Outbreak of Klebsiella pneumoniae Carbapenemase-Producing Enterobacter cloacae Associated with a Long Term Acute Care Hospital, 2010

Background: Carbapenem-resistant Enterobacteriaceae (CRE) infections are associated with increased mortality and can be transmitted in healthcare settings. MN Dept. Health (MDH) instituted statewide surveillance for CRE in March, 2009 following identification of a K. pneumoniae isolate that was bla_KPC positive by PCR. Clinical labs were instructed to perform a Modified Hodge Test (MHT) on all Enterobacteriaceae isolates with elevated MICs for at least 1 carbapenem and to submit MHT positive isolates to MDH. Upon detection of CRE, CDC infection prevention measures and enhanced surveillance recommendations were discussed with healthcare facilities.

Objective: To investigate a cluster of Enterobacter cloacae bla_KPC positive isolates.

Methods: PCR for bla_KPC was performed on MHT positive E. cloacae isolates submitted to MDH. Isolates positive for bla_KPC were typed by PFGE. Demographic information was obtained on patients, including admission dates to an acute care hospital or long term acute care hospital (LTACH) prior to culture date.

Results: From 12/09 – 10/10, 11 MHT positive E. cloacae isolates were submitted; 6 were bla_KPC positive. 4 of the 6 isolates were indistinguishable by PFGE (PFGE type ECL 1); 2 were highly similar with 2 and 3 band differences from PFGE type ECL 1 (PFGE type ECL 14 and ECL 8, respectively). All were from patients in northwestern MN. 3 isolates with PFGE type ECL 1 (1 from blood, 2 urine) were obtained from patients in an LTACH and the fourth isolate (wound) was from a patient in an acute care facility associated with this LTACH. The PFGE type ECL 14 and ECL 8 isolates (1 from sputum, 1 wound) were also from patients in the same LTACH.  2 of 6 patients died within 3 months. MDH provided the facilities with infection prevention and control recommendations upon identification of each bla_KPC positive isolate. Contact Precautions were strictly adhered to in the acute care facility; no additional cases were identified by active surveillance testing. Contact Precautions were recommended in the LTACH but the level of barrier precautions implemented is unknown. 1 additional isolate (blood) obtained from the same LTACH from a non-MN resident was also PFGE type ECL 1.

Conclusions: Lab surveillance uncovered a cluster of bla_KPC positive E. cloacae isolates associated with an LTACH. Although infection prevention recommendations were reviewed with the LTACH, additional cases were detected months later in the same facility and in an associated acute care facility. This outbreak highlights the importance of establishing heightened infection prevention and control practices, communication between laboratory and clinical staff, and surveillance for CRE in all healthcare settings.