Now there’s another one, called CRE, or Carbapenem-resistant Enterobacteriaceae. Enterobacteriaceae typically reside in the gut (a very common enterobacteriaceae is E. coli). Some strains of enterobacteriaceae (like MRSA) have become resistant to most known antibiotics, including carbapenem, which is generally an antibiotic of last resort.
According to the Centers for Disease Control, CRE infections are still fairly rare. They tend to occur primarily in patients who are hospitalized for other conditions and who are on ventilators, have bladder catheters, or are connected to IV (intravenous) catheters. However, when CRE infections do occur they are exceedingly dangerous because they are so hard to treat – according to one estimate they contribute to death in perhaps half of all patients who are infected.
The fact that CRE is currently limited to certain types of hospitalized patients is mildly reassuring, for now. But because enterobacteriaceae are fairly common in humans, health care workers are concerned that resistant strains like CRE could make the jump to the wider human community. Prevention strategies are being worked out as we speak.