New research from the University of South Alabama reports on Jul. 23 that Pseudomonas aeruginosa, an emerging bacterial cause of urinary tract infections, is more common along the Gulf Coast than previously recognized.
The study, published in the American Society for Microbiology's journal mSphere, found that Pseudomonas aeruginosa accounted for about 4% of local UTI cases—nearly double the national average. Researchers also identified previously unknown genetic strains and patterns of antibiotic resistance among local samples.
Allyson Shea, Ph.D., assistant professor at the Frederick P. Whiddon College of Medicine and lead author, said, "Pseudomonas aeruginosa is relatively understudied in the UTI field compared to pathogens like E. coli. Most of what we know about Pseudomonas virulence comes from lung and wound infection models, but the urinary tract is a very different environment. Our goal was to better define the genomic and phenotypic characteristics of urinary isolates specifically." The research team analyzed 55 bacterial samples collected from patients with UTIs to examine genetic differences, disease mechanisms, and antibiotic responses.
Among their findings was substantial uncharacterized diversity among urinary Pseudomonas aeruginosa isolates. Shea said, "Many of the strains circulating in our local patient population did not match previously described sequence types, which highlights how little we still know about P. aeruginosa in the urinary tract." The study also found links between certain bacterial strains and specific patient populations; one strain appeared more frequently in patients with urinary catheters while another was associated with diabetes.
Researchers observed concerning antibiotic resistance patterns as well: nearly one-third of isolates were resistant to levofloxacin—a commonly prescribed antibiotic—and several strains were resistant to multiple antibiotics.
Shea said researchers do not yet know why there is a higher regional prevalence but suggested it may be due to factors such as climate, patient population characteristics, or healthcare-associated exposures: "It is likely multifactorial... larger epidemiologic studies would be needed to determine that." While there are no immediate implications for patient care from this study, Shea added, "We hope this work helps highlight the genomic and phenotypic diversity of P. aeruginosa strains causing UTIs... Defining that diversity is an important first step toward understanding how these infections develop and persist in the urinary tract."
