2053. In vitro susceptibility testing of essential oils against carbapenem-resistant Enterobacteriaceae and selected ATCC strains.
Session: Poster Abstract Session: Antimicrobial Resistant Infections: Treatment
Saturday, October 29, 2016
Room: Poster Hall
Background:

In the era of antibiotic resistance, alternative anti-infectives must be explored. The National Action Plan for Combating Antibiotic-Resistant Bacteria calls for developing non-traditional therapeutics, including natural compounds such as essential oils (Goal 4.4). To that end, the in vitro activity of essential oils and the oil blend, Thieves® (cinnamon, clove, lemon, eucalyptus, rosemary) were studied against CRE from our institution. Selected ATCC isolates were also tested to explore the potential spectrum of essential oils.

Methods:

Oils were obtained from Young Living Essential Oils & lot #s recorded. CRE were defined as isolates resistant to imipenem, meropenem AND resistance to ceftriaxone, cefotaxime, or ceftazidime using CLSI methods. 23 CRE were identified from 2014-15 at university-affiliated hospitals. Isolates were grown overnight on TSA; 0.5 McFarland suspensions in sterile water were swabbed over Mueller-Hinton agar using the Kirby- Bauer method. 20 ml of full-strength oils were pipetted onto blank paper disks in a sterile dish. Disks were placed aseptically onto the plates immediately after inoculating disks. Plates were incubated overnight at 37C in ambient air. Zone diameters are shown.

Results:

Table 1. Zone Diameters (mm for Essential Oils against CRE and ATCC strains)

CRE isolate

Lavender

Lemongrass

Eucalyptus

Oregano

Rosemary

Thieves®

Thyme

C. freundii

0

11

10

34

13

16.5

38

E. aerogenes

8

10

7

21

0

15

20

E. cloacae

8

9

0

19

9

17

18

E. cloacae

0

0

0

12

0

11

11

E. coli (n=4; median)

0

10

0

18.5

4

15.5

16.5

E. coli ATCC

10

17

10

28

9

16

30

K. pneumo (n=14;median)

0

9.5

0

19.5

8

13

16.5

S. marcescens

8

9

0

15

8

11

14

P. aeruginosa ATCC

0

0

0

7

0

11

8

S. pneumo ATCC

26

54

13

52

18

34

56

S. pyogenes ATCC

30

>50

18

50

30

36

>50

MRSA ATCC

13

42

10

37

0

24

42

S. aureus ATCC

11

36

0

29

0

16

34

Conclusion:

Essential oils oregano and thyme had the largest zones of inhibition against CRE organisms, followed by lemongrass and Thieves®. Oregano and Thieves® had the largest zones of inhibition for P. aeruginosa. Lemongrass had very large zones of inhibition against gram-positive ATCC strains, followed by oregano, thyme, Thieves®, and lavender. The in vitro and in vivo activity of essential oils against clinical pathogens deserves further study.

Jan E. Patterson, MD, FIDSA, FSHEA1, Jose Cadena, MD/ID2,3, Kristi Traugott, PharmD4, Cynthia Kelly, BS, MT(ASCP)5 and Steven Dallas, PhD5, (1)Medicine/ID, University of Texas Health Science Center San Antonio, San Antonio, TX, (2)University of Texas Health Science Center, San Antonio, TX, (3)South Texas Veterans Health Care System, San Antonio, TX, (4)University Health System, San Antonio, TX, (5)University of Texas Health Science Center at San Antonio, San Antonio, TX

Disclosures:

J. E. Patterson, Young Living Essential Oils: Distributor , Salary

J. Cadena, None

K. Traugott, None

C. Kelly, None

S. Dallas, None

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