The discovery of a potentially deadly superbug in Connecticut has scientists majorly concerned — it’s the fourth time such a superbug has been found, and it could portend to a disturbing new trend that threatens humanity itself. This superbug, a straing of Escherichia coli that is resistant evne to antibiotics of a last resort, was confirmed by the Centers for Disease Control and Prevention in a recent statement.

In this case, the girl who had been infected had traveled to the Caribbean. She leter devleoped fever and bloody diarrhea in June, two days before she came back to the United States. She made several visits to the doctor but did not require hospitalization. Eventually, they found E. coli in her stool sample, including the mcr-1 gene, which is resistant to antibiotic drugs.

Scientists are worried about superbugs developing because of our overuse of antibiotics. By hastening the evolution of these extremely difficult to kill superbugs, we risk creating diseases through our antibiotic use that not even our most powerful antibiotics can kill, scientists worry.

“In this investigation of potentially travel-associated mcr-1 acquisition, no transmission beyond the index patient or persistent environmental contamination were identified, and the patient was transiently colonized,” the CDC statement reads. “At this time, CDC recommends that Enterobacteriaceae isolates with a colistin or polymyxin B MIC ≥4 μg/ml be tested for the presence of mcr-1; testing is available through CDC (5). Prompt reporting of mcr-1–carrying isolates to public health officials allows for a rapid response to identify transmission and limit further spread.”