For many years, antibiotics have been prescribed and used widely, and at times, unnecessarily. Studies have estimated that 28 percent of antibiotic prescriptions are not needed. It's been thought that this expansive use of antibiotics has contributed to a problematic and dramatic rise in antibiotic-resistant bacteria, and studies have shown how quickly a population of bacterial cells is able to gain resistance to a particular drug. Scientists have thought that reducing the overprescription and overuse of antibiotic drugs could help limit the spread of resistance. But a new study has shown that even when prescriptions for the antibiotic ciproflaxin were reduced nearly threefold from 2015 to 2021, the rates of ciprofloxacin-resistant E. coli bacteria that were circulating did not decline.
Researchers also determined that the rate of E. coli that live in the gut and are resistant to ciproflaxin actually increased in some women over the age of 50 who did not take any antibiotics for over one year. This phenomenon was seen in about one in five study participants. The findings have been reported in Communications Medicine.
This study confirms previous theoretical studies that have shown that when a drug-resistant strain of E. coli emerges, it can hang out for a long time in the gut, and continue to spread.
Infectious E. coli that live in the gut are sometimes able to move into the urinary tract opening and cause infections. Women are more likely to have this issue because of the pelvic anatomy, and severe, drug-resistant infections are risky to postmenopausal women in particular. Severe E. coli infections may lead to hospitalization or death from sepsis. When the infection is caused by a drug-resistant strain, E. coli infections can be very challenging to eliminate.
Ciprofloxacin other drugs like it are commonly prescribed for urinary tract infections (UTIs). Because of increasing resistance, experts have recommended that the use of these drugs to treat UTIs should be discouraged when there are other options. However, it's now unclear whether that reduction can reduce resistant infection rates.
"Evidence from studies such as this one may be changing lots of paradigms on how to fight the rise in antibiotic resistance," said study leader Dr. Evgeni V. Sokurenko, a professor of microbiology at the University of Washington School of Medicine.
In this work, the researchers assessed the E. coli strains found in patients, and identified a particular dangerous strain called ST1193. If this strain ends up residing in many people's guts, more resistant UTIs may occur, even when prescription use is reduced. The rates of another strain called ST69 that tends to infect children were also found to be increasing.
The study authors suggested that in some patients, other options like probiotics or bacteriophages might be considered.
Sources: University of Washington School of Medicine, Communications Medicine
