Quinolones for Streptococcus pneumoniae? No thanks (still)

CDC – Antimicrobial Susceptibility Breakpoints and First-Step parC Mutations in Streptococcus pneumoniae: Redefining Fluoroquinolone Resistance

"Since effective surveillance depends upon the ability to detect the emergence of resistance, the prevalence of pneumococci that harbor resistance mechanisms to the fluoroquinolones may not be accurately represented if surveillance systems that rely on levofloxacin MIC data are used."

The article is a bit hard to follow, but it's important — so worth the read.  My quick summary:  The method that is currently used to determine quinolone resistance is innacurate, and cannot adequately measure what we intend to measure. 

In summary, levofloxacin susceptibility testing that uses current MIC clinical breakpoints does not identify most S. pneumoniae isolates with only first-step parC mutations. This finding may not only have implications for the ability of surveillance programs to detect emerging resistance, but therapeutic implications as well.

Tharaputic implications indeed.  Despite great populatiry, I've never embraced quinolones for the treatment of anything other than gram negative UTI's (as a second-line agent, of course!).