KPC: An Emerging Threat

No, KPC isn't a new fast food restaurant. It's short for Klebsiella pneumoniae carbapenemase. The bad news: it's very hard to treat. The good news: it's very rare...for now.

Actually, the correct term is KPC-possessing K. pneumoniae*, but we'll just use the slang 'KPC'--it's what all the cool microbiologists use (I'll refer to the carbapenemase gene as the 'KPC gene'). KPC causes pneumonia, urinary tract infections, and sepsis; the mortality rate from these infections is extremely high.

The KPC gene confers resistance to all cephalosporins and Ã-lactam antibiotics: basically, anything named "-cillin", "-penem", or "cef-" won't kill it. Aztreonam doesn't kill it either. And, of course, it happens to have evolved resistance to most of the other classes of antibiotics, so, like some Acinetobacter, it is only treatable with colistin and tigecycline, which works...except when resistance evolves in the patient, which has been observed multiple times (this is alarming given the relatively few times this therapy has been used).

The KPC gene is found on a highly transmissible plasmid, which means it can be transferred within Klebsiella and can also spread to other Gram-negative bacteria (E. coli, Enterobacter, and others). The good news is that the plasmid is unstable: it doesn't always manage to wind up in both daughter** cells after cell division.

The good news is that KPC is very rare. Even in the epicenter, New York City, there have been relatively few cases (I've heard varying estimates, from less than 100 to 2000 over the last five years). New York has had the good sense to make KPC a reportable organism, and hospitals are engaging in strict patient quarantine. This is the correct policy.

Unfortunately, this is not a national policy, and bacteria don't do state boundaries. While Massachusetts has been very fortunate (there is only one verified case, although two more are under investigation), like most states, KPC is not a mandatory reportable disease in Massachusetts, or in most other states. Nor are there requirements for strict quarantine.

Now is the time to enact national mandatory quarantine and reporting requirements. If KPC becomes prevalent to even a fraction of the extent that MRSA is, we are really in trouble, since MRSA can almost always be treated successfully with vancomycin. KPC is a lot more difficult to treat.

We have a chance to get out in front of a potential public health problem rather than reacting to it once it has already become a severe problem. This one is really scary--if it gets out of control, it will be a lot worse than Acinetobacter ever could be.

*Considering that microbiologists use acronyms such as HACO-MRSA, I'm surprised no one has come up with KPKP (pronounced 'kip-kip').

**I have no idea why the daughter cells are called 'daughter.' I blame the patriarchy.