Cellular mediators in human leishmaniasis: Critical determinants in parasite killing or disease progression.

Data on cellular immunity mediators in the early phase of human leishmaniasis are still limited and controversial. In order to mimic the changes of humoral mediators during the early phase of human natural infection, some Th1, Th2, Treg, and Breg cytokines, MCP-1, and the nitric oxide (NO) from human PBMC, stimulated by Leishmania infantum, Leishmania major, Leishmania donovani and Leishmania tropica infective metacyclic promastigotes, were determined. After 4 h of L. major, L. donovani, and L. tropica challenge, TNFα, IL-1ß, IL-6 levels were significantly higher than negative control cultures with saline (SF) instead of Leishmania promastigotes, unlike L. infantum-stimulated TNFα and L. major-stimulated IL-1ß. We obtained higher levels of IL-4 and IL-10 cytokines after stimulation of human PBMCs by L. infantum and L. donovani, compared to those observed after the challenge of PBMCs by L. major and L. tropica. Regarding IL-35, such cytokine levels were significantly increased following infection with L. infantum and L. donovani, in contrast to L. major and L. tropica. Up to our knowledge, we are the first to study the effect of four different species of Leishmania on IL-35 levels in human cells. Our study highlights how several Leishmania species can up-regulate different groups of cytokines (Th1, Th2, Treg and Breg) and modulate NO release in a different way. This original aspect can be explained by different Leishmania cell products, such as LPG, obtained from different strains/species of live parasites. Our findings would contribute to the development of new therapeutics or vaccination strategies.

Direct antimicrobial susceptibility testing (AST) from positive blood cultures using Microscan system for early detection of bacterial resistance phenotypes.

Antimicrobial Susceptibility Testing is mandatory for Bloodstream Infections management in order to establish appropriate antimicrobial therapy. Herein we evaluated new approach based on AST results directly from positive blood cultures, using Microscan WA to carry out rapid phenotypical profile of antibiotic resistance. Our investigations allow to reduce time versus traditional results.

Long-term immunogenicity of hepatitis B vaccination in children and adolescents in a southern Italian town.

PURPOSE: Universal anti-hepatitis B vaccination of infants and of 12-year-old children became mandatory in Italy in 1991. The purpose of this study was to evaluate the persistence of anti-hepatitis B surface (HBs) antibodies several years after a primary course of vaccination. METHODS: In 2010, anti-HBs titers were measured in all subjects aged between 5 and 25 years residing in a southern Italian town. Individuals with an anti-hepatitis B antibody concentration of 10 IU/ml or more were considered to be protected. RESULTS: Of the 671 subjects evaluated, 149 (30%) lacked protective antibodies. Fifty-three (29.4%) of the subjects had been vaccinated ≤10 years earlier and 96 (30.3%) more than 10 years earlier (P = not significant). Subjects vaccinated in infancy were more likely to lack protective anti-HBs antibodies than subjects vaccinated at 12 years of age, regardless of the years elapsed since immunization. CONCLUSIONS: Most subjects maintained protective antibodies for a considerable number of years after vaccination. Vaccination in adolescence results in more prolonged immunogenicity than vaccination in infancy.

Applications of LightCycler Staphylococcus M-GRADE assay to detect Staphylococcus aureus and coagulase-negative staphylococci in clinical blood samples and in blood culture bottles.

We evaluated the applicability of the LightCycler Staphylococcus M(GRADE0 assay on artificially infected blood samples from healthy donors and on clinical specimens of 31 hospitalized patients. The sensitivity and specificity of the assay for detecting Staphylococcus aureus was 100% in blood samples, and 100% in blood culture bottles, when data from the BACTEC 9120 blood culture system were taken as gold standard. The same specificity and sensitivity was found during the search for CoNS (Coagulase Negative Staphylococci) in blood culture bottles, whereas a 93.33% sensitivity and 100% specificity was observed for detecting CoNS directly in blood clinical specimens.

Fourteen-year experience with imported malaria.

Geographical position, an increasing flow of immigrants and refugees coming from regions where malaria is endemic might further increase those cases of malaria imported to Calabria due to travel on military missions, visiting relatives, business and leisure. However, few reports have been published regarding malaria imported into the southern Italian region of Calabria. Based on data from our laboratory, official reports received from the Italian Ministry of Health and Regional Health Offices, an epidemiological analysis of malaria cases registered in Calabria from January 1988 to December 2001 is reported. The epidemiological and clinical features concerning the cases are discussed. A total of 34 slide-confirmed malaria cases were observed in Calabria during the period in question. Infections were mostly acquired in Africa (84.8%), while remaining infections came from Asia (9.1%) and South America and Europe (6.0%). Length of stay in the endemic area did not increase the infection risk. Etiological diagnosis indicated Plasmodium falciparum as the species most often involved (60.6%), followed by Plasmodium vivax (36.3%) and P. vivax/Plasmodium malariae mixed infection (3.0%). The mortality rate was about 3.0%. The number of cases during the second seven-year period of this study was almost double that of the first seven-year period. Correct chemoprophylaxis was performed by only 27.3% of our studied subjects. Delay of malaria diagnosis ranged between 4 days and 1 month. In conclusion, increases in malaria cases, mostly due to P. falciparum, delay in diagnosis and reporting to the Regional Health Office, as well as the increasing arrival of refugees from endemic areas, are epidemiological concerns in Calabria, the southernmost region of continental Italy.

Early detection of Leishmania promastigotes in dog bone marrow cultures by acridine orange stain.

An acridine orange staining technique was evaluated in comparison with other well-known methods for the laboratory diagnosis of leishmaniasis. A higher number of promastigotes was found in Novy-MacNeal-Nicolle (NNN) cultures inoculated with canine bone marrow, when culture samples were stained with acridine orange vital stain, compared with those detected using either Giemsa staining or unstained wet mount examination. Based on our data the acridine orange stain is a useful and timely technique in reflecting the true numbers of microorganisms present in a culture and also enhances the visualization of the parasites. The present results warrant further studies with human samples from suspected leishmaniasis patients.

Kinetics of IL-8, MIP-1 alpha, TNF alpha, IL-1 beta, IL-1ra and IL-10 in human whole blood samples triggered by smooth and rough LPS.

An in vitro model for the study of sepsis mediators was used to investigate the effects of two different lipopolysaccharides (LPS), a smooth (LPS-S) and a rough (LPS-R) type, on the release of chemokines (IL-8 and MIP-1 alpha) and cytokines (TNF alpha, IL-1 beta, IL-1ra and IL-10) from human whole blood samples. TNF alpha level increased significantly vs. control, at 4 h and 8 h after the challenge with smooth and rough type of LPS respectively. Concentrations of the two chemokines studied, IL-8 and MIP-1 alpha, were significantly elevated following stimulation by both LPS, and reached concentrations significantly different from controls at 4, 8 and 24 h. After 24 h of incubation both LPS produced a significant IL-10 increase, although such change was more substantial with the rough type. Present data suggest an early and maintained release of chemokines regardless of the type of LPS used and often in absence of a significant increase in primary pro-inflammatory cytokines.

Microscopic observation of progressive immobilization of leishmania promastigotes in acridine orange stain.

To rapidly isolate Leishmania donovani promastigotes in samples from Novy-MacNeal-Nicolle (NNN) cultures, a method of staining with acridine orange was developed. Such vital staining combines the advantages of direct microscopic examination (e.g., observation of motility) with more accurate cytological and structural imaging of the stained parasites (usually obtained by Giemsa staining). Progressive immobilization of Leishmania promastigotes associated with a change in fluorescence color was also studied. Our findings may be useful for the early confirmation of a positive culture inoculated with a clinical sample.

Effect of RO 23-9424, cefotaxime and fleroxacin on functions of human polymorphonuclear cells and cytokine production by human monocytes.

The way in which an antibiotic interacts with host defences could influence the clinical outcome of many infectious diseases. The impact of RO 23-9424, a novel dual-action and extended-spectrum antibiotic, was studied on several functions of human polymorphonuclear neutrophils (PMNs). A significant (P < 0.05) increase of the superoxide (O2-) released by phorbol-myristate acetate (PMA) -stimulated PMN (10-100 mg/L) can be observed in the RO 23-9424 pre-treated cells. RO 23-9424, particularly at low dosages, showed an interesting but not statistically significant effect on PMN phagocytosis. Higher dosages of RO 23-9424 (50-200 mg/L) and fleroxacin (20-200 mg/L) significantly reduced PMN chemotaxis. Cytokine production by human monocytes were also evaluated after incubation with the antibiotic (100-200 mg/L) in both basal conditions and in response to endotoxin (lipopolysaccharide, LPS). In the LPS-treated cells, RO 23-9424 (100 mg/L) significantly (P < 0.05) enhanced the tumour necrosis factor-alpha (TNF-alpha) levels, compared with LPS controls after 4 h of incubation. RO 23-9424 (200 mg/L) was able to reduce in a dose-dependent way LPS-induced interleukin-1 beta (IL-1 beta) after 4 and 24 h of incubation. Interleukin-8 (IL-8) release was not significantly changed by RO 23-9424. Cefotaxime (200 mg/L) significantly (P < 0.05) increased the basal levels of IL-1 beta and reduced basal IL-8 concentration after 24 h of incubation. The lower concentration of cefotaxime reduced the LPS-stimulated IL-8 levels. Fleroxacin (100 mg/L) enhanced basal levels of IL-8. The potentiated PMN phagocytosis, the significantly enhanced O2- release by PMA-stimulated PMN and the dimetric changes of TNF-alpha and IL-1 beta appeared peculiar for RO 23-9424 and may have useful therapeutical implications.