Detection of Pseudomonas aeruginosa in water samples using a novel synthetic medium and impedimetric technology

AIMS

To investigate whether the use of a novel synthetic medium in conjunction with impedimetric technology could provide a rapid and automated detection of Pseudomonas aeruginosa in water samples.

METHODS AND RESULTS

A selective synthetic medium (Z-broth) in which the only carbon and nitrogen source is acetamide was applied in direct impedimetric examination for the selective isolation of P. aeruginosa. A total of 1036 tap-water, well-water, swimming-pool water and dialysis water samples were investigated, and any P. aeruginosa contamination was detected in 7-24 h. Neither false-negative nor false-positive results were observed.

CONCLUSIONS

The results of the present evaluation demonstrate that impedance measurement with the use of Z-broth is suitable for the rapid and automatic detection of P. aeruginosa in water.

SIGNIFICANCE AND IMPACT OF THE STUDY

The main advantages of the method: 240 samples can be examined in one step, the procedure is fully automated, the results are obtained quickly and the labour and media requirements are low.

Haemorrhagic nephritis and enteritis of geese: pathomorphological investigations and proposed pathogenesis

Haemorrhagic nephritis and enteritis of geese as a new disease was first described in Hungary in 1969. The authors identified the causative agent of the outbreaks occurring in 1969 as a polyomavirus by PCR in 2001. In order to study the pathogenesis of the virus, one-day-old goslings were infected with tissue homogenate that tested positive for polyomavirus by PCR. Morphological, light and transmission electron microscopic (TEM) examinations have revealed that goose haemorrhagic polyomavirus replicates in the endothelial cells of the blood vessels and capillaries of diseased birds. Infection causes damage and necrosis of the endothelial cells. The virus was not observed in the parenchymal cells. Oedema and haemorrhages found throughout the body may be due to the dysfunction or functional deficiency of endothelial cells damaged by the virus.

BGP-15, a hydroximic acid derivative, protects against cisplatin- or taxol-induced peripheral neuropathy in rats

The neuroprotective effect of BGP-15 against peripheral sensory neuropathy was studied in rats that were exposed to short-term cisplatin or taxol administration. The changes of nerve conduction velocity were determined in situ after treating the Wistar rats with BGP-15 (50, 100, and 200 mg/kg po daily doses throughout the experiment), cisplatin (1.5 mg/kg ip daily dose for 5 days), or taxol (5.0 mg/kg ip daily dose every other day in a 10-day interval) alone or giving the test compound in combination with cisplatin or taxol. Electrophysiological recordings were carried out in vivo by stimulating the sciatic nerve at both sciatic notch and ankle site. Neither motor nor sensory nerve conduction velocity was altered by any dose level of BGP-15 tested. Both anticancer drugs decreased the sensory nerve conduction velocity (SNCV). BGP-15 treatment prevented the impairment of SNCV either in part or totally in the cisplatin- or taxol-treated groups. This neuroprotective potential of BGP-15 could be well correlated with its recently described poly(ADP-ribose) polymerase- inhibitory effect and its ability to protect against the damages induced by the increased level of reactive oxygen species in response to anticancer treatment.

Intestinal absorption of colostral lymphoid cells in newborn animals

Intestinal absorption of colostral lymphoid cells was studied in 23 piglets of four sows and 17 lambs of ewes. From the colostrum and blood of the dams the lymphoid cells were isolated with Ficoll-Paque and labelled with technetium (Na99mTcO4). In the 7th hour after birth, 10 ml volume of the cell suspensions (piglets: 10(7) cells, lambs: 5 x 10(7) cells) were injected, following laparotomy, directly into the stomach or into the jejunum, or through a nasooesophageal tube. Cryostat sections of duodenum, jejunum and lymph node samples of animals were examined by autoradiography. It was found that lymphoid cells present in the colostrum of a piglet and lamb of their own mother were absorbed from the digestive tract and, via the lymphatic vessel, were transported to the mesenteric lypmph nodes. Electron microscopy revealed that absorption takes place intercellularly. Colostral cells of sows other than a piglet's own mother (allogeneic cells), the lymphoid cells isolated from the blood and heat-treated colostral lymphoid cells were not absorbed. The immunization of ewes and their lambs by tetanus anatoxin demonstrate, that the absorbed lymphoid cells remain immunologically active, and may transfer immune information to the lambs.

Computerized comparison of the protein compositions of Erysipelothrix rhusiopathiae and Erysipelothrix tonsillarum strains

Protein profiles of six Erysipelothrix rhusiopathiae strains, five Erysipelothrix tonsillarum strains and three Erysipelothrix strains of uncertain taxonomic position were studied by sodium dodecyl sulphate-polyactylamide gel electrophoresis (SDS-PAGE). In a computerized comparison of the protein patterns of the strains, the level of similarity between the strains was determined. The SDS-PAGE protein bands were divided into 14 groups based on molecular weight. The relative distribution of proteins within these groups was used to characterize the strains. These distribution patterns were analysed by computing Pearson's correlation coefficient between strains, and by cluster analysis based on Euclidean distances and the unweighted pair-group method of arithmetic averages (UPGMA). The geometric mean of the similarities calculated by Pearson's correlation coefficient was 0.980 +/- 0.018 between the E. rhusiopathiae strains and 0.979 +/- 0.013 for E. tonsillarum strains. The value was 0.932 +/- 0.036 between the strains belonging to different species. However, a threshold value applicable for identification of a given strain to a species could not be established. Of the three strains of uncertain taxonomic position, the strains designated Rotzunge and Iszap 4 had a protein composition more similar to that of E. tonsillarum than to that of the E. rhusiopathiae type strain. The strain designated Pécs 56, which may be a member of a new species according to literature data, gave inconsistent results by the two methods used. The computerized evaluation method developed here is suitable for the comparison of the protein composition of the strains and for the construction of the protein similarity tree by cluster analysis.

Computerized evaluation procedure for comparing the electrophoretic protein patterns of bacterial strains

The advantages and drawbacks of different methods of evaluating electrophoretic (SDS-PAGE) protein patterns were studied by comparing Erysipelothrix rhusiopathiae strains. The computerized evaluation procedure recommended by the authors renders it possible to determine objectively the degree of similarity of the protein composition of the different strains according to molecular mass. The degree of similarity obtained in four parallel analyses of a given strain was 988 +/- 0.55 on a scale on which 1000 equals complete identity. the method can be used without adjustment even in those cases where the two strains to be compared contain unequal amounts of electrophoresed proteins.

Comparison of the protein composition of Erysipelothrix rhusiopathiae strains of subtype 1A isolated from ducks and pigs

Erysipelothrix rhusiopathiae strains isolated from duck carcasses and pigs were examined by sodium dodecyl sulphate--polyacrylamide gel electrophoresis (SDS-PAGE) and the results were evaluated by a computerised method in order to compare the strains for protein composition according to molecular mass. To characterise the similarity of the strains, Pearson's correlation coefficient was calculated. The degree of similarity between duck strains originating from the same flock was 980-991, while that of strains isolated from ducks and pigs varied between 836 and 991 on a scale of 0 to 1000. The method gives highly reproducible results and can be utilised in epidemiological investigations. Its use may provide new data on E. rhusiopathiae strains, complementing the results of methods recommended for this purpose earlier and increasing the efficiency of epidemiological investigations.

Comparison of the protein patterns of Erysipelothrix rhusiopathiae strains by SDS-PAGE and autoradiography

The proteins of 12 Erysipelothrix rhusiopathiae strains were radiolabelled with L-[35S] methionine, and the protein fractions were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and autoradiography. The strains were found to differ from each other in their protein patterns; thus, it was concluded that the method applied could provide useful data for the identification of strains. The described procedure was used for determining the percentage contents of protein fractions of identical molecular mass within the strains compared. The results show that there is no significant correlation between the type of the strains and the percentage of identical molecular weight fractions.

Suspected adverse drug reactions in the Hungarian veterinary practice between 1982 and 1992

The most characteristic adverse drug reactions observed after the use of home-manufactured or imported veterinary medicinal products in Hungary between 1982 and 1992 included toxicosis, severe local reaction, lack of efficacy, and presence of residues in the edible tissues of food animals. The causes of adverse drug reactions comprised manufacturing defects, lack of chemical or microbiological stability, misuse or extra label use, and neglecting the warnings in the directions for use. Collection and analysis of data relating to adverse drug reactions are indispensable for the prevention of similar cases. The authorities can facilitate data collection by supplying veterinary practitioners with the necessary report forms.

Intestinal absorption of colostral lymphoid cells in newborn piglets

Intestinal absorption of colostral lymphoid cells was studied in 23 piglets of four sows (sows A, B, C and D). From the colostrum and blood of the sows the lymphoid cells were isolated with Ficoll-Paque and labelled with technetium (Na99mTcO4). In the 7th hour after birth, 5-ml volumes of the cell suspensions were injected, following laparotomy, directly into the stomach (piglets of sow A) or into the jejunum (piglets of sow B), whereas piglets of sows C and D received the suspensions through a naso-oesophageal tube. Cryostat sections of duodenum, jejunum and lymph node samples of piglets killed by bleeding 8 h after the treatment were examined by autoradiography. It was found that lymphoid cells present in the colostrum of a piglet's own mother were absorbed from the digestive tract and, via the lymphatic vessels, were transported to the mesenteric lymph nodes. Electron microscopy revealed that absorption took place intercellularly. Colostral cells of sows other than a piglet's own mother were observed only in the epithelial layer of the mucous membrane. The lymphoid cells isolated from the sows' blood and heat-treated colostral lymphoid cells were not absorbed. The results indicate that in the pig, an animal having an epitheliochorial placenta, the colostral lymphoid cells are absorbed from the digestive tract and, hence, they can confer an active cellular immunity on the newborn piglets.

Solid-phase radioimmunoassays for quantitative antibody determination of Clostridium perfringens type D epsilon toxin

Two reversed solid-phase radioimmunoassays were developed for quantitative determination of antibodies against Clostridium perfringens type D epsilon toxin. 125I-labeled prototoxin was used in the bromoacetylcellulose-bound antibody method and in the antibody-coated tube method. The antibody values which can be detected by the assays are in the range of 0.004 IU/ml of investigated serum. The methods allow the screening investigation of large groups of vaccinated sheep in a rapid and inexpensive way, and are very suitable for measuring small amounts of C. perfringens D epsilon antibodies with a small experimental error.

Preparation, measurement and possible use of human antitoxin against Cl. botulinum A, B, and E toxins

Human antibodies against botulinum toxins A, B, and E have been raised by repeated injections of pentavalent toxoid in a healthy volunteer. The final titer was 3.2 U anti-A, 0.4 U anti-B, and 2.5 U anti-E/ml. In mice, the efficacy of the antitoxin decreases with the time between poisoning and application of the antiserum. The dose recommended for prophylactic purposes in man is 1 ml/kg. In overt poisoning, therapy should be started with higher titer animal serum since in animal experiments high titer sera can stop (although not reverse) the symptoms of overt botulism within an-admittedly not too broad-rnage of time and dosage. Later on, therapy can be continued with human antiserum. An inverse radioimmunassay for botulinum A antitoxin using labeled botulinum toxin and antibody-coated tubes is described. The serum is available upon request from the author.