practical intervention strategies for campylobacter

Practical intervention strategies for Campylobacter

M. PattisonSun Valley Foods, Hereford, UK

1. SUMMARY

Campylobacter organisms are present in the environment of

the farm and it is accepted that the chance of infection

transferring to chickens is very high. Sources of infection

may include any of the standard requirements for poultry

such as feed, water and litter. Any form of human

intervention as a result of routine animal husbandry

requirements may also introduce infection. It has been

shown that on some farms it is possible to delay infection by

various improvements to bio-security arrangements. The use

of dedicated wellington boots for each poultry house and the

regular use of foot dips were found to be important factors.

The daily use of water sanitiser was also important in

delaying the onset of infection. The ef®ciency of cleaning and

disinfection and the construction of the buildings were less

signi®cant factors. If ¯ocks were thinned, which involves

entry by catching crews and equipment, the risk of infection

was dramatically increased. After 42 d of age, the likelihood

of infection was also much greater. The effectiveness of these

intervention procedures applied in one integrated poultry

company are described. Generally, it was felt that even the

most stringent bio-security measures applied conscientiously

would not be able to prevent infection occurring. Once

infection has entered the house, all birds become Campylo-bacter carriers very quickly. A pen trial was set up to

investigate this and the results are described.

2. INTRODUCTION

Most broiler (meat) chickens and breeders produced in the

U.K. are reared in closed, environmentally controlled houses.

House design will vary from farm to farm but all tend to have

similar lighting, heating, feeding and watering systems.

Feed is supplied by an automatic auger system with feed

pans and water is provided through nipple and cup drinker

systems, which have replaced the older, rather unhygienic,

bell drinkers.

Chicks are delivered as `day olds' to the farm and placed

on a litter of wood shavings or chopped straw. The number

of chicks in a typical house would be about 30 000, but it

may vary from 5000 to 50 000. Stocking density is calculated

to ensure that a maximum of 36 kg m)2 is not exceeded at

time of slaughter. Birds remain in the same house and will

be killed usually between 40 and 53 d. Frequently, a house is

`thinned' once or twice, where a proportion of the birds are

taken for slaughter before the remainder which are kept for

heavier weights. Modern houses are `clear span', without

posts and roof supports, and this makes them more easy to

clean. Birds are free to roam throughout the house. As

specialist markets develop, a small number of chickens are

kept as `free range' or `organic' where they must spend part

of their time outside the houses on pasture. Usually one

stock person looks after three or four houses or 100 000

birds.

This paper describes observations made in the ®eld as part

of our ongoing quest to understand Campylobacter inci-

dence, speed of dissemination and possible interventions

that can be used to prevent or delay infection.

3. SOURCES OF CAMPYLOBACTERINFECTION

The main source of infection is not known but possibilities

include: feed, water, staff and visitors, equipment, litter,

wild birds, rodents, insects and air.

4. MATERIALS AND METHODS

All observations have been made during the course of

normal commercial growing practice. Campylobacter were

1. Summary, 121S

2. Introduction, 121S

3. Sources of Campylobacter infection, 121S

4. Materials and methods, 121S

4.1 Bacterial culture and speciation, 122S

4.2 Fla-typing analysis, 122S

5. Results, 122S

6. Spread of Campylobacter infection, 122S

7. Conclusions, 124S

8. References and Appendix, 125S

Correspondence to: Mark Pattison, Sun Valley Foods,

Hereford HR4 9PB, UK.

ã 2001 The Society for Applied Microbiology

Journal of Applied Microbiology 2001, 90, 121S±125S

isolated from cloacal swabs transported in Amie's transport

medium with charcoal (Bibby Sterilin Ltd. UK) and were

cultured within 48 h of collection. The intervention tech-

niques employed are largely self-explanatory and detailed in

Appendix 1.

4.1. Bacterial culture and speciation

Swabs were incubated in 10 ml Exeter medium for 48 h at

37°C under microaerobic conditions (6% O2, 10% CO2,

84% N2). A sample of 50 ll was then removed for plating

on blood agar containing selective antibiotics with actidione

(100 lg ml)1) and cefoperazone (30 mg ml)1). The plates

were incubated microaerobically as before at 37°C for 2 d.

All Campylobacter isolates were speciated by standard

microbiological procedures. Identi®cation was based on

growth at 42°C, hippurate and indoxylacetate hydrolysis,

catalase and oxidase activity, and resistance to nalidixic

acid and cephalohtin. A single colony from each bird was

stored in glycerol broth (10% v/v glycerol in 1% w/v

proteose peptone) at ) 70°C for subsequent molecular

typing.

4.2. Fla-typing analysis

PCR-RFLP of the ¯aA and ¯aB genes was performed

according to the technique of Ayling et al. (1996) excepting

that two separate digestion reactions were carried out using

the restriction enzymes Ddel and Hin¯.

5. RESULTS

In a survey involving 100 ¯ocks in ®ve integrated companies,

it was found that 45% of farms were positive for Campy-lobacter at 3 weeks of age and 90% were positive by 7 weeks

(Evans 2000; Evans and Sayers 2000). My own company was

one of the ®ve and there was no noticeable difference in the

results between companies.

There is no consistent pattern of infection on farms as

shown in another integration where ®ve farms were

monitored over a 2-year period (Gooderham, personal

communication1 ) of 13 crops (Table 1). Each farm had 10

houses. It can be seen that some farms remained negative for

Campylobacter throughout the crop, but no farms were

either consistently positive or negative. A house was de®ned

as positive if one or more birds tested positive. This was

appropriate because infection spread so quickly once

established.

As a company, we took part in a national study involving

two other companies to examine the effects of various

interventions on Campylobacter incidence (Gibbens et al.2000). The special measures focused on an improved

cleaning and disinfection routine and a set procedure for all

personnel entering a poultry house. The improved cleaning

and disinfection procedure is detailed in the appendix. The

results of this study are shown in Table 2. It can be seen that

one ¯ock in the intervention group stayed negative. In the

other intervention ¯ocks there was generally a delay in the

time of infection compared with the control farms.

As a result of analysis of questionnaires, the authors found

that the use of boot dips and changing the boot dip solution

had the biggest effect on delaying infection. The daily use of

water sanitiser and the ef®ciency of poultry house cleaning

were also major factors. The risk of infection rose sharply

after 42 d, which probably related to the entry of catching

crews to `thin' the ¯ocks.

6. SPREAD OF CAMPYLOBACTERINFECTION

We had the opportunity within a trials house to investigate

the spread of Campylobacter between groups of birds penned

separately.

The results are reported by Shreeve et al. (2000). The

trial houses consisted of 72 pens of 100 birds. Five birds

were sampled weekly in each of 12 pens as shown in Fig. 1.

All birds remained free of Campylobacter to 32 d of age,

when six of the 60 sampled were found to be colonized.

There were four positive in pen 64 and two in pen 70, both

situated towards the rear of the house. One week later 56 of

the 60 birds sampled were positive, as shown in Table 3.

Table 1 Number of positive houses per crop

Farm A 0 10 10 0 10 9 9 10 0 0 9 10 10

Farm B 10 10 0 0 0 10 4 6 10 4 8 8 5

Farm C 10 1 10 0 10 10 10 0 2 0 9 10 10

Farm D 8 9 0 7 0 ± 10 0 0 ± 9 3 6

Farm E 0 0 0 10 10 2 0 0 0 0 0 9 10

Table 2 Results of cleaning and disinfection intervention

Site ID Status

1 Positive @ 21 d*

2 Positive @ 28 d

3 Positive @ 42 d

4 Positive @ 21 d

5 Positive @ 49 d

6 Negative throughout study*

7 Positive @ 49 d

8 Positive @ 49 d

9 Positive @ 42 d

10 Positive @ 35 d

11 Positive @ 49 d

Sites in bold are intervention ¯ocks.

*Positive/negative for Campylobacter infection.

122S M. PATTISON

ã 2001 The Society for Applied Microbiology, Journal of Applied Microbiology Symposium Supplement, 90, 121S±125S

The strains isolated at 32 & 39 d were all C. jejuni, with

identical subtypes: serotype LEP 6, ¯a-type 1á9. On the next

sampling at 46 d, some of the birds in ®ve of the pens (40, 52,

58, 64 & 70) were found to be colonized with a different

strain, C. jejuni, LEP 23, ¯a-type 3á7. All other birds sampled

at this time were colonized with the ®rst strain.

In the second ¯ock (Fig. 2) infection occurred at 35 d,

when 42 out of 80 birds were positive with C. jejuni, ¯a-

type 1á1. The pens with positive birds were again towards

the rear of the house. By 42 d, all birds were positive with

the same strain of organism which persisted to slaughter at

49 d.

Fig. 1 Plan of broiler house and sampling strategy for ¯ock 1. h Pens sampled; pens containing the ®rst positive birds detected with strain ¯a type

1á9; pens containing the ®rst positive birds detected with strain ¯a type 3á7

Table 3 Isolation and Fla-types of Campylobacter spp. from penned birds

Age of birds (d)

Pen No. 18 25 32 39 46

4 ± ± ± + ¯a 1á9 + ¯a 1á910 ± ± ± + (4) ¯a 1á9 + ¯a 1á916 ± ± ± + (4) ¯a 1á9 + ¯a 1á922 ± ± ± + (4) ¯a 1á9 + ¯a 1á928 ± ± ± + ¯a 1á9 + ¯a 1á934 ± ± ± + ¯a 1á9 + ¯a 1á940 ± ± ± + ¯a 1á9 + ¯a 1á9 (4); ¯a 3á7 (1)

46 ± ± ± + (4) ¯a 1á9 + ¯a 1á952 ± ± ± + ¯a 1á9 + ¯a 1á9 (3); ¯a 3á7 (2)

58 ± ± ± + ¯a 1á9 + ¯a 1á9 (3); ¯a 3á7 (2)

64 ± ± + (4) ¯a 1á9 + ¯a 1á9 + ¯a 1á9 (2); ¯a 3á7 (3)

70 ± ± + (2) ¯a 1á9 + ¯a 1á9 + ¯a 1á9 (3); ¯a 3á7 (2)

Total No. ± ± 6 56 60

-, Campylobacter spp. not isolated from any of 5 birds sampled.

+, Campylobacter spp. isolated from each of 5 birds sampled.

(), No. birds positive for Campylobacter spp. if < 5 birds positive.

¯a, Figures denote ¯a type.

(), No. birds positive for ¯a type if < number of strains examined.

PRACTICAL INTERVENTION STRATEGIES FOR CAMPYLOBACTER 123S


It was interesting that infection seemed to start at the near

of the house and may have related to occasional opening of

door A, which was adjacent to the site incinerator.

7. CONCLUSIONS

These and other studies indicate that it is dif®cult and

probably impossible to guarantee keeping Campylobacterinfection out of poultry houses, and also that, once infection

is present in a small number of birds, it spreads very quickly

even if birds are separated by wire pens.

Bio-security measures on poultry farms have improved

in many ways in recent years and have undoubtedly helped

with control of infectious disease and Salmonella in

particular. The use of foot dips and hygiene barriers at

the entrance to houses is becoming standard practice. In

addition, the daily use of a water sanitiser is more widely

practised, yet Campylobacter infection still occurs. It may

be unrealistic to keep out an organism which is so

widespread and colonizes poultry so readily. Hald et al.(2000), as in this report, have noted that the standard of

cleanout is important. In addition, these authors observed

that if the houses were left empty for more than 14 d,

Campylobacter was less likely in the subsequent ¯ock. This

is probably due to the adverse effect of drying on the

organisms. Allowing time to dry between washing and

disinfection during cleanout is also a critical factor. Hald

et al. (2000) also reported that addition of bought-in wheat

rather than home-produced wheat to feed also increases the

risk of infection, as also do the presence of other livestock

on the farm.

The operation of an effective hygiene barrier is thus the

single most signi®cant intervention. Figure 3 shows that

there should be a step-over bench in the demarcation zone

between the outside and inside of the house. This acts as a

physical barrier and stops items such as a wheelbarrow

crossing the demarcation line. Separate wellington boots and

overalls should be used outside and inside, dipping each time

in disinfectant solution. The ef®ciency of boot dipping can be

improved by cleaning and washing the boots each time using

a hose and brush. In reality this is a rather time-consuming

regime and requires great conscientiousness on the part of

the manager. It is probably unrealistic to expect farmers to

operate this system for all staff effectively day in and day out.

As soon as the barrier has to be broken, for example for

thinning, the risk of infection increases markedly.

Fig. 2 Plan of broiler house an sampling strategy for ¯ock 2. h Pens sampled; pens containing the ®rst positive birds detected with strain ¯a

type 1á1

Fig. 3 Hygiene barrier

124S M. PATTISON


8. REFERENCES2

Ayling, R.D., Woodward, M.J., Evans, S. and Newell, D.G. (1996)

Restriction fragement length polymophism of polymerase chain

reaction products applied to the differentiation of poultry

Campylobacters for epidemiological investigations. Research in

Veterinary Science 60, 168±172.

Evans, S.J. (2000) A cross sectional survey of thermophilie

Campylobacter infection of broiler ¯ocks in England and Wales.

Epidemiology and Infection (in press).

Evans, S.J. and Sayers, A.R.3 (2000) A longitudinal study of Campy-

lobacter infection of broiler ¯ocks in Great Britain. Preventive

Veterinary Medicine 46, 209±223.

Gibbens, J.C., Pascoe, S.J.S., Evans, S.J. and Davies, R.H. (2000)

Disease security as a means of control of Campylobacter infection of

broiler chickens: a randomised intervention trial. Preventive

Veterinary Medicine (in press).4

Gooderhan, K.R. (2000) Personal Communication.

Hald, B., Wedderkopp, A. and Madsen, M. (2000) Thermophilic

Campylobacter spp. in Danish broiler production: a cross sectional

survey and a retrospective analysis of risk factors for occurrence in

broiler ¯ocks. Avian Pathology 29, 123±131.

Shreeve, J.E., Toszeghy, M., Pattison, M. and Newell, D.G. (2000)

Sequential spread of Campylobacter infection in a multi-pen broiler

house. Avian Diseases (in press).

APPENDIX 1: INTERVENTIONPROCEDURES

Cleansing and disinfection routine of studyhouse at previous depopulation

· Approved insecticide band sprayed at the time of

depopulation.

· Dust removal from all surfaces including the ¯oor, by

blowing.

· All internal surfaces washed with a sanitiser sold for

the purpose (de®ned dilution and application rate), thorough

wetting achieved and allowed to soak for at least 1 h; special

attention paid to soaking drinker cups.

· Minimum overnight drying period between washing

and disinfection.

· Inspection of house before disinfection; any pools of

water swept out.

· All internal surfaces disinfected with a speci®ed

product at a de®ned dilution (MAFF `General Order')

and application rate (quaternary ammonium/glutaralde-

hyde/formaldehyde).

· Brooding chick equipment washed and disinfected in

main house at the same time, if not disposable.

· Adjoining rooms to poultry house hand washed and

disinfected if not included in main wash/disinfection

programme.

· Water system (header tank and lines) cleaned and then

disinfected for a minimum of 24 h with an iodine-based

disinfectant at MAFF General Orders dilution rate.

· Approved insecticide band sprayed before litter

placed.

· Concrete areas on the site disinfected before litter

placed.

Disease security during study period; houseentry procedure applied to all personnel

· Dip boots* on entry to anteroom.

· Changed into dedicated boots and overalls (used only

in study house).

· Move into separate (chalk line or bench) clean area of

anteroom.

· Sanitize hands.

· Dip dedicated boots* before entry to main house.

* Speci®ed disinfectant (blend of organic acids and

surfactants) with dilution (MAFF `TB orders' rate) and

frequency of replacement (twice weekly) also speci®ed, used

in all boot dips.

PRACTICAL INTERVENTION STRATEGIES FOR CAMPYLOBACTER 125S


practical intervention strategies for campylobacter

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