Carbapenem resistant Enterobacteriaceae (CRE) in the Veterans Health Administration (VHA): a “second epidemic” of carbapenem resistance among Enterobacter cloacae after that of Klebsiella pneumoniae

Background: CRE/carbapenemase producing Enterobacteriaceae (CPE) is a serious threat to public health. The “first epidemic” of CRE/CPE in the US was caused by K. pneumoniae producing KPC-2 and 3. A “second epidemic”, E. cloacae harboring KPC-3, first occurred in North Dakota and Minnesota. We examined rates and temporal trends of carbapenem non-susceptibility (NS) in K. pneumoniae and E. cloacae at VHA facilities.

Methods: Using VHA databases, we identified E. cloacae and K. pneumoniae tested for carbapenem susceptibility isolated in patients hospitalized from 2012 to 2014. Facilities that tested < 90% of isolates were excluded; one isolate per patient was counted. We examined carbapenem NS by year, sorting facilities according to regions designated by the US Department of Health and Human Services.

Results: Among 10,973 E. cloacae and 28,218 K. pneumoniae isolates from VHA facilities in 42 states, the District of Columbia (DC), and Puerto Rico (PR), carbapenem NS was 3.3% and 2.8% for E. cloacae and K. pneumoniae, respectively. Rates among E. cloacae trended upwards to reach above 3% and rates in K. pneumoniae decreased from 3.3% to 2.1% over the 3 years examined. Trends remained after removing PR, which had the highest rates at 12.2% and 23.3%, respectively. The rate of carbapenem NS in E. cloacae exceeded that of K. pneumoniae in all regions except Region 2 (Table and Maps). Despite these regional trends, there were exceptions in several large cities outside of Region 2 with higher rates of NS in K. pneumoniae than in E. cloacae.

Conclusion: Nationwide VHA data suggests a “second epidemic” of CRE/CPE mediated by E. cloacae. Robust surveillance integrating susceptibility data, resistance mechanisms, genotyping and antibiotic use is essential to understand the changing epidemiology of CRE/CPE in the VHA system.

Region	States	E. cloacae		K. pneumoniae
		Range of % NS *	% NS	Range of % NS *	% NS
1	ME, VT, RI, MA	0-3.1	2.5	0-0.9	0.10
2	NY, NJ, PR	1.0 -12.3	6.1	0.8-23.5	12.1
3	VA, PA, MD, WV, DC	0-5.8	2.4	0-4.8	2.1
4	AL, GA, MS, NC, SC, TN, FL	0-5.9	2.6	0-3.4	1.0
5	IL, IN, MI, MN, OH, WI	0-6.9	1.9	0-4.3	1.8
6	AR, LA,  OK, TX	0-8	3.4	0-4.7	1.9
7	IA, KS, MO, NE	0-4	1.6	0-3.8	0.8
8	CO, SD, ND, MT, UT, WY	0-4	1.9	0-0	0.2
9	AZ, CA, NV	0-11.3	4.0	0-3.4	1.5
10	OR, WA	0-15.1	8.9	0-0.6	0.3

 

 

 

 

 

 

 

 

 

Including facilities with > 30 isolates