Publications by authors named "Paola Prati"

9 Publications

  • Page 1 of 1

Residual SARS-CoV-2 RNA in nasal swabs of convalescent COVID-19 patients: Is prolonged quarantine always justified?

Int J Infect Dis 2021 Jan 30;102:299-302. Epub 2020 Oct 30.

Molecular Virology Unit, Microbiology and Virology Department, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy; Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy. Electronic address:

Real-time reverse transcription PCR is currently the most sensitive method to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Defining whether a patient could be contagious or not contagious in the presence of residual SARS-CoV-2 RNA is of extreme importance in the context of public health. In this prospective multicenter study, virus isolation was prospectively attempted in 387 nasal swabs from clinically recovered patients showing low viral load (quantification cycle, Cq, value greater than 30). The median Cq value was 36.8 (range 30.0-39.4). Overall, a cytopathic effect was detected in nine samples, corresponding to a culture positivity rate of 2.3% (9/387). The results of this study help to dissect true virus replication and residual viral RNA detection in recovered patients.
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http://dx.doi.org/10.1016/j.ijid.2020.10.072DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7834568PMC
January 2021

Deadly Puppy Infection Caused by an MDR O39 , , , and - Positive in a Breeding Kennel in Central Italy.

Front Microbiol 2020 15;11:584. Epub 2020 Apr 15.

Unit of Microbiology and Clinical Microbiology, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy.

Antimicrobial consumption in veterinary medicine has led to the spread of multi drug-resistance in clinically important bacteria, with the companion animals and their environment involved as emerging reservoirs. While CTX-M-15 and CMY-2 acquired β-lactamases have been widely detected in the bacterial population of companion and breeding animals in European area, DHA-1 enzymes have been rarely reported in veterinary medicine. The aim of the study was to characterize the associated with mortality of a litter of Bulldog puppies in a breeding kennel located in Pesaro area, Central Italy. The strains O39 serotype were resistant to 3rd/4th generation cephalosporins, chloramphenicol, aminoglycosides, trimethoprim-sulfamethoxazole, and ciprofloxacin, retaining susceptibility to carbapenems, colistin, fosfomycin, and levofloxacin (by Microscan Autoscan4, EUCAST clinical breakpoints). Pulse field gel electrophoreses (PFGE-XbaI) on five strains revealed the presence of a single profile. Whole genome sequencing (WGS) analysis revealed a complex resistome, harboring , , , , , , , , , , , , , and genes located on a 302597 bp IncHI2/HI2A plasmid. Moreover, , , , , and determinants were carried on an 83,429 bp IncFII plasmid. A determinant was carried on a 90,249 bp IncI1 plasmid. Two IncX1 and IncX4 plasmids without antimicrobial resistance genes were also detected. The presence of , , , and virulence factors was highlighted. This is the first report in Italy on an invasive infection in eight 2-weeks old dogs caused by the same MDR O39 , , , and positive strain. The above MDR clone caused the death of the entire litter, despite amoxicillin-clavulanate and enrofloxacin administration. The tank for storage of the water used to prepare the milk-based meal for the litter was the suspected reservoir.
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http://dx.doi.org/10.3389/fmicb.2020.00584DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7174561PMC
April 2020

Lack of viable parasites in cured 'Parma Ham' (PDO), following experimental Toxoplasma gondii infection of pigs.

Food Microbiol 2017 Sep 22;66:157-164. Epub 2017 Apr 22.

Istituto Zooprofilattico Sperimentale della Lombardia, Emilia Romagna, Pavia, Italy.

Twelve Large White pigs were experimentally infected with 1000 Toxoplasma gondii oocysts/each. Serology was carried out at different time points post infection (p.i.) and animals were slaughtered at four months p.i. One of two thighs was examined for T. gondii infection status by PCR and bioassay in mice. The other thigh was processed for Parma ham production. Four thighs were examined after twelve months of curing, four after fourteen months and four were examined after sixteen months. Cured hams were analyzed by PCR, bioassay and in-vitro cultivation on Vero cells followed by real-time PCR. Pigs seroconverted from day 21 p.i. Bioassays were positive for all fresh thighs, but negative for cured hams. PCR was positive for parasite DNA from most thighs both at slaughter and post curing, but parasite growth was not observed following in vitro cultivation and real-time PCR. Results indicate that the curing process of Parma Ham (PDO), when carried out according to the Parma Ham consortium regulations, can inactivate T. gondii tissue cysts. Results would suggest that food-borne transmission of T. gondii to consumers from Parma ham can be excluded.
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http://dx.doi.org/10.1016/j.fm.2017.04.007DOI Listing
September 2017

Swine influenza A (H1N1) virus (SIV) infection requiring extracorporeal life support in an immunocompetent adult patient with indirect exposure to pigs, Italy, October 2016.

Euro Surveill 2017 Feb;22(5)

Dipartimento di Scienze Clinico-Chirurgiche, Diagnostiche e Pediatriche, Università degli Studi di Pavia, Pavia, Italy.

We describe a case of severe swine influenza A(H1N1) virus infection in an immunocompetent middle-aged man in October 2016 in Italy who had only indirect exposure to pigs. The patient developed a severe acute distress respiratory syndrome which was successfully supported by extracorporeal membrane oxygenation and treated with antiviral therapy. The sole risk factor for influenza was a body mass index > 30 kg/m. After a month of hospitalisation, the patient was discharged in good health.
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http://dx.doi.org/10.2807/1560-7917.ES.2017.22.5.30456DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5388119PMC
February 2017

Francisella tularensis: No Evidence for Transovarial Transmission in the Tularemia Tick Vectors Dermacentor reticulatus and Ixodes ricinus.

PLoS One 2015 5;10(8):e0133593. Epub 2015 Aug 5.

National Reference Laboratory for Tularemia, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna "Bruno Ubertini", Pavia, Italy.

Background: Tularemia is a zoonosis caused by the Francisella tularensis, a highly infectious Gram-negative coccobacillus. Due to easy dissemination, multiple routes of infection, high environmental contamination and morbidity and mortality rates, Francisella is considered a potential bioterrorism threat and classified as a category A select agent by the CDC. Tick bites are among the most prevalent modes of transmission, and ticks have been indicated as a possible reservoir, although their reservoir competence has yet to be defined. Tick-borne transmission of F. tularensis was recognized in 1923, and transstadial transmission has been demonstrated in several tick species. Studies on transovarial transmission, however, have reported conflicting results.

Objective: The aim of this study was to evaluate the role of ticks as reservoirs for Francisella, assessing the transovarial transmission of F. tularensis subsp. holarctica in ticks, using experimentally-infected females of Dermacentor reticulatus and Ixodes ricinus.

Results: Transmission electron microscopy and fluorescence in situ hybridization showed F. tularensis within oocytes. However, cultures and bioassays of eggs and larvae were negative; in addition, microscopy techniques revealed bacterial degeneration/death in the oocytes.

Conclusions: These results suggest that bacterial death might occur in oocytes, preventing the transovarial transmission of Francisella. We can speculate that Francisella does not have a defined reservoir, but that rather various biological niches (e.g. ticks, rodents), that allow the bacterium to persist in the environment. Our results, suggesting that ticks are not competent for the bacterium vertical transmission, are congruent with this view.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0133593PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4526560PMC
May 2016

γ-PGA Hydrolases of Phage Origin in Bacillus subtilis and Other Microbial Genomes.

PLoS One 2015 9;10(7):e0130810. Epub 2015 Jul 9.

Dept. of Biology and Biotechnology, Università degli Studi di Pavia, Pavia 27100 (I), Italy; Italian Interuniversity Consortium on Materials, Science, and Technology (INSTM), Pavia Research Unit, Pavia 27100 (I), Italy.

Poly-γ-glutamate (γ-PGA) is an industrially interesting polymer secreted mainly by members of the class Bacilli which forms a shield able to protect bacteria from phagocytosis and phages. Few enzymes are known to degrade γ-PGA; among them is a phage-encoded γ-PGA hydrolase, PghP. The supposed role of PghP in phages is to ensure access to the surface of bacterial cells by dismantling the γ-PGA barrier. We identified four unannotated B. subtilis genes through similarity of their encoded products to PghP; in fact these genes reside in prophage elements of B. subtilis genome. The recombinant products of two of them demonstrate efficient polymer degradation, confirming that sequence similarity reflects functional homology. Genes encoding similar γ-PGA hydrolases were identified in phages specific for the order Bacillales and in numerous microbial genomes, not only belonging to that order. The distribution of the γ-PGA biosynthesis operon was also investigated with a bioinformatics approach; it was found that the list of organisms endowed with γ-PGA biosynthetic functions is larger than expected and includes several pathogenic species. Moreover in non-Bacillales bacteria the predicted γ-PGA hydrolase genes are preferentially found in species that do not have the genetic asset for polymer production. Our findings suggest that γ-PGA hydrolase genes might have spread across microbial genomes via horizontal exchanges rather than via phage infection. We hypothesize that, in natural habitats rich in γ-PGA supplied by producer organisms, the availability of hydrolases that release glutamate oligomers from γ-PGA might be a beneficial trait under positive selection.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0130810PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4497714PMC
April 2016

Detection and molecular analysis of Pseudorabies virus strains isolated from dogs and a wild boar in Italy.

Vet Microbiol 2015 Jun 14;177(3-4):359-65. Epub 2015 Apr 14.

National Reference Center for Aujeszky Disease - Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna (IZSLER), via Bianchi 7/9, 25124 Brescia, Italy. Electronic address:

Aujeszky's disease (AD) is one of the most economically important diseases of farmed pigs. Wild boars can act as reservoirs and might represent a potential threat for domestic animals, including dogs. The aim of this study was to report the results of an AD survey based on the Pseudorabies virus (PRV) genome detection in samples of dogs clinically suspected of AD and of wild boars collected during four consecutive hunting seasons in the period 2010-2014. Genomic characterization was based on the partial gC sequence of the Italian strains and the comparison with those from domestic pigs and European PRV strains circulating in wild boars. The Italian PRV strains were mainly distributed into three different clusters and revealed two interesting findings. First, there was a clear distinction between the viral strains that were isolated from dogs used for hunting and subsequently traced back to wild boars and the strains that were isolated from working dogs and subsequently found to be closely related to domestic pigs. Second, the Italian epidemiological situation was found to be different from those of European countries in that the Italian situation was characterized by the presence of both the typical Italian clades 1 and 2 and supported by new patterns of aa deletions/insertions. Italian clade 1 included strains from hunting dogs and two Italian wild boars, and Italian clade 2 grouped with recent strains from dogs that were unable to hunt and domestic pigs that were related to one old reference strain (S66) and not included elsewhere. Molecular and phylogenetic analyses of PRV strains are therefore necessary to improve the understanding of the distribution of the PRV clusters and their evolution.
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http://dx.doi.org/10.1016/j.vetmic.2015.04.001DOI Listing
June 2015

Analytical performance and clinical results of a fully automated MEIA system for brain natriuretic peptide assay: comparison with a point of care testing method.

Clin Chem Lab Med 2004 ;42(10):1178-85

Laboratory of Cardiovascular Endocrinology, CNR Institute of Clinical Physiology, Pisa, Italy.

The aim of this study was to evaluate the analytical performance of a recently available immunoassay for brain natriuretic peptide (BNP), based on microparticle enzyme immunoassay (MEIA, AxSYM System, Abbott Laboratories), whose analytical characteristics and clinical results were compared with those of a point of care testing (POCT) method (TRIAGE system, Biosite Diagnostics). The within-run and total imprecision of the MEIA system were 18.4% and 19.8% at 21 ng/l, 8.0% and 14.8% at 183 ng/l, and 5.7% and 14.0% at 319 ng/l, respectively. The detection limit of the MEIA system was tested by repeatedly measuring (n=20) the 0 calibrator in four different runs; a mean +3 SD value of 5.6+/-4.8 ng/l (range 1.8-12.6 ng/l) was obtained. A close linear relationship (MEIA= -22.5+/-1.71 POCT method, R=0.950, n=296) was found (BNP concentration: 5-5500 ng/l), with a significant bias (mean difference: 164.8 ng/l, p<0.0001). Mean BNP concentration measured in 94 reference subjects (57 women and 37 men; mean age 43.5+/-14.0 years) was higher with MEIA than POCT, (25.9+/-32.7 ng/l vs. 11.7+/-8.9 ng/l, p<0.0001). The same trend was observed also in 202 cardiac patients (620.6+/-1082.2 ng/l vs. 386.1+/-594.5 ng/l, p<0.0001). Our data suggest that MEIA and POCT have quite similar analytical performance but different clinical results. Then, different reference values, as well as cut-off values, should be taken into account for the clinical use of these two immunoassays.
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http://dx.doi.org/10.1515/CCLM.2004.238DOI Listing
April 2005