Several themes have emerged during this year’s conference with implications for the care of patients with genitourinary infections and inflammatory disorders. Intriguing studies in each of these general themes are discussed below.

Theme 1: The Urinary Microbiome

What can we learn from next generation sequencing (NGS) of urine samples?

Fairly recent work has revealed that urine is not sterile and that in fact a urinary microbiome exists.¹ This has led to speculation that patients with issues ranging from recurrent urinary tract infections (UTIs) to chronic pelvic pain syndrome may well have previously undetected bacteria to blame for their persistent symptoms. In recent years, we have seen the emergence of several companies who provide NGS of urinary microbiota as a means of diagnosis. But what can we deduce from these troves of data that is of practical benefit to patients? During AUA2021, several research teams presented their investigations of the urinary microbiome of asymptomatic as well as UTI patients. This includes the new identification of nonrandom bacterial communities called bacterial consortia by Vollstedt and team (MP25-10). Nickel and colleagues investigated the urinary microbiome of healthy patients using an NGS platform and found tremendous diversity among patients and even in the same patient at different timepoints (MP25-02). There may be differences based on sex and age as well as antibiotic use but no clear pattern has currently been elucidated.

Does hormonal status affect urinary microbiome diversity?

Nickel and team did not find differences due to menopause. In contrast, Nettey et al found that the genera of bacteria present in urine samples change after women undergo menopause (fig. 1; MP-25-03).

Figure 1. Hormonal status may affect urinary microbial diversity (Provided by Dr. A. Lenore Ackerman, UCLA).

Takeaway: The urinary microbiome is complex with no consistent pattern even for asymptomatic volunteers. Thus, we cannot yet interpret NGS findings for UTI, interstitial cystitis/chronic pelvic pain syndrome and prostatitis patients.

Theme 2: Management of Life-Threatening Infections

Fournier’s gangrene

Substantial work is being done by several groups to determine new ways to improve outcomes for patients with Fournier’s gangrene. Warner et al showed that the diagnostic opportunity for Fournier’s is much earlier than assumed (MP35-05). They found that approximately 50% of patients had at least 1 visit to an emergency room or outpatient clinic for a symptomatically similar diagnosis within 20 days of Fournier’s diagnosis.

Takeaway: We should have a higher index of suspicion for Fournier’s, particularly in patients at risk for this disease.

The importance of renal pelvis cultures

Preoperative midstream urine culture samples are unreliable at predicting blood culture results in patients with subsequent sepsis.² Two independent studies addressed the importance of renal pelvis urine cultures in patients presenting with obstructing infected ureteral calculi. Belle at al investigated sample discordance between bladder urine culture and subsequent blood culture as compared to renal pelvis culture and blood culture (MP29-08). They revealed decreased discordance of renal pelvis samples which had the real consequence of decreasing hospital stay by as much as half the number of days for patients with bladder samples only (fig. 2). A different study by Thakker and Mirzazadeh also revealed the importance of pelvic culture in obstructive stone surgery; in 22% of patients with positive blood cultures, cultures were only positive from the renal pelvis and not the bladder (MP29-05). However, it must be noted that in 35% of patients with positive blood cultures both renal and bladder cultures were negative.

Figure 2. Nationwide antibiograms of common uropathogens. Image provided by Dr. Geoffrey Rosen, University of Missouri.

Takeaway: Yes, we should collect renal pelvis urine in obstructed infected stone patients since it seems to be more reliable than bladder samples only. However, renal samples are still often negative in patients with a positive blood culture so we must be vigilant in monitoring all patients for evidence of sepsis.

Theme 3: Antibiotic Stewardship in Urology

Antibiotic stewardship was the focus of several new studies. Based on work by Najafabadi et al, the clinical utility of antibiotic prophylaxis for shockwave lithotripsy is not currently clear (MP25-17). A separate study by Rosen et al revealed that local antibiograms in several states suggest the use of antibiotics other than those recommended by the AUA best practice statement for transurethral procedures (fig. 3; MP25-15).

Figure 3. Discordance between bladder urine, renal pelvis and blood cultures in infected obstructed stone patients. (Provided by Dr. Duane Baldwin, Loma Linda University). E coli, Escherichia coli. MRSA, methicillin-resistant Staphylococcus aureus.

Takeaway: Check your local state and institutional antibiogram.

Theme 4: Sublingual Vaccine

Finally, in a late-breaking abstract Dr. Nickel presented the promising results from the first multi-center randomized double-blind controlled trial of a sublingual vaccine for recurrent UTI patients (PLLBA-02). This mucosal vaccine comprises 4 whole cell inactivated bacteria and is administered daily for a 3-month period. He reports time to first UTI was 275 days for patients administered the vaccine versus 48 days in the placebo group and with milder UTI severity.

Takeaway: This vaccine may potentially be an alternative to antibiotics in patients with recurrent UTIs. Larger studies are warranted.