Giornale di batteriologia, virologia ed immunologia最新文献

The increasingly more frequent occurrences of epidemic nidus of Listeria monocytogenes induced the E.E.C. Health Organisation to research into the diffusion of such microorganism. During the first six months of 1988 the "Istituto Superiore di Sanità" began a research into the presence of Listeria monocytogenes in milk and dairy products. The biological section of the "Laboratorio di Sanità Pubblica" of Grugliasco (Torino) participated in this study and in this work methods and results are reported. Changing the F.D.A. methods, incubation time was reduced. The percentage of positive samples was 4.6%, especially in dairy products with cheese mould. These results confirm an environmental diffusion of Listeria monocytogenes, nevertheless non illness caused by Listeria monocytogenes was recorded in the population who ate these products. Therefore the problem of Listeria monocytogenes pathogenicity and its diffusion by food remains to be clarified.

Concerning the modulatory role of LPS on immunocompetent cells, the production of interferon by macrophages primed with human gamma interferon (HUIFN gamma), was studied. In particular the production of IFN from primed macrophages of patients affected by breast cancer, differentiated in presence of autologous serum or in serum from healthy donors, was compared with the IFN production from macrophages of healthy donors. The levels of endotoxin-induced IFN were enhanced by priming macrophages with HUIFN gamma. The "in vitro" treatment with Escherichia coli LPS restores the interferon production of primed macrophages, obtained from patients affected by breast cancer, differentiated in presence of serum from healthy donors. Moreover, LPS treatment of primed macrophages from patients, differentiated in autologous serum, did not influence the interferon production of these cells. Nevertheless, primed macrophages from healthy donors appeared to be more sensitive to LPS treatment in comparison with primed macrophages from patients affected by breast cancer.

The effects of interferon (IFN gamma) and of IFN alpha/beta on normal T and B lymphocytes and various T and non-T human and murine cell lines have been investigated. IFN gamma, unlike IFN alpha/beta, did not promote the antiviral state in T cells. The lack of antiviral activity was confirmed at the biochemical level by the finding that 2',5' oligoadenylate synthetase activity is not induced in T cells by IFN gamma only.

The antimicrobial susceptibilities of 572 strains of Escherichia coli were evaluated. The strains were divided according to the biotypes and the differences between the strains towards various antibiotics were examined. We found a correlation between biotype and antibiotype. This correlation lead us to think of a possible existence of more resistant biotypes than others. Now we are doing other studies in order to show if this correlation is constant during time and if similar differences are present for other microorganisms, as well.

In this study we have examined whether resident peritoneal macrophages could be activated in vitro by immune T lymphocytes obtained from mice which were immunized with live Trichomonas vaginalis (T. vaginalis). T lymphocytes obtained from mice previously sensitized against T. vaginalis, showed a significant proliferative response when cultured in vitro in the presence of T. vaginalis. Resident peritoneal macrophages obtained from untreated syngenic Balb/c mice revealed an increasing cytotoxic activity against the protozoa when seeded with increasing concentrations of purified immune T lymphocytes and a constant number of H3 thymidine-labeled T. vaginalis. This cytotoxicity was detectable after 24 h of culture and peaked after 48 h. Supernatants obtained from cocultures of macrophages, immune T lymphocytes and T. vaginalis contained gamma-Interferon and TNF alpha/beta.

Numerous studies have been carried out to specify bacterial frequencies in the urinary tract infections. In such researches the prevalence of Gram negative bacterial species has generally emerged, the most part of these ones would be Enterobatteriaceae (and among them E. coli has a special prominent position); on the other hand several Authors have often found, among other bacterial groups (Gram positive bacteria, Pseudomonas etc.) involved in such pathologies, some differences (also remarkable) in relation to various factors, among them, the hospitalizing condition, the clinical situation, the type of infection etc. In this research we have carried out a statistical analysis of the bacterial frequencies relative to 321 positive urine cultures, trying to point out their differences in relation to hospitalized or ambulatorial patients and to single are mixed infections; above all with regard to three bacterial groups: Enterobatteriaceae, Pseudomonas species and Gram positive bacteria. The most evident result has been the absolute prevalence of Enterobacteriaceae, among them the E. coli has represented, almost always, the most frequent isolated species, followed by Proteus mirabilis, in every kind of patient (hospitalized or ambulatorial) and infection, single or double (we didn't notice, in this research, infections supported by more than two species). Moreover, we noticed, but with less clearness, especially in relation to the numerical dimension of the observations and to the short comparison of the two kind of patients, some indications pointing out that hospitalized patients (in comparison with the ambulatorial) were charged with a major frequency of the two kind of patients, some indications pointing out that hospitalized patients (in comparison with the ambulatorial) were charged with a major frequency of infections supported by Gram + bacteria and Proteus mirabilis, while the Pseudomonas species presented an opposite behaviour (contrary to what several Authors generally report in literature: but a pollution problem of the specimen might have had some influence); and as regard the single infections we observed, among them, a greater frequency of the E. coli and Gram + bacteria than among the double infections, while the Pseudomonas species happened the contrary.

The authors report a case of mycetoma from Scedosporium apiospermum in a 19 years old patient affected by adult's CGD. They emphasize the importance of mycetes' identification from clinical specimens' isolates, to consent a correct interpretation of the bacteriological result from physician.

Current methods for the "in vitro" study of antibiotic activity, as minimum inhibitory concentration, expose bacteria to constant concentrations of antibiotics. The "in vivo" situation is significantly different, since the antibiotic concentration changes with time. Pharmacokinetic models are "in vitro" experimental systems that seek to simulate conditions of exposure of bacteria to antimicrobial agents that exist in blood and tissues. All of these systems are complicated constructions. A new simple "in vitro" kinetic model, based on solid phase growth, is described.

It has been valued a new quick latex method (Staphaurex Wellcome) for the identification of the aureus Staphylococcus. This shown simultaneously the Clumping Factor (CF) and the A protein; the production of the free Coagulase (CL) and the Thermonuclease (TNase), has been utilized as methods of remarking. On 120 bacterial stocks isolated by many biological materials, belonging to the family of the Micrococcaceae, 56 stocks was identified as aureus. St. and 64 as not aureus St. For what concerns the quick Staphaurex method, it has shown a sensitivity of 83.4, with 8 false negatives on 120 cases, while it proved very satisfactory as specification with one false positive.