875. Emergence of ST-258 in Klebsiella pneumoniaeCarbapenemase Resistant Isolates in 19 Hospitals: 1999-2013
Session: Poster Abstract Session: Bacterial Infections: Pathogenesis and Immunity
Friday, October 9, 2015
Room: Poster Hall

Background:

Increased use of carbapenems has led to rising resistance in Klebsiella pneumoniae, particularly in the Northeastern US. Carbapenem resistant Klebsiella pneumoniae (CRKP) infection mortality rates are 47-57%. ST-258 is a strain type discovered in 2009 and found to be associated with CRKP. The chronology of the emergence of ST-258 as the dominant strain type in CRKP is unknown.

Methods:

Between 1999 and 2013, 571 Klebsiella pneumoniae bloodstream isolates were collected at 19 hospitals. The isolates have been characterized by RT-PCR using molecular beacons for gapA, blaKPC and mutations in tonB at positions 118 and 297. ST-258 was defined as both tonB mutations present by RT-PCR. Data was evaluated by both amplification curve and melting curve.

Results:

RT-PCR was performed on 441 isolates: one was not Klebsiella by gapA RT-PCR and 4 had inadequate DNA. Of the remaining 436, 79 were KPC positive and 119 were positive for ST-258. Of KPC positive isolates, 62 (70%) were St-258. While 57 (16%) of KPC negative isolates were ST-258. Distribution of isolates is shown in Table 1. The 17 KPC positive, ST-258 negative isolates are listed by year in Figure 1.

Conclusion:

In this collection of Klebsiella pneumoniae isolates, we have captured the first ST-258 isolate in 2001 and the first ST-258 positive KPC containing isolate in 2003. Both the genetic determinants of ST-258 and blaKPC are plasmid mediated, the rising percentage of ST-258 among KPC containing isolates suggests they were frequently passed together during the study period. Not surprisingly, KPC positive strains in 1999, 2001 and 2003 were non-ST-258 strain types that were later displaced by ST-258. However, the increase of non-ST-258 KPC positive isolates in 2013 is novel and suggests a new strain type may be emerging in KPC containing strains. Further work is needed to identify the strain types other than ST-258 present in KPC containing isolates.

Table 1 Isolate KPC and ST-258 status by year

1999

2001

2003

2004

2006

2009

2013

KPC+/ST258+

0

0

2

7

11

37

5

KPC+/ST258-

1

4

2

0

2

2

6

KPC-/ST258+

0

1

9

2

34

8

3

KPC-/ST258-

77

48

39

14

51

37

34

Total

78

53

52

23

98

84

48

Figure 1 KPC (+) / ST-258 (-) isolates by year as a percentage of total isolates.

Brandon Eilertson, MD1, Audrey Li, BS2, Liang Chen, PhD3, David Landman, MD, FIDSA4, John Quale, MD, FIDSA4 and Barry N. Kreiswirth, PhD5, (1)Infectious Diseases, SUNY Downstate, Brooklyn, NY, (2)School of Medicine, SUNY Downstate, Brooklyn, NY, (3)Public Health Research Institute - Rutgers University, Newark, NJ, (4)Medicine, SUNY Downstate Medical Center, Brooklyn, NY, (5)Phri TB Center, Rutgers University, Newark, NJ

Disclosures:

B. Eilertson, None

A. Li, None

L. Chen, None

D. Landman, None

J. Quale, None

B. N. Kreiswirth, None

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