"Leaky" hospitals redux: When HA is CA

The CDC work below and several other papers published recently attribute a good proportion of CA-MRSA to hospital strains that have left the institution in a colonized patient and sickened that patient at some point post-discharge. But several papers presented at the annual meeting of the Society for Healthcare Epidemiology of America underline that MRSA traffic is two-way: Community strains can enter the hospital and cause outbreaks there as well.

Cases in point:

• Between 2004 and 2007, the Medical University of South Carolina in Charleston identified 272 hospital-acquired infections that were caused by USA300, the dominant CA-MRSA clone. That's 21.3% of all HAIs in that hospital in those years. (Lead author K Hardman)
• At Johns Hopkins University in Baltimore, nine out of 757 patients admitted to the pediatric intensive care unit became colonized or infected with MRSA 48 hours or longer after they were admitted. Six of the nine were found to have USA300, and one developed invasive MRSA disease. (Lead author AM Milstone, MD)
• And at New York-Presbyterian Hospital, a 5-day-old baby who had not yet left the hospital became infected with USA300, the first casualty in a complex outbreak involving several MRSA strains that eventually comprised 21 infants (12 colonized and nine with infection; 14 of the 21 with USA300) and 10 mothers (five infected Caesarean incisions, two with breast abscesses, two with mastitis and one with a skin infection; six out of 10 with USA300). (Lead author Jean-Marie Cannon, RN)