Background: the nature of alpha-D-mannose - natural aldohexose sugar, C-2 glucose epimer, whose intended use is for preventing urinary tract infections - in the interaction with E. coli is addressed in order to drive the issue of its regulatory classification as a medicinal product or medical device. Methods: PRISMA systematic review approach was applied; Delphi Panel method used to target consensus on statements retrieved from evidence. Results: Based of regulatory definitions and research evidences, the mechanism of D-mannose does not involve a metabolic or immunological action while there is an uncertainty regarding the pharmacological action. Specific interaction between the product and the bacteria within the body occurs, but its nature is inert: it does not induce a direct response activating or inhibiting body processes. Moreover, the action of D-mannose takes place, even if inside the bladder, outside the epithelium on bacteria that have not yet invaded the urothelial tissue. Therefore, its mechanism of action is not directed to host structures but to structures (bacteria) external to the host's tissues. Conclusions: From a regulatory perspective, D-mannose maintains the current medical device classification: new regulations and legal judgments can add further considerations. From a pharmacological perspective, research is driven versus synthetic mannosides: no further considerations are expected on alpha-D-mannose.

A 40 years old male Nile crocodile (Crocodylus niloticus) was diagnosed with pulmonary mycobacteriosis caused by a member of Mycobacterium chelonae/abscessus group. Post-mortem examination showed a severe systemic visceral granulomatous involvement, with lesions in lungs, heart, liver, spleen and kidneys. Histopathological examination of lung, spleen, heart and liver revealed multifocal to coalescing granulomas showing eterophils in central zone and outer rim of epithelioid histiocytes, multinucleated giant cells and lymphocytes. The Ziehl–Neelsen histological staining revealed rare vacuoles containing numerous alcohol-acid resistant bacteria. Mycobacterial infection was confirmed by culture and PCR targeting rRNA 16S gene. Sequence analysis of the DNA amplicon revealed a 100% homology with the M. chelonae/ abscessus group. Even if the classification of the memebrr of this group is still on updating, to the best of our knowledge, this is the first report of M. chelonae/abscessus member infection in a Nile crocodile species.