Efficacy of seven disinfectant sanitisers on field isolates ofBrachyspira pilosicoli

Abstract

AMONG the intestinal spirochaete species of pigs, Brachyspira hyodysenteriae and Brachyspira pilosicoli are important agents of disease. B pilosicoli infection is variously termed spirochaetal diarrhoea (Taylor 1992), porcine colonic spirochaetosis (Muniappa and others 1997) or porcine intestinal spirochaetosis (Duhamel 1995). A recent study on pig herds with infectious colitis in the UK showed that Bpilosicoli was found in 25-0 per cent as a single pathogen, and in another 27-0 per cent as a copathogen (Thomson and others 1998). Transmission of Bpilosicoli occurs either through contamination of the immediate environment, or by direct contact between pigs. B pilosicoli can remain viable in contaminated water for 66 days (Oxberry and others 1998), thus increasing the potential for transmission. As there is no information on the activity of disinfectants against B pilosicoli, this short communication describes a study of the efficacy of seven disinfectant sanitisers against six field isolates and the type strain, ATCC-51139, of B pilosicoli, in the absence and presence of organic matter.The field isolates were from cases of porcine colitis, obtained as part of a surveillance programme for porcine colitis conducted by the Scottish Agricultural College (SAC). B pilosicoli grown anaerobically in brain heart infusion broth (Oxoid) supplemented with 5 per cent (w/v) filter-sterilised rabbit serum at 380C for two days was used as a bacterial suspension for assessing the disinfectant sanitisers.The tested products were of four different chemical groups, all manufactured by Antec International, and included three quaternary ammonium compounds, Ambicide (a disinfectant), DSC-1000 (a sanitiser) and HD-3 (a sanitiser); one amphoteric surfactant-caustic soda compound, Heavy Duty (a sanitiser); two tar organic acid compounds, Farm Fluid (a disinfectant) and Long Life (a disinfectant); and one peroxygen compound, Virkon S (a disinfectant).The efficacy tests were carried out according to the recommendations of the National Committee for Clinical Laboratory Standards for (NCCLS) antimicrobial susceptibility on anaerobic bacteria (NCCLS 1989), and adapted for testing the disinfectants. Ten-fold dilutions ( 1:10 up to 1 :100,000) of the disinfectant sanitisers were prepared in sterile deionised water (SDW) (for testing in the absence of organic matter) or in a suspension of sterile pig faeces (SPF) (for testing in the presence of organic matter) diluted 1:20 in phosphatebuffered saline solution. An aliquot of 0-1 ml ofbacterial suspension (approximately 105 colony-forming units/ml) was added to 0-9 ml of each serial dilution and the mixture was left for contact times of 30 or 60 minutes at room temperature (220C). Each suspension was then inoculated in triplicate on to blood agar plates, allowed to dry, and incubated anaerobically at 380C for three to four days. Control inocula, with no disinfectant, of each isolate were included.

Bactericidal efficacy of two disinfectants against Brachyspira hyodysenteriae and one feed supplement against B. hyodysenteriae and B. pilosicoli

“…A�er a 10-minute exposure under the load of organic ma�er in 10% SPF suspension, their effective concentrations expressed as MBCs were 0.125% in Chirox and <0.03% in Virkon S and it was approximately 16 times lower than the recommended working dilutions (Chirox 2%, Virkon S 1%), which is very important from the practical aspect of their use on farms. Comparable results were also obtained by Corona-Barrera et al (2002), who tested the efficacy of Virkon S and another six disinfecting and cleaning agents against B. pilosicoli strains. The benefits of the use of disinfectants based on peroxygen compounds in pig herds include minimum negative impacts on the environment as well as administration at the presence of the animals.…”

“…The cleaning and effective disinfection of surfaces of equipment, transport vehicles, footwear, instruments and the pigs themselves will be a necessity not only in all in-all out operations and eradication programmes, but also in the treatment of dysentery and porcine intestinal spirochetosis. Efficacy evaluation of disinfectants against B. pilosicoli has been studied sporadically (Corona-Barrera et al, 2002). There are no experimental data available on the efficacy of disinfectants used to control B. hyodysenteriae.…”

Combined in-vitro and on-farm evaluation of commercial disinfectants used against Brachyspira hyodysenteriae

“…The results of our study under laboratory conditions confirmed the antibacterial activity of most commercial disinfectants tested against field isolates of B. hyodysenteriae. Earlier studies evaluating the in-vitro activity of disinfectants from different chemical groups against a type strain and a field B. hyodysenteriae isolate [ 20 ] or a collection of seven B. pilosicoli [ 21 ] converged in the conclusion that disinfectants were effective against Brachyspira spp . , even at concentrations lower than that recommended by manufacturers.…”

Brachyspira pilosicoli-induced avian intestinal spirochaetosis

“…Prevention of AIS outbreaks can be achieved using appropriate hygiene and biosecurity rules as demonstrated by several studies ( 68 ). B. pilosicoli is readily eliminated by standard farm disinfection processes ( 69 ), and the potential of vaccination against B. pilosicoli has been explored primarily in pigs and may be applicable in poultry ( 70 ). However, treatment is commonly achieved using antibiotics such as linco-spectin and tiamulin at 25 mg/kg of body weight per day, although this dosage regimen is derived from studies in pigs.…”