Tedizolid-Rifampicin Combination Prevents Rifampicin-Resistance on in vitro Model of Staphylococcus aureus Mature Biofilm.

Staphylococcus aureus infections associated with implanted medical devices are difficult to treat and require long-lasting antibiotic therapies, especially when device removal is not possible or easy such as in the case of joint prostheses. Biofilm formation is a major cause of treatment failure and infection recurrence. This study aimed to test, for the first time, the in vitro combination of tedizolid plus rifampicin on methicillin-sensitive (MSSA ATCC 6538) and methicillin-resistant (MRSA ATCC 43300) S. aureus mature biofilm. Here, we demonstrated that the combination of tedizolid with rifampicin significantly disaggregated pre-formed biofilm of both strains, reduced their metabolic activity and exerted bactericidal activity at clinically meaningful concentrations. Notably, tedizolid was able to completely prevent the emergence of resistance to rifampicin. Moreover these effects were similar to those obtained with daptomycin plus rifampicin, a well-known and widely used combination. Preliminary results on some MRSA clinical isolates confirmed the efficacy of this combination in reducing biofilm biomass and preventing rifampicin resistance onset. Further in vivo studies are needed to confirm the validity of this promising therapeutic option that can be useful against biofilm-associated S. aureus infections.

Partial Achievement of the 90-90-90 UNAIDS Target in a Cohort of HIV Infected Patients from Central Italy.

BACKGROUND: Despite progress in the prevention and treatment of HIV, persistent issues concerning the evaluation of continuum in care from the serological diagnosis to virologic success remains. Considering the 2020 UNAIDS target 90-90-90 for diagnosis, treatment, and viral suppression of people living with HIV (PLWH), our purpose was to verify if, starting from new diagnoses, the viral suppression rate of our cohort of new PLWH satisfied the second and the third steps. METHODS: This retrospective study regards all patients aged ≥15 undergoing HIV test at our clinic between January 2005 and December 2017. We evaluated the second and the third '90 UNAIDS targets and the unclaimed tests, linkage to care, retention in ART, and the viral suppression at 1 and 2 years. Logistic regression (odds ratio, 95% confidence interval) was performed. RESULTS: We observed 592 new diagnoses for HIV infection: 61.4% on Italians, 38.5% on foreigners. An antiretroviral treatment was started on 78.8% of the new diagnoses (467/592) (second UNAIDS target), and a viral suppression was obtained at 2 years on 82% of PLWH who had started ART (383/467) (third UNAIDS target), namely only 64.7% of the new diagnoses instead of the hoped-for 81% of the UNAIDS target. Logistic regressions demonstrated that second and third '90 UNAIDS targets were unrelated to sex, nationality, CD4 cells count, HIV-RNA and CDC stage (p>0.05). The age class 25-50 years (OR=2.24; 95% CI = 1.06-4.37; p=0.04) achieves more likely viral suppression when compared with patients <25 years. Considering the continuum of care, 88 (15%) PLWH were lost to engagement in care (55 unclaimed tests and 33 unlinked to care), 37 didn't start ART, 51 were LFTU at 2 years. CONCLUSIONS: UNAIDS goal was far to be reached. The main challenges were unreturned tests as well as the retention in ART. Rapid tests for a test-treat strategy and frequent phone communications in the first ART years could facilitate UNAIDS target achievement.

Tuberculosis-Related Hospitalizations in a Low-Incidence Country: A Retrospective Analysis in Two Italian Infectious Diseases Wards.

In recent years, a decrease in the incidence of tuberculosis (TB) has been recorded worldwide. However, an increase in TB cases has been reported in foreign people living in low-incidence countries, with an increase in extrapulmonary TB (EPTB) in the western region of the world. In the present work, a retrospective study was conducted in two Italian infectious diseases wards to evaluate the clinical characteristics of TB admission in the time period 2013-2017. A significant increase in TB was shown in the study period: 166 (71% males) patients with TB were enrolled, with ~70% coming from outside Italy (30% from Africa, 25% from Europe, and 13% from Asia and South America). Compared to foreign people, Italians were significantly older (71.5 (interquartile range, IQR: 44.5-80.0) vs. 30 (IQR: 24-40) years; p < 0.0001) more immunocompromised (48% vs. 17%; p < 0.0001), and affected by comorbidities (44% vs. 14%; p < 0.0001). EPTB represented 37% of all forms of the disease, and it was more incident in subjects coming from Africa than in those coming from Europe (39.3% vs. 20%, respectively). In logistic regression analysis, being European was protective (odd ratio, OR (95% CI): 0.2 (0.1-0.6); p = 0.004) against the development of EPTB forms. In conclusion, an increase in the rate of TB diagnosis was documented in two Italian reference centers in the period 2013-2017, with 39% of EPTB diagnosed in patients from outside Europe.

Maraviroc Intensification Modulates Atherosclerotic Progression in HIV-Suppressed Patients at High Cardiovascular Risk. A Randomized, Crossover Pilot Study.

BACKGROUND: Experimental CCR5 antagonism with maraviroc in atherosclerosis-prone mice and preliminary data in humans suggest an anti-atherosclerotic effect of the drug. We assessed the impact of maraviroc treatment in persons living with HIV on subclinical indicators of atherosclerosis. METHODS: Persons living with HIV on effective antiretroviral therapy (ART) including only protease inhibitors were recruited if they had a Framingham risk score >20% and brachial flow-mediated dilation (bFMD) <4%, as indices of high cardiovascular risk. Maraviroc (300 mg per os for 24 weeks) was administered, in addition to ongoing ART, to all patients using a crossover design. Brachial FMD, carotid-femoral pulse wave velocity (cfPWV), and carotid intima-media thickness (cIMT) were measured as markers of atherosclerosis. Vascular competence-as expressed by the ratio of circulating endothelial microparticles (EMPs) to endothelial progenitor cells (EPCs)-and markers of systemic inflammation and monocyte and platelet activation were assessed. RESULTS: Maraviroc treatment significantly improved bFMD, cfPWV, and cIMT by 66%, 11%, and 13%, respectively (P = .002, P = .022, P = .038, respectively). We also found a beneficial effect of maraviroc on the EMP/EPC ratio (P < .001) and platelet/leucocyte aggregates (P = .013). No significant changes in markers of systemic inflammation, monocyte activation, and microbial translocation were observed. CONCLUSIONS: Maraviroc led to significant improvements in several markers for cardiovascular risk, endothelial dysfunction, arterial stiffness, and early carotid atherosclerosis, which was accompanied by an increase of vascular competence, without seeming to affect systemic inflammation. Our data support the need for larger studies to test for any effects of maraviroc on preventing atherosclerosis-driven pathologies.

Meningitis with cranial polyneuritis and cavernous sinus thrombosis by Borrelia crocidurae: First autochthonous case in Europe.

Borrelia crocidurae is endemic in West Africa, where it represents the leading cause of tick-borne relapsing fever (TBRF). TBRF typically presents with high fever and systemic symptoms, followed by recurrent episodes. Neurological complications may occur during febrile relapses. B. crocidurae is considered the most neurotropic agent of TBRF and is associated to severe neurological manifestations i.e. meningitis and encephalitis. To date, European cases of B. crocidurae infection have been reported in travelers returning from endemic areas. We report the first autochthonous case in Europe of B. crocidurae infection, presenting as meningitis with cranial polyneuritis and cavernous sinus thrombosis that were not preceded by classic febrile recurrences.

Role of pretreatment variables on plasma HIV RNA value at the sixth month of antiretroviral therapy including all first line drugs in HIV naïve patients: A path analysis approach.

BACKGROUND AND AIMS: We investigated the conditioning roles of viral tropism and other variables on plasma HIV RNA levels after 6 months of combination antiretroviral therapy (cART) in an HIV-infected Italian naïve population using regression tree, random forest regression, and path analysis (PA). Patients in this multicenter observational study were treated with all antiviral drugs that are currently recommended as first-line therapies. METHODS: Adult patients with chronic HIV infection were enrolled at the beginning of first-line cART (T0). The main variables were age, gender, tropism, "lcd4_0" and "lcd4_6" (log10 CD4+counts at T0 and after 6 months of cART, respectively), and "lrna0" (log10 HIV RNA at T0). Regression tree and random forest analyses were applied. The predictive effect on lrna6 (log10-transformed plasma HIV RNA after 6 months of cART) was also investigated via PA (x4->lcd4_0->lrna0->lrna6) with a treatment selection step included as a dependent (mediator) variable for each third drug and, as predictive covariates, age, female, x4_10, x4_5, lcd4_0, and lrna0. Tropism was assessed in plasma using the Geno2pheno algorithm with 2 false positive rate (FPR) cut-offs: 5% (x4_5) and 10% (x4_10). RESULTS: The study included 571 subjects (21% x4_10 and 10.7% x4_5). The only important predictor of lrna6 was lrna0, and a positive indirect effect of bearing X4 virus in plasma was suggested. A significant direct positive effect of protease inhibitors on lrna6 was found (p = 0.022), and a significant negative effect of integrase strand transfer inhibitor (INSTI) was also detected (p = 0.003 for FPR ≤ 5% and p = 0.01 for FPR < 10%). PA predicted mean residual viremias of 40 copies/mL without INSTI and 3 copies/mL with INSTI. CONCLUSIONS: PA indicated a possible indirect role of HIV tropism on lrna6 with both FPR < 10% and ≤ 5%. Patients treated with INSTI had a predicted residual viremia of 3 copies/mL.

NUtraceutical TReatment for hYpercholesterolemia in HIV-infected patients: The NU-TRY(HIV) randomized cross-over trial.

BACKGROUND AND AIMS: Despite hypercholesterolemia has been recognized to increase cardiovascular risk in human immunodeficiency virus (HIV)-infected patients, cholesterol-lowering therapy is underused in this population, due to fear of drug-drug interactions with antiretroviral therapy (ART). We investigated the effects of a nutraceutical combination (NC) on lipid profile, proprotein convertase subtilisin/kexin type 9 (PCSK9), subclinical inflammation and arterial stiffness in ART-treated HIV-infected patients. METHODS: This was a prospective randomized open-label trial with a cross-over design including 30 stable HIV-infected patients on ART with low-density lipoprotein cholesterol (LDL-C) >115 mg/dL, not taking lipid-lowering treatment. After a 3-week lipid stabilization period, the effects associated with 3 months of an oral NC containing red yeast rice and berberine vs. no active treatment (noNC) were assessed for plasma total cholesterol (TC), LDL-C, high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), lipoprotein(a), PCSK9, high-sensitivity C-reactive protein (hs-CRP) levels and aortic pulse wave velocity (aPWV). RESULTS: At baseline, significant correlations between PCSK9 levels, age (rho = -0.51, p=0.004), waist circumference (rho = 0.36, p=0.005) and CD4+ cell count (rho = -0.40, p=0.027) were observed. NC treatment effects corrected for noNC were significant for TC (-14%, p<0.001), LDL-C (-19%, p<0.001), PCSK9 (-12%, p=0.02), hs-CRP (-14%, p=0.03) and aPWV (-6%, p=0.005). No significant effects were observed for HDL-C, TG and lipoprotein(a). NC treatment was safe and no significant alterations in muscle, liver and immunovirological parameters were observed. No carry over effect was recorded. CONCLUSIONS: The tested NC significantly reduced plasma cholesterol and PCSK9 levels, attenuated subclinical inflammation and improved arterial stiffness in stable HIV-infected patients on ART.

Effect of aspirin treatment on abacavir-associated platelet hyperreactivity in HIV-infected patients.

BACKGROUND: Ischemic cardiovascular events are a relevant cause of morbidity and mortality in HIV-infected patients. Use of abacavir (ABC), a nucleoside analog reverse transcriptase inhibitor, has been associated with increased risk of myocardial infarction (MI) and with platelet hyperreactivity. We explored whether low-dose aspirin reduces in vivo platelet activation and platelet hyperreactivity induced by ABC in HIV-infected subjects. METHODS AND RESULTS: In a randomized, placebo-controlled, cross-over study forty HIV-infected patients with ABC-associated platelet hyperreactivity, defined by a score based on laboratory variables reflecting in vivo platelet activation and ex vivo platelet hyperresponsiveness, were randomized to aspirin 100 mg daily for 15 days with subsequent cross-over to placebo for additional 15 days or placebo for 15 days with subsequent cross-over to aspirin for further 15 days. In vivo and ex vivo platelet activation markers were measured at day 15 and 30. One group of healthy subjects, one of untreated HIV infected-patients and one treated without ABC, were studied concomitantly. Serum TxB2 and urinary 11-dehydro-TxB2 were decreased by aspirin in ABC-treated patients, but not as much as in healthy controls. Aspirin therapy reduced significantly platelet hyperreactivity (score: from 9.3, 95% CIs 8.7 to 10.0, to 7.5, 6.9 to 8.0), however without bringing it back to the levels of healthy controls (score: 4.6, 95% CIs 3.6 to 5.6). CONCLUSION: Aspirin reduces ABC-induced in vivo platelet activation and platelet hyperreactivity in HIV-infected patients, however without normalizing them. Whether the observed reduction of platelet activation is sufficient to prevent cardiovascular events requires a prospective trial.

Early abdominal aortic graft infection due to Propionibacterium acnes: a case report and review of the literature.

Propionibacterium acnes is a member of the human microbiota that has been recently associated with late-onset infections of indwelling devices, especially shoulder prosthesis. Aortic graft infection are rare events with significant morbidity and mortality. Here, we describe the case of an abdominal aortic graft infection due to P. acnes with an unusual early onset. A review of the recent English language literature has been added.

Durability and tolerability of first-line regimens including two nucleoside reverse transcriptase inhibitors and raltegravir or ritonavir boosted-atazanavir or -darunavir: data from the ICONA Cohort.

Background We aimed to mimic the ACTG 5257 trial, comparing raltegravir (RAL), ritonavir-boosted atazavavir (ATV/r) and ritonavir-boosted darunavir (DRV/r) in the observational setting. Methods All the ICONA patients starting a first cART with 2NRTI + ATV/r, DRV/r or RAL were included. Primary end-point was treatment failure, i.e. virological failure (confirmed HIV-RNA > 200copies/mL > 6 months therapy) or discontinuation for any reason of the third drug. Secondary end-points: virological failure50 (50 copies/mL threshold), and discontinuation of the third drug due to intolerance/toxicity. Cox regression analyses were run to compare the risk of outcomes between the three regimens. Results 2249 patients were included, 985 (44%) initiated ATV/r, 1023 (45%) DRV/r and 241 (11%) RAL; median follow-up of 3.6 years (IQR: 2.3-5.2). After controlling for baseline confounding factors, patients given ATV/r showed a 26% higher risk of treatment failure (TF) vs. DRV/r (AHR 1.26, 95%CI 1.11-1.43); patients on RAL had a lower risk of TF vs. ATV/r (AHR 0.81, 95%CI 0.66-0.99). The probability of virological failure50 was significantly lower for people initiating RAL vs. DRV/r (AHR 0.46, 95%CI 0.24-0.87) or ATV/r (AHR 0.52, 95%CI 0.27-0.99). In addition, RAL was associated to a lower risk of discontinuation for toxicity vs. both DRV/r (AHR: 0.37, 95%CI: 0.19-0.72) and ATV/r (AHR: 0.18, 95%CI: 0.09-0.34). ATV/r was associated with a higher risk of discontinuing due to toxicity (AHR 2.09, 95%CI 1.63-2.67) vs. DRV/r. Conclusions In our observational study, we confirmed higher risk of treatment failure and lower tolerability of ATV/r-based regimens as compared to those including DRV/r or RAL.

Elevated serum uric acid levels are associated with endothelial dysfunction in HIV patients receiving highly-active antiretroviral therapy.

BACKGROUND AND AIMS: Elevated serum uric acid (SUA) levels may be associated with endothelial dysfunction. Increased rates of metabolic syndrome (MS) and elevated SUA levels were described in human immunodeficiency virus (HIV) infected patients. We investigated whether SUA levels are associated with endothelial dysfunction in HIV positive patients receiving highly-active antiretroviral therapy (HAART) irrespective of MS. METHODS: In this cross-sectional study of 250 HIV positive patients receiving stable HAART, we evaluated the relationship between MS, SUA levels and endothelial function. SUA levels and brachial artery flow-mediated dilation (bFMD) were measured. The relationship between logarithmic (LG)-transformed SUA levels and bFMD was evaluated after correction for MS. RESULTS: MS was detected in 28.4% of patients and elevated SUA levels (≥6 mg/dL) in 25.2%. MS was associated with higher LG-SUA levels (age-, gender- and glomerular filtration rate-adjusted beta = 0.204, p = 0.001). The crude linear association between LG-SUA levels and LG-bFMD (beta = -0.166, p = 0.008) was abolished after correction for MS (beta = -0.089, p = 0.172). When SUA levels were used as a categorical variable (≥6 mg/dL or <6 mg/dL and SUA quartiles, respectively), the association between LG-SUA levels and LG-bFMD remained significant after adjustment for MS (beta = -0.142, p = 0.022 and beta = -0.163, p = 0.010, respectively). CONCLUSIONS: MS significantly affects SUA levels in HAART-treated HIV infected patients. The negative association between SUA and bFMD is independent of MS only for elevated SUA levels.

Screening for Squamous Cell Anal Cancer in HIV Positive Patients: A Five-Year Experience.

AIM: Potential screening modalities for early diagnosis of squamous cell anal cancer (SCC) in HIV patients include digital anorectal examination (DARE), anal Papanicolaou testing (Pap test), human papilloma virus (HPV) co-testing, and high-resolution anoscopy. The aim of this study was to demonstrate the results of a five-year screening program for SCC in HIV patients. MATERIALS AND METHODS: We conducted a retrospective study on 204 HIV patients who underwent a screening program for SCC from October 2010 to January 2015. All patients were screened by DARE, anal Pap test, including HPV test and cytology, and high-resolution video-proctoscopy (HR-VPS) with and without acetic acid 3%. Depending on macroscopic appearance and biopsies, patients underwent observation or treatment. Median follow-up was 36 months. RESULTS: Cytologic abnormalities (Cyt+) for high-risk HPV genotypes were recorded in 34% of patients. HR-VPS was positive in 59 patients (29%), of whom 13 patients (22%) were positive for warts; the rest have typical features of anal intraepithelial neoplasia (AIN). Sixteen (8%) patients had AIN (AIN I-III) and underwent wide local excision, ablation, or imiquimod. Absence of progression was recorded. Fourteen patients (7%) had SCC: eight (57%) with no evidence of recurrence, two (14%) had recurrence, and four (29%) died from metastatic disease. CONCLUSIONS: Our data demonstrated a successful screening program in preventing SCC in HIV patients. We demonstrate the advantages of progression towards SCC. Moreover, we used a new screening tool, the HR-VPS, a low-cost and manageable instrument to collect patients' long-term data.

Genetic and Pharmacological Dissection of the Role of Spleen Tyrosine Kinase (Syk) in Intestinal Inflammation and Immune Dysfunction in Inflammatory Bowel Diseases.

Background: The DNAX adaptor protein 12 (DAP12) is a transmembrane adaptor molecule that signals through the activation of Syk (Spleen Tyrosine Kinase) in myeloid cells. The purpose of this study is to investigate the role of DAP12 and Syk pathways in inflammatory bowel diseases (IBDs). Methods: DAP12 deficient and DAP12 transgenic, overexpressing an increased amount of DAP12, mice and Syk deficient mice in the C57/BL6 background were used for these studies. Colitis was induced by administering mice with dextran sulfate sodium (DSS), in drinking water, or 2,4,6-trinitrobenzene sulfonic acid (TNBS), by intrarectal enema. Results: Abundant expression of DAP12 and Syk was detected in colon samples obtained from Crohn's disease patients with expression restricted to immune cells infiltrating the colonic wall. In rodents development of DSS colitis as measured by assessing severity of wasting diseases, global colitis score,and macroscopic and histology scores was robustly attenuated in DAP12-/- and Syk-/- mice. In contrast, DAP12 overexpression resulted in a striking exacerbation of colon damage caused by DSS. Induction of colon expression of proinflammatory cytokines and chemokines in response to DSS administration was attenuated in DAP12-/- and Syk-/- mice, whereas opposite results were observed in DAP12 transgenic mice. Treating wild-type mice with a DAP-12 inhibitor or a Syk inhibitor caused a robust attenuation of colitis induced by DSS and TNBS. Conclusions: DAP12 and Syk are essential mediators in inflammation-driven immune dysfunction in murine colitides. Because DAP12 and Syk expression is upregulated in patients with active disease, present findings suggest a beneficial role for DAP12 and Syk inhibitors in IBD.

Hepatitis C virus and proprotein convertase subtilisin/kexin type 9: a detrimental interaction to increase viral infectivity and disrupt lipid metabolism.

From viral binding to the hepatocyte surface to extracellular virion release, the replication cycle of the hepatitis C virus (HCV) intersects at various levels with lipid metabolism; this leads to a derangement of the lipid profile and to increased viral infectivity. Accumulating evidence supports the crucial regulatory role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in lipoprotein metabolism. Notably, a complex interaction between HCV and PCSK9 has been documented. Indeed, either increased or reduced circulating PCSK9 levels have been observed in HCV patients; this discrepancy might be related to several confounders, including HCV genotype, human immunodeficiency virus (HIV) coinfection and the ambiguous HCV-mediated influence on PCSK9 transcription factors. On the other hand, PCSK9 may itself influence HCV infectivity, inasmuch as the expression of different hepatocyte surface entry proteins and receptors is regulated by PCSK9. The aim of this review is to summarize the current evidence about the complex interaction between HCV and liver lipoprotein metabolism, with a specific focus on PCSK9. The underlying assumption of this review is that the interconnections between HCV and PCSK9 may be central to explain viral infectivity.

Observed versus predicted cardiovascular events and all-cause death in HIV infection: a longitudinal cohort study.

BACKGROUND: The aim of the study was to assess the applicability of an algorithm predicting 10-year cardiovascular disease (CVD) generated in the setting of the Framingham Heart Study to a real-life, contemporary Italian cohort of HIV-positive subjects. METHODS: The study was an observational longitudinal cohort study. The probability for 10-year CVD events according to the Framingham algorithm was assessed in 369 consecutive HIV-positive participants free from overt CVD enrolled in 2004, who were followed for a median of 10.0 years (interquartile range, 9.1-10.1). Cardiovascular events included myocardial infarction, hospitalized heart failure, revascularized angina, sudden cardiac death, stroke, peripheral arterial disease. RESULTS: Over 3097 person-years of observation, we observed a total of 34 CVD events, whereas Framingham algorithm predicted the occurrence of 34.3 CVD events. CVD event rate was 11.0/1000 person-years of follow-up. In a receiver operating characteristics curve analysis, Framingham risk equation showed an excellent predictive value for incident CVD events (c-statistics, 0.83; 95% confidence interval, 0.76-0.90). In a multivariable Cox analysis, age, smoking and diabetes were independent predictors of CVD events. All-cause death rate was 20.0/1000 person-years of follow-up (n = 62 deaths). Causes of death included liver diseases (18), malignancies (14), AIDS-related (11); cardiovascular (9) and others (10). In a Cox analysis, age, AIDS diagnosis and chronic hepatitis were independent predictors of death. CONCLUSIONS: Observed CVD events in HIV-infected patients were well predicted by Framingham algorithm. Established major CVD risk factors are the strongest determinants of CVD morbidity in an Italian contemporary cohort of HIV-positive subjects. Interventions to modify traditional risk factors are urgently needed in HIV people.

Imported arboviral infections in Italy, July 2014-October 2015: a National Reference Laboratory report.

BACKGROUND: Imported cases of infections due to Dengue (DENV) and Chikungunya (CHIKV) viruses and, more recently, Zika virus (ZIKV) are commonly reported among travelers returning from endemic regions. In areas where potentially competent vectors are present, the risk of autochthonous transmission of these vector-borne pathogens is relatively high. Laboratory surveillance is crucial to rapidly detect imported cases in order to reduce the risk of transmission. This study describes the laboratory activity performed by the National Reference Laboratory for Arboviruses (NRLA) at the Italian National Institute of Health in the period from July 2014 to October 2015. METHODS: Samples from 180 patients visited/hospitalized with a suspected DENV/CHIKV/ZIKV infection were sent to the NRLA from several Italian Hospitals and from Regional Reference Laboratories for Arboviruses, in agreement with the National Plan on human surveillance of vector-borne diseases. Both serological (ELISA IgM test and Plaque Reduction Neutralization Test-PRNT) and molecular assays (Real Time PCR tests, RT-PCR plus nested PCR and sequencing of positive samples) were performed. RESULTS: DENV infection was the most frequently diagnosed (80 confirmed/probable cases), and all four genotypes were detected. However, an increase in imported CHIKV cases (41 confirmed/probable cases) was observed, along with the detection of the first ZIKV cases (4 confirmed cases), as a consequence of the recent spread of both CHIKV and ZIKV in the Americas. CONCLUSIONS: Main diagnostic issues highlighted in our study are sensitivity limitations of molecular tests, and the importance of PRNT to confirm serological results for differential diagnosis of Arboviruses. The continuous evaluation of diagnostic strategy, and the implementation of laboratories networks involved in surveillance activities is essential to ensure correct diagnosis, and to improve the preparedness for a rapid and proper identification of viral threats.