Via the Archives of Internal Medicine, a new study from Cook County Hospital and Rush University Medical Center in Chicago. Betwen 2000 and 2005, the incidence of CA-MRSA at the hospital and its neighborhood clinics increased 6.84 times. Notably, meth-sensitive staph (MSSA) did not decrease - this was a true addition, not a substitution of one strain for another. And 79% of the strains identified were USA300. Important clues to the rapid spread of the bug: Those infected were more likely to have been incarcerated more than once (carrying the bug from the known epicenters of jails and prisons back out into the community) or to live in public housing (possibly because of overcrowding as Chicago demolishes its old-style projects and moves the people who live there into its remaining public housing). The paper raises but can't answer the question of a synergy between those factors: People coming out of jail may be returning to households in public housing creating a bridge between a known epicenter and a population whose living conditions put them at greater risk.
Find the paper here.