Is Cytotoxin K from XXXX a bona fide enterotoxin?

@entity66 @entity6766 @entity71810 @entity751 @entity5259
UNASSIGNED: Cytotoxin K (CytK) produced by @entity5259 s.l. has generally been considered to be associated with the @entity6766 . Two distinct variants of CytK have been reported: CytK-1 from @entity71810 and CytK-2 from @entity5259 . In order to determine whether CytK plays a significant role in the @entity66 , the occurrence of cytK genes was assessed among 390 @entity5259 isolates with different origins including clinical and @entity6766 samples and was found to be 46%. Interestingly, the cytK occurrence was slightly lower in @entity6766 and clinical isolates than in environmental samples. Seventy cytK-2 positive strains (including 28 isolates from foodborne outbreaks) were then selected in order to assess their genetic diversity. A genetic dendrogram based on the cytK-2 sequences of these 70 strains and on two cytK-1 sequences from strains NVH 391-98 and 883-00 showed an important diversity. However, no strain clustering according to the origin or source of isolation was observed. These observations were confirmed by Multi-Locus Sequences Typing (MLST) based on five different loci of housekeeping genes (ccpA, recF, sucC, purF and gdpD) for which no grouping of foodborne outbreak strains could be identified. Therefore, the choice of cytK as virulence factor for the diarrhoeal pathotype does not seem to be relevant per se, even though the involvement of CytK in the @entity751 cannot be fully excluded. Potential synergistic effects between CytK and other virulence factors, together with their potential variable expression levels should be further investigated.
