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The microbial activity plays an important role in the biodegradative processes implied in stonework decay. In natural environments it is not possible to separate the damage produced by microorganisms from damage caused by physical and chemical agents. In vitro assays carried out with microbes isolated from weathered stones are required in order to understand the biological mechanisms involved in stone deterioration. We have described, as commented in the text, how fungal colonization observed on scaglia may be the result of the fine grain size of rock, whereas inhibition of growth on marble may depend on the surface characteristics of calcite grains after grinding. The extent of microbial growth clearly depends on the quantity of cations released in solution. However, fungal growth may, in turn, induce a decrease in pH, thus promoting mineral chemical attack. These observation points to selective action of fungal species in promoting weathering well evidenced by the presence of different extents of cations released in suspension from the same sample. Detailed studies are in progress in order to go into this question.

Background: Silicosis is mediated by macrophages, their soluble mediators, and extracellular matrix molecules. In this study, we investigated the effects of silica and/or hyaluronate (HA) on several alveolar macrophage responses., Methods: We evaluated glycosaminoglycan (GAG) production by radiolabeled precursors, nitric oxide (NO) release by its oxidation product, phagocytic activity by Candida albicans internalization, and the secretion of two fibrogenic cytokines, tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta, by specific assays., Results: Silica significantly reduced GAG secretion, particularly HA secretion. Alone, it decreased Candida uptake; associated with HA, it enhanced the reduction. Silica and Candida reduced NO release, which was not significantly affected when silica- or Candida-exposed cells were also treated with HA. TNF-alpha and TGF-beta activities were stimulated by silica but reduced by HA., Conclusions: The results suggest that silica and HA modify alveolar macrophage functional differentiation. Silica- and HA-induced modifications of the microenvironment could determine whether the response proceeds toward healing and repair or toward lung chronic pathology.

Preliminary results on limestone weathering caused by air pollution and microbial colonization are presented in this study. Outdoor exposure experimental assays were performed on Scaglia limestone samples. Samples were exposed in two areas in Perugia (Italy) that differ for degree of urban air pollution. At different times of exposure, ranging from 1 to 12 months, microbial contamination and textural modifications of sampled surfaces were evaluated by microbiological procedures, X-ray diffraction, and scanning electron microscopy. After one year of exposure a significant fungal colonization and the presence of weathering products (i.e. gypsum) were detected on sampled surfaces.

Susceptibility patterns to 27 antimicrobial agents and beta-lactamase production were investigated in potentially pathogenic halophilic vibrios from seafood. The effect of salinity on the response to the drugs in vitro was also studied. All isolates were uniformly sensitive to choramphenicol, imipenem, meropenem but resistant to lincomycin. All were highly sensitive to oxolinic acid, trimethoprim-sulphamethoxazole, doxycycline, flumequine, cefotaxime, nalidixic acid and ciprofloxacin. Some strains of V. harveyi, V. alginolyticus and V. parahaemolyticus apparently had mechanisms of resistance to several beta-lactam antibiotics other than by the production of beta-lactamases. Sixty-nine strains produced penicillinase but a low correlation between beta-lactamase activity and resistance to beta-lactam antibiotics was noted. The salt concentration affected the in vitro susceptibility of halophilic vibrios and the effect of salinity depended on both the individual strains and the antimicrobial tested.

Aims: The metabolic characterization and pathogenicity of vibrios isolated from seafood were studied., Methods and Results: Strains of halophilic vibrios, grown in the presence of 0.5% glucose, induced high medium acidification and were non-culturable after 24 h, while moderately acidifying strains were culturable, produced cytotoxins, and remained lethal when inoculated intraperitoneally in mice. Highly acidifying strains failed to elicit pathogenicity in vivo and in vitro., Conclusion: The high acidification of the medium and the self-killing activity of NCVs might be considered a significant phenotypic marker of virulence and/or cytotoxicity., Significance and Impact of the Study: We suggest the medium acidification test as possible screening method for pathogenic NCVs in food microbiology.

OBJECTIVE: To evaluate the new BBL mycobacteria growth indicator tube (MGIT) in comparison with other media. METHODS: MGIT was evaluated in 10 Italian centers on 433 clinical samples, mainly of respiratory origin and mainly smear positive, in comparison with Löwenstein---Jensen and with one or more other methods represented, according to participating centers, by the BACTEC radiometric method or by the biphasic BBL Septi-Chek AFB system. While MGIT and Löwenstein---Jensen were used for all the samples, 285 of them were also inoculated in BACTEC vials and 274 in biphasic bottles. Of these samples, 132 were investigated with all the four methods. RESULTS: Although less rapid and sensitive than the radiometric method, the results of MGIT were equal when compared with the other two media with respect to overall isolation yield; furthermore, it allowed the detection of growth in significantly shorter times. CONCLUSIONS: The results of this study indicate the value of MGIT for the detection of mycobacteria and, thanks to its extreme simplicity of use, its suitability for small and large laboratories. Its combined use with a solid medium can substantially improve the diagnosis of mycobacterial infection.

OBJECTIVE: To evaluate the validity of the IgG avidity test in the serodiagnosis of acute T. gondii infection; to verify the maturation of IgG avidity during the course of infection; to observe whether the kinetics of IgG maturation could be affected by antibiotic treatment. METHODS: Serial serum samples, collected in three Italian hospitals (Perugia, Treviso and Bologna), from untreated and antibiotic-treated patients with primary toxoplasmic infection, were assayed for IgG avidity, and IgM and IgA positivity. Single serum samples from patients at different stages of infection were assayed for IgG avidity and the results were correlated to the likely stage of infection. RESULTS: The IgG avidity value increased from 3.5% in the first month to 38.7% 1 year from the onset of infection. Antibiotic-treated patients showed significantly different values of IgG avidity at 2 and 4 months after the onset of infection. In single serum samples the IgG avidity values correlated with the likely stage of infection. CONCLUSIONS: The IgG avidity test was confirmed as a useful tool in the serodiagnosis of acute T. gondii infection and could be predictive of the stage of infection. Antibiotic treatment may affect the kinetics of the maturation of IgG avidity.

The activity of seven antimicrobial agents (and five two-drug combinations and five three-drug combinations) was investigated against 37 clinical isolates of Mycobacterium avium recovered from blood cultures of AIDS patients. The susceptibility tests were performed in Middlebrook 7H12 broth using a radiometric method. MICs of amikacin, ciprofloxacin, clarithromycin, clofazimine, ethambutol, rifabutin and sparfloxacin were determined. Five antimicrobial agents were tested in combination with clarithromycin and also with clarithromycin plus amikacin to look for possible synergic activity. Synergic activity in combination with clarithromycin and with clarithromycin plus amikacin, was detected for rifabutin (54% and 51% of isolates, respectively), clofazimine (38% and 35%), ethambutol (16% and 32%), ciprofloxacin (8% and 14%) and sparfloxacin (3% and 8%). No antagonism was observed. We conclude that clarithromycin is an essential component in the chemotherapy of M. avium complex disease.

This paper investigates the ability of macrophages and of non-typically phagocitic cells such as fibroblasts to internalize 51Cr-labelled C. albicans in presence or in absence of lectin concanavalin A (Con A). The results obtained demonstrate that fibroblasts are also able to internalize C. albicans and that this property is potentiated by the presence of Con A. Lectin modifies only the phenotype of the fibroblast, which, poorly attached to the substrate, is globular in shape. Despite reduced cellular spreading, phagocytosis is stimulated by the lectin. In both cell populations, changes in the organization of some cytoskeletal proteins such as tubulin, actin and alpha-actinin are evident during the C. albicans infection; such rearrangements are more evident and longlasting in the fibroblasts treated with Con A.

Immune L3T4+ and Lyt-2+ lymphocytes play an important role in the acquired resistance of mice to challenge with virulent Candida albicans, and release macrophage-activating cytokines in response to yeast cells in vitro. To determine whether antigen (Ag)-specific cytotoxic T lymphocytes are generated during fungal infection, purified L3T4+ and Lyt-2+ lymphocytes from immunized mice were cultured in the presence of syngeneic accessory cells, Candida Ag, and IL-2. Yeast-infected bone marrow macrophages and peritoneal exudate neutrophils were used as target cells in a standard 51Cr release assay. Ag-specific, MHC-unrestricted lysis of infected macrophages was evident with immune Lyt-2+ cells after 5-10 days in culture. Under the same experimental conditions, the cytotoxic activity of L3T4+ cells was negligible, but its expression could be induced by the addition of anti-CD3 antibody. Culturing immune Lyt-2+ cells for shorter periods of time (1-2 days) resulted in preferential lysis of infected neutrophils. In addition, at limiting effector cell numbers, Ag-specific MHC-restricted lymphocytes with cytotoxic activity to infected macrophages could be identified. We suggest that C. albicans infection stimulates multiple cytotoxic T-cell precursors with varying recognition stringency, which may have an important role in antifungal resistance in vivo.

The in-vitro effects on human neutrophil (PMN) functions of three structurally related glycopeptide antibiotics, vancomycin, teicoplanin and the teicoplanin derivative MDL 62211 were investigated. Teicoplanin and MDL 62211 significantly inhibited adherence, chemotaxis, phagocytosis and killing of Candida albicans by PMN's at a concentration of 500 mg/l, whereas PMN viability was only affected at drug concentrations of 2000 mg/l. Vancomycin interfered with PMN adherence and phagocytosis only at a concentration of 2000 mg/l without affecting PMN viability. Chemotaxis and killing of C. albicans were also not affected by this concentration. Teicoplanin and the teicoplanin-derivative MDL 62211 was found to have adverse effects on selected indices of PMN function in vitro only at concentrations higher than those employed in therapy, while vancomycin interfered only at very high concentrations.

Infections caused by methicillin-resistant Staphylococcus strains (MRSS) have become an increasing problem both as community-acquired and nosocomial infections. In order to eradicate colonization as well as to cure infections, optimal antibiotic treatment is required. In this study we examined the incidence of MRSS in clinical samples and compared the antibiotic susceptibility pattern of methicillin-resistant Staphylococcus aureus with that of methicillin-resistant Staphylococcus non-aureus strains. All the MRSS were resistant to penicillin. Among them there was a variation in the percentage of strains resistant to various antimicrobial agents. Within MRSS the most frequent resistances were those to erythromycin and norfloxacin. Ciprofloxacin and teicoplanin were the most effective antibiotics tested against MRSS, followed in activity by vancomycin and imipenem. The incidence of antibiotic resistance among MRSS was significantly higher than that among methicillin-susceptibility staphylococcal species.

The experimental pathogenicity of Candida albicans, C. krusei, C. guilliermondii, C. parapsilosis, C. tropicalis and C. viswanathii was tested in normal and in cyclophosphamide-(Cy) immunodepressed mice. In unpretreated CD1 mice only C. albicans, C. tropicalis and C. viswanathii were pathogenic on intravenous challenge, with LD50 of 1.0 X 10(6), 4.8 X 10(6), 7.2 X 10(8) cells, respectively, per kg. Three days after a single intraperitoneal injection of Cy (150 mg kg-1) mice had a marked decrease in spleen weight and cellularity as well as reduced numbers of circulating leukocytes. Under these conditions, there was a significant, proportional increase in pathogenicity of C. albicans, C. tropicalis and C. viswanathii but the animals were still resistant to challenge with C. krusei, C. guilliermondii and C. parapsilosis. This pattern of susceptibility was not influenced by higher doses of Cy. Only C. albicans and C. tropicalis were capable of rapid and extensive multiplication in target organs such as kidney and brain in normal and Cy-treated mice and for both these species of Candida, there was a 'rebound' effect of increased resistance to experimental infection after 12 days from Cy administration. This study shows that the strong immunodepression provoked by Cy does not modify significantly the susceptibility of the animal to those species of Candida which were endowed with low or no pathogenicity for normal mice, but it greatly increases the susceptibility to those species of Candida that are already pathogenic for unmodified host.

The synthesis and germicidal properties of 28 new derivatives of furyl-2-benzimidazole are described. The compounds are substituted both in position 5 of the benzene moiety and in position 5' of the heterocycle moiety. The germicidal properties of the new molecules were tested using 9 strains of bacteria and Candida albicans. Some of them exhibited germicidal properties versus Gram + bacteria and versus Candida. Some derivatives were also tested using Mycobacterium aurum: two isonicotinoylhydrazones derivatives exhibited tubercolostatic activity comparable to that of streptomycin and not much lower than that of isoniazide.

The Authors carried out a research work to study the dose-dependence of antibody response in BD2F, mice injected with tetanus toxoid. Experimental data show that it is possible to obtain an earlier resistance at least 14 days after immunization, increasing ten-fold the usual anatoxin dose administered in humans. The protection test toward 4 MLD i.v. injected of tetanus toxin proved a valuable tool for assessing the first appearance of acquired immunity.

The effect of administration of BCG in association with chemotherapy in histocompatible CD2F1 mice challenged ip with Moloney-virus-induced lymphoma LSTRA of Balb/c origin was studied. All untreated mice died with comparable median survival time (MST). Immunochemotherapy experiments were performed in histocompatible mice using BCG according to various treatment schedules with respect to tumor challenge and 3 nitrosureas of clinical interest (i.e. BCNU, MeCCNU and CCNU) administration. If recipients were subjected to ip treatment with drugs alone or in association with the non specific immunoadjuvant (IA) given after tumor challenge (on day +1); no significant antitumor effect was detected. Synergistic antitumor effects were evidenced when the antineoplastic agents were associated with IA administered on the "-14+1" regimen with respect to the tumor. The results pointed out that the antilymphoma effects of chemotherapy could be amplified by IA only when the treatment schedule included adjuvants administration prior to tumor challenge.