STRTEGIES TO REDUCE THE USE OF …...STRTEGIES TO REDUCE THE USE OF ANTIMICROBIALS IN LIVER ABSCESS...
Transcript of STRTEGIES TO REDUCE THE USE OF …...STRTEGIES TO REDUCE THE USE OF ANTIMICROBIALS IN LIVER ABSCESS...
STRTEGIES TO REDUCE THE USE OF
ANTIMICROBIALS IN LIVER ABSCESS
CONTROL
Tim McAllister1, Rob Gruninger1, Taylor Davedow1, Rahat Zaheer1, Leluo Guan2,
Greg Penner3 and Gabriel Ribeiro3
1 2 3
Antimicrobial use and resistance
� Raises concerns about
antimicrobial use in feed
and antimicrobial
resistance (AMR)
development in bacteria
PHAC, 2017
Spread in
environment
including via
contaminated water
and manure
Spread in
environment
including via
contaminated water
and manure
Spread
between
animals
Spread
between
animals
Spread
between
animals
and
humans,
including
via food
Spread
between
animals
and
humans,
including
via food
Spread
between
humans
Spread
between
humans
Introduction Cont.
Health Canada
Directive
Veterinary oversight
Vet prescription
for MIA
No growth promotion
claim
Responsible use
statement
Liver Abscesses
Human
Consumption
68%
Condemned
22%
Pet Food
10%
� Liver abscess prevalence
in cattle = 12-32% (Brink et al., 1990)
� 11% reduction in average
daily gain, 9.7% reduction in
feed efficiency (Brink et al., 1990)
BCRC, 2018
A+
severe
A+
severe
A
mild
A
mild
0
none
0
none
Identification of novel vaccine targets
The main reason for in-feed macrolide use in feedlots
• Increased prevalence from13% in 1999 to 23% in 2011
• Associated with consumption of high-grain diets
Fusobacterium necrophorum (1o)
Trueperella pyogenes (20)
Cattle liver abscesses: Elanco Liver Scoring System
0 A- A A+
Liver abscesses – identification of novel
vaccine targets
� Costs industry $61.2 M /yr
• Due to animal performance and liver condemnation
• A 10% reduction in both acidosis and liver abscesses would
save
the industry over $40M per year
• Prevalence is expected to reach 70% if in-feed
antimicrobials are banned
� Currently, vaccine efficacy is low
• Polymicrobial disease
���� Novel vaccine targets are needed
Bacteriology: culture-based approach
Genus Species Recovery %
Fusobacterium necrophorum 100
Trueperella pyogenes 49.8
Salmonella5 ≠ serotypes
Lubbock 60.8%25.3
Escherichia coli 32.4
Klebsiella pneumoniae 14.9
Enterobacter cloacae 14.4
Enterococcus faecalis 17.7
Lactococcus garviae 18.8
Bacillus cereus NS
Propionibacterium acnes NS
Corynebacterium falsenii NS
Streptococcus spp. 7.3
Acinetobacter spp. 5.5
Aeromonas spp. 5.5
Staphylococcus spp. 5.5
Citrobacter spp. 4.4
Pseudomonas spp. 2.4
Leclercia spp. 2.1
Proteus spp. 1.3
Bacteroides spp. 1
Micrococcus spp. 1
Shewanella spp. 1
Bacillus spp. 0.8
Peptoniphilus spp. 0.8
Wautersiella spp. 0.5
� Holstein steers vs Crossbred cattle
• More diversity in Holstein steers
• Fn in all samples
• No differences on % Salmonella
• Higher Tp cross breed
� Tyl vs no tylosin
• Tyl group higher Tp, lower
Salmonella
� 24 different genus
Amachawadi et al J. Anim. Sci. 95: 3425-3434
Liver abscesses – identification of
novel vaccine targets
Liver abscess microbiome – US cattle fed corn
(Weinroth et al. 2017).
• Samples of abscess
fluid in corn-fed cattle
• Canada has a higher
incident rate
compared to the US
- may be due to
different diets
• Tissue-adherent
population in barley-
fed cattle
- using a 16S
rRNA sequencing
as a targeted
approach for
identification of
novel vaccine
candidates
T. pyrogenes
F. necrophorum
Alternative Strategies
Prebiotics
VaccinesNutritional Management
53.3
33.3
20.0 20.0 20.0
6.7
0
10
20
30
40
50
60
70
80
0 12 15 18 eXPC ANT
Ab
sce
ss P
erc
en
tag
e (
%)
Treatments
Total Severe
Figure 1. Effect of Saccharomyces cerevisiae fermentation product (SCFP;
NaturSafe®), encapsulated XPC (eXPC) or antibiotics (TYL) on total and
severely abscessed livers (%) in finishing steers
Total (P = 0.97); Severe (P = 0.10).
TYL
In press
Objectives
15
3 Cattle performance
2 AMR development in enteric enterococci populations
1 Liver abscess prevalence and severity
Determine effect of shorter duration tylosin administration
(FIRST-78, LAST-75) compared to continuous feeding (CTRL) on:
Hypotheses
1
• Cattle in the two shorter duration tylosin feeding regimens (FIRST-78, LAST-75), will have no significant difference on liver abscess prevalence or growth performance.
2
• The proportion of macrolide resistant enterococci will decrease only for cattle that were fed tylosin in the FIRST-78 treatment
0 20 40 60 80 100 120 140 160
CTRL
LAST-75
FIRST-78
Days on feed
Tre
atm
en
ts
TYLOSIN NO TYLOSIN
Experimental Design
Fecal Collection:
� Beef cattle randomly assigned to 1 of 3 treatments
� Allocated in replicates: 1 pen/ group/rep
� 250 head/pen� 10 reps
n = 2526 n = 2525 n = 2525
FIRST-78 LAST-75 CTRLTylosin phosphate in-feed: 11 ppm
Materials and Methods:
Fecal Composite
Bile esculin azide (BEA)
agar
BEA + erythromycin (8 �g/mL; BEAE)
% EryR Enterococci = ��������� ��������� ������������
������������� ������������ �����% EryR Enterococci =
��������� ��������� ������������
������������� ������������ �����
Sample Processing
Enterococci Isolation & Enumeration
Enterococcus spp. Characterization
• Duplex PCR of groES-EL intergenic region& mur2 gene to target E. hirae
Enterococcus spp. Characterization
• Duplex PCR of groES-EL intergenic region& mur2 gene to target E. hirae
Antibiotic Susceptibility Testing: Disc Diffusion
• Panel of 12 antibiotics with medium or high importance in human health
Antibiotic Susceptibility Testing: Disc Diffusion
• Panel of 12 antibiotics with medium or high importance in human health
Resistant Gene Determinant PCR
• Macrolide resistant genes erm(B) & msrC
• Tetracycline resistant genes tet(L,M & O)
Resistant Gene Determinant PCR
• Macrolide resistant genes erm(B) & msrC
• Tetracycline resistant genes tet(L,M & O)
Sample Analysis
RESULTS & DISCUSSION
Results
Proportion of erythromycin resistant fecal enterococci isolates.
Method of tylosin administration, P = 0.34; Tylosin administration X
Days on feed, P =0.37; Days on feed, P < 0.01.
0
20
40
60
80
100
0 81 160
Pro
po
rtio
n o
f m
acr
olid
e
resi
sta
nce
(%
)
Days on feed
FIRST-78 LAST-75 CTRL
Results
Enterococcus species distribution of characterized isolates from
feedlot cattle. Isolates are pooled across all pens, experimental
groups and media type.
0
20
40
60
80
100
0 81 160
Spe
cie
s p
reva
len
ce (
%)
Days on feed
E. hirae E. villorum E. faecium E. durans
Antibiograms of enterococci (n=176) isolated from feedlot
cattle feces from cattle fed tylosin during the feeding period1
1 Isolates pooled across all treatments, sampling days, and isolation media types2 There were 16 antibiogram profiles in total3 Doxycycline, DOX; Erythromycin, ERY; Linezolid, LIN; Nitrofurantoin, NIT; Quinupristin-
dalfopristin, Q-D; Streptomycin, STR; Tigecycline, TIG; Tylosin, TYL. Upper case denotes
complete resistance and lower case denotes intermediate resistance.
Profile2 Phenotype3 n = 176 (%)
A1 No Resistance 21 11.9
A5 ERY-TYL 81 46.0
A7 dox-ERY-TYL 42 23.9
Treatment
No. Positive (%)1
Macrolide Tetracycline
n erm(B) msrC Negative n tet(L) tet(M) tet(O) Negative
FIRST-78 51 49 (96.1) 1 (2.0) 2 (3.9) 17 13 (61.9) 13 (61.9) 4 (19.0) 0 (0)
LAST-75 51 48 (94.1) 3 (5.9) 3 (5.9) 21 18 (85.7) 19 (90.5) 2 (9.5) 0 (0)
CTRL 51 47 (92.2) 2 (3.9) 4 (7.8) 16 10 (62.5) 10 (62.5) 5 (31.3) 1 (6.3)
Total 153 144 (94.1) 6 (3.9) 9 (5.9) 54 41 (75.9) 42 (77.8) 11 (20.4) 1 (6.3)
Distribution of enterococci isolates grouped according to macrolide
(n = 153) and tetracycline (n= 54) resistance genes and by treatment
1Isolates pooled across all media types and sampling days
Liver abscesses of feedlot cattle from cattle fed tylosin for
the FIRST-78%, LAST-75%, or continuously (CTRL) during the
feeding period.
1 Severely abscessed (A+), total liver abscesses (A and A+), and no liver
abscesses (none = 0). 2 Reference group = CTRL; Comparison groups = FIRST-78 and LAST-75
Treatment
Liver Abscesses (%)1 Risk Ratio2
Abscessed Severe None Total Abscessed Severe
FIRST-78 61.00 23.47 39.00 100.00 0.99 1.18
LAST-75 64.15 22.95 35.85 100.00 1.04 1.16
CTRL 61.88 19.83 38.12 100.00 1.00 1.00
Growth performance of feedlot cattle.
1 DMI = dry matter intake; ADG = average daily gain; F:G = feed-to-gain ratio2 Based on live weight
Item1
Treatment P – values
FIRST-78 LAST-75 CTRL SEMFIRST-78
vs CTRL
LAST-75
vs CTRL
No. of Cattle 2525 2526 2525
Initial BW (kg) 393.5 395.2 393.6 5.49 0.99 0.22
Final BW (kg) 681.0 680.0 677.5 9.25 0.25 0.40
DMI (kg/d) 11.9 11.9 11.8 0.14 0.80 0.22
ADG (kg/d)2 1.8 1.8 1.7 0.03 0.25 0.69
F:G2 6.7 6.8 6.8 0.07 0.23 0.70
Composition of Capsule microbiome was similar to interior of abscess
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Fusobacterium BacteroidesEscherichia-Shigella Campylobacter
Rela
tive A
bundance (
%)
Capsule Interior
� Levels of liver abscesses can be very high – even with contol measures
�Undeniably a diseased state even if it does not always impact growth performance
�Solutions:• Vaccine??
• More forage less concentrate??
• Grain processing?
• Balanced protein levels?
• Genetic predisposition?
�A clear problem that needs a solution.
Conlusions:
Conclusions� E. hirae a species that seldom causes disease in people was the
predominant species in beef cattle
� Removal of tylosin did not alter levels of macrolide resistant
enterococci
� Removal of tylosin tended to result in more severe abscesses
� Overall total number of liver abscesses not affected by reduced
tylosin
� Removal of tylosin did not impact growth performance or health
� Mileage in letting it be known that antimicrobial use has been
reduced in beef??
Conlusions:
Thank you!
�Abscess microbiome had low diversity and was
dominated by Fusobacterium
�Small differences in the relative abundance of taxa
between inner abscess wall and pus
�Treatment did not have a significant effect on abscess
microbiome however small shifts in taxonomy were
detected.
�Need to validate whether these shifts were
statistically significant