Thursday, August 28, 2014

Carbapenem-Resistant Enterobacter cloacae Isolates Producing KPC-3 in North Dakota, USA.

A recent letter in the Emerging Infectious Diseases journal discussed the emerging threat of Carbapenem-Resistant Enterobacter cloacae (CRE) in the "far-flung" land of North Dakota (ND).

CRE infections are usually mediated by acquisition of Klebsiella pneumoniae carbapenemase (KPC) expressed by Klebsiella spp.

Klebsiella pneumoniae on a MacConkey Agar Plate
After reporting of CRE infections became mandatory in ND in 2011, 20 CRE cases were noted in 12 of 53 counties. Most cases occurred in Cass County, where ND's largest city (Fargo) is located.

Sanford Health is a 538-bed, acute-care facility that represents roughly 70% of acute-care beds in Fargo. Sanford Health is currently in the process of attempting to bring a quality healthcare product to rural areas of ND, SD and MN. Sanford has been slowly working its way west, buying out healthcare facilities and attempting to revamp healthcare in rural areas.

According to the letter, during the period between December 2011 and December 2012, all isolates of Enterobacteriacea (a large family of Gram-negative bacteria that include normal gut microbiota, pathogens, and normal gut microbiota that can become pathogens in certain circumstances) with reduced susceptibility to ertapenem (MIC > 1 ug/mL) identified at the hospital's clinical microbiology laboratory were screened for carbapenemase production using the modified Hodge tests (mHT)

Ertapenem is a carbapenem antibiotic (broad-spectrum beta-lactam) marketed by Merck as Invanz. Ertapenem has been designed to be effective against both Gram-negative and Gram-positive bacteria. It is not active against Methycillin-resistant Staphylococcus aureus (MRSA), ampicillin-resistant enterococci, Pseudomonas aeruginosa, or Acinetobacter species.

If you have questions, use the comments section below!

Identification and sensitivity testing were done with the MicroScan system and MICs of carbapenems were done with Etest.

MicroScan System

Etest - Biomerieux










The 20 patients from whom KPC-producing CRE isolates were obtained had been hospitalized at Sanford Health during the three months before CRE isolation; of the 20, 13 were admitted to intensive care. 13 was also the number of patients that had been admitted to the long-term care facility during the year before CRE isolation. Co-colonization with multi-drug resistant bacteria was documented in 16 patients, including extended-spectrum beta-lactamase producing and carbapenem-resistant organisms in four and two patients respectively. Seven of the documented patients died with three of those deaths being attributed to the CRE infection.

If you have questions, use the comments section below!

The authors end with...

"This outbreak of KPC-producing E. cloacae infections in a health care system in North Dakota highlights the infection control challenges of long-term care facilities and the potential role they play in CRE dissemination."

CRE's have been identified in almost every state in the U.S. and with rising rates, figure to be an important factor for every infectious disease practitioner.

  • Lance D. Presser has a PhD in microbiology and immunology and is a clinical/public health laboratorian.
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