CLEVELAND — There’s an old saying about traditional household pests like mice: Build a better mousetrap and the mice get smarter.

Something similar may be happening in local communities across the United States when it comes to pesky bacterial pests like salmonella and E. coli.

They’re becoming increasingly resistant to antibiotics – indeed dangerously so, according to a recent study conducted by researchers at the Case Western Reserve University School of Medicine.

Researchers, led by Dr. Sharon B. Meropol, a pediatrician and epidemiologist, analyzed medical data from 94,000 patients under the age of 18 years who were diagnosed with bacteria-associated infections at 48 children’s hospitals across the United States.

Meropol’s team found that the share of these infections resistant to multiple antibiotics rose from 0.2 percent in 2007 to 1.5 percent in 2015, a whopping 700% increase over a short, eight-year span.

What accounts for increased resistance? Numerous studies have documented the overuse and misuse of antibiotics as well as a lack of new drug development by pharmaceutical companies because of reduced profit margins and increasingly cumbersome regulatory requirements.

And the pattern is hardly limited to the United States. In Europe and numerous countries in Asia and Latin America, the antibiotic resistance trend is far worse.

Young children are especially vulnerable because in the United States, at least, they are often prevented by law from being treated with antibiotics commonly available to adults. The average age of the patients examined in Meropol’s study was just 4.1 years.

In one small respect, the study results were encouraging: Rising antibiotic resistance among children was not due to conditions they experienced during their hospital stays, a finding widely accepted in past studies.

However, this revised finding also means that children are likely facing heightened exposure to antibiotic-resistant bacteria in their communities, leaving them ever more vulnerable to disease.

Not all children are affected equally, however. Children with a greater number of health conditions are far more likely to face antibiotic-resistant bacteria, as are older children and children living in the West — though the reasons for these last two associations remain unclear.

Meropol’s team also found that resistance to antibiotics was resulting in longer hospital stays – about 20% longer– and contributing to a higher probability of pediatric death.

“Escalating antibiotic resistance limits our treatment options, worsens clinical results, and is a growing global public health crisis. What’s more, the development of new antibacterial drugs, especially ones appropriate for children, remains essentially stagnant,” Dr. Meropol warns in a university release.

The Case Western Reserve findings were first published in the March issue of the Journal of the Pediatric Infectious Diseases Society. A grant from the National Institute for Allergy and Infectious Diseases at the National Institutes of Health helped fund the research.