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The clearance of B19 parvovirus from peripheral blood was followed after acute infection to determine how long the virus is present in blood, even at low titer. The presence of B19 DNA in serum was investigated with dot blot hybridization during an epidemic. Fourteen patients positive for B19 DNA were followed for up to 1 year for its presence in samples taken monthly, using both dot blot hybridization and nested polymerase chain reaction (PCR). All patients examined showed medium to high viremic titers (detectable with hybridization assay) only at the beginning of observation; later the virus titer decreased and was detectable only by nested PCR. Of the 14 patients followed, 13 were positive for B19 DNA by nested PCR for 2-6 months; 1 patient showed a persistent infection associated with chronic arthritis and was positive for B19 DNA for 1 year without clearance of the virus.

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Non-Escherichia coli Enterobacterales (NECE) can colonize the human gut and may present virulence determinants and phenotypes that represent severe heath concerns. Most information is available for virulent NECE strains, isolated from patients with an ongoing infection, while the commensal NECE population of healthy subjects is understudied. In this study, 32 NECE strains were isolated from the feces of 20 healthy adults. 16S rRNA gene sequencing and mass spectrometry attributed the isolates to Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Enterobacter aerogenes, Enterobacter kobei, Citrobacter freundii, Citrobacter amalonaticus, Cronobacter sp., and Hafnia alvei, Morganella morganii, and Serratia liquefaciens. Multiplex PCR revealed that K. pneumoniae harbored virulence genes for adhesins (mrkD, ycfM, and kpn) and enterobactin (entB) and, in one case, also for yersiniabactin (ybtS, irp1, irp2, and fyuA). Virulence genes were less numerous in the other NECE species. Biofilm formation was spread across all the species, while curli and cellulose were mainly produced by Citrobacter and Enterobacter. Among the most common antibiotics, amoxicillin-clavulanic acid was the sole against which resistance was observed, only Klebsiella strains being susceptible. The NECE inhabiting the intestine of healthy subjects have traits that may pose a health threat, taking into account the possibility of horizontal gene transfer.

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All currently used first-line and second-line drugs for the treatment of leishmaniasis exhibit several drawbacks including toxicity, high costs and route of administration. Furthermore, some drugs are associated with the emergence of drug resistance. Thus, the development of new treatments for leishmaniasis is a priority in the field of neglected tropical diseases. The present work highlights the use of natural derived products, i.e. chalcones, as potential source of antileishmanial agents. Thirty-one novel chalcone compounds have been synthesized and their activity has been evaluated against promastigotes of Leishmania donovani; 16 compounds resulted active against L. donovani in a range from 3.0 to 21.5 μM, showing low toxicity against mammalian cells. Among these molecules, 6 and 16 showed good inhibitory activity on both promastigotes and intracellular amastigotes, coupled with an high selectivity index. Furthermore, compounds 6 and 16 inhibited the promastigote growth of other leishmanial species, including L. tropica, L. major and L. infantum. Finally, 6 and 16 interacted with high affinity with trypanothione reductase (TR), an essential enzyme for the leishmanial parasite and compound 6 inhibited TR with sub-micromolar potency. Thus, the effective inhibitory activity against Leishmania, the lack of toxicity on mammalian cells and the ability to block a crucial parasite's enzyme, highlight the potential for compound 6 to be optimized as novel drug candidate against leishmaniasis.

In order to evaluate the optimal and essential diagnostic test(s) for a correct diagnosis of B19 diseases, 344 consecutive serum samples were tested from 344 patients with clinical suspicion of B19 infection during an epidemic period (early Spring-Autumn 2000). Sera were tested for B19 DNA by a standardized competitive polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA) and dot-blot hybridization and for specific IgM and IgG by ELISA. Of 344 patients examined, 125 were positive for markers of B19-associated disease: 49 had both B19 DNA and IgM, 50 had B19 DNA without IgM, and 26 had IgM without B19 DNA. After examination of the different patterns of B19 markers as diagnostic tools for B19 infection, IgM determination detected only 60% of B19-documented infections. IgM tests were nevertheless fundamental, as they were the unique diagnostic marker in 20.8% of documented infections (26 of 125 patients), in the diagnosis of recent, but still symptomatic infections when B19 DNA was no longer detectable. The determination of B19 DNA with PCR permitted detection of 79.2% of infections and therefore represented an essential test. PCR was fundamental for the diagnosis of B19 disease, as the unique diagnostic marker in 32% of documented infections (50 of 125 patients), both in acute infections at the onset of symptoms before the appearance of immunological response, and during the course of persistent B19 infections in which IgM had cleared. The contemporaneous determination of B19 DNA by PCR and specific IgM appears to be the most appropriate diagnostic protocol for the correct laboratory diagnosis of B19 infection.

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