E. coli superbug strains can persist in healthy women's guts
A recent study of more than 1,000 healthy women with no symptoms of urinary tract infection showed that nearly 9% of them had multi-resistant Escherichia coli strains in their intestines.
This is a clinical concern because pathogenic E. coli bacteria can be transmitted from the digestive tract to the female urinary tract through the urethra, the urinary tract, which is shorter and positioned differently in women than in men. Bacteria can then find their way into the bladder and other parts of the urinary tract.
More than one-third of urine samples provided by those with fluoroquinolone-resistant intestinal E. coli (Cipro) tested positive for the growth of E. coli. Of these, nearly 77% were cipro-resistant and the clonal type of the bacterium matched the fecal sample.
Most of the pathogenic E. coli found belonged to the multi-resistant pandemic clonal groups ST131-H30R or ST1193 which currently cause the majority of drug-resistant urinary tract and bloodstream infections. They were detected twice as often in the urine of people who had these specific strains in the intestine, compared to other strains of E. coli in general.
In addition, the presence of ST ST131-H30R in the intestine in this study was associated with older age.
The researchers also verified which participants may have received a prescription for antibiotics during the study for any type of infection, including a respiratory infection.
Three months after this first urine collection, urinary tract infections were diagnosed in nearly 7% of the 45 previously asymptomatic carriers who consented to a follow-up examination of the electronic medical record. The study participants came from the Puget Sound area.
"The two fluoroquinolone-resistant pathogenic strains of E. coli found in clinical samples are superior intestinal colonizers and tend to persist in them," the researchers noted. "They may also occur, at an abnormally high rate, in the urine of healthy women who did not have a documented diagnosis of urinary tract infection at the time of sample analysis. The two phenomena seem to be linked."
The researchers pointed out that it has long been known that a patient's intestinal microbial flora often contains strains that cause urinary tract infections. It was not clear that drug-resistant pandemic strains had distinct docking profiles in the intestine or lower urinary tract of healthy individuals.
The study was published in the journal Clinical Infectious Diseases of Oxford University Press.
According to Evgeni V. Sokurenko, professor of microbiology at the University of Washington's Faculty of Medicine, the results could have several implications for clinical care and infection control. He was the principal investigator of the study. Several other microbiology professors from the UW and researchers from the Kaiser Permanent Research Institute in Seattle collaborated on this work. The principal investigator was Veronika L. Tchesnokova, from the Department of Microbiology at the Faculty of Medicine, UW.
The results suggest that the specific multidrug-resistant E. coli strains detected in this study take a much longer residence in the intestine than some other resistant strains, and may also become present in the urine of healthy women without causing burns, emergencies, blood in the urine or other early signs of bacterial infection.
Sokurenko explained that knowing whether several drug-resistant strains are present in a woman's intestine could help predict the resistance profile of a subsequent clinical infection. Efforts to rid carriers of pandemic strains of E. coli in their intestines could reduce their rate of multidrug-resistant infections and perhaps even protect their family or other contacts.
Mr. Sokurenko also said that medicine may need to review the clinical significance of detecting bacteria in urine, even in the absence of symptoms, during this pandemic of multiple antibiotic-resistant strains of E. coli, as these strains could expose carriers to a risk of bacterial disease that is difficult to treat.
Fluoroquinolones are the most commonly prescribed drugs for urinary tract infections. Despite efforts to limit its use, strains resistant to this class of antibiotics are spreading and spreading worldwide, according to researchers.
The superior ability of the two pandemic strains, ST131-H30R and ST119, to settle permanently in people's bellies may have contributed to their rapid global spread, he said. They can be maintained and transmitted to healthy people, even in the absence of antibiotic use, which can disrupt the microbial composition of the intestinal flora.
This study, the researchers concluded, highlights the likely physiological reasons for the pandemic of these resistant strains of E. coli. He also emphasizes the importance of determining the carrier status of patients to predict future resistant infections and the need to rethink the clinical significance of bacteria present in the urine without symptoms, especially since these pandemic strains can be superbugs: highly pathogenic to the urinary system and resistant to treatment.
Sokurenko has filed patent applications for the detection of strains of E. coli and is a major shareholder of ID Genomics.
