LISTERIOSIS ASSOCIATED WITH RESPIRATORY SYMPTOMS: RARE, BUT DESERVING ATTENTION

Two rare cases of Listeria monocytogenes -(L. monocytogenes) associated respiratory infections were recorded in central Italy during 2020 summer, at a time when hospitals were still in a state of alert for the SARS-CoV2 pandemic. The collaboration between the clinical facilities treating them and Istituto Zooprofilattico Sperimentale dell’Umbria and Marche “Togo Rosati” (IZSUM) and Istituto Zooprofilattico Sperimentale dell’Abruzzo and Molise “G.Caporale” (IZSAM) led to investigate the genome of the responsible bacterium and to close gaps for surveillance.

The rarity of this particular form of listeriosis (a food-borne infection caused by the bacterium Listeria monocytogenes), together with description of the two cases and of procedures followed, are at the core of a scientific report published in the journal Frontiers in Cellular and Infection Microbiology. The two patients, an elderly man suffering from lung cancer and a pregnant woman, arrived at the hospital with symptoms suggesting pneumonia. Ruling out Covid-19 was the first step. Pulmonary imaging revealed pleural empyema (a collection of pus in the pleural cavity) in the elderly and focal lesions in the woman. Subsequently, microbiological cultures of a pleural drainage for the first patient and of a blood sample in the second one led to detection of L. monocytogenes. Then samples were sent to the Fermo branch of the IZSUM, Reference Center for listeriosis surveillance in the corresponding regions. The bacteria were then submitted to the National Reference Laboratory (NRL) for L. monocytogenes of the IZSAM, and analysed by Whole Genome Sequencing in order to deeply investigate the genome for virulence characteristics.

"In both cases - says Dr. Fabrizia Guidi, of the IZSUM Food Control Laboratory, first author of the paper – we identified hypervirulent strains of L. monocytogenes. This feature, combined with patients’ clinical situation (one with cancer and the other pregnant), determined disease severity, with a pulmonary involvement".

“This research - comments Dr. Francesco Pomilio of the NRL for L. monocytogenes of IZSAM - highlights how L. monocytogenes can lead, even if rarely and in particular categories of immunocompromised patients, to complications involving pleura or lungs. It is a possibility to consider, in order to avoid diagnostic delays and to promptly deal with the pathology".

HYPER-VIRULENT LISTERIA MONOCYTOGENES STRAINS ASSOCIATED WITH RESPIRATORY INFECTIONS IN CENTRAL ITALY

Guidi, F., Chiaverini, A., Repetto, A., Lorenzetti, C., Centorotola, G., Bazzucchi, V., Palombo, B., Gattuso, A., Pomilio, F. and Blasi, G. (2021). Hyper-Virulent Listeria monocytogenes Strains Associated With Respiratory Infections in Central Italy. Frontiers in Cellular and Infection Microbiology, 11.

DOI: https://dx.doi.org/10.3389/fcimb.2021.765540