Effect of competitive exclusion in reducing the occurrence of Escherichia coli producing extended-spectrum β-lactamases in the ceca of broiler chicks.

Extended-spectrum β-lactamases (ESBL) and class C serine β-lactamases (pAmpC) able to hydrolyze third-generation cephalosporins are a recognized threat to the efficacy of these drugs in treating serious infections. Broiler chicks are a known source of Escherichia coli harboring genes for these enzymes. Competitive exclusion (CE) has been used for decades in Finland to prevent the colonization of broiler ceca by Salmonella, but has not been widely used in Sweden.

Rapid field detection assays for Bacillus anthracis, Brucella spp., Francisella tularensis and Yersinia pestis.

Rapid detection is essential for timely initiation of medical post-exposure prophylactic measures in the event of intentional release of biological threat agents. We compared real-time PCR assay performance between the Applied Biosystems 7300/7500 and the RAZOR instruments for specific detection of the causative agents of anthrax, brucellosis, tularemia and plague. Furthermore, an assay detecting Bacillus thuringiensis, a Bacillus anthracis surrogate, was developed for field-training purposes.

A multiplatform real-time polymerase chain reaction detection assay for Vibrio cholerae.

We report a multiplatform real-time polymerase chain reaction methodology based on genes encoding for the regulatory toxR activator and enterotoxin A protein to determine enterotoxigenic Vibrio cholerae types from other vibrios. This assay, which was successfully validated on a collection of 87 bacterial strains, including 63 representatives of V. cholerae and 8 noncholera vibrios provides a rapid tool for detection and identification of cholera.

Antiresistance?

After billions of years of evolution and untold numbers of bacterial generations there appears to be only a finite number of genera belonging mainly to order Actinomycetales, producing largely similar types of antibiotics all over the world. It is hypothesized that this not just a result of limited number of susceptible targets or a transitory situation in the evolutionary process. It is proposed that there is some stabilizing factor associated with the commonly encountered antibiotics that alleviates the selection pressure to design new antibiotics.

Transmission of bovine viral diarrhoea virus through the semen of acutely infected bulls under field conditions.

Epidemiological investigations implicated the semen of artificial insemination (ai) bulls as the only plausible source of infection with bovine viral diarrhoea virus (bvdv) in 10 Finnish dairy herds. The infection was traced back to two northern Finncattle bulls that had been transiently infected when their semen had been collected while they were in a gene bank herd containing persistently infected (pi) animals. The isolates of bvdv from the animals in the gene bank herd, from the semen of the two bulls and from a pi calf born in one of the herds using the semen belonged to a rare genetic type in Finland and, on the basis of the nucleotide sequences in the 5' untranslated region, were identical.

Vaccine coverage, herd immunity and occurrence of canine distemper from 1990-1996 in Finland.

Official vaccine sales statistics, the development of the young dog population and the takes of available vaccines were used to calculate the vaccine coverage and herd immunity (HI) against canine distemper, endemic during 1990-1993 and epidemic in 1994-1995 in Finland. Despite the satisfactory vaccine coverage, HI was no more than 50-65% in 1990-1993 because low-take vaccines dominated the market. Replacement of the low-take with high-take vaccines in 1995 raised the HI to 90%, which coincided with the ending of the epidemic.

Simulation of human exposure to benzylpenicillin residues via pork originating from pigs fed with a dairy by-product.

The use of food industry by-products for feeding is restricted by European Union by-product regulation (1774/2002). However, the actual public health risks involved in the use of such products are poorly recognized. This study focuses on bovine milk rejected at the dairy because of a positive result in antimicrobial drug testing and thereafter used as feed for finisher pigs in Finland.

Epidemiology and eradication of infectious bovine rhinotracheitis/infectious pustular vulvovaginitis (IBR/IPV) virus in Finland.

Background: Infectious bovine rhinotracheitis/infectious pustular vulvovaginitis (IBR/IPV) is a significant disease among domestic and wild cattle. The BHV-1 infection was first detected in Finland in 1970; presumably it was imported in 1968. The infection reappeared in the large-scale bulk-tank milk surveillances which started in 1990, and was eradicated in 1994.

Bovine viral diarrhoea virus control in Finland 1998-2004.

The bovine viral diarrhoea virus (BVDV) situation among dairy herds and suckler-cow herds was monitored annually from 1998 to 2004. Bulk-tank milk (BTM) samples from all dairy herds and serum samples from beef animals at slaughter were examined for BVDV antibodies using a commercial indirect ELISA test. New BTM antibody-positive herds and herds with a history of BTM antibodies, but previously untested were sampled individually and tested for evidence of BVDV.

An automated turbidimetric method for the identification of certain antibiotic groups in incurred kidney samples.

An automated turbidimetric method was developed for group level identification of penicillinase sensitive penicillins, tetracyclines and fluoroquinolones in kidney samples. A sample pretreatment procedure was elaborated for the extraction of incurred residues from kidney tissue in a translucent solution to enable the measurement of changes in optical density. The method was comprised of three pairs, one for each antibiotic group: a sensitive test bacterium strain and a resistant strain for the identification of fluoroquinolones and tetracyclines, and a sensitive strain with and without penicillinase for the identification of penicillinase sensitive penicillins.

Eradication of enzootic bovine leukosis from Finland.

Enzootic bovine leukosis (EBL) was recognized among Finnish cattle in 1966. Administrative decisions specifying and refining official control measures were given in 1966, 1976, 1980, and 1993. The measures' key principle always has been 'test and slaughter'.

An indirect conductimetric screening method for the detection of antibiotic residues in bovine kidneys.

An indirect conductimetric screening method using three test bacterium-medium combinations was developed for rapid detection of antibiotic residues in bovine carcasses. The detection time (DT), i.e.

A microbiological six-plate method for the identification of certain antibiotic groups in incurred kidney and muscle samples.

A microbiological method was developed for group level identification of antibiotics in incurred kidney and muscle samples from cattle and pigs. The method was composed of six test bacterium-plate growth medium combinations and the result was recorded as a profile of growth inhibition zones. The sample profiles were compared to two sets of references: one constructed with standard antibiotic solution profiles, and the other with these combined with profiles of microbiologically and chemically identified residues from incurred samples.

Canine distemper virus neutralising antibodies in vaccinated dogs.

The associations between the levels of canine distemper virus neutralising antibodies and vaccination history, age and gender were investigated in a cross-sectional study of a sample of 4627 dogs from the Finnish urban dog population. Dogs vaccinated with either Canlan (Langford Laboratories) or Dohyvac (Solvay Animal Health) or with both, had significantly lower titres than those vaccinated with Candur (Behringwerke), Duramune (Fort Dodge Laboratories) or Nobivac (Intervet), or with combinations including at least one of these. The vaccines were classified as having low and high immunogenicity on the basis of the geometric mean titre achieved by the vaccine when compared with the geometric mean titre of the entire dataset.

Preventing the spread of maedi-visna in sheep through a voluntary control programme in Finland.

The sheep disease maedi-visna (MV) was introduced into Finland in 1981 and had spread to eight flocks in the southwestern part of the country when first detected in a survey in 1994. Six more seropositive flocks were subsequently traced, bringing the total to 14. MV has a notifiable disease status in Finland that provides for official restrictive measures to which all infected herds are subject.

Serological survey and epidemiological investigation of maedi-visna in sheep in Finland.

A survey for antibodies to maedi-visna virus (MV) in the Finnish sheep surveillance flocks was conducted in 1994. Examination of a total of 12931 serum samples from animals over 1 year of age from 545 flocks (81% of all flocks) revealed eight seropositive flocks and the subsequent epidemiological investigation yielded one additional seropositive flock, indicating a low prevalence of 1.6%.

Prevalence and geographic distribution of bovine viral diarrhoea (BVD) infection in Finland 1993-1997.

Bulk milk samples from every herd supplying milk to dairies in Finland were examined for the presence of antibodies to BVD virus (BVDV) annually during 1993-1997. The highest prevalence, 0.99% in 1994, declined to 0.

Outbreak off canine distemper in vaccinated dogs in Finland.

Canine distemper reappeared in dogs in Finland in 1990 after a 16-year absence. In 1994 to 1995 an outbreak occurred in areas with a high density dog population which involved dogs vaccinated against distemper. The estimated total number of cases was at least 5000, and 865 cases were confirmed by indirect fluorescent antibody testing of 3649 epithelial cell samples.

Note: inhibition of the growth of Yersinia enterocolitica O:3 by the microflora of porcine caecum and ileum in an in vitro model.

The growth of Yersinia enterocolitica O:3 was tested in an in vitro model of the porcine intestine at the physiological temperature of 39 degrees C of growing pigs. The model supported a stable population of Y. enterocolitica at a level 10(8)-10(9) cells ml-1.

An in vitro model for studies on bacterial interactions in the avian caecum.

An in vitro intermittent-flow model was developed for studying bacterial interactions in the avian caecum. The model provides a closer simulation of caecal conditions than others described previously but does not require elaborate instrumentation. In preliminary trials, growth of caecal bacteria from an adult chicken was shown to be inhibitory to both Salmonella infantis and entero-haemorrhagic Escherichia coli.

Adhesion of Lactobacillus acidophilus to avian intestinal epithelial cells mediated by the crystalline bacterial cell surface layer (S-layer).

Lactobacillus acidophilus was isolated from washed and homogenized walls of the crop and caecum of an adult fowl. A strain that adhered well in the Fuller adhesion test was subcultured until colonies on Lactobacillus Selective agar changed from rough to smooth. This coincided with a change from aggregate to planktonic growth in liquid medium and a marked loss of ability to adhere.

Use of competitive exclusion to protect newly-hatched chicks against intestinal colonisation and invasion by Salmonella enteritidis PT4.

1. The recommended dose of a commercial competitive exclusion (CE) product (BROILACT) was given orally to newly-hatched broiler chicks to protect them against oral challenge by Salmonella enteritidis PT4. 2.

Efficacy of different microbial preparations for controlling Salmonella colonisation in chicks and turkey poults by competitive exclusion.

1. Control by competitive exclusion of intestinal colonisation by Salmonella infantis was studied in domestic chicks and turkey poults given a commercial product developed for use with chickens, compared with two similar preparations containing intestinal microorganisms from turkeys. 2.

Long-term experience with competitive exclusion and salmonellas in Finland.

Poultry production is under strict official control in Finland. Fifteen years after the introduction of 'competitive exclusion' treatment the majority of growers (over 70%) use it routinely. The number of Salmonella-positive flocks is less than 5% and the incidence of Salmonella-contaminated broiler carcasses has been 5-11% in the last two years.