AHEAD IN ANIMAL HEALTH
Antimicrobial sensitivity of Dutch porcine A. pleuropneumoniae, E. coli and S. suis 2016 - 2020 Jobke van Hout1,3, Marieke Augustijn1, Els Broens2, Maaike Gonggrijp1, Annet Heuvelink1 1 Royal GD, 2 Utrecht University, 3 Presenting author
Aim of the study
A
Access to representative, reliable antimicrobial susceptibility testing (AST) data is a prerequisite for further promotion of prudent use of antimicrobials and provision of solid evidence for policies aimed at reducing antimicrobial resistance levels in bacterial pathogens. Therefore, this study aimed to assess the effect of several potential factors on representativeness and reliability of AST results of Actinobacillus pleuropneumoniae (APP), Escherichia coli (ECO), and Streptococcus suis (SSU) from pigs.
Figure 1a-d. Distribution of the farms of origin of APP, ECO and SSU (a-c) isolates in the dataset of 2016-2020 and the distribution of all pig farms (d) in the Netherlands
Materials & Methods
Table 2a - 2c
AST results (Minimal Inhibitory Concentration (MIC)) were extracted from the Laboratory Information Management System of GD for the period 2016-2020. Next, additional data (age category, farm and province of origin) were collected and merged with the MIC databases. Subsequently statistical analyses were carried out using STATA 15.1 (StataCorp, 2017).
Results • Overall, the number of APP (n=761), ECO (n=1141) and SSU (n=2816) isolates were well representative considering the number of pigs and number of farms per province they originated from. Although less APP isolates were available compared to ECO and SSU, for all bacterial species fairly precise estimations of resistance levels were determined as shown by the confidence intervals in the MIC distributions (<17% but most <9%). • The dataset also allows for detection of year-to-year trends in resistance; hardly any significant changes in resistance percentages in time were found. • Multilevel analyses revealed significant associations between resistance levels and age category (ECO and SSU); generally, resistance levels decreased with increasing age. • For several antimicrobials a significant association between farm of origin and level of resistance was shown.
B
C
Antimicrobial 0.125 Amoxicillin/Clavulanic acida Ampicillin Apramycin Cefepime Cefotaxime Colistin Enrofloxacin Florfenicol Flumequine Gentamicin Neomycin Spectinomycin Streptomycin Sulfamethoxazole Tetracycline Tiamulin Tilmicosin Trimethoprim Trimethoprim/Sulfamethoxazoleb Tylosin
0.0
0.25 98.0 90.1
0.5 2.0 2.6
100.0
96.0 0.0
4.0
4.0
43.0 0.7
39.7 15.2 0.0
Actinobacillus pleuropneumoniae 2020 (n=151) MIC values (µg/mL) 1 2 4 8 16 32 64 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.7 0.0 2.6 4.0 16.6 68.2 15.2 0.0 100.0 0.0 0.0 0.0 0.0 0.0 0.0 98.7 1.3 0.0 0.0 2.6 1.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 99.3 0.7 0.0 0.0 98.7 1.3 0.0 0.0 0.0 71.5 23.2 5.3 0.0 0.0 15.9 72.8 11.3 0.7 0.0 6.0 82.1 2.0 10.6 51.0 27.2 4.0 1.3 3.3 66.9 12.6 0.7 4.6 2.6 4.6 99.3 0.7 0.0 0.0 49.0 47.7 3.3 0.0 0.0 0.0 9.9 11.9 10.6 11.3 4.6 11.9 17.9 13.9 8.6 1.3 0.0 0.0 1.3 98.0
Antimicrobial 0.125 Amoxicillin/Clavulanic acida Ampicillin Apramycin Cefepime Cefotaxime Colistin Enrofloxacin Florfenicol Flumequine Gentamicin Neomycin Spectinomycin Streptomycin Sulfamethoxazole Tetracycline Tiamulin Tilmicosin Trimethoprim Trimethoprim/Sulfamethoxazoleb Tylosin
0.25 0.0 0.0
97.2
0.0
36.4 0.0
0.5 0.7 0.7
1 7.0 8.4
88.1 2.1
99.3 99.3 5.6 0.7
2.8
37.1 0.7 0.0
33.6
0.0 0.0 0.0
Escherichia coli 2020 (n=143) MIC values (µg/mL) 2 4 8 16 32 22.4 35.7 33.6 0.7 0.0 21.7 2.8 0.0 0.7 0.0 95.1 4.9 0.0 0.0 0.7 0.0 0.0 0.0 0.0 0.0 0.7 2.1 2.1 2.1 0.0 0.0 0.0 0.0 4.2 48.3 35.7 11.9 91.6 4.9 3.5 0.0 0.0 100.0 0.0 0.0 0.0 93.7 0.0 2.1 4.2 0.7 1.4 36.4 33.6 5.6 4.9 8.4 4.9 2.8 0.0 0.0 1.4 0.0
Conclusions All factors associated with susceptibility levels should be considered before sharing aggregated susceptibility patterns for use in antimicrobial treatment guidelines and in veterinary practice. This project was funded by The Netherlands Organisation for Health Research and Development (ZonMw); Dossier number: 541003007.
Antimicrobial 0.03125 Amoxicillin/Clavulanic acida Ampicillin Cefepime Ceftiofur Clindamycin Enrofloxacin Erythromycin Florfenicol Neomycin Oxacillin Penicillin G Sulfamethoxazole Tetracycline Tilmicosin Trimethoprim/Sulfamethoxazoleb
0.0625 96.0
89.1
0.125 2.0
0.25 97.8 0.0
51.3
94.7 51.9 86.7 2.0
4.2
68.1 2.0 4.2
50.5
1.6
10.5
D
1.2
0.5 0.6 0.4 99.0 2.8 0.8 12.9 0.4
28.9 2.8 5.0 13.5
0.0 0.0 0.7 0.0 0.0
0.7 0.7 0.0 0.0 61.5 100.0
0.0 0.0 0.0 0.0
60.1 3.5 9.1 62.2
64 0.0 65.7
128
10.6 4.0 6.6
128
256
512
0.7 8.6
256
81.5
512
0.0
21.7 6.3 10.5
10.5 36.4 2.1
29.4 2.8
84.6
95.8 90.9
Streptoccus suis 2020 (n=505) MIC values (µg/mL) 1 2 4 8 16 0.2 0.8 0.4 0.2 0.0 0.2 0.8 0.4 0.0 0.2 0.6 0.4 0.0 0.0 0.0 0.8 0.8 0.4 0.4 0.2 0.2 0.8 1.6 44.8 0.2 0.0 0.0 0.2 0.4 0.4 0.4 1.4 43.8 97.8 1.8 0.0 0.2 9.3 9.3 39.6 1.8 0.8 0.2 0.2 0.0 0.6 1.2 0.0 0.2 0.0 3.4 18.6 5.1 1.0 3.8 15.0 15.4 35.0 3.8 1.8 6.9 2.0 12.1
32 0.0 0.0 0.0
64 0.0 0.0
128
256
MIC50 (μg/mL) ≤0.25 0.25 16 ≤1 ≤1 ≤0.5 ≤0.25 ≤2 ≤2 ≤2 16 64 8 >256 1 ≤8 4 2 0.5 >4
MIC90 (μg/mL) ≤0.25 0.25 32 ≤1 ≤1 ≤0.5 ≤0.25 ≤2 2 4 >16 128 16 >256 8 ≤8 4 >16 2 >4
S (%) 92.7 100.0 99.3 8.0 100.0 100.0 -
R (%) 7.3 0.0 0.7 92.0 0.0 0.0 -
MIC50 (μg/mL) 4 >32 ≤8 ≤1 ≤1 ≤0.5 ≤0.25 4 ≤2 ≤2 ≤4 64 16 >256 >16 >32 >32 >16 >4 >4
MIC90 (μg/mL) 8 >32 ≤8 ≤1 ≤1 1 ≤0.25 >8 ≤2 ≤2 ≤4 >128 >64 >256 >16 >32 >32 >16 >4 >4
S (%) 99.3 33.6 99.3 99.3 95.8 91.6 100.0 93.7 60.1 52.4 39.2 37.8 38.5 -
R (%) 0.7 66.4 0.7 0.7 4.2 8.4 0.0 6.3 39.9 47.6 60.8 62.2 61.5 -
MIC90 (μg/mL) ≤0.25 ≤0.0625 ≤0.5 ≤0.25 >4 0.5 >8 ≤2 >16 0.5 0.125 >512 >16 >32 >4
S (%) 98.4 99.0 99.6 53.3 97.8 95.3 9.2 63.8
512
1024
0.2 41.8 0.0 0.4 47.3 0.2
0.0 0.4 45.5
0.0
0.0
0.8
95.0
MIC50 (μg/mL) ≤0.25 ≤0.0625 ≤0.5 ≤0.25 ≤0.25 ≤0.25 ≤0.125 ≤2 16 ≤0.25 ≤0.0625 >512 16 8 ≤0.0313
R CI 3.7 - 12.7 0.0 - 2.4 0.0 - 3.6 86.5 - 95.8 0.0 - 2.4 0.0 - 2.4 -
R CI 0.0 - 3.8 58.1 - 74.1 0.0 - 3.8 0.0 - 3.8 1.6 - 8.9 4.4 - 14.2 0.0 - 2.5 2.9 - 11.6 31.8 - 48.4 39.1 - 56.1 52.3 - 68.9 53.8 - 70.2 53.0 - 69.5 -
R (%) 1.6 1.0 0.4 46.7 2.2 4.7 90.8 36.2
R CI 0.7 – 3.1 0.3 – 2.3 0.04 – 1.4 42.3 – 51.2 1.1 – 3.9 3.1 – 7.0 88.0 – 93.3 32.0 – 40.6
Dilution series applied for each individual antimicrobial are marked white, green vertical lines indicate the breakpoint/cut off used for interpretation. To the right of the dilution ranges, percentages of isolates with a MIC value higher than the highest concentration of the dilution range are mentioned in red. The percentage of isolates mentioned at the lowest concentration of a dilution range, refers to isolates with a MIC value equal to or lower than the lowest concentration evaluated in the specific dilution range. a Only the concentration of amoxicillin, tested in a 2:1 ratio (amoxicillin:clavulanic acid), is mentioned; b Only the concentration of trimethoprim, tested in a 1:19 ratio (trimethoprim:sulfamethoxazole) is mentioned; n = number of observations; MIC50 = Minimum Inhibitory Concentration required to inhibit the growth of 50% of the isolates; MIC90 = Minimum Inhibitory Concentration required to inhibit the growth of 90% of the isolates; S = susceptible; R = resistant; CI = 95% Confidence Interval.
j.v.hout@gdanimalhealth.com www.gdanimalhealth.com
GD2826/03-23