E. coli superbug strains can persist in healthy women’s guts

July 29, 2019

A recent study of over 1,000 healthy women with no symptoms of urinary tract infections showed nearly nine percent carried multi-drug resistant Escherichia coli (E. coli) strains in their guts.

This is of clinical concern because disease-causing E. coli bacteria can transfer from the digestive tract to the female urinary tract via the urethra, the urine duct, which is shorter and positioned differently in females than in males. The bacteria can then make their way into the bladder and other parts of the urinary tract.

More than a third of urine samples provided by those who had fluoroquinolone (Cipro) resistant gut E. coli tested positive for E. coli growth. Of those, nearly 77 percent were Cipro-resistant, and the clonal type of the bacteria matched the fecal sample.

Most of the pathogenic E. coli found belonged to the pandemic, multi-drug resistant ST131-H30R or ST1193 clonal groups that currently cause the majority of drug-resistant urinary tract and bloodstream infections.  They were detected twice as frequently in the urine of people who had these specific strains in their gut, compared to other strains of E. coli in general.

In addition, the presence of ST ST131-H30R in the gut in this study was associated with older age.

The researchers also checked to see which participants might have had an antibiotic prescription during the study for any type of infection, including respiratory.

Three months after that earlier urine collection, urinary tract infections were diagnosed in nearly seven percent of the 45 previously asymptomatic carries who consented to follow-up electronic medical record examination. The study participants were from the Puget Sound area.

“The two pandemic fluoroquinolone-resistant urinary tract pathogenic strains of E. coli found in the clinical specimens are superior gut colonizers and tend to persist there,” noted the researchers. “They can also show up, at an unusually high rate, in the urine of healthy women who did not have a documented urinary tract infection diagnosis at the time of sample testing. Both phenomena appear to be interconnected.”

The researchers pointed out that it has long been known that a patient’s gut microbial flora often harbors urinary tract infection-causing strains.  It was not certain whether pandemic, drug-resistant strains have distinct moorage patterns in the gut or lower urinary tract of healthy people.

The study was published in the Oxford University Press journal, Clinical Infectious Diseases.

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