Biomedical subjects

K T Veldman

Publications and source records attributed to K T Veldman.

7 recordsLinked to original sources

PubMed2003

Investigations of Enterococcus faecalis-induced bacteraemia in brown layer pullets through different inoculation routes in relation to the production of arthritis.

In the present aerosol experiment, assessment of the respiratory tract of 1-day-old birds as a natural route of infection for induction of Enterococcus faecalis bacteraemia and arthritis was performed. Second, the severity and type of arthritis produced through intramuscular infection in two different inoculation sites (musculus pectoralis versus musculus gastrocnemius) was studied. Third, the resulting bacteraemia was assessed qualitatively and quantitatively in relation to the occurrence of arthritis. Exposure of 1-day-old brown layer pullets to aerosolized E. faecalis with an estimated uptake of 10(4) to 10(5) colony forming units per chick resulted in bacteraemia; however, joint lesions were not induced. In contrast, 3/10 birds inoculated intratracheally with 10(8) colony forming units developed both bacteraemia and arthritis. This suggests the occurrence of a dose effect and a role for the respiratory tract as a natural infection route in young chickens. In both intramuscularly inoculated groups the incidence of arthritis was 10/10 birds and 9/10 birds, respectively. Birds inoculated in the m. pectoralis developed symmetric polyarthritis, which harmonizes with haematogenous colonization of joints. In contrast, m. gastrocnemius-inoculated chicks mostly had asymmetric (poly)arthritis of the injected leg and varus deformation of the contralateral leg, suggesting predominantly local spread. The qualitative and quantitative results of bacteriology of blood samples show that arthritis develops in those groups with the highest number of bacteraemic birds and the highest median bacterial colony forming units per millilitre of blood during the first 24 to 36 h after treatment.

Aerosols↗

PubMed2002

Molecular epidemiology of unilateral amyloid arthropathy in broiler breeders associated with Enterococcus faecalis.

Although symmetrical polyarticular amyloidosis has been described extensively in brown layers, spontaneous unilateral amyloid arthropathy has not been described previously in chickens. Birds from nine flocks of broiler parent stock (PS) had unilateral lameness associated with severe swelling of the left hock joint and the caudal aspect of the metatarsus. Gross pathology was restricted to the left hock joint and the left digital flexor tendons in almost all cases, suggesting an association with administration of Marek's disease vaccine. Amyloid deposits were found in 83% (25/30) of affected joints by histological examination of Congo red stained sections. Systemic amyloidosis, involving mainly the liver and spleen, was found in 59% (10/17) of birds. Enterococcus faecalis was isolated from joints in 77% (23/30) of cases and Staphylococcus aureus was isolated from the joint in one case (1/30). Thirty-five E. faecalis isolates from joints, tendons and blood samples from birds in five affected PS flocks were compared using pulsed-field gel electrophoresis (PFGE) to separate genomic fragments after digestion with SmaI. All but one isolate had identical or closely related restriction endonuclease digestion (RED) patterns that were very similar to a known arthropathic and amyloidogenic E. faecalis isolate. A further 30 E. faecalis isolates from seven grandparent stock (GPS) flocks and two isolates from two unaffected PS flocks of the same genetic background were analysed by PFGE. Among these isolates, 11 originating from four GPS flocks had RED patterns identical to or closely related to the reference amyloid-inducing strain. Moreover, one E. faecalis isolate from amyloidotic joints of brown layers housed in California, USA was included in the analysis and appeared to be identical to the reference strain. This study showed that the E. faecalis isolates involved in these outbreaks of unilateral amyloid arthropathy in broiler breeders belonged to the same clone as that responsible for outbreaks in brown layers.

Amyloidosis↗

PubMed2001

Study on the vertical transmission of arthropathic and amyloidogenic Enterococcus faecalis in a flock of brown layer chickens.

Enterococcus faecalis-related amyloid arthropathy was diagnosed in a sample of birds from a flock of brown layer parent chickens aged 57 weeks. E. faecalis was isolated from amyloidotic knee joints and from blood samples from lame birds. From this flock a smaller one was kept for production purposes to study the vertical transmission of arthropathic and amyloidogenic E. faecalis. Three batches of non-soiled and thoroughly disinfected eggs, to prevent egg-shell contamination, were collected for 6 weeks and submitted for incubation every 2 weeks. No joint pathology was found in the offspring chicks (n = 458) monitored for joint disease until 16 or 21 weeks of age. Fresh and candled eggs (infertiles and dead embryos) obtained at day 18 of the incubation period had negative results at bacteriological examination of the yolk sac, except one non-hatched egg (late embryonal death in shell) from which E. faecalis was isolated. Genotyping by pulsed-field gel electrophoresis (PFGE) of all E. faecalis isolates obtained from blood and joints (except one) of the parent birds and of the non-hatched egg after Sma I digestion showed that all isolates were genetically closely related or identical to a known arthropathic and amyloidogenic E. faecalis strain. In this study, vertical transmission of E. faecalis, although it may occur on a small scale as shown by PFGE, did not seem to play a significant role. Conversely, the chronicity of the condition and the development of an immune response may have affected the efficiency of its transmission.

Amyloidosis↗

PubMed2000

[Preliminary results of antibiotic resistance monitoring in the Netherlands].

Qualitative tests are used to monitor antimicrobial resistance in bacteria of animal origin in the Netherlands. Quantitative information on trends in resistance is thus not obtained. Moreover, in general a limited panel of antibiotics is tested. The present study describes resistance in zoonotic food-borne pathogens Salmonella, Campylobacter, and Escherichia coli O157 isolated from human clinical cases and from faeces of healthy food animals in 1998 and 1999, as determined with quantitative susceptibility tests. The resistance of the indicator organisms E. coli and Enterococcus faecium isolated from faecal samples of broilers and pigs randomly sampled at slaughterhouses was also determined. For this end, faecal samples from veal calves were sampled in 1996 and 1997 at the three main Dutch veal calf slaughterhouses. In 1998 only a limited number of faecal samples of veal calves were taken at farms. For E. coli and Salmonella the following antibiotics were tested: amoxicillin, amoxicillin-clavulanic acid, piperacillin, cefotaxime, ceftazidime, imipenem, gentamicin, doxycycline, trimethoprim, trimethoprim/sulphamethoxazole, ciprofloxacin, chloramphenicol, florfenicol, carbadox, and flumequine. For E. faecium the following antibiotics were tested: amoxicillin, amoxicillin-clavulanic acid, chloramphenicol, doxycycline, erythromycin, vancomycin, teicoplanin, streptomycin ('high level' > 2000 mg/ml), gentamicin ('high level' > 500 mg/ml), ciprofloxacin, bacitracin, flavofosfolipol, salinomycin, quinupristin-dalfopristin, virginiamycin, tilmicosin, avilamycin, and everninomycin. For Campylobacter the following antibiotics were tested: erythromycin, doxycycline, gentamicin, carbadox, flavofosfolipol, ciprofloxacin, trimethoprim/sulphamethoxazole, amoxicillin, and metronidazole.

Animals↗

PubMed1999

Sensitivity testing of veterinary pathogens with a semi-automatic image analysis system compared with tablet diffusion and agar dilution tests.

Recently a commercial computer-controlled image analysis system (IAS) was introduced to measure automatically the diameters of inhibition zones in the agar diffusion test. However, there is little information on the precision of this method. In the present study clinical isolates of Salmonella spp. (N = 104), Escherichia coli (N = 100), Pasteurella spp. (N = 99), Actinobacillus pleuropneumoniae (N = 85), porcine streptococci (N = 100), and Staphylococcus aureus (N = 95) were tested in the agar diffusion test, using nineteen different antibiotics in tablets. All inhibition zone diameters were first measured by a laboratory technician and then by the IAS. Although the zone diameters of all bacteria-antibiotic combinations measured by the IAS and those measured by the laboratory technician showed a significant positive correlation, the size of the inhibition zone diameters measured by the technician and the IAS differed significantly in 59% of the combinations. However, these differences were very small and may have no clinical relevance. The IAS was also used to calculate minimum inhibitory concentrations (MIC values) from the zone diameters. In 82% of the bacteria-antibiotic combinations MIC values calculated by the IAS showed a significant positive correlation with MIC values obtained with the reference agar dilution test. However, in 92% of the bacteria-antibiotic combinations, the calculated MIC values differed significantly from the reference values. In some cases these differences were so large that they could be of clinical relevance. The IAS was unable to measure the diameter of inhibition zones of porcine streptococci properly, due to poor contrast. We concluded that when tablets are used as antibiotic carriers the IAS accurately measures the diameter of inhibition zones for bacteria species that give good contrast between the agar and bacterial growth. MIC values determined with the IAS were only indicative of those determined with the reference agar dilution test.

Agar↗

PubMed1999

The effect of flavophospholipol (Flavomycin) and salinomycin sodium (Sacox) on the excretion of Clostridium perfringens, Salmonella enteritidis, and Campylobacter jejuni in broilers after experimental infection.

Intestinal colonization and shedding of pathogenic bacteria in animal feces is an important factor in both human food safety and animal health. The effect of broiler feed additives flavophospholipol (FPL; Flavomycin, bambermycins) and salinomycin sodium (SAL; Sacox) given singly on the excretion of Salmonella enteritidis, Campylobacter jejuni, and Clostridium perfringens was studied following controlled infection. The incidence of shedding (number of birds with positive fecal cultures) and the degree of shedding (cfu per gram of feces in positive birds) were measured to determine the influence of these two common feed additive antibiotics on shedding rates of potential pathogens. A total of 216 Ross broiler chickens, housed in battery cages, were fed either an unmedicated feed (controls), feed containing FPL, or feed containing SAL. Feed treatment groups were subdivided into three bacterial challenge groups of 24 chicks, each receiving only one of the pathogens. Bacterial challenge was administered orally on Days 11 and 12 for Salmonella and Campylobacter and on Days 2 and 3 for Clostridium. Fecal samples were collected weekly up to 6 wk of age and cultured for presence of the target organism. The shedding rate was determined by decimal dilutions of the fecal samples. Feeding FPL resulted in a reduced (P < or = 0.05) degree and incidence of Salmonella and Clostridium shedding at 6 wk. Feeding SAL reduced (P < or = 0.05) the incidence of Salmonella shedding at 6 wk. Neither feed additive affected the incidence nor the degree of Campylobacter shedding. The results of this study indicate that these feed additives may reduce the incidence of these potential human and animal pathogens in preslaughter broilers.

Animal Feed↗

PubMedDate not supplied

Aerosol transmission of arthropathic and amyloidogenic Enterococcus faecalis.

One-day-old brown layer chicks were exposed to an aerosol of an arthropathic and amyloidogenic Enterococcus faecalis strain alone or after being subjected to treatment with formaldehyde gas (100-200 ppm). Four-day-old chicks were also treated with the same aerosol but after treatment with a Newcastle disease vaccine virus (NDVV) aerosol or intramuscular injection with methylprednisolon at day 1. The same E. faecalis strain was inoculated intramuscularly in day-old chicks as positive control. Bacteremia with time showed that 24 hr after the aerosol the day-old exposed chicks had the highest rate of positive blood cultures (70%-80%). Lower numbers of bacteremic birds at this point in time were found in the chicks treated with E. faecalis aerosol at day 4 (3/10 in the methylprednisolon-treated group and 0/10 in the NDVV-treated group) and the E. faecalis intramuscular-injected group at day 1 (2/10). Formaldehyde gas treatment did not favor the occurrence of bacteremia. NDVV aerosol exposure or injection with corticosteroids did not favor the occurrence of bacteremia 24 hr after E. faecalis aerosol exposure at day 4 either, although 66 days after aerosol, one bird (1/14) treated with NDVV showed bacteremia. A few bacteremic birds were found 10 days after aerosol in the NDVV- and methylprednisolon-treated groups, whereas at 14 days after aerosol, one bacteremic bird was seen in the group subjected to E. faecalis aerosol at day 1, indicating the occurrence of chronic bacteremia. In contrast to the E. faecalis intramuscular-inoculated birds, no joint pathology was seen in the aerosol-exposed groups in spite of the occurrence of chronic bacteremia.

Aerosols↗