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L Calegari

Publications and source records attributed to L Calegari.

10 recordsLinked to original sources
PubMed1991

Enterococcus faecalis: specific and non-specific interactions with human polymorphonuclear leukocytes.

In previous studies we have demonstrated that the ability of Enterococcus faecalis to adhere to and to be internalized in human urinary tract epithelial cells, Girardi Heart cells and human polymorphonuclear leukocytes (PMNs), was dependent on whether the strain had been isolated from urinary tract infections (UTI) or endocarditis (EN) respectively. These properties were further modified by growth of the organism in human serum. In the present report, using competition assays we show that adhesins containing a D-glucose moiety play a role in mediating the interactions between human PMNs and E. faecalis strains isolated from UTI and grown in brain-heart infusion broth (BHIB). On the other hand, adhesins containing both D-glucose and D-galactose moieties were involved in the interactions between PMNs and serum grown UTI isolates or EN isolates grown in either BHIB or human serum. Moreover, the impairment in the association between both UTI and EN strains after growth in serum appears to be at least partially related to a decrease in enterococcal surface hydrophobicity.

Adult↗
PubMed1991

Serum dependent expression of Enterococcus faecalis adhesins involved in the colonization of heart cells.

Our previous studies have shown that the adhesive ability of Enterococcus faecalis is dependent on the strain and is further modified by growth in serum. The data reported here demonstrate that E. faecalis adherence is mediated by carbohydrate residues present on the bacterial cell surface. Some of these (D-mannose and D-glucose) are expressed by strains isolated from both urinary tract infections (UTI) and endocarditis (EN) when the cells are grown in brain-heart infusion broth (BHIB), and mediate adherence to either urinary tract epithelial cells or the Girardi Heart (GH) cell line. Other residues are present only on EN strains (D-galactose and L-fucose) and mainly mediate adherence to GH cells. These ligands can also be expressed by UTI isolates after growth in serum. D-galactose-bearing adhesins also seem to be involved in internalization of serum grown UTI strains and BHIB or serum grown EN isolates into GH cells.

Bacterial Adhesion↗
PubMed1989

Role of adherence in pathogenesis of Enterococcus faecalis urinary tract infection and endocarditis.

Enterococcus faecalis strains isolated from urinary tract infections (UTIs) and endocarditis were analyzed for their ability to adhere to urinary tract epithelial cells (ECs) and Girardi heart (GH) and human embryonic kidney (HEK) cell cultures. UTI isolates adhered to urinary tract ECs more efficiently than to the cultured cells, at the same time showing the least affinity for GH cells. In contrast, endocarditis isolates adhered to GH cell cultures more readily than to urinary tract ECs. Moreover, although strains isolated from endocarditis adhered to GH cells more efficiently than those derived from UTI, the latter strains adhered to urinary tract cells better than the former. Studies of the ability of GH and HEK cells to internalize E. faecalis showed that for UTI isolates, 9 to 74% of adhered bacteria were internalized, while for endocarditis isolates, the percentage varied from 76 to 82%. All strains were able to associate with human neutrophils; endocarditis strains, however, associated less efficiently than UTI isolates. Growth in serum raised the adherence of all tested strains by at least 1.5- to 3-fold, with the greatest increase being observed in UTI strain adherence to GH cells (8-fold). In contrast, the association of serum-grown cells with polymorphonuclear leukocytes was reduced by two- to fivefold. In both cases, the observed serum-dependent alterations were cancelled by a few subcultures in brain heart infusion broth. These results indicate that adhesive properties are important virulence factors in the pathogenesis of UTI and endocarditis and also suggest that UTI strains showing the highest invasion and adhesive potential invade the kidneys, cause bacteremia, and, after having expressed the serum-dependent surface modification, colonize the heart.

Adult↗
PubMed1979

Paracoccidioidal infection in the wife of a patient with paracoccidioidomycosis.

Three agar immunoprecipitin techniques (double immunodiffusion, immunoelectrophoresis and immunoelectroosmophoresis-immunodiffusion) made with paracoccidioidin and serum of a paracoccidioidomycosis patient's wife, permitted us to observe a specific band in 6 successive samples of blood taken from the wife over a period of 21 months. The case represents an example of a subclinical paracoccidioidomycosis infection that is usually diagnosed in its disseminated, progressive form. Three possible sources of infection are discussed. But an interhuman contagion appears to be the most feasible.

Antibodies, Fungal↗
PubMed1978

[Comparative study of immunoelectrophoresis (IEF) and immunoelectroosmophoresis-immunodiffusion (IEOF-ID) used in the diagnosis of paracoccidioidomycosis].

Immunoelectroporesis (IEF) and immunoelectroosmophoresis-immunodiffusion (IEOP-ID) (1) were comparatively used in the diagnosis of 16 patients with mycologically proved paracocidioidomycosis. In IEF, 5 different precipitin arcs were found and identified with arabic numbers. Arc. '1', cathodic, present in all the patients, is assimilated to specific arcs previously described by other authors. In IEOP-ID both 'cathodic' and 'anodic' arcs were observed in all the sera. A high number of precipitin arcs were revealed by IEOP-ID technique in comparison to IEF in every case. This should be due to the presence of cathodic arcs 'I' and '2' of the immunoelectrophoregram at both sides of the IEOP-ID preparate.

Antigens, Fungal↗
PubMed1978

Lysogenic conversion in Klebsiella pneumoniae: system which requires active immunity regulation for expression of the conversion phenomenon.

We have previously described Klebsiella pneumoniae MirM7b, which, although stably lysogenic for the inducible and nondefective phages FR2 and AP3, is not immune to superinfection by these same viruses. MirA12b, a strain which is lysogenic for FR2 and AP3 and immune to superinfection, has been derived from MirM7b. The sensitivity of this strain and that of the nonimmune parent to several bacteriophages have been compared in this work. It has been found that, whereas MirM7b is sensitive to coliphages P1, T3, T7, and phiI, MirA12b is fully resistant to all of them. It is shown that phages FR2 and AP3 convert Klebsiella strains to resistance to coliphage P1 and coliphages T3, T7, and phiI, respectively, and cause loss of surface antigens in lysogenic cells. To determine such a conversion, both FR2 and AP3 require expression of immunity to superinfection. This explains the differences that exist between MirM7b and MirA12b in both phage sensitivity and surface antigens. Hypotheses are presented to explain the peculiar need for an active superinfection repressor to express lysogenic conversion.

Antigens, Bacterial↗
PubMed1978

The peculiar behaviour of coliphage P1vir mutants on restricting hosts.

The sensitivity of two vir coliphage P1 mutants, to the host-specificity systems A, K, RII, and B of Escherichia coli, and to the newly identified host-specificity systems Mir and 59 of Klebsiella pneumoniae has been studied. Both 1 vir phages were completely resistant to the E. coli K, but were restricted 10(-5) by the B, mir and 59 systems. The P1 parent, on the contrary, was restricted 10(-2) by all of the above mentioned hosts. The possible role of phage coded proteins in the altered sensitivity of the vir strains has been studied by analysing the sensitivity of both P1, and P1vir to the various systems in the presence of chloramphenicol. Protein synthesis inhibition by chloramphenicol did not significantly influence the sensitivity of P1 and P1vir to various restricting hosts. It is concluded that the altered sensitivity of vir mutants depends on the different affinities of the mutated phage DNA sequence for the enzymes of the various restriction and modification systems. The possibility that the phage repressor contributes to the regulation of the restriction and modification enzymes is also discussed.

Chloramphenicol↗
PubMedDate not supplied

Treatment of human cutaneous sporotrichosis with itraconazole.

Eighteen adult white male patients with cutaneous sporotrichosis were treated with itraconazole following different daily dose schemes. Cure was obtained in all cases after periods of 15-75 days (median 44 days) with total doses between 3.1 and 14.8 g (median 8.4 g). No serious side effects were observed and no relapses occurred in the follow-up period of between 1 and 26 months (median 14.7). These results show that itraconazole represents a safe and effective drug for the treatment of sporotrichosis. Comparison with other studies leads us to consider a daily dose of 200 mg as the most appropriate. A concomitant warming of the affected limbs should be recommended.

Adult↗