Antimicrobial Sensitivity Data
for the major
Poultry Bacterial Pathogens

by
DGS Burch  BVetMed MRCVS
Octagon Services Ltd   Copyright © November 2002
On-line at: www.octagon-services.co.uk

On the Oral Antimicrobial Pharmacokinetics spreadsheets for chickens and turkeys we tabulated the major pharmacokinetic characteristics of most of the major oral antimicrobial medicines used in poultry. The concentrations that can be found in blood (serum), for systemic infections, lung for respiratory infections and eggs for vertically transmitted infections are described as far as possible. These can then be compared with the minimal inhibitory concentrations (MICs) of the various antimicrobials against the various pathogens, which are tabulated below: -

 

Respiratory/systemic infections	Enteric/systemic infections
1. Escherichia coli	1. Salmonella
2. Pasteurella multocida	2. Erysipelas rhusiopathiae
3. Ornithobacterium rhinotracheale	3. Clostridium perfringens
4. Haemophilus paragallinarum	4. Brachyspira pilosicoli
5. Mycoplasma (gallisepticum, synoviae	Other
meleagridis & iowae)	1. Staphylococci

 

Virus infections tend to dominate in poultry and bacterial infections are frequently secondary invaders.  E. coli infections, following Infectious Bronchitis (IB), Infectious Bursal Disease (IBD), Newcastle Disease (ND), and Avian Pneumovirus (AP), especially in turkeys (TRT), and mycoplasma infections, account for much of the antimicrobial medication used in poultry production.  Salmonella, Pasteurella multocida, Ornithobacterium rhinotracheale and Haemophilus paragallinarum in warmer climates regularly occur and respiratory and systemic infections play a very important role.  The recent ban of growth promoters in the EU, all of which had activity against Clostridium perfringens, has resulted in an upsurge of Necrotic Enteritis (NE) in broilers.

 

In some cases there is no comparative MIC data, only sensitivity data, based on disc diffusion tests and I have tried to use data from a number of countries for comparison purposes. The MIC is the lowest concentration of an antimicrobial, which will inhibit the growth of an organism. Often there is an MIC50 figure, which means that concentration will inhibit 50% of the different bacterial strains of bacteria tested. Similarly the MIC90 is the concentration that inhibits 90% of the strains and the Range is the variation between the most and least sensitive. The effective concentration or clinical ‘breakpoint’ can be determined where the concentration of the antimicrobial in the blood or target tissue is higher than the MIC for that organism. For regulatory purposes this level is deemed as being above the MIC90 and for clinical purposes this is a good  target as it means that there is a high chance that the product will inhibit that organism’s growth (bacteriostatic effect) and enable the bird’s own immune system to destroy it. Some antibacterials will kill a bacterium directly and this is known as the bactericidal effect. The tetracyclines, macrolides and pleuromutilins exert primarily a bacteriostatic effect and the quinolones, aminoglycosides, trimethoprim/sulphas and penicillins a bactericidal effect. The bacteriostatic antimicrobials are therefore time dependent on their killing effect where as the bactericidal ones are more concentration dependent, except for the penicillins.

 

Respiratory/Systemic Infections:

 

1a. Escherichia coli - United Kingdom, Sensitivity (%)

Antimicrobial (Disc Conc. mg)	Lasswade (n = 286)	Shrewsbury (n =198)	Overall (n = 484)
Apramycin (15)	98	98	98
Neomycin (10)	79	89	83
Spectinomycin (25)	-	88	88
Linco/spectin (150)*	91	-	91
Amoxycillin (2)	15	-	15
Ampicillin (10)	-	62	62
Doxycycline (30)	56	-	56
Tetracycline (10)	46	61	52
Trimeth/Sulpha (25)	72	82	76
Enrofloxacin (5)	99	98	99
Difloxacin (10)**	95	-	95

*Lincomycin/spectinomycin – 239 isolates         Source: (Burch, 2000)

** Difloxacin – 71 isolates

 

 

1b. E. coli Comparison – UK, EU (slaughter survey), Canada, USA (turkeys),

Sensitivity (%)

Country	UK	UK	EU (slaughter)	Canada	USA (Turkeys)
Year Isolated	1999	1986-91	1995	1993	1995
No. Isolates	484	274	1154	294	1204
Antimicrobial
Apramycin	98	-	-	97	-
Neomycin	83	84	94	50	13
Spectinomycin	88	-	-	38	54
Ampicillin	62	84	66	58	67
Tetracycline	52	48	55	11	-
Trimeth/Sulpha	76	85	64	78	87
Enrofloxacin	99	-	97	99	99

Sources (Burch, 2000; Wray et al, 1993; Scheer et al, 1997; Laperle et al, 1996; Salmon and Watts, 2000)

 

 

 

 

1c. E. coli - USA turkeys, MIC data (µ/ml) – 1204 isolates

Antimicrobial	MIC 50	MIC 90	Range
Ampicillin	4.0	>32	1->32
Ceftiofur	0.5	1.0	0.13->32
Enrofloxacin	<0.03	0.13	<0.03-8
Florfenicol	4.0	8.0	0.25->64
Gentamicin	0.5	32	<0.06->64
Neomycin	16	512	0.5->512
Spectinomycin	16	>128	8->128
Sulfamethazine	>512	>512	16->512
Tetracycline	>32	>32	0.25->32
Trimethoprim/sulphadiazine	0.13	2.0	0.03->16

Source: (Salmon & Watts, 2000)

 

2. Pasteurella multocida – Canada, sensitivity; MICs (µ/ml) global - 107 isolates

 

Antimicrobial	Sensitivity (%)	Mode MIC	MIC 90	Range
Ampicillin	100	-	-	-
Ceftiofur	100	-	-	-
Danofloxacin	-	0.03	0.25	<0.008-1.0
Erythromycin	73	-	-	-
Gentamicin	93	-	-	-
Lincomycin	-	32	64	0.25->64
Penicillin	100	-	-	-
Spectinomycin	87	32	64	<1->128
Sulfasoxazole	60	-	-	-
Trimethoprim/S	100	-	-	-
Tetracycline	93	-	-	-
Oxytetracycline	-	<0.5	16	<0.05->64

Source; (Laperle et al, 1996; Raemdonck et al, 1992)

 

3a. Ornithobacterium rhinotracheale – Belgium, MICs (µ/ml) – 45 isolates

Antimicrobial	MIC 50	MIC 90	Range
Ampicillin	4	8	0.12-16
Ceftiofur	8	16	1-32
Lincomycin	>64	>64	>64
Tilmicosin	>64	>64	0.5->64
Tylosin	8	16	1-16
Enrofloxacin	2	2	0.12-2
Doxycycline	8	16	0.12-16
Tiamulin	0.12	0.25	0.12-0.25

Source: (Devriese et al, 2001)

 

 

 

 

3b. O. rhinotracheale – Hungary, MICs (µ/ml) – 12 isolates

Varga et al, 2001	MIC50	MIC90	Range
Amoxycillin	0.12	≥64	≤0.06-≥64
Enrofloxacin	4.0	8.0	≤0.06-8.0
Erythromycin	0.25	0.25	0.12-0.5
Lincomycin	1.0	32	1.0-32
Oxytetracycline	4.0	4.0	2.0-8.0
Penicillin	<0.06	<0.06	<0.06-0.5
Spectinomycin	>64	>64	>64
Trimethoprim	>64	>64	>64
Tylosin	0.12	4.0	≤0.06-8.0
Tilmicosin	0.12	0.25	≤0.06-1.0
Tiamulin	0.25	2.0	<0.06-2.0
Varga, 2002 (10 isolates)
Tilmicosin	0.12	0.5	≤0.06-1.0

Source:(Varga et al, 2001; Varga, 2002)

 

3c. O. rhinotracheale – Holland, Sensitivity (%)

Antimicrobial	1996 (52 isolates)	1999 (105 isolates)
Amoxycillin	65	16
Tetracycline	60	11
Enrofloxacin	15	13
Trimethoprim/S	35	10

Source: (van Veen et al, 2001)

 

4. Haemophilus paragallinarum - Japan, MICs (µ/ml) – 24 isolates

Antimicrobial	MIC 50	MIC 90	Range
Ofloxacin	0.05	0.1	0.05-0.2
Oxytetracycline	3.13	3.13	0.78-12.5
Doxycycline	0.39	1.56	0.2-1.56
Spectinomycin	6.25	6.25	1.56-25
Chloramphenicol	0.39	0.78	0.39-0.78
Thiamphenicol	0.39	0.39	0.1-1.56
Tiamulin	3.13	6.25	0.78-6.25
Tylosin	3.13	6.25	0.78-12.5
Sulphamethoxazole	50	100	25-200
Trimethoprim	0.2	0.78	0.1-1.56
Trimethoprim/S (1:20)	3.13	3.13	1.56-3.13

Source: (Takahashi et al, 1990)

 

5. Mycoplasma – Worldwide – summary of 20 references and reports

13 were from before 1990 and seven from 1990 and after. There was information on 241 isolates of MG, 105 of MS, 28 of MM and 111 of MI. The comparative MIC data and resistance development for four mycoplasma species are summarized in the tables below.

 

5a. Mycoplasma gallisepticum, MIC ranges (µ/ml) by time period (no. of isolates)

Antimicrobial	1975-1989 (175)	1990-2000 (66)
Tiamulin	0.0039-0.78	0.006-0.39
Tylosin	0.01-75	0.006-400
Oxytetracycline	0.12-10	0.05-200
Lincomycin	0.4-64	0.125-6.25
Enrofloxacin	0.01-0.25	0.0125-2.0

 

 

5b. Mycoplasma synoviae, MIC ranges (µ/ml) by time period (no. of isolates)

Antimicrobial	1975-1989 (53)	1990-2000 (52)
Tiamulin	0.031-1.0	0.006-0.5
Tylosin	0.015-75	0.006-50
Oxytetracycline	0.06-0.08	0.025-100
Lincomycin	0.31-6.0	0.05-1.56
Enrofloxacin	0.1-1.0	0.025-1.56

 

 

5c. Mycoplasma meleagridis, MIC ranges (µ/ml) by time period (no. of isolates)

Antimicrobial	1975-1989 (17)	1990-2000 (11)
Tiamulin	0.03-1.0	0.025-3.13
Tylosin	0.015-3.0	0.78-50
Oxytetracycline	0.3-5.0	0.05-25
Lincomycin	0.5-5.0	0.05-25
Enrofloxacin	0.015-1.0	0.1-3.13

 

 

5d. Mycoplasma iowae, MIC ranges (µ/ml) by time period (no. of isolates)

Antimicrobial	1975-1989 (25)	1990-2000 (86)
Tiamulin	0.015-10	0.006-0.125
Tylosin	0.05-64	0.05-100
Oxytetracycline	1-3	0.025-100
Lincomycin	3-64	0.05-100
Enrofloxacin	0.1-1.0	0.005-1.0

(Valks and Burch, 2002)

 

5e. Mycoplasma, Worldwide, MICs (µ/ml)

 

Organism (no. of isolates) and antimicrobial agent	MIC (mg/ml)
	Type strain	Field strains
		Range	MIC 50%	MIC 90%
M. gallisepticum (20)
Enrofloxacin	0.01	0.025-1	0.05	0.1
Danofloxacin	0.005	0.01-0.5	0.05	0.1
Flumequine	0.5	2.5-10	5	10
Tiamulin	0.0025	0.0005-0.25	0.001	0.025
Tylosin	0.01	0.0025-10	0.01	2.5
Oxytetracycline	0.1	0.05-0.5	0.25	0.5
M. synoviae (28)
Enrofloxacin	0.5	0.05-0.5	0.25	0.5
Danofloxacin	0.5	0.1-0.5	0.25	0.5
Flumequine	10	5-50	25	50
Tiamulin	0.1	0.05-0.5	0.1	0.25
Tylosin	0.025	0.0025-50	0.025	50
Oxytetracycline	0.1	0.025->100	0.1	100
M. iowae (19)
Enrofloxacin	0.005	0.005-1	0.025	0.5
Danofloxacin	0.01	0.01-1	0.025	0.5
Flumequine	5	2.5-100	10	25
Tiamulin	0.005	0.005-0.1	0.01	0.1
Tylosin	0.5	10->100	>100	>100
Oxytetracycline	0.25	0.25-10	1	1

Source: (Hannan et al, 1997)

 

Enteric/Systemic infections:

 

1a. Salmonella – Canada - upto 41 isolates; UK - 1439 isolates, Sensitivity (%)

Antimicrobial	Canada	United Kingdom
Ampicillin	66	90
Apramycin	100	100
Ceftiofur	100	-
Enrofloxacin (nalidixic acid)	98	(89)
Gentamicin	73	-
Neomycin	83	99
Spectinomycin	37	-
Sulphonamide	27	75
Tetracycline	32	87
Trimethoprim/S	98	84

Source: (Laperle et al, 1997); VLA/DEFRA, 2001)

 

1b. Salmonella – USA, turkeys, MICs (µ/ml) - 24 isolates

Antimicrobial	MIC 50	MIC 90	Range
Ampicillin	1.0	1.0	0.5-1.0
Ceftiofur	1.0	1.0	0.5-1.0
Enrofloxacin	0.06	0.13	0.06-0.13
Florfenicol	0.5	8.0	0.25-8.0
Gentamicin	0.5	0.5	0.25-0.5
Neomycin	8.0	64	4->512
Spectinomycin	32	64	16->128

Source: (Salmon and Watts, 2000)

 

2. Erysipelas rhusiopathiae – UK, Sensitivity (%) - 7 isolates

Antimicrobial	Sensitive (%)
Ampicillin	100
Tetracycline	43
Penicillin	100
Trimethoprim/S	50
Erythromycin	100
Ceftiofur	100

Source: (VLA/DEFRA, 2001)

 

3a. Clostridium perfringens – Belgium, MICs (mg/ml) - 27 avian isolates

Product	Class	MIC 50	MIC 90	Range (mg/ml)
Avoparcin	Banned GP	0.5	0.5	0.5
Bacitracin	Banned GP	0.06	0.5	0.03-16
Carbadox	Banned GP	0.03	0.06	0.007-0.15
Nitrovin	Banned GP	0.25	0.5	0.12-0.5
Virginiamycin	Banned GP	0.25	0.5	0.12-0.5
Bambermycin	GP	128	128	128
Monensin	GP/Coccci.	2	4	2.0-4.0
Chloramphenicol	Medicine	2	4	1.0-4.0
Erythromycin	Medicine	1	2	1.0-2.0
Lincomycin	Medicine	0.25	2	0.12-2.0
Penicillin G	Medicine	0.25	0.25	0.12-0.5
Tetracycline	Medicine	8	32	0.12-64
Tiamulin	Medicine			0.25-4.0

Source: (Dutta & Devriese, 1980)

 

3b. C. perfringens – Belgium, MICs (mg/ml) - 95 mixed isolates from poultry, calves and pig

Product	Class	MIC 50	MIC 90	Range (mg/ml)
Avoparcin	Banned GP	0.25	0.5	0.12-0.5
Bacitracin	Banned GP	0.25	0.5	0.12-64
Virginiamycin	Banned GP	0.25	0.25	0.12-8
Avilamycin	GP	0.12	0.5	0.12-0.5
Flavomycin	GP	64	64	64
Salinomycin	GP/Cocci.	0.12	0.12	0.12
Tylosin	Medicine (GP)	0.12	0.12	0.12-0.25

Source: (Devriese et al, 1993)

 

 3c. C. perfringens - UK, Sensitivity (%) - 49 isolates

 

Antimicrobial	Disc strength (mg)	Sensitive (%)
Chloramphenicol	10	84
Tetracycline	10	33
Doxycycline	30	45
Apramycin	15	33
Neomycin	10	24
Lincomycin/spectinomycin	150	88
Trimethoprim/sulpha	25	6
Enrofloxacin	5	96
Difloxacin	10	96

Source: (Burch, 2000, unpublished data)

 

4. Brachyspira pilosicoli - Australia, MICs (mg/ml) - 35 isolates

 

Antimicrobial	MIC 50	MIC 90
Tiamulin	<0.1	0.5
Tylosin	>100	>100
Lincomycin	17	47
Tetracycline	<1	18
Neomycin	117	190
Metronidazole	0.5	1.5

Source:  (Oxberry & Hampson, 1998)

 

Other infections:

 

1. Staphylococcus spp – Canada, Sensitivity (%) - 60 isolates

Antimicrobial	Sensitive (%)
Ampicillin	97
Ceftiofur	95
Erythromycin	73
Gentamicin	98
Oxacillin	100
Penicillin	90
Sulfasoxazole	87
Trimethoprim / S	100
Tetracycline	32

Source: (Laperle et al, 1996)

 

Poultry technical papers on-line:  index
Pig technical papers on-line:  index

- top of page -

~ www.octagon-services.co.uk ~