A five year retrospective study on Syphilis in the Sexual Transmitted Disease Centre (STDC) of the teaching Hospital Umberto I in Rome.

OBJECTIVES: A retrospective study describing syphilis epidemiological and clinical features in patients referring to an infectious diseases centre in Rome, Italy. METHODS: Between January 2011 and December 2015 demographic, behavioral and clinical data were collected from all adult patients attending the Sexually Transmitted Diseases Centre of the Teaching Hospital Umberto I in Rome. RESULTS: Overall 723 patients, 495 males and 228 females, with syphilis infection diagnosis were included. Average age 39.6 ± 13.6 years (median 38) was higher in men than women (41.1 ± 13.6 vs. 36.3 ± 13.1; p<0.001). Patients were from Italy (486 or 67.2%), EU (90 or 12.4%), rest of Europe (38 or 5.3 %), Americas (46 or 6.4%), Africa (36 or 5.0%) and Asia (27 or 3.7%). One-hundred-twenty-three (17.0%) presented primary syphilis, 43 (5.9%) secondary syphilis, 8 (1.1%) tertiary syphilis, 246 (34.0%) serological syphilis, 80 (11.1%) preceding syphilis, 56 (7.7%) gravidic syphilis and 167 (23.1%) came to the Sexually Transmitted Diseases Centre to control a preceding syphilis treatment. Fifty-six (24.6%) women were diagnosed with syphilis during their pregnancies. Among Chinese female patients, those pregnant represented 87.5%. There were 100 subjects (13.8%) simultaneously HIV+ and 623 (86.2%) HIV- patients. HIV co-infection affected more frequently men (RR 5.30; CI 2.62 - 10.72; p<0.001). In males HIV co-infection affected more frequently homosexuals (RR 11.72; CI 6.72 - 20.45; p<0.001). Overall HIV co-infection affected more frequently foreign patients, specially from the Americas (26.1%), Africa (25.7%) and Asia (22.2%). CONCLUSION: A serious problem of "gravidic syphilis" suggests the need for Public Health preventive action. Also an early diagnosis of both syphilis and HIV infection should be reinforced.

Role of empirical and targeted therapy in hospitalized patients with bloodstream infections caused by ESBL-producing Enterobacteriaceae.

BACKGROUND: Bloodstream infection (BSI) due to extended-spectrum ß-lactamase (ESBL) producing Enterobacteriaceae are a major cause of in-hospital mortality. The effect on survival of empirical and targeted antibiotic therapy in these patients remains controversial. METHODS: A prospective cohort study was conducted analyzing data from 94 patients (age 59 ± 21 years) with BSI due to ESBL producing strains (Sixty-one E. coli, 26 K. pneumoniae, 4 Proteus spp and 3 Enterobacter spp). RESULTS: Risk factors associated with 21-day mortality at univariate analysis were: recent administration of antibiotic therapy (p=0.049), higher SOFA score (p=0.05), ICU stay (p <0.01), hypotension at presentation (p =0.001) or septic shock (p <0.001) and bacteremia from source other than urinary tract (p=0.03). Regardless of antibiotic class used, no differences in survival were noted between patients receiving or not adequate initial antimicrobial treatment (37.1% vs 23.7% p=0.23); on the other hand, compared with the administration of other in vitro active antibiotics, the use of carbapenem as definitive therapy was associated with a significantly lower 21-day mortality (54.3% vs 28.5% p=0.02). CONCLUSIONS: These findings suggest that the administration of an adequate initial therapy is not associated with mortality in hospitalized patients with BSI due to Enterobacteriaceae. The severity of clinical conditions at presentation and the administration of carbapenems as definitive therapy seems to be really important in affecting the outcome of patients with BSI due to ESBL producing strains.

Risk factors for recurrence in patients with Clostridium difficile infection due to 027 and non-027 ribotypes.

OBJECTIVES: Our objective was to evaluate factors associated with recurrence in patients with 027+ and 027- Clostridium difficile infection (CDI). METHODS: Patients with CDI observed between January and December 2014 in six hospitals were consecutively included in the study. The 027 ribotype was deduced by the presence of tcdB, tcdB, cdt genes and the deletion Δ117 in tcdC (Xpert® C. difficile/Epi). Recurrence was defined as a positive laboratory test result for C. difficile more than 14 days but within 8 weeks after the initial diagnosis date with reappearance of symptoms. To identify factors associated with recurrence in 027+ and 027- CDI, a multivariate analysis was performed in each patient group. Subdistributional hazard ratios (sHRs) and 95% confidence intervals (95%CIs) were calculated. RESULTS: Overall, 238 patients with 027+ CDI and 267 with 027- CDI were analysed. On multivariate analysis metronidazole monotherapy (sHR 2.380, 95%CI 1.549-3.60, p <0.001) and immunosuppressive treatment (sHR 3.116, 95%CI 1.906-5.090, p <0.001) were factors associated with recurrence in patients with 027+ CDI. In this patient group, metronidazole monotherapy was independently associated with recurrence in both mild/moderate (sHR 1.894, 95%CI 1.051-3.410, p 0.033) and severe CDI (sHR 2.476, 95%CI 1.281-4.790, p 0.007). Conversely, non-severe disease (sHR 3.704, 95%CI 1.437-9.524, p 0.007) and absence of chronic renal failure (sHR 16.129, 95%CI 2.155-125.000, p 0.007) were associated with recurrence in 027- CDI. CONCLUSIONS: Compared to vancomycin, metronidazole monotherapy appears less effective in curing CDI without relapse in the 027+ patient group, independently of disease severity.

Growth of Legionella spp. under conditions of iron restriction.

The growth inhibiting activity of transferrins, citrate, 2-2' dipyridyl and desferrioxamine methanesulphonate towards Legionella spp. and their serogroups was investigated. The inhibitory activity of all these compounds depended upon the iron-free state of the molecules and was abolished by saturation with iron. No bactericidal effect by transferrins was observed at concentrations up to four times the minimal bacteriostatic concentration. No interaction of transferrins with the legionella cell surface was detected by direct or indirect fluorescence assay, or by dialysis culture experiments in which transferrin was separated from the bacterial cells. The demonstration of a siderophore-like activity in supernates of iron-deficient legionella cultures may account for the ability of Legionella spp. to multiply in conditions of iron restriction.

Effect of monensin on the invasiveness and multiplication of Legionella pneumophila.

The polyether antibiotic monensin exhibited bacteriostatic activity against a clinical isolate of Legionella pneumophila in vitro. Experiments designed to test the effect of the compound on the invasiveness and multiplication of L. pneumophila in HeLa cells showed that, in the presence of the antibiotic, legionellas that penetrated the cells did not multiply. However, monensin did not alter the characteristics of phagosomes that contained ingested legionellas. In the presence of monensin, infected cells exhibited extensive vacuolation and a noticeable reduction in the number of intracellular micro-organisms was evident a few hours after infection.

Effect of sub-inhibitory concentrations of antibiotics on the hemolytic activity of Legionella.

The effect of sub-inhibitory concentrations of various antibiotics on the hemolytic activity of different strains of Legionella has been tested. By means of a gradient plate technique it was possible to demonstrate that in a limited range of sub-inhibitory concentrations, antibiotics did not affect bacterial growth but inhibited the hemolytic activity of the strains examined.

Effect of biological and synthetic polymers on BK virus infectivity and hemagglutination.

The effect of several biological and synthetic polymers, chosen on the basis of different physical and chemical properties, was investigated on BK virus infectivity and hemagglutination. It was observed that polyanions like mucin, dextran sulfate and heparin depressed the viral binding, whereas polycations had no significant activity, with the exception of poly-L-lysine, which enhanced it. The effect of the active polymers was studied in different experimental conditions and the results obtained suggested that polyanions may act directly on the virus particle, whereas the target of polycations could be at the level of cell membranes. However, the effect shown by the active compounds did not appear to be simply related to the electric charge since neutral compounds, such as tamarind gum and locust bean gum, showed a marked inhibitory effect on BK virus binding to the cells.

Effect of various detergents on the interaction between BK virus and susceptible cells.

The activity of various types of detergents towards the infectivity and the hemagglutinating activity of BK virus was studied. Similarly to other non enveloped small viruses, BK virus showed a significant resistance to non cytotoxic concentrations of the compounds tested, with the exception of N-Dodecyl-N,N-dimethyl-3-ammonio-1-propane-sulfonate. In some cases, mainly with N-Octylglucoside, both the infectivity and the hemagglutinating activity of BK virus was enhanced.

Legionella pneumophila serogroup 1 population in Italy by monoclonal subtyping.

The Oxford panel of monoclonal antibodies was used to subtype 83 strains of Legionella pneumophila serogroup 1 of human and environmental origin. The International panel was also used to subtype 50 of them. All the 18 patients' isolates were of the Pontiac subgroup, and 40/43 of the environmental strains of the Pontiac subgroup were associated with human infection. The remaining environmental strains were subgroups Olda (15 strains), Camperdown (5 strains), and Bellingham (2 strains). The Philadelphia subgroup was the commonest among the environmental strains tested with the international MABs panel. This study confirms previous findings that L. pneumophila serogroup 1 isolates with the Pontiac (Oxford panel) or MAB-2 (international panel) reacting antigen marker seem to be more virulent than the other subgroups.

Metal complexes of lactoferrin and their effect on the intracellular multiplication of Legionella pneumophila.

The action of bovine lactoferrin saturated with iron, zinc and manganese on the intracellular multiplication of Legionella pneumophila in HeLa cells has been tested. The results obtained showed that lactoferrin did not influence the invasive efficiency of Legionella. The intracellular multiplication of the bacterium was inhibited by apo-lactoferrin and by lactoferrin saturated with manganese and zinc, whereas lactoferrin saturated with iron enhanced the intracellular growth. Experiments in parallel were performed with iron, manganese and zinc citrate to test the effect due to the metal ions alone. Even in this condition the addition of an iron chelate enhanced the multiplication of Legionella while the manganese chelate produced a certain inhibition.

Characterization of membrane components of the erythrocyte involved in vesicular stomatitis virus attachment and fusion at acidic pH.

Goose erythrocyte membranes were isolated and tested for their ability to compete with red cell receptors for vesicular stomatitis virus (VSV) attachment and fusion at acidic pH. Crude membranes, solubilized with Triton X-100, Tween 80 and octyl-beta-D-glucopyranoside, showed a dose-dependent inhibitory effect on virus binding and haemolysis. The chemical nature of the active molecules was investigated by enzyme digestion and by separation of purified components. Only the lipid moiety, specifically phospholipid and glycolipid, was found to inhibit VSV attachment; a more detailed analysis of these molecules showed that phosphatidylinositol, phosphatidylserine and GM3 ganglioside were responsible for the inhibitory activity and could therefore represent VSV binding sites on goose erythrocyte membranes. Removal of negatively charged groups from these molecules by enzymic treatment significantly reduced their activity, suggesting that electrostatic interactions play an important role in the binding of VSV to the cell surface. Enzymic digestion of whole erythrocytes confirmed the involvement of membrane lipid molecules in the cell surface receptor for VSV.

Bafilomycin A1 and intracellular multiplication of Legionella pneumophila.

Multiplication of Legionella pneumophila in HeLa cells was found to be inhibited by noncytotoxic concentrations of bafilomycin A1, with blockage of bacterial growth at a concentration 15.6 nM. The inhibiting action was evident only when the antibiotic was present during the initial phase of intracellular multiplication, i.e., during the formation of the phagosome, whereas the addition of the drug did not affect microorganisms already actively multiplying within the phagosome.

Multiplication of Legionella pneumophila in HeLa cells in the presence of cytoskeleton and metabolic inhibitors.

A study has been carried out on the action of cytoskeleton and metabolic inhibitors on intracellular multiplication in HeLa cells of a virulent strain of Legionella pneumophila serogroup 6. The effects of the substances were separately tested on both penetration and intracellular multiplication of L. pneumophila. Only cytochalasin A and 2-deoxy-D-glucose (2dG) affected bacterial internalisation, whereas intracellular multiplication was inhibited by cytochalasins A, B, C, D and J (D being the most active) and by 2dG with a dose-response effect. The action of 2dG was counteracted by 50 mM glucose. Experiments carried out with cytochalasin D and a rhodamine-phalloidin conjugate showed the involvement of cytoskeletal elements in intracellular multiplication of Legionella; compounds acting on microtubules had no effect.

Involvement of gangliosides in the interaction between BK virus and Vero cells.

BK virus infectivity was inhibited by gangliosides extracted from Vero cells and by standard preparations of different gangliosides. Gangliosides were also able to restore the susceptibility of glycosidase-treated Vero cells to BK virus infection.

Gangliosides in early interactions between vesicular stomatitis virus and CER cells.

In the present report an attempt was made to elucidate the role of gangliosides in early interactions between vesicular stomatitis virus (VSV) and CER cells. Research was carried out to test the ability of gangliosides from mammal brains and from CER cells to inhibit viral attachment to susceptible cells. The incubation of VSV in the presence of gangliosides decreased the subsequent infection of CER cells by the virus. When similar experiments were performed with gangliosides inserted in liposomes the inhibition of infection was enhanced. Since carbohydrate moieties could participate to rhabdovirus binding as a part of a glycolipid receptor, CER cells were subjected to the action of glycosidases and these produced a fall in the viral attachment. Deglycosilated CER cells reacquired their susceptibility to virus infection after coating with gangliosides immediately after enzyme treatment. Results obtained show the participation of gangliosides in the receptorial structure for vesiculovirus of susceptible CER cells.

Inhibition of BK virus haemagglutination by gangliosides.

The effect of gangliosides extracted from human group O Rh+ erythrocytes on haemagglutination by BK virus was investigated. Experiments were performed on both ganglioside mixtures and isolated fractions separated by column chromatography and characterized by thin-layer chromatography. These results were compared with those obtained with standard preparations of gangliosides, and the inhibiting activity was shown to be confined mainly to gangliosides with a RF lower than GM1. It was also observed that the insertion of gangliosides in liposomes increased the haemagglutination-inhibiting activity and that ganglioside coating restored the ability of glycosidase-treated human red blood cells to agglutinate.

Involvement of gangliosides in rabies virus infection.

The role of gangliosides in rabies virus infection of chick embryo-related (CER) cells was investigated. Cultured cells were pretreated with neuraminidase to render the cells transiently non-susceptible to viral infection. Incubation of these desialylated cells with gangliosides allowed them to incorporate exogenous gangliosides and they recovered their susceptibility to rabies virus infection. Infection of CER cells was monitored by specific fluorescence 24 h after virus inoculation. The use of individual purified gangliosides or mixtures of two gangliosides to restore cellular susceptibility to viral infection showed that GT1b and GQ1b were the most effective. The disialogangliosides were also active, principally GD1b, whereas GM1, GM3 were poorly active and GD3 inactive. Incubation of rabies virus with gangliosides prior to virus infection reduced the percentage of infected cells. The results indicate that highly sialylated gangliosides are part of the cellular membrane receptor structure for the attachment of infective rabies virus. However, it is possible that other glycoconjugates such as glycoproteins or glycolipids also participate as components of a receptor structure for rabies virus.

Role of phospholipids in BK virus infection and haemagglutination.

The role of phospholipids in BK virus infection and haemagglutination was studied by competition binding experiments and by treatment of susceptible cells with phospholipases. Phospholipids extracted from Vero cells and some commercial phospholipids showed an inhibiting activity on both BK virus infectivity and haemagglutination. The treatment of Vero cells with phospholipases affected the binding of BK virus, but the addition of phospholipids to enzyme-treated cells restored their susceptibility to both viral infectivity and haemagglutination.