A MALDI-TOF MS database for fast identification of Vibrio spp. potentially pathogenic to marine mollusks.

In mollusk aquaculture, a large number of Vibrio species are considered major pathogens. Conventional methods based on DNA amplification and sequencing used to accurately identify Vibrio species are unsuitable for monitoring programs because they are time-consuming and expensive. The aim of this study was, therefore, to develop the MALDI-TOF MS method in order to establish a rapid identification technique for a large panel of Vibrio species. We created the EnviBase containing 120 main spectra projections (MSP) of the Vibrio species that are potentially responsible for mollusk diseases, comprising 25 species: V. aestuarianus, V. cortegadensis, V. tapetis and species belonging to the Coralliilyticus, Harveyi, Mediterranei, and Orientalis clades. Each MSP was constructed by the merger of raw spectra obtained from three different media and generated by three collaborating laboratories to increase the diversity of the conditions and thus obtain a good technique robustness. Perfect discrimination was obtained with all of the MSP created for the Vibrio species and even for very closely related species as V. europaeus and V. bivalvicida. The new EnviBase library was validated through a blind test on 100 Vibrio strains performed by our three collaborators who used the direct transfer and protein extraction methods. The majority of the Vibrio strains were successfully identified with the newly created EnviBase by the three laboratories for both protocol methods. This study documents the first development of a freely accessible database exclusively devoted to Vibrio found in marine environments, taking into account the high diversity of this genus. KEY POINTS: • Development of a MALDI-TOF MS database to quickly affiliate Vibrio species. • Increase of the reactivity when faced with Vibrio associated with mollusk diseases. • Validation of MALDI-TOF MS as routine diagnostic tool.

A European epidemiological survey of Vibrio splendidus clade shows unexplored diversity and massive exchange of virulence factors.

The Vibrio splendidus clade has previously been associated with epidemic outbreaks of various aquatic animals, as in the case of the cupped oyster, Crassostrea gigas. To investigate whether involved strains could present a clonal origin and to identify possible alternative background carriage animals or zooplankton, a large epidemiological survey was conducted on isolates of the splendidus clade. For this purpose, Vibrio strains were isolated from various samples including oysters, mussels, sediments, zooplankton, and sea water on the basis of a North/South gradient of the European sea water zone (Ireland, The Netherlands, France, Italy, and Spain). A total of 435 isolates were successfully associated to the V. splendidus clade using real time polymerase chain reaction with 16S specific primers and probes. A multiple-locus variable-number tandem-repeat analysis (VNTR) was conducted on all isolates based on a multiplex PCR-VNTR with a set of primer pairs designed from the V. tasmaniensis LGP32 genome. Preliminary validation of the primers on a set of collection strains from the V. splendidus clade confirmed that the former V. splendidus-related LGP32 and relative strains were related to V. tasmaniensis rather than to the type strain V. splendidus LMG 4042. The VNTR analysis was then successfully conducted on 335 isolates which led to the characterization of 87 different profiles. Our results showed that (1) the high diversity of VNTR did not enlighten significant correlation between a specific pattern and the origin of collected samples. However, populations isolated from animal samples tend to differ from those of the background environment; (2) oyster mortality events could not be linked to the clonal proliferation of a particular VNTR type. However, few different patterns seemed successively associated with samples collected during peaks of oyster's mortality. (3) Finally, no correlation could be seen between specific VNTR patterns and sequence phylogeny of the virulence factors vsm and ompU that were detected among strains isolated during as well as outside mortality events. These results, combined with incongruence observed between the ompU and vsm phylogenetic trees, suggested both large diffusion of strains and massive lateral gene transfer within the V. splendidus clade.

Peripheral neuropathy in systemic vasculitis: clinical and electrophysiologic study of 22 patients.

Twenty-two patients with evidence of systemic vasculitis and peripheral neuropathy were clinically and electrophysiologically investigated in a retrospective study. Ten had a polyarteritis nodosa, 6 a probable polyarteritis nodosa, and 6 a Churg-Strauss syndrome. Nine patients presented clinically with mononeuropathy or mononeuropathy multiplex considered typical of ischemic involvement of peripheral nerve; nine had more diffuse neuropathy, two of them a symmetric polyneuropathy. EMG examination revealed more diffuse neuropathy than clinically predicted. Findings were of acute or subacute axonal neuropathy.

[The anterior interosseous nerve syndrome. A rare lesion of a median nerve branch in the forearm. A case]. / Le syndrome du nerf interosseux antérieur. Une atteinte rare d'une branche du nerf médian à l'avant-bras. Une observation.

Apparently spontaneous and isolated lesions of the anterior interosseous nerve--a purely motor branch of the median nerve in the forearm--are extremely rare. Their clinical manifestations are fairly stereotyped, consisting of paralysis restricted to the long flexor muscle of the thumb, the deep flexor muscle of the index finger and the quadrate pronator muscle, without sensory disorders. The diagnosis is confirmed by electromyography. The syndrome may caused by traumas of the forearm or may develop spontaneously, although underlying anatomical abnormalities which may act as predisposing factors are not infrequently found in this case. The natural outcome may be favourable, but surgery may be required to release the nerve.

[Peripheral neuropathies associated with monoclonal gammapathies. Value of electrophysiologic studies]. / Les neuropathies péripheriques associées aux gammapathies monoclonales. Intérêt des études électrophysiologiques.

An electrophysiological study was performed in 19 patients with polyneuropathy associated with a monoclonal gammopathy. This study has shown some difference according to the type of the gammopathy and the benign or malignant nature of the disease. Patients with benign IgM gammopathy are in an homogenous group. In every case the neuropathy is of the demyelinating type. In the other groups, the neuropathy is less homogenous. Most of the time it was predominantly of axonal type. Within the myeloma group, the neuropathy is more severe and the denervation pattern is marked.