus supplements, and making changes to diet may prevent urinary diseases that occur commonly among pediatric patients. A research team led by Children’s faculty is exploring whether changes in the built environment also affect the urinary microbiome.

Emerging evidence suggests that the variety and volume of bacteria that reside in the bladder – the urinary microbiome – significantly impact whether people’s genitourinary systems remain healthy or become susceptible to disease.

Already, clinicians suspect that taking probiotics and making changes to diet may prevent urinary diseases that occur commonly among pediatric patients. A research team led by Children’s faculty is exploring whether changes in the built environment also affect the urinary microbiome.

Using experimental models, they looked at how stable the urinary microbiome was over time. Then, they measured the potential effect of changing the built environment on the urinary microbiome of preclinical models.

They did this by following six C57BL/6 experimental models for five months, starting from when they were nine weeks old. They collected urine specimens when the study began and repeated sample collections each month. The multidisciplinary team isolated microbial DNA from these specimens to determine the makeup of the bacterial community present in their urinary tracts.

All of the experimental models shared a single cage, drank the same water and ate the exact same chow. At four months, however, they moved the preclinical models to a different facility within the same county. Their chow and bedding remained unchanged, but the water source changed since they received tap water at both locations.

“There were no changes in the proportion of specific bacteria in the urinary microbiomes from month zero through month five, which means the urinary microbiomes of healthy experimental models remain stable over time,” says Michael Hsieh, M.D., Ph.D., a urologist at Children’s National Health System and senior author of the work presented during the Pediatric Urology Fall Conference. “However, the convergence of the Shannon Diversity Index, the clustering seen on Principal coordinate analyses and changes in functional analyses taken as a whole suggest that an overall shift of the urinary microbiome occurred due to a change in the physical environment.”

This work suggests that where patients live could influence which bacteria grow in the urinary tracts, including during urinary tract infections.

The Societies for Pediatric Urology’s Pediatric Urology Fall Conference

  • “Effects of time and the built environment on the stability of the mouse urinary microbiome: implications for clinical utility.”

Catherine S. Forster, M.D., MS, pediatric hospitalist, Children’s National; James Cody, Ph.D., Biomedical Research Institute; Nirad Banskota, MS, Biomedical Research Institute; Crystal Stroud, MS, Children’s National; Ljubica Caldovic, Ph.D., principal investigator, Children’s National; and Michael Hsieh, M.D., Ph.D., urologist, Children’s National.

E coli bacteria

Urinary bacteria in spinal cord injury cases may tip balance toward UTIs

E coli bacteria

Patients with spinal cord injuries nearly universally have bacteria present in their urine regardless of whether they have a urinary tract infection.

The fallout from spinal cord injury doesn’t end with loss of mobility: Patients can have a range of other issues resulting from this complex problem, including loss of bladder control that can lead to urine retention. One of the most serious implications is urinary tract infections (UTIs), the most common cause of repeat hospitalization in people with spinal cord injuries, explains Hans G. Pohl, M.D., associate chief in the division of Urology at Children’s National Health System.

Diagnosing UTIs in people with spinal cord injuries is trickier than in people who are otherwise healthy, Dr. Pohl explains. Patients with spinal cord injuries nearly universally have bacteria present in their urine regardless of whether they have a UTI. It’s unclear whether these bacteria are innocent bystanders or precursors to UTIs in patients who don’t yet show symptoms. And although antibiotics can wipe out this bacterial population, these drugs can have undesirable side effects and frequent use can promote development of antibiotic-resistant bacteria.

Although clinical dogma has long promoted the idea that “healthy” urine is sterile, Dr. Pohl and colleagues have shown that a variety of bacteria live in urine, even in people without symptoms. These microorganisms, like the intestinal microbiome, live in harmony with their hosts and may even help promote health. However, it’s unclear what this urinary microbiome might look like for patients with spinal cord injury before, during and after UTIs.

To start investigating this question, Dr. Pohl and co-authors recently reported a case study they published online Sept. 21, 2018, in Spinal Cord Series and Cases. The case report about a 55-year-old man who had injured the thoracic segment of his spinal cord—about the level of the bottom of his shoulder blades—in a skiing accident when he was 19 was selected as “Editor’s Choice” for the journal’s October 2018 issue.  The patient had a neurogenic bladder, which doesn’t function normally due to impaired communication with the spinal cord. To compensate for this loss of function, this patient needed to have urine removed every four to six hours by catheterization.

Over eight months Dr. Pohl, the study’s senior author, and colleagues collected 12 urine samples from this patient:

  • One was collected at a time the patient didn’t show any symptoms of a UTI
  • Nine were collected when the patient had UTI symptoms, such as bladder spasticity
  • Two samples were collected when the patient had finished antibiotic treatment for the UTI.

The researchers split each sample in half. One part was put through a standard urinalysis and culture, much like what patients with a suspected UTI would receive at the doctor’s office. The other part was analyzed using a technique that searched for genetic material to identify bacteria that might be present and to estimate their abundance.

The researchers found a variety of different bacteria present in these urine samples. Regardless of the patient’s health status and symptoms, the majority of these bacterial species are known to be pathogenic or potentially pathogenic. By contrast, this patient’s urine microbiome appeared to largely lack bacterial species known to be either neutral or with potentially probiotic properties, such as Lactobacillus.

All of the bacteria that grew in culture also were identified by their genetic material in the samples. However, genetic sequencing also identified a possible novel uropathogenic species called Burkholderia fungorum that didn’t grow in the lab in five of the samples. This bacterium is ubiquitous in the environment and has been identified in soil- and plant-based samples. It also has been discovered in the respiratory secretions of patients with cystic fibrosis, in patients with a heart condition called infectious endocarditis, in the vaginal microbiota of patients with bacterial vaginosis, and in the gut of patients with HIV who have low T-cell counts. Dr. Pohl says it’s unclear whether this species played an infectious role in this patient’s UTI or whether it’s just part of his normal urine flora.

“Consistent with our previous work, this case report demonstrates that rather than healthy urine being sterile, there is a diverse urine bacterial ecosystem during various states of health and disease,” Dr. Pohl says. “Rather than UTIs resulting from the growth or overgrowth of a single organism, it’s more likely that a change in the healthy balance of the urine ecosystem might cause these infections.”

By monitoring the relative abundance of different bacteria types present in the urine of patients with spinal cord injury and combining this information with a patient’s symptoms, Dr. Pohl says doctors may be able to make more accurate UTI diagnoses in this unique population.

In addition to Dr. Pohl, study co-authors include Marcos Pérez-Losada, Ljubica Caldovic, Ph.D., Bruce Sprague and Michael H. Hsieh, M.D., Children’s National; Emma Nally, Suzanne L. Groah and Inger Ljungberg, MedStar National Rehabilitation Hospital; and Neel J. Chandel, Montefiore Medical Center.

Bladder cancer’s unique bacterial “fingerprint”

Michael H. Hsieh, M.D., Ph.D.

Michael H. Hsieh, M.D., Ph.D.

Decades ago, researchers thought that the native bacteria scattered throughout the human body—such as in the gut, the oral cavity and the skin—served little useful purpose. This microbiota, whose numbers at least match those of the cells in the body they live on and in, were considered mostly harmless hitchhikers.

More recently, research has revealed that these natural flora play key roles in maintaining and promoting health. In addition, studies have shown that understanding what a “typical” microbiome looks like and how it might change over time can provide an early warning system for some health conditions, including cancer.

Now, a small, multi-institutional study conducted in experimental models suggests that as bladder cancer progresses, it appears to be associated with a unique bacterial fingerprint within the bladder—a place thought to be bacteria-free except in the case of infection until just a few years ago. The finding opens the possibility of a new way to spot the disease earlier.

Bladder cancer is the fourth-most common malignancy among U.S. men but, despite its prevalence, mortality rates have remained stubbornly high. Patients often are diagnosed late, after bladder cancer has advanced. And, it remains difficult to discern which patients with non-invasive bladder cancer will go on to develop muscle-invasive disease.

Already, researchers know that patients with grade 4 oral squamous cell carcinoma, women with increasingly severe grades of cervical cancer and patients with cirrhosis who develop liver cancer have altered oral, vaginal and gut microbiomes, respectively.

New technological advances have led to identification of a diverse community of bacteria within the bladder, the urinary microbiome. Leveraging these tools, a research team that includes Children’s National Health System investigators studied whether an experimental model’s urinary bacterial community changed as bladder cancer progressed, evolving from a microbiome into a urinary “oncobiome.”

To test the hypothesis, the research team led by Michael H. Hsieh, M.D., Ph.D., a Children’s urologist, exposed an experimental model of bladder cancer to a bladder-specific cancer-causing agent, n-butyl-n-(4-hydroxybutyl) nitrosamine (BBN). Bladder cancers induced by BBN closely resemble human cancers in tissue structure at the microscopic level and by gene expression analyses. Ten of the preclinical models received a .05 percent concentration of BBN in their drinking water over five months and were housed together. Ten other experimental models received regular tap water and shared a separate, adjacent cage.

Researchers collected urine samples ranging from 10 to 100 microliters at the beginning of the longitudinal study, one week after it began, then once monthly. They isolated microbial DNA from the urine and quantified it to determine how much DNA was microbial. All of the bladders from experimental models exposed to BBN and two bladders from the control group were analyzed by a pathologist trained in bladder biology.

According to the study published online July 5, 2018, by the biology preprint server Biorxiv, they found a range of pathologies:

  • Five of the experimental models that received BBN did not develop cancer but had histology consistent with inflammation. Three had precancer on histology: urothelial dysplasia, hyperplasia or carcinoma in situ. Two developed cancer: invasive urothelial carcinomas, one of which had features of a squamous cell carcinoma.
  • The experimental model that developed invasive carcinoma had markedly different urinary bacteria at baseline, with Rubellimicrobium, a gram negative organism found in soil that has not been associated with disease previously, Escherichia and Kaistobacter, also found in soil, as the most prominent bacteria. By contrast, in the other experimental models the most common urinary bacteria were Escherichia, Prevotella, Veillonella, Streptococcus, Staphyloccoccus and Neisseria.
  • By month four, the majority of experimental models exposed to BBN had significantly higher proportion of Gardnerella and Bifidobacterium compared with their control group counterparts.

“Closely analyzing the urinary bacterial community among experimental models exposed to BBN, we saw distinct differences in microbial profiles by month four that were not present in earlier months,” Dr. Hsieh says. “While Gardnerella is associated with the development of cancer, Bifidobacterium has been shown to exert antitumor immunity, and its increasing abundance points to the need for additional research to understand its precise role in oncogenesis.”

Dr. Hsieh adds that although the study is small, its findings are of significance to children who are prone to developing urinary tract infections (UTIs), including children with spina bifida, due to the association between UTIs and bladder cancer. “This work is important because it not only suggests that the urinary microbiome could be used to diagnose bladder cancer, but that it could also perhaps predict cancer outcomes. If the urinary microbiome contributes to bladder carcinogenesis, it may be possible to favorably change the microbiome through antibiotics and/or probiotics in order to treat bladder cancer.”

In addition to Dr. Hsieh, co-authors include Catherine S. Forster, M.D., M.S., and Crystal Stroud, of Children’s National; James J. Cody, Nirad Banskota, Yi-Ju Hsieh and Olivia Lamanna, of the Biomedical Research Institute; Dannah Farah and Ljubica Caldovic, of The George Washington University; and Olfat Hammam, of Theodor Bilharz Research Institute.

Research reported in this news release was supported by the National Institutes of Health under award number R01 DK113504 and the Margaret A. Stirewalt Endowment.

Staphylococcus

How our bladder’s microbiota affect health

Staphylococcus

The presence of bacteria such as Staphylococcus in the urine is linked to the incidence and severity of urge urinary incontinence as well as treatment success.

About half of the cells in our bodies aren’t really “ours” at all. They’re the microbiota: The vast array of microorganisms that live in our gut, skin, oral cavity and other places. Decades ago, researchers thought that these organisms simply happened to colonize these areas, playing only a tangential role in health, for example, helping to break down food in the intestines or causing cavities. More recent work has revealed the incredibly complex role they play in diseases ranging from diabetes and schizophrenia.

The bladder is no exception. Just a single decade ago, the bladder was thought to be a sterile environment. But that view has shifted radically, with more sensitive cultivation methods and precise 16S rRNA gene-sequencing techniques revealing a significant bladder microbiome that could have an enormous impact on pediatric urologic diseases. These findings have opened brand new fields of research aimed at clarifying the role that the bladder’s microbiome plays in common urological diseases that affect children, according to a review article published online Feb. 22, 2018, by Current Urology Reports.

“There is a growing appreciation for the role of diverse bacteria in contributing to improved health as well as triggering disease processes or exacerbating illness,” says Michael H. Hsieh, M.D., Ph.D., director of the Clinic for Adolescent and Adult Pediatric Onset Urology (CAPITUL) at Children’s National Health System and study senior author. “Already, we know that probiotics and dietary modifications have the potential to play powerful roles in preventing urinary diseases that commonly occur among pediatric patients,” Dr. Hsieh says. This underscores the importance of conducting even more studies to improve our understanding and to identify new therapies for health conditions that resist current treatment options.”

The review conducted by Dr. Hsieh and co-authors highlights the effects of the microbiome on a number of urologic diseases that affect children, including:

  • Urinary tract infection A number of studies point to the association between decreased microbial diversity and the incidence of what is commonly called urinary tract infection (UTI) or “dysbiosis.” This relationship suggests that using probiotics to replace or supplement antibiotics could favorably alter the urinary microbiome. Future research will focus on the pathophysiological role of the microbiome to determine whether it can be manipulated to prevent or treat UTIs.
  • Urge urinary incontinence While data vary by study, the presence of bacteria in the urine, especially certain bacterial species – such as Gardnerella, Staphylococcus, Streptococcus, Actinomyces, Aerococcus, Corynebacterium and Oligella – are linked to the incidence and severity of urge urinary incontinence (UUI) as well as treatment success. Most studies find an association between greater genitourinary biodiversity and reduced incidence and lessened severity of UUI as well as improved treatment response. Future research will focus on further clarifying this relationship.
  • Urolithiasis Calcium oxalate stones, the most common type of kidney stone, have a microbiome that differs from the urinary microbiome leading researchers to question whether the stone’s own bacterial makeup could help to predict recurrence of future kidney stones. What’s more, Oxalobacter formigenes, a gram-negative bacterium, lowers oxalate levels in the blood and are associated with a 70 percent reduction in the risk of kidney stones forming. In an experimental model, fecal transplants with the full microbiome represented had a pronounced and persistent effect on oxalate production. Patients who receive some antibiotics often have reduced rates of formigenes colonization. However, the bacteria are resistant to amoxicillin, augmentin, ceftriaxone and vancomycin, which could point to preferential use of these antibiotics to stave off disease and ward off kidney stone formation.

Additional authors include Daniel Gerber, study lead author, The Georgetown University School of Medicine and Health Sciences; and Catherine Forster, M.D., study co-author, Children’s National.