Tiziano Allice

COBAS AmpliPrep-COBAS TaqMan Hepatitis B Virus (HBV) Test: a Novel Automated Real-Time PCR Assay for Quantification of HBV DNA in Plasma

ABSTRACT Success in antiviral therapy for chronic hepatitis B is supported by highly sensitive PCR-based assays for hepatitis B virus (HBV) DNA. Nucleic acid extraction from biologic specimens is technically demanding, and reliable PCR results depend on it. The performances of the fully automatic system COBAS AmpliPrep-COBAS TaqMan 48 (CAP-CTM; Roche, Branchburg, NJ) for HBV DNA extraction and real-time PCR quantification were assessed and compared to the endpoint PCR COBAS AMPLICOR HBV monitor (CAHBM; Roche). Analytical evaluation with a proficiency panel showed that CAP-CTM quantitated HBV DNA levels in one single run over a wide dynamic range (7 logs) with a close correlation between expected and observed values (r = 0.976, interassay variability below 5%). Clinical evaluation, as tested with samples from 92 HBsAg-positive patients, demonstrated excellent correlation with CAHBM (r = 0.966, mean difference in quantitation = 0.36 log10 IU/ml). CAP-CTM detected 10% more viremic patients and longer periods of residual viremia in those on therapy. In lamivudine (LAM)-resistant patients, the reduction of HBV DNA after 12 months of Adefovir (ADF) was higher in the combination (LAM+ADF) schedule than in ADF monotherapy (5.1 logs versus 3.5 logs), suggesting a benefit in continuing LAM. CAP-CTM detected HBV DNA in liver biopsy samples from 15% of HBsAg-negative, anti-HBcAg-positive graft donors with no HBV DNA in plasma. The amount of intrahepatic HBV DNA was significantly lower in occult HBV infection than in overt disease. CAP-CTM can improve the management of HBV infection and the assessment of antiviral therapy and drug resistance, supporting further insights in the emerging area of occult HBV infection.

Antimicrobial Activity of Euplotin C, the Sesquiterpene Taxonomic Marker from the Marine Ciliate Euplotes crassus

ABSTRACT Strains of the marine ciliate protist Euplotes crassus produce exclusive terpenoids called euplotins that play an ecological role. Among these derivatives, euplotin C is the main of four secondary metabolites isolated from cultures of this protozoon and represents the sesquiterpene taxonomic marker from E. crassus. Because different terpenoid metabolites of plant origin showed a certain antimicrobial activity, we assessed the compound euplotin C, purified by high-pressure liquid chromatography and solubilized in two solubility enhancers, against the protozoa Leishmania major and Leishmani infantum, the fungus Candida albicans, and nine strains of gram-positive and gram-negative microorganisms. An activity of euplotin C against Leishmania promastigotes was demonstrated (50% lethal doses were 4.6 or 8.1 μg/ml depending on the agent used to solubilize the compound), while the effect was less evident on Candida and nearly absent on bacteria. A nonsignificant cytotoxicity (50% lethal dose, >200 μg/ml) against the J774 cell line was observed. A leishmanicidal activity was also shown by the living, euplotin-producing cells of E. crassus cultured together with promastigotes; this activity increased with time from 10 min to 6 h of incubation. This study provides an initial rationale for the evaluation of euplotin C and other similar natural products as alternative or possibly synergistic compounds for current antiprotozoon chemotherapeutics.

Valganciclovir as pre-emptive therapy for cytomegalovirus infection post-allogenic stem cell transplantation: implications for the emergence of drug-resistant cytomegalovirus

OBJECTIVES Valganciclovir is a well established drug for the management of cytomegalovirus (CMV) infection in haematopoietic stem cell transplantation (HSCT). Data concerning its safety regarding the development of drug resistance are required. The aim of the present study was to retrospectively investigate CMV drug resistance in a group of HSCT patients experiencing relapses of CMV infection after a first-line pre-emptive antiviral therapy. METHODS Thirteen adult HSCT patients out of 26 with asymptomatic CMV infection, experiencing relapsing infections 45-155 days after either intravenous (iv) ganciclovir (2 patients) or valganciclovir (11 patients), were studied. Genotypic assays for mutations in the viral phosphotransferase (UL97) and DNA-polymerase (UL54) genes were directly applied on patient specimens. Baseline CMV sequences were compared with those at the time of relapses to identify drug-resistant strains. RESULTS UL97 mutations A594V and M460V known to confer drug resistance developed in one relapsing patient who received iv ganciclovir as first-line therapy, corresponding to a rate of 7.7% of relapses due to drug-resistant strains and an overall 3.8% rate of infections due to CMV drug-resistant strains. UL54 drug resistance mutations were absent. No evidence of drug resistance was found in patients on valganciclovir either as first-line therapy or as treatment for relapses. CONCLUSIONS The safety profile of valganciclovir as anti-CMV pre-emptive therapy was confirmed, as well as that monitoring CMV drug resistance with genotypic tests on sequential isolates over the time-course of therapy offers guidance to tailor antiviral treatment in a clinically relevant time frame.

Recent outbreak of aseptic meningitis in Italy due to Echovirus 30 and phylogenetic relationship with other European circulating strains

BACKGROUND Enteroviruses (EVs) are common human viral pathogens, causing a variety of diseases, including aseptic meningitis. Recently, EV aseptic meningitis outbreaks have been reported across Europe, but, in Italy, knowledge of recent EV molecular epidemiology is very limited. OBJECTIVES We report an outbreak of EV aseptic meningitis in 10 adults in North-Western Italy, from October to November 2012. Patients were parents or close relatives of children <5 years old attending the same class of a nursery school, suffering from a mild febrile upper respiratory disease. Phylogenetic relationship with other European circulating strains was analyzed updating E30 circulation in Italy in recent years. STUDY DESIGN EVs were detected from cerebrospinal fluid (CSF) specimens with a real-time reverse transcription polymerase chain reaction and virus isolation was achieved from rectal and pharyngeal swabs. For cluster definition and phylogenetic studies, viral VP1 region was directly amplified and sequenced from CSF. RESULTS EVs were identified in CSF from all patients and from rectal and pharyngeal swabs in 7 of them. Direct sequencing of CSF revealed the presence of the same Echovirus 30 (E30) in all patients and phylogenetic analysis identified it as a diverging clade within E30 genotype VII, the most recent strain circulating in UK, Finland and Denmark since 2006. CONCLUSION Molecular techniques allowed the rapid identification and typing of E30 from CSF. Phylogenetic analysis revealed that the cluster might be due to a new E30 variant within the genotype VII currently circulating in Europe, thus updating the epidemiology of EV circulation in Italy.

Combination of conventional blood cultures and the SeptiFast molecular test in patients with suspected sepsis for the identification of bloodstream pathogens

We evaluated performances of the molecular test SeptiFast (SF) for the detection of agents of bloodstream infection (BSI) in patients with suspected sepsis, the majority of them under antibiotic treatment and at high prevalence of HIV-1 infection (10.5%). Matched SF and blood culture (BC) samples (n=1186) from 1024 patients were studied. Two hundred fifty-one episodes of BSI out of 1144 were identified with the combined methods (22%). SF identified more episodes of BSI than BC: 206 versus 176 (χ(2)=7.008, P=0.0081) and a significantly higher number of Gram-negative bacteria than BC (77 versus 53, χ(2)=9.12; P=0.0025), as well as of polymicrobial infections (χ(2)=4.50, P=0.0339). In conclusion, SF combined with BC improved the diagnosis of sepsis, especially in immunocompromised patients.

Diagnosis of dengue fever in North West Italy in travelers from endemic areas: A retrospective study

BACKGROUND Domestic outbreaks of Dengue (DENV) fever from imported cases have to be considered a possible risk in non-endemic countries where Dengue vectors are present, such as in Italy. OBJECTIVE To review imported acute/recent DENV infections in a one-year survey in a North West Italy region where the presence of Aedes albopictus is documented. STUDY DESIGN We retrospectively reviewed laboratory and clinical records of Italian febrile travelers from Dengue endemic areas referring to the local reference Centre for Infectious Disease, covering a population of about 4 million people. RESULTS Acute/recent DENV infection was identified in 15 out of 91 travelers from endemic areas (16.5%) including 12 primary and 3 secondary infections; in 6 patients the virus was detectable in blood according to molecular real-time Polymerase Chain Reaction-based assays: in 9 patients the diagnosis of DENV infection was accomplished by the combination of specific IgM reactivity, high IgG titers, IgG seroconversion from negative to positive and increasing (four-fold) IgG titers in paired serum samples. Two cases of DENV infections were imported from South Egypt in patients travelling together, confirming the importance of returning travelers as sentinels of a rapidly changing epidemiology in specific geographic areas. CONCLUSIONS Our findings outline the high rate of imported Dengue infection in North West Italy and emphasize the need for a continued Dengue surveillance in non-endemic countries as well as a careful evaluation and follow-up of febrile patients returning from Dengue endemic countries.

Clinical impact of A/H1/N1/09 influenza in patients with cirrhosis: Experience from a nosocomial cluster of infection†‡

A/H1N1/09 influenza is associated with a high risk of complications in patients with chronic diseases, but data on morbidity and mortality in patients with cirrhosis are limited. A cluster of A/H1N1/09 infection in 48 patients admitted to a Gastro‐Hepatology Unit is reported. Nosocomial spread, clinical outcome, and viral characteristics of A/H1N1/09 strains from a study group of 48 inpatients (21 and 27 with and without cirrhosis, respectively) were compared with those from a control group of 44 outpatients with mild influenza‐like illness and without cirrhosis. A/H1N1/09 infection was confirmed in 8/48 (17%) inpatients. A/H1N1/09 infection rate did not differ in patients with and without cirrhosis (4/21, 19%; 4/27, 15%), but three patients with cirrhosis died of pneumonia and acute respiratory distress syndrome, with fungal or bacterial superinfection in two cases, despite antiviral treatment. None of patients without cirrhosis died. Viral sequences showed the presence of hemagglutinin mutation D222G in two out of three fatal cases and S183P in seven out of eight infected patients. These mutants were not detected in the outpatients group. Even if A/H1N1/09 infection rate in hospitalized patients with and without cirrhosis was not significantly different, cirrhosis and D222G/S183P substitutions were significantly associated with severe disease and poor outcome, also suggesting fungal or bacterial superinfection and portal hypertension as risk factors for A/H1N1/09 disease severity in patients with cirrhosis. Vaccination, preventive and early treatment and a strict control of nosocomial spread should be activated carefully in patients with cirrhosis during epidemics influenza. J. Med. Virol. 85:1–7, 2012.

A(H1N1)pdm09 hemagglutinin D222G and D222N variants are frequently harbored by patients requiring extracorporeal membrane oxygenation and advanced respiratory assistance for severe A(H1N1)pdm09 infection

In patients with A(H1N1)pdm09 infection, severe lung involvement requiring admission to intensive care units (ICU) has been reported. Mutations at the hemagglutinin (HA) receptor binding site (RBS) have been associated with increased virulence and disease severity, representing a potential marker of critical illness.

Survey of phenotypic and genetic features of Streptococcus pyogenes strains isolated in northwest Italy

Streptococcus pyogenes (group A Streptococcus [GAS]) is an important pathogen whose virulence is related to the production of exotoxins and the presence of particular surface components. One hundred eighty-two GAS strains were collected in northwestern Italy between 1994 and 2002 and analyzed for phenotypic characteristics (opacity factor, proteolyic activity, and antimicrobial susceptibility) and by polymerase chain reaction for the presence of genes responsible for the production of exotoxins implicated in pathogenesis speA and speF and of prtF1 (encoding fibronectin-binding protein F1). All strains were speF positive and 19.2% were speA positive and prtF1 negative, whereas the prtF1 gene was identified in 39.5% of the other strains. Of these, approximately half revealed the same pulse-field gel electrophoresis (PFGE) pattern but differed in both speA gene and macrolide resistance.

Etiological diagnosis of bloodstream infections through a multiplex real-time polymerase chain reaction test in pediatric patients: a case series from a tertiary Italian hospital

Abstract Background: The outcome of bloodstream infections (BSIs) is strongly related to microbiological diagnosis. Several factors may reduce blood culture (BC) diagnostic yield in pediatric BSIs, making the application of molecular methods quite promising. Methods: Multiplex real-time polymerase chain reaction (PCR) tests (the LightCycler Septifast Test MGRADE by Roche Diagnostics - LC-SF) performed in the tertiary centre of Regina Margherita Childrens Hospital (Turin, Italy) over a 3-year period were retrospectively evaluated. Results of the LC-SF test were compared with those of BC (Automated Bact/Alert 3D, Biomerieux) collected at a close time point. Results: 545 LC-SF tests were collected from 289 patients (183 males, median age 6.8 years, interquartile range (IQR) = 2.7–13.1); 163 had congenital or acquired immunodeficiency. In 515 cases (94.5%) the LC-SF test was performed with ongoing empirical antimicrobial therapy. Etiological definition was achieved in 111 BSI cases (20.4%). Both LC-SF and BC identified the responsible pathogen in 39 episodes. The LC-SF test alone gave a positive result in 29 septic episodes; BC alone permitted the etiological diagnosis in 43 episodes, but isolates were not included in the LC-SF master list in 10 cases. A 26% increase in bacterial identification chances due to the LC-SF test was documented. Cohens kappa test indicated a moderate strength of agreement (0.49) between LC-SF tests and BCs closely collected. Conclusions: BC remains the gold standard for the etiological diagnosis of BSIs, but PCR methods proved to be a valuable adjunctive diagnostic tool in pediatric BSIs, especially in children receiving empirical chemotherapy.