Chemical disinfectants commonly used in the poultry sector and their impact on Salmonella – an outline of methods and results Kim O. Gradel Danish Veterinary Institute, Århus, Denmark SYMPOSIUM: DISINFECTION IN ANIMAL PRODUCTION Tuesday 18 November, 2003, Aarhus, Denmark
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Chemical disinfectants commonly used in the poultry sector and their impact on Salmonella – an outline of methods and results Kim O. Gradel Danish Veterinary.
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Chemical disinfectants commonly used in the
poultry sector and their impact on Salmonella – an
outline of methods and results
Kim O. GradelDanish Veterinary Institute,
Århus, Denmark
SYMPOSIUM: DISINFECTION IN ANIMAL PRODUCTIONTuesday 18 November, 2003, Aarhus, Denmark
Disposition Resistance against disinfectants
Minimum inhibitory concentration (MIC) tests
Adaptation and de-adaptation tests Conclusions
Surface disinfection tests Materials and methods Results Conclusions
General conclusions
Chemical tests related to general disinfection factors
Micro-organism
Disinfectant Surroundings
Type”State/condition”
Organic matterTemperaturepHBiofilm
TypeConcentration
Resistance to disinfectants
Surface disinfection tests
Resistance against disinfectants
Hypothesis:There is an association between persistence of
Salmonella in poultry houses and the common use of a few types of disinfectants in these.
Aims: To see if minimum inhibitory concentrations
(MICs) against five commonly used disinfectants could be related to Salmonella persistence or use of disinfectants in Danish broiler houses.
To see if resistance against the five disinfectants could be introduced and maintained in the laboratory.
Resistance against disinfectants:
epidemiological tools
Since 1992, for all Danish broiler flocks/crop cycles:
samples for Salmonella have been submitted.
The use of disinfectants has been registered by a veterinarian visiting the flock.
All data have been registered in a central database.
Salmonella sources in broiler flocks (1/11/96-31/10/99)
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
No
v-9
6
De
c-9
6
Jan
-97
Fe
b-9
7
Ma
r-9
7
Ap
r-9
7
Ma
y-9
7
Jun
-97
Jul-
97
Au
g-9
7
Se
p-9
7
Oct
-97
No
v-9
7
De
c-9
7
Jan
-98
Fe
b-9
8
Ma
r-9
8
Ap
r-9
8
Ma
y-9
8
Jun
-98
Jul-
98
Au
g-9
8
Se
p-9
8
Oct
-98
No
v-9
8
De
c-9
8
Jan
-99
Fe
b-9
9
Ma
r-9
9
Ap
r-9
9
Ma
y-9
9
Jun
-99
Jul-
99
Au
g-9
9
Se
p-9
9
Oct
-99
Month/year
No
. o
f fl
ocks
Unknown source
Other animals
Exotic, not PI
Ent/Typ, unknown source
Hatchery
PI-houses
Resistance against disinfectants:persistently Salmonella-infected
broiler houses
Salmonella serotypeNumber of crops with the same
Salmonella type12345
6-1011-2021-30> 30
Enteritidis
51
64 2
Typhimurium2743122
Tennessee 44112
4.12:b:-132246451
Infantis 923364
Indiana112113
Resistance against disinfectants:
persistence in broiler houses
No. of crops with the same Salmonella type Salmo- nella type 1 2 3 4 5
6-10
11-20
21-30
>30
Ent. 5 6 4 2
Typh. 2 7 4 3 1 2 2
Tenn. 4 4 1 1 2
4.12:b:- 1 3 2 2 4 6 4 5 1
Inf 9 2 3 3 6 4
Ind 1 1 2 1 1 3
•In this study, 67 and 21 broiler houses were represented with two or more than two isolates, respectively.
11 21 31 41 51Nr. 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 I alt1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 E E E E E E E E E E E E 212 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 E E E E E E E E 193 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 E E E E E E E 194 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 E E E E 175 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 E E E E E E E 176 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 E E E E E 157 E E E 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 E E E E E 158 1 1 1 1 1 1 1 1 1 1 1 1 1 1 E E E E E E 149 1 1 1 1 1 1 1 1 1 1 1 1 1 E E E E E E E E 1310 1 1 1 1 1 1 1 1 1 1 1 1 1 E E E E E E E E E E E E 1311 1 1 1 1 1 1 1 1 1 1 1 1 E E E E E 1212 1 1 1 1 1 1 1 1 1 1 1 1 E E E E E E 1213 1 1 1 1 1 1 1 1 1 1 1 E E E E E E E 1114 1 1 1 1 1 1 1 1 1 1 1 E E E E E E E E 1115 1 1 1 1 1 1 1 1 1 1 E E E E E 1016 1 1 1 1 1 1 1 1 1 E E E E 917 1 1 1 1 1 1 1 1 E E E E E E E E E E E E 818 1 1 1 1 1 1 1 1 E E E E E E E E E E E E E E E E E E E E E E E E E E E E 819 1 1 1 1 1 1 1 E E E E E E E E E E E E E 720 1 1 1 1 1 1 1 E E E E E E E E E 721 E E E E E E E 1 1 1 1 1 1 1 E E E E E E 722 1 1 1 1 1 1 1 E E E E E E E E E E E E E E E E E E E E E E E 723 1 1 1 1 1 1 E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E 624 1 1 1 1 1 1 E E E E E E E E E E E E E 625 1 1 1 1 1 1 E E E E E E E 626 E E E E E E E E E E 1 1 1 1 1 1 E E E E E E E E E E E E E E E E E 627 E E E E E E E E E E E E E E E E E E E E E E E E 1 1 1 1 1 1 E E E E E E 628 1 1 1 1 1 E E E E 529 1 1 1 1 1 E E E E 530 1 1 1 1 1 E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E 531 1 1 1 1 1 E E E E E 532 1 1 1 1 1 E E E E E E E E E E E E E E E 533 1 1 1 1 1 E E E E E E E 534 1 1 1 1 1 E E E E E E 535 1 1 1 1 E E E E 436 E E E E E E E E E E E E E E E E E E E E E E E E E E 1 1 1 1 E E E E E E 437 1 1 1 1 E E E E E 438 1 1 1 1 E E E E E E 439 1 1 1 1 E E E E E E E 4
Resistance against disinfectants:persistently Salmonella-infected broiler houses
First isolateselected
”Middle” isolateselected
Last isolateselected
Resistance against disinfectants:
sources of bacterial isolates
Country Type No. of isolates Source and descriptionDenmark S . Enteritidis 34 Danish broiler houses, “non-persistent type”Denmark S . Typhimurium 39 Danish broiler houses, “non-persistent type”Denmark S . Tennessee 24 Danish broiler houses, “non-persistent type”Denmark S . 4.12:b:- 81 Danish broiler houses, “persistent type”Denmark S . Infantis 61 Danish broiler houses, “persistent type”Denmark S. Indiana 17 Danish broiler houses, “persistent type”Denmark S . Senftenberg 13 Poultry sectorUK S. Choleraesuis NCTC 10653 1 Strain used in English disinfection testsUK S . Typhimurium, DT104 8 Pig and broiler farmsUK S . 4.12:d:- 4 Feed mill and hatcheryUK S . Senftenberg 4 HatcheryUK E. coli NCTC 10418 1 Control strainUK E. coli AG100 1 Control strainUK E. coli AG102 1 Control strain, mar mutant of E. coli AG100
Resistance against disinfectants: disinfectants
used in the study
Formaldehyde (24.5%) Glutaraldehyde (23%) and benzalkonium chloride (5%) compound (Bio Komplet Plus) Oxidising compound (blend of peroxygen
compounds) (Virkon S)
Phenol (30-45% high boiling tar acids) (FFS) Iodophor (FAM 30)
• 67 broiler houses represented with two isolates.• 21 broiler houses represented with more than two isolates.• Generally, no significant changes (p = 0.30).• Oxidising compound has relatively most increases, but p = 0.10.
Resistance to disinfectants:more results (data not
shown)
•No associations between MICs and use of disinfectants in the preceding download period.
• Adaptation or de-adaptation did not alter any MICs beyond one doubling dilution, i.e. within normal biological variation.
Resistance to disinfectants:conclusions
• Resistance to commonly used disinfectants does not play a major role in persistence of Salmonella in Danish broiler houses.
• In the laboratory, it was not possible to adapt selected strains to the actual disinfectants.
before and after disinfection, where the oxidising compound apparently was the most effective.
Formalin is better than glutaraldehyde/benzalkonium chloride at 6 oC, although it is often stated that formalin is only effective above 16 oC, whereas glutaraldehyde is effective down to 5 oC!
Surface disinfection tests: conclusions II
For the effective disinfectants (formalin and glutaraldehyde/benzalkonium chloride) there were no differences between the two Salmonella isolates, whereas S. Senftenberg was more susceptible than S. Enteritidis in tests with the oxidising compound and water, in spite of higher MICs for S. Senftenberg (for formalin and the oxidising compound).
In general, Enterococcus faecalis was more recalcitrant than the two Salmonella isolates, i.e. it is a putative indicator bacterium, e.g. in field trials.
Fats seem to be the best protectant for the bacteria among the types of organic matter used.
In general, there were few differences between the different poultry house materials.
General conclusions
For Salmonella, resistance to commonly used disinfectants does not seem to be an important aspect of persistence.
Results from unrealistic tests are difficult to extrapolate to realistic tests.
For Salmonella and other vegetative bacteria, results indicate that the surroundings are more important for the efficacy of disinfection than the type of bacteria.