Mucus-Activatable Shiga Toxin Genotype stx2d in Escherichia coli O157:H7

We identified the mucus-activatable Shiga toxin genotype stx2d in the most common hemolytic uremic syndrome–associated Escherichia coli serotype, O157:H7. stx2d was detected in a strain isolated from a 2-year-old boy with bloody diarrhea in Spain, and whole-genome sequencing was used to confirm and fully characterize the strain.

D irofilariosis, caused by Dirofilaria repens or D. immitis nematodes, is a zoonotic filarial infection transmitted through the bite of various mosquitoes.The most frequent manifestations in humans are subcutaneously migrating worms and formation of nodules in various body parts (1).Increasing numbers of human D. repens infections have been reported from Europe, Africa, and Asia (2,3).Austria was considered nonendemic, until the first autochthonous case in a human was reported in 2006 (4) from the most eastern province, the Burgenland, where D. repens nematodes were recently also found for the first time in 2 Anopheles mosquito species (5).We describe a case of imported ocular dirofilariosis caused by the recently newly proposed species Candidatus Dirofilaria hongkongensis (6).
The patient, a 38-year-old woman, had recurrent eyelid swelling in both eyes and conjunctival inflammation with watery discharge beginning in June 2011 (online Technical Results of serologic testing for filariae were negative before and after extraction of the worm, as were results for testing of EDTA blood for microfilariae.Blood test results, including differential blood counts, were within reference ranges throughout the case history.The patient had returned from a 7-week stay in India, including the areas of Goa, Maharashtra, Delhi, and Uttar Pradesh, 3 months before initial onset of symptoms.Her travel history of the preceding 3 years included 4 more trips to India of several weeks each; a 2-week stay in Israel (October 2010); and a 2-week stay in Dubai, United Arab Emirates (July 2009).
The 329 bp COI fragment (accession no.KY750548) showed 99%-100% identity to 2 sequences from Candidatus Dirofilaria hongkongensis (accession nos.KX265050 and JX187591).Identity to D. repens sequences was 95%-96%, to D. immitis 89%, and to Onchocerca spp. up to 92%.The 466 bp mitochondrial 12S rDNA fragment (accession no.KY750549) showed 99% identity to Candidatus Dirofilaria hongkongensis sequences from case-patients in India (accession no.KX265050) and Hong Kong (accession no.KY750550), the latter derived from original material of the first description of Candidatus Dirofilaria hongkongensis (6).Identity to a Dirofilaria sp. from a patient returning from India and Sri Lanka and to Dirofilaria sp.Thailand II, recently reported among dogs in Thailand (accession nos.KX265092 and KX265093) (8), was also 99%.Phylogenetic analysis using the COI sequence clearly placed the sequence into the Candidatus Dirofilaria hongkongensis cluster, the sister taxon to D. repens (Figure).Although D. immitis shows virtually identical COI sequences from 4 continents, genetic variability in D. repens-like parasites is obviously much higher, possibly associated with varying zoonotic potentials, reservoirs, and vectors; however, molecular data on Dirofilaria are still scarce.
In this case, Candidatus Dirofilaria hongkongensis was most likely acquired in India.An infection in Austria seems unlikely because, until now, only 1 singular autochthonous Dirofilaria infection has been reported, and that case was classic D. repens infection (4).Dubai is considered nonendemic for Dirofilaria spp.parasites, whereas Israel is known to be endemic for D. repens nematodes (1,3), but the patient's trips to these countries were much longer ago than her latest trip to India.Moreover, all cases from India or Sri Lanka analyzed by us so far represented Candidatus Dirofilaria hongkongensis (8,9; S. Poppert, unpub.data), suggesting that this species is widely distributed on the Indian subcontinent.In fact, whether classical D. repens infection occurs in India at all is unclear.Infections with Candidatus Dirofilaria hongkongensis nematodes might take a similar course as infections with classical D. repens; however, a case of meningoencephalitis caused by nematodes of this candidate species also has been described (9).Dirofilaria spp.parasites isolated from human case-patients should be investigated by molecular methods to establish an exact species diagnosis, especially if infections were acquired outside Europe.

Figure .
Figure.Phylogenetic analysis of the genus Dirofilaria based on cytochrome C oxidase subunit I gene sequences from a worm surgically extracted from the eye of a patient who had returned to Austria after travel to India.Bootstrap values and results of the Shimodaira-Hasegawa test are shown before and after the slash.The sequence from the current patient is shown in bold, and clusters within Candidatus Dirofilaria hongkongensis, with Dirofilaria repens as the sister taxon.Two samples, classified as Dirofilaria sp.MK-2010 (GenBank accession no.GU474429) and D. repens from Romania (accession no.KU321603), show very high divergence and probably represent different species.The scale bar represents 0.1 substitutions per site.The samples are identified by GenBank accession numbers, country, and host origin, when available.The genera Dirofilaria (D.) and Onchocerca (O.) as well as the Candidatus status (C.) are abbreviated in species names.