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PubMed1982

Development of a modified live, canine origin parvovirus vaccine.

A modified live, canine origin parvovirus vaccine was tested for safety, efficacy, and clinical performance. The vaccine protected dogs from challenge of immunity with canine parvovirus (CPV) that caused clinical illness in all nonvaccinated dogs. Vaccinates all developed CPV serum neutralization antibody titers, with a mean value of 1,664. Challenge virus was not isolated from vaccinates, but feces from nonvaccinated dogs were CPV-positive for up to 4 days following challenge. In a pathogenicity test, dogs inoculated orally with 10 times the label dose remained clinically normal. In a reversion-to-virulence test, the vaccine strain remained nonpathogenic through 6 passages in seronegative test dogs. An immunologic interference test demonstrated that test dogs developed antibodies for all antigens in a combined canine distemper virus-adenovirus 2-parainfluenza virus-parvovirus vaccine and a Leptospira interrogans serovars canicola and icterohaemorrhagiae bacterin. A total of 1,796 doses of the multivalent preparation was administered in a field study, with veterinary practitioners reporting 36 local and 5 generalized reactions.

Animals↗
PubMed2002

The macrolide binding site on the bacterial ribosome.

Macrolides are a diverse group of antimicrobials that are widely prescribed in clinical and veterinary medicine. Macrolides inhibit bacterial growth by interacting with the large (50S) subunit of the ribosome and thereby blocking protein synthesis. The liberal application of macrolides and the mechanistically similar lincosamide and streptogramin B compounds has in recent years led to increased prevalence of resistance to these drugs. To counteract this trend and improve the efficacy of treatment, numerous macrolide derivatives have been developed and the latest of these, the ketolides, are now becoming available for clinical use. However, in the on-going battle against resistance pathogens continual improvement of drugs will be necessary, and more efficient means of drug development are required. An indication of how rational drug design might be feasible is offered by the recent crystallographic structures of the bacterial ribosome. These structures give us a view of the macrolide target at previously unseen resolution, enabling us to understand the molecular details of macrolide interaction and resistance, and provide strong clues about potential new drug targets.

Anti-Bacterial Agents↗
PubMedDate not supplied

[The current concepts of the mechanisms of the therapeutic-prophylactic action of probiotics from bacteria in the genus Bacillus].

Data from literature as well as the authors' experimental data on the mechanism of the effect of probiotics from aerobic sporeforming bacteria have been first generalized. The authors made a conclusion that the effect of biopreparations from bacilli is the multifactor process, when bacilli get to the gastrointestinal tract they begin producing biologically active substances which make the immediate effect on pathogenic and conditionally pathogenic microorganisms as well as activate specific and nonspecific systems of the macroorganism protection. The unknown before phenomenon of bacteria translocation is analyzed in detail as one of the most important factors of activation of non-specific resistance of the macroorganisms. Aerobic sporeforming bacteria produce a number of enzymes, amino acids, antibiotic substances and other biologically active substrates which add to the complex treatment-prophylactic effect of biopreparations from these bacteria. Prospects of the use of probiotics based on aerobic sporeforming bacteria in medicine and veterinary are considered. It is emphasized, in particular, that the potential multifactor character of the treatment-prophylactic efficiency of biological preparations from Bacillus is of positive value, since no negative effects are evoked by the known mechanisms of specific effect of aerobic sporeforming bacteria. This opens wide potentialities for improving the schemes and methods of application of probiotics from bacilli, creation of new forms of drugs on their base as well as to combine them with other preparations.

Animals↗
PubMed1996

[Isolation of Corynebacterium diphtheriae subsp. belfanti from a cow with chronic active dermatitis].

Diphtheria is an acute communicable disease of man caused by C. diphtheriae. Pharyngeal and cutaneous forms are described, where from both toxigenic and nontoxigenic strains can be isolated. The occurrence of C. diphtheriae in dairy cattle has already been reported in the past. The pathogens were isolated from ulcerated teats and from the milk of cows with mastitis as well. These animals were considered to play a role in the transmission of the disease to man. This paper describes the isolation and characterization of C. diphtheriae in a 4 years old cow with generalized, partly ulcerative and purulent skin lesions. Bacteriological examination revealed the presence of very numerous corynebacterium-like organisms, which were characterized as C. diphtheriae subsp. belfanti, a nontoxigenic subspecies of C. diphtheriae. The significance of C. diphtheriae in veterinary medicine and the possible role of cattle as a reservoir of these organisms are discussed.

Animals↗
PubMed1997

Prevalence of intestinal chlamydial infection in pigs in the midwest, as determined by immunoperoxidase staining.

OBJECTIVE: To determine prevalence of intestinal chlamydial infection in pigs and to compare prevalence of diarrhea in infected pigs with that in noninfected pigs to evaluate the importance of Chlamydia sp as causes of diarrhea in pigs. ANIMALS AND PROCEDURES: Intestines from 351 sick pigs submitted to 2 veterinary diagnostic laboratories and from 96 healthy pigs that were part of an Escherichia coli susceptibility study were examined by immunoperoxidase staining for chlamydial antigen. The proportion of Chlamydia-infected pigs in each group was calculated and compared. The proportion of Chlamydia-infected pigs with diarrhea was compared with the proportion of noninfected pigs with diarrhea. RESULTS: 15% of the sick and healthy pigs were infected with Chlamydia sp. Prevalence of diarrhea was equal between infected and noninfected pigs. Chlamydia sp were the third most common pathogens identified, and prevalence of chlamydial infection increased after 3 weeks of age. CONCLUSIONS AND CLINICAL RELEVANCE: Intestinal chlamydiosis is common in commercial pigs, but most, if not all, infections are subclinical Without collaborative evidence, simply identifying Chlamydia sp in feces or the intestinal tract of pigs with enteritis or diseases of other organ systems should not be considered proof that the organism caused the clinical signs of disease.

Animals↗
PubMed1993

TnphoA Salmonella abortusovis mutants unable to adhere to epithelial cells and with reduced virulence in mice.

Salmonella abortusovis is a pathogenic bacterium highly specific to sheep, causing spontaneous abortion. In order to understand the role of genes involved in pathogenicity, we investigated S. abortusovis with the random mutagenic TnphoA transposon. A total of 95 S. abortusovis TnphoA mutants yielding alkaline phosphatase active fusion protein were obtained. In this way we created a bank of strains in order to identify any phenotypic modification which could affect the periplasmic and/or exported proteins involved in virulence. The TnphoA mutants were screened for the ability to adhere to epithelial cells: a total of 23 mutant strains lost this phenotypic feature. To detect the chromosomal TnphoA insertions, DNA was restricted by the enzyme EcoRV, which does not cleave the TnphoA sequence. Southern blotting analysis revealed the existence of four classes of integration. Colonies of adhesiveless mutants appear to be as smooth as the S. abortusovis wild type, and electrophoretic analysis indicates a normal lipopolysaccharide profile. To identify mutations affecting genes encoding for outer membrane proteins (OMPs), the alkaline phosphatase portion of the fusion proteins was revealed in TnphoA mutants by immunoblotting with specific antibodies. A mutation in OMPs was detected in seven mutants. Restriction analysis identified in four mutants a common region of 2 kb where alterations in genes coding for OMPs occur. We suggested that this region is involved in pathogenicity in mice, since a group of mutant strains has shown reduced virulence in mice and one mutant is completely avirulent. Furthermore, after mice were exposed orally to these mutants, significant protection against oral challenge with the parental virulent strain resulted.

Abortion, Veterinary↗
PubMed2026

Performance of the IR Biotyper, Nanopore, and Illumina sequencing to discriminate Escherichia coli strains originating from poultry.

UNLABELLED: Escherichia coli is a highly diverse bacterial species that includes avian pathogenic E. coli (APEC), one of the most prevalent causative agents of disease in poultry worldwide. Rapid and accurate discrimination of E. coli strains is essential for outbreak management, antimicrobial resistance surveillance, and vaccine development. In this study, we compared the performance of Fourier Transform Infrared (FTIR) spectroscopy using the IR Biotyper system with Nanopore and Illumina whole-genome sequencing (WGS) for typing 200 E. coli isolates, originating from four poultry rearing farms in the Netherlands. From each farm, we sampled 10 one-day-old meat type rearing chicks, and from every chick, we isolated 5 E. coli strains. FTIR clustering showed strong concordance with WGS-based classifications, particularly serotyping and core-genome similarity determined by PopPUNK analysis (Adjusted Rand Index 0.75-0.92). While Nanopore and Illumina sequencing provided the highest genetic resolution, FTIR offered a faster (max 6 vs 12-28 days for 200 isolates) and more cost-effective alternative for assessing clonality. Across all methods, multiple strains were detected per farm, whereas most birds carried a single dominant E. coli strain. Our findings demonstrate that FTIR provides a reliable and scalable phenotypic method for rapid strain discrimination in E. coli, complementing WGS in diagnostic, surveillance, and epidemiological settings where speed and throughput are critical. IMPORTANCE: Escherichia coli is a major pathogen in poultry and a potential zoonotic risk for humans. Rapid and accurate discrimination of avian pathogenic E. coli (APEC) strains is critical for outbreak management, antimicrobial resistance surveillance, and the design of effective autogenous vaccines. In this study, we compared Fourier Transform Infrared (FTIR) spectroscopy with Nanopore and Illumina whole-genome sequencing for strain typing of E. coli isolates originating from poultry. The results show that FTIR provides comparable clustering accuracy to genomic approaches at a fraction of the time and costs. This work demonstrates that FTIR can serve as a practical, high-throughput alternative for routine monitoring of E. coli in veterinary diagnostics and food safety of poultry meat, enabling faster decision-making and more targeted interventions across the poultry production chain.

Animals↗
PubMed2002

Dogs, zoonoses and immunosuppression.

Dogs are the source of a wide range of zoonotic infections that pose a significant threat to human health. This is particularly the case for immunocompromised people, although there are few robust studies that determine immunosuppression as a risk factor for transmission of zoonoses from dogs to humans. An increasing proportion of human society is immunodeficient, principally through the advent of HIV infection and through more people, particularly the expanding elderly group, being subjected to immunosuppressive agents. This is happening at a time when more such people are capitalizing on the acknowledged benefits of dog ownership, making for a potentially dangerous mix. Enteric pathogens (for example, Salmonella, Campylobacter and Cryptosporidium species, that may be canine derived) are a frequent risk to the health of immunocompromised persons. Veterinarians and physicians can be criticised for not communicating with each other, and for not providing adequate risk assessment to pet owners. There is scope for voluntary groups to provide information and support for the immunosuppressed who wish to keep their dogs. Key recommendations are to maintain a clean personal environment and intact mucocutaneous barriers. Public health professionals could help rectify the current communications gap between veterinary and medical staff and so facilitate in the appropriate management of dog-owning immunocompromised people.

Animals↗
PubMed2000

DANMAP: monitoring antimicrobial resistance in Denmark.

The objectives of the Danish Integrated Antimicrobial Resistance Monitoring and Research Programme (DANMAP) are to monitor trends in resistance among bacteria from animals, food and humans, to monitor the consumption of antimicrobial agents and to determine the association between consumption and occurrence of resistance and to model transmission of resistance from animals to humans. DANMAP is based on the examination of representative bacterial isolates of animal and human pathogens, of zoonotic bacteria and of indicator bacteria. For food animals, both diseased and the healthy populations are studied. Isolates from all three reservoirs are examined for their susceptibility to a basic panel of antibiotics that includes representatives of the major classes of compounds, making comparison of resistance levels in the reservoirs possible. Isolates are stored in a strain collection and are available for further study. The data are stored in databases as MIC values or mm inhibition zones with all identifiers. A system for recording all use of the veterinary medicines, VETSTAT, is currently under implementation. For production animals, the consumption will be recorded for each herd, providing a basis for detailed modelling of the effect of consumption on resistance.

Animal Diseases↗
PubMed2000

Characterization of PaxA and its operon: a cohemolytic RTX toxin determinant from pathogenic Pasteurella aerogenes.

Pasteurella aerogenes is known as a commensal bacterium or as an opportunistic pathogen, as well as a primary pathogen found to be involved in abortion cases of humans, swine, and other mammals. Using broad-range DNA probes for bacterial RTX toxin genes, we cloned and subsequently sequenced a new operon named paxCABD encoding the RTX toxin PaxA in P. aerogenes. The pax operon is organized analogous to the classical RTX operons containing the activator gene paxC upstream of the structural toxin gene paxA, which is followed by the secretion protein genes paxB and paxD. The highest sequence similarity of paxA with known RTX toxin genes is found with apxIIIA (82%). PaxA is structurally similar to ApxIIIA and also shows functional analogy to ApxIIIA, since it shows cohemolytic activity with the sphingomyelinase of Staphylococcus aureus, known as the CAMP effect, but is devoid of direct hemolytic activity. In addition, it shows to some extent immunological cross-reactions with ApxIIIA. P. aerogenes isolated from various specimens showed that the pax operon was present in about one-third of the strains. All of the pax-positive strains were specifically related to swine abortion cases or septicemia of newborn piglets. These strains were also shown to produce the PaxA toxin as determined by the CAMP phenomenon, whereas none of the pax-negative strains did. This indicated that the PaxA toxin is involved in the pathogenic potential of P. aerogenes. The examined P. aerogenes isolates were phylogenetically analyzed by 16S rRNA gene (rrs) sequencing in order to confirm their species. Only a small heterogeneity (<0.5%) was observed between the rrs genes of the strains originating from geographically distant farms and isolated at different times.

Abortion, Veterinary↗
PubMedDate not supplied

In vitro susceptibility of avian Escherichia coli and Pasteurella multocida to danofloxacin and five other antimicrobials.

The in vitro susceptibility of Escherichia coli and Pasteurella multocida isolated from poultry was determined to danofloxacin, a novel fluoroquinolone, and five other commonly used antimicrobials. A total of 1737 E. coli field isolates and 107 P. multocida isolates were tested by veterinary diagnostic laboratories in Europe, Japan, South Africa, and North America during the period 1989-91. The antimicrobial susceptibility of these isolates was determined using the Sensititre broth microdilution technique. The minimum inhibitory concentrations (MIC) of danofloxacin, furaltadone, lincomycin, oxytetracycline, spectinomycin, and trimethoprim:sulfamethoxazole that prevented growth of 90% of the bacteria were 0.25 > 64, > 64, > 64, > 128, and > 16 micrograms/ml, respectively, against E. coli isolates and 0.25, 64, 64, 16, 128, and 8 micrograms/ml, respectively, against P. multocida isolates. Danofloxacin demonstrated considerable in vitro potency against these important poultry pathogens, many of which showed extensive resistance to the other antimicrobials tested.

Animals↗
PubMed2003

West Nile virus encephalomyelitis in horses in Ontario: 28 cases.

West Nile virus encephalomyelitis was diagnosed in 28 horses presented to the Ontario Veterinary College Veterinary Teaching Hospital between August 20 and October 15, 2002. The age range of affected horses was 5 months to 20 years (mean 6.9 years, median 6 years). Clinical signs were highly variable. Duration of hospitalization ranged from < 1 to 12 days (mean 5 days, median 5.4 days). Overall, 16 of the 28 (57%) horses were discharged and, of the 14 from which follow-up information was available, 13 (93%) were reported to be clinically normal 4 to 6 weeks following discharge, while the other horse had markedly improved. This pathogen is emerging as an important cause of neurological disease in Canada.

Animals↗
PubMed1994

Increase of ciprofloxacin resistance in Campylobacter species in Styria, Austria.

Salmonella spp. and thermophilic Campylobacter spp. are the most important diarrhea-causing pathogens in the area investigated in Styria, Austria. The isolation rate of Campylobacter in the more than 62,000 stool specimens investigated in the six-year period between 1988 and 1993 ranged between 1.90% in 1988 and 3.58% in 1991. The testing of susceptibility to nalidixic acid has been an usual characteristic for species identification. Nalidixic acid-resistant strains were rare in 1988-1990, but in the summer of 1991, we found an increasing number of these isolates. At the same time, we learnt about the increasing use of enrofloxacin in veterinary medicine, especially in the poultry industry, and therefore we started routine testing of Campylobacter spp. susceptibility to ciprofloxacin in 1992. In 1992, the resistance rate to ciprofloxacin was already 16.9%, rising to 22.1% in 1993.

Campylobacter↗
PubMed1980

Listeriosis in humans and animals in the Netherlands (1958-1977).

During the past twenty years 793 strains of Listeria monocytogenes were isolated from human beings in the Netherlands; of these 193 were taken from neonates and babies up to two months old. Isolations from adults came from patients (242) as well as clinically healthy people (358). Septicaemia appeared to occur to an equal extent in men and women (20 and 29 respectively), whereas meningitis was found more often in men than in women (50 and 22 respectively). A clear predisposition for L.m. develops after administration of immunosuppressive treatment and also in cases of liver disorders. Among veterinary surgeons listeriosis has been observed as an occupational disease. Isolations from animals have shown that L.m. may cause infections in every species of warm-blooded animal. Next to meningitis and abortus chronic and atypcial symptoms of the disease may be observed in animals. Epizootic spread of the disease has hardly ever been observed in the Netherlands. In clinically healthy humans and animals both the haemolytic and the non-haemolytic type of L.m. have been isolated from feces; as regards the latter type it is very questionable whether it has any pathogenic significance. When inoculating 10 days old hen's eggs the haemolytic strains will kill all embryo's within 4 days whereas all embryo's inoculated with non-haemolytic strains will survive. Both types of strains have also been isolated from waste- and surface waters. As regards epidemiological and epizootiological aspects the conclusion is warranted that continued research will be needed to get a clear picture of the course of infection of L.m. When isolating strains from contaminated material the so-called cold enrichment icubation at 4 degrees C continues to be of great value; in the course of our experiments the nalidixic-acid trypaflavine serum agar proved to be a very good selective medium. A number of stable biochemical reactions of L.m. are rather characteristic (salicine+, galactose-) but provide no clue to distinguish between haemolytic and non-haemolytic strains.

Adolescent↗
PubMed1996

Biological control. Aspects of biological control--with special reference to arthropods, protozoans and helminths of domesticated animals.

Biological control describes situations in which a living antagonist (a predator, parasite, parasitoid or a pathogen) is distributed by man to lower pest (parasite) populations to acceptable sub-clinical densities or to keep the population at a non-harmful level. Ideally, biological control has no negative effects on the environment, whereas chemical control is not always so harmless. Laboratory and field observations have revealed many organisms, such as viruses, bacteria, fungi, protozoans, turbellarians, nematodes, earthworms, tardigrades, insects, copepods and mites as antagonists to parasitic arthropods, protozoans and helminths of domesticated animals. However, only very few of these antagonists have shown promising qualities as biological control agents within veterinary science. The lack of success should be linked to the lack of knowledge about complex natural biological systems and the antagonists that may be found there. This situation has restricted the interest of industry in developing biological products. In the future, however, industry may become more interested in biological control considering the increasing problems with parasite resistance to drugs in combination with the increasing cost of developing new chemical products, and because of increasing public concern about chemical residues in animal products and in the environment.

Animals↗
PubMed2006

Pet ownership in immunocompromised children--a review of the literature and survey of existing guidelines.

Pet ownership has been associated with both emotional and physical health benefits. However, owning pets may also pose health risks to immunocompromised patients through zoonotic transmission of disease. Our initial impression was that there is a lack of any evidence base in information given by health care professionals regarding these risks. We therefore aimed to produce evidence-based guidelines addressing this issue. A Pubmed search was undertaken and a variety of literature on zoonoses reviewed. Existing guidelines were evaluated and a survey of all Paediatric Oncology Centres in the UK performed. There is a paucity of level 1 and 2 data addressing this issue and clearly more studies, particularly Randomised Controlled Trials (RCTs), are required. Nevertheless, general themes emerged and certain specific guidance was produced based on that produced by the Centres for Disease Control and Prevention in the US. Animal-associated pathogens of concern include Toxoplasma gondii, Cryptosporidium spp., Salmonella spp., Campylobacter spp., Giardia lamblia, Rhodococcus equi, Bartonella spp., Bordetella bronchiseptica, Chlamydia psittaci and dermatophytes. Despite this, the literature would suggest that with the exception of Bartonella henselae and dermatophytes only a relatively small number of infections in people are likely to be associated with pet contact. The majority of pet species do not appear to pose a major risk to immunocompromised children. Some animals, particularly reptiles, should be avoided because of the high risk of salmonellosis. Guidelines include general advice on good hygiene practices, veterinary care, pet foods, purchasing of new pets and age restrictions. Health care professionals should actively enquire about household pets and provide accurate information and practical advice on how to minimise the risk of infection. However, the overall benefits of the human-animal bond must be considered and with proper handling and husbandry immunocompromised patients should be able to continue to enjoy the significant benefits of pet ownership.

Age Factors↗
PubMed1990

Is there a role for lactobacilli in prevention of urogenital and intestinal infections?

This review describes the importance of microbial adhesion in the ecology of the urogenital and intestinal tracts and the influence of host and microbial factors in bacterial interference. In a recent revival of interest in bacterial interference, lactobacillus administration has been studied as a means of treating and preventing disease. Although evidence is conflicting, Lactobacillus acidophilus appears to be involved in beneficial antagonistic and cooperative reactions that interfere with establishment of pathogens in the gastrointestinal tract. The mechanisms of action are believed to involve competitive exclusion and production of inhibitory substances, including bacteriocins. These characteristics, as well as demonstrated adherence abilities in vitro, led to selection of certain Lactobacillus strains for clinical studies of cystitis. Weekly intravaginal Lactobacillus therapy reduced the recurrence rate of uncomplicated lower urinary tract infections in women. Use of Lactobacillus strains resistant to Nonoxynol-9, a spermicide that kills members of the protective normal vaginal flora, may have potential for use in women with recurrent cystitis using this contraceptive agent. In veterinary studies, bacterial interference by administration of probiotics has also been beneficial in disease prevention in animals. Carefully selected bacterial mixtures integrate with the gastrointestinal flora of the animals and can confer disease resistance and improve physiological function. Additional human and animal trials are needed to determine the practical, long-term usefulness of bacterial interference as a protective mechanism against infectious diseases.

Bacterial Physiological Phenomena↗
PubMed2006

The geographic distribution of the putative agent of epizootic bovine abortion in the tick vector, Ornithodoros coriaceus.

Epizootic bovine abortion (EBA), also known as "foothill abortion", is a vector borne disease of beef cattle that graze in the mountainous regions of California, southern Oregon and western Nevada transmitted by the argasid tick Ornithodoros coriaceus. Recently, the putative agent of EBA was identified as a novel Deltaproteobacter in the order Myxococcales. In this study, a TaqMan real-time PCR (TM-PCR) protocol specific to the putative EBA agent was developed. The new real-time TM-PCR assay functioned sensitively and specifically to detect pathogen DNA in field-collected O. coriaceus ticks. The assay had an analytical sensitivity of a single plasmid copy and, when evaluated with a collection of tick-borne pathogens, yielded a positive PCR-result only for the agent of EBA. Use of the TM-PCR represents an effective tool for rapid and highly sensitive assessment of environmental risk and spatial and statistical analysis to highlight areas where there may be increased risk for EBA in susceptible cattle.

Abortion, Veterinary↗