Comparative efficiency of nitrocellulose membranes versus RODAC plates in microbial sampling on surfaces.

The efficiency of nitrocelluose membranes in collecting microbial samples from rigid and flat surfaces has been studied and compared with that of RODAC plates. The experimental design was based on multiple samplings in close succession in the same place. The median efficiency of membrane filters (78.55) was higher than that of RODAC plates (65.37). The data demonstrate the reliability of membranes and show that membranes are more efficient than RODAC plates as a sampling method for measuring surface microbial contamination.

Serum and skin lysozyme activity in non-diabetic and diabetic subjects.

Lysozyme activity was significantly reduced in the skin of patients with clinical diabetes, but not in the skin of other diabetics or in serum of all these patients. Sex and age had no influence on serum or skin lysozyme activity in either nondiabetic or diabetic subjects. The reduction of cutaneous lysozyme activity is suggested as a factor for the seriousness and the relapses of cutaneous infections in subjects with clinical diabetes.

New methods for microbial contamination monitoring: an experiment on board the MIR orbital station.

Experiment T2, carried out during the Euromir'95 mission, was an important step toward innovative methods for spacecraft microbial contamination monitoring. A new standard sampling technique permitted samples to be analysed by different means. On board, two analysis methods were tested in parallel: Bioluminescence and Miniculture. In turn, downloaded samples are being analysed by polymerase chain reaction (PCR), a powerful and promising method for the rapid detection, identification and quantification of pathogens and biofouling agents in closed manned habitats.

[Evaluation of the microbial burden using rinsing of the oral cavity in patients undergoing bone marrow transplantation]. / Valutazione della carica microbica mediante sciacquo del cavo orale in pazienti sottoposti a trapianto di midollo osseo.

We report the methodology and the results of our research on the total microbic charge of the oral cavity carried out in 35 (thirty-five) patients undergoing bone marrow transplant and selective decontamination at the Bone Marrow Transplant Unit Perugia, between July 1985 and December 1988. The specimens, obtained by washing the oral cavity for 15 seconds with 10 ml of sterile distilled water, were taken from each patient during his stay in the Laminar Air Flow Room (from day -7 to day +28 of the transplant). The first sample was taken before starting the selective decontamination and the microbiological controls were carried out weekly. The quantitative determination of the microbic charge was made by diluting and plating, while selective media for gram-positive and gram-negative microorganisms were used for the qualitative evaluation. The results obtained prove the effectiveness of the mouth-wash method as an instrument for the evaluation of microbial contamination of the "mouth"-area, since it determines the oral microbic flora by standardized counting and testing methods which are simple to use and give rapid and reliable results. Furthermore, this method has proved to be especially useful for studying the effectiveness of the decontamination and chemoprophylaxis treatments carried out on the patients undergoing bone marrow transplants.

[Discovery of viroids and possible relationship with human and veterinary medicine]. / La Scoperta dei Viroidi e le Possibili Connessioni con la Medicina Umana e Veterinaria

The researches of DIENER and co-workers and those of the SEMANCIK'S group, have recently established that some plant diseases, such as potato spindle tuber, citrus exocortis disease and chrysanthemum stunt, are caused by a new class of pathogens, named viroids. These are the smallest known agents (they are smaller than viruses) having a molecular weight of ca 10(5) daltons, and composed of a highly structured RNA, rich in guanine-cytosine base pairs without a capsid. Little is known about the origin, replication model and pathogenic mechanism of viroids and until now only speculations are possible on these subjects. Some properties of the unknown agents of slow virus diseases (scrapie, Kuru, Creutzfeldt-Jakob disease and mink transmissible encephalopathy), suggest that these alterations in the central nervous system are caused by a sort of animal viroid.

Determination of immunity against tetanus infection by passive haemagglutination assay.

Evaluation of anti-tetanus antibody level in human sera is of primary importance for a prophylaxis of tetanus infection. Many efforts have been made to develop simple, sensitive and reproducible in vitro methods for detecting and quantifying antibodies to tetanus toxin. We have recently developed an HA assay using lyophilized turkey red blood cells (TRBC-HA). In this paper we demonstrated that the TRBC-HA test is more sensitive than the most widely used sheep red blood cell assay (SRBC-HA) and that TRBC-HA assay shows a high correlation with the neutralization test (NT). Furthermore, comparisons of TRBC-HA assay with enzyme-linked immunosorbent assay (ELISA) and counterimmunoelectrophoresis (CIE) indicate that TRBC-HA and ELISA assays detected the same antibody level with a sensitivity up to 400-fold higher than that determined by CIE. However, TRBC-HA also offers many advantages over the ELISA test, because TRBC-HA can be performed in only 40 minutes instead of the 24 hrs. needed for the ELISA, it is less expensive than ELISA and requires no special equipment. Therefore, the overall results suggest that the TRBC-HA is the most appropriate method for rapid and sensitive determination of tetanus antibody levels.

[The use of passive hemagglutination with turkey erythrocytes for the effective prevention of tetanus in wounded patients]. / Uso della emoagglutinazione passiva con globuli rossi di tacchino per una efficace prevenzione del tetano nei feriti.

The passive haemagglutination assay is at present the most common method available for evaluating tetanus antibody levels. We recently developed a modification of the technique of HA by Mai and Rosin using turkey red blood cells (TRBC-HA) instead of sheep red blood cells (SRBC-HA). TRBC-HA assay seems to offer the advantages of being more sensitive and easier to perform than the SRBC-HA method. More important, with the TRBC-HA assay, we found that the HA values greater than 0.5 H.U./ml always correspond to NT values greater than 0.01 IU/ml. Therefore this value (0.5 H.U./ml) was chosen as a discriminating level between protected and non protected persons. On this rationale base we have tested sera from injured persons in order to individualize a single prophylactic treatment under a rationale guideline against the alternative of a blind intervention under anamnestic basis. Among 437 persons tested 248 did not remember if they had been vaccinated or not. According to the anamnestic basis all these persons should require injection of human antitetanus Ig plus a basic course of vaccination. On the contrary antitetanus antibody levels monitored by TRBC-HA assay indicate that 132 were protected and did not require any treatment; 79 were partially protected and required a boosting of tetanus toxoid and only 37 were not protected and needed human antitetanus IgG plus a complete course of vaccination. These results underline the necessity of monitoring a single person for antitetanus antibodies in order to prevent both under or over evaluation of their tetanus immune status.

Anti-candida antibodies in human serum. Detection and definition of Ig classes by a new elution technique.

The Partigen Elution Test (P.E.T.), a partially quantitative method for the determination of Ig classes to which the antibodies against superficial Candida antigens belong, has been assessed. The sensitivity of the test is comparable to that of the Ouchterlony test. The P.E.T. has the advantage of simplicity, great reproducibility and absolute specificity. With P.E.T. the level of single class antibodies can be quantitated on the basis of the diameter of immunoprecipitation ring. It seems possible to establish a correlation between the number of precipitation lines in the Ouchterlony test and the diameter of the precipitation ring in LC-Partigen plates. In addition as association among the width of the ring diameter, the Ig classes implicated and the severity of Candida affection is apparent.

Cadmium uptake by growing cells of gram-positive and gram-negative bacteria.

The present study evaluates the effect of the cadmium (Cd2+) on the growth and protein synthesis of some Gram-positive (Staphylococcus aureus, Bacillus subtilis and Streptococcus faecium) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria and the cadmium uptake by the same micro-organisms. The Gram-negative bacteria tested were less sensitive to metal ions than the Gram-positive, and P. aeruginosa was the most resistant. The Gram-negative bacteria were also able to accumulate higher amounts of cadmium during growth than the Gram-positive bacteria. The maximum values of specific metal uptake (microgram of Cd2+ incorporated per mg of protein) were: 0.52 for S. aureus, 0.65 for S. faecium, 0.79 for B. subtilis, 2.79 for E. coli and 24.15 for P. aeruginosa, respectively. The differences in the ability to accumulate metal found between Gram-negative and Gram-positive bacteria seems to account for different mechanisms of metal resistance.

[Antitetanus prophylaxis: actual practice and cost benefit analysis of a hypothetical mass vaccination]. / Profilassi antitetanica: pratica attuale ed analisi costo-benefici di una ipotesi di vaccinazione di massa.

The actual practice of immunoprophylaxis in a Sanitary District of Campania (Italy) is described. As everywhere in Italy, in subjects at risk (wounded) the passive immunoprophylaxis by human specific immunoglobins is currently applied: at very high cost and with unreliable protection. The Authors suggest to implement antitetanus mass vaccination, with benefits incoming from lower expenses and higher protection.

Use of turkey red blood cells in the passive haemagglutination test for studying tetanus immunity.

Passive haemagglutination (HA) assays were performed using turkey red blood cells (TRBC-HA) on sera from normal healthy people, from normal people previously immunized against tetanus, and from tetanus patients receiving human antitetanus immunoglobulins. The TRBC-HA test was compared with haemagglutination assays using sheep red blood cells (SRBC-HA) and with the neutralization (NT) test, and was found to be more sensitive than the SRBC-HA test and showed good correlation with the NT test.While the SRBC-HA assay calls for adsorption of sheep red blood cell agglutinins from the sera to be tested, the use of turkey red blood cells does not require any such adsorption. In addition, the TRBC-HA assay can be performed in 40 minutes compared with 6 hours for the SRBC-HA assay. All these advantages make the TRBC-HA assay a more useful test for screening large numbers of sera in the evaluation of tetanus immunity of normal people and of patients with wounds when seen in the emergency room of hospitals.

[Microbiological diagnosis of tetanus and serological verification of the immunological status. Serological monitoring in the course of therapy and prophylaxis]. / Diagnosi microbiologica del tetano e verifica sierological dello stato immunitario. Monitoraggio sierologico nel corso della terapia e della profilassi.

The tests for tetanus aetiological diagnosis are briefly surveyed: with particular attention to Passive Haemagglutination on Turkey Red Blood Cells (P.H./T.R.B.C.), for the assessment of antitoxin serum level. The P.H./T.R.B.C. proves a valuable tool in different occasions: -in patients, to control the immunotherapy; -in subjects at risk, to apply a correct prophylaxis; -in the whole population, to verify the outcome of compulsory vaccination.