Severe meningoencephalitis secondary to calvarial invasion of Lagenidium giganteum forma caninum in a dog

Background: The oomycete Lagenidium giganteum forma caninum is an uncommon cause of severe dermal and subcutaneous infections in dogs with possible vascular invasion and other fatal sequelae. Infection within the central nervous system of affected dogs has not been previously reported.Case Description: A 6-year-old spayed female mixed-breed dog was evaluated at a referral institution with a 2-month history of suspected fungal infection in the region of the right mandibular lymph node that was refractory to surgical resection and empiric medical therapy. Physical examination identified a 6-cm fluctuant subcutaneous mass caudoventral to the ramus of the right mandible and a second firm mass in the region of the right caudal maxilla. Lesional punch biopsies were submitted for fungal culture and polymerase chain reaction (PCR), which subsequentlyidentified L. giganteum forma caninum infection. Initial treatment consisted of anti-inflammatory doses of prednisone and hyperbaric oxygen therapy. Four weeks following initial evaluation, the patient was presented with progressive neurological signs consistent with a forebrain lesion. Magnetic resonance imaging revealed soft-tissue, contrastenhancing lesions ventral to the calvarium adjacent to the site of original surgical resection and throughout the brain. Humane euthanasia was elected, and postmortem examination was consistent with the extension of local disease from the right masseter muscle into the right ventral calvarium. Postmortem DNA sequencing confirmed the identity of the organism as L. giganteum forma caninum.Conclusion: This is the first reported case of intracranial lagenidiosis in the dog. PCR distinguished this species from other Lagenidium species and from oomycetes of other genera, such as Pythium insidiosum and Paralagenidium karlingii. Regional extension of cutaneous lagenidiosis should therefore be considered in cases with concurrent or spontaneous neurologic disease. Keywords: Hyperbaric oxygen therapy, Lagenidium giganteum forma caninum, Neurologic disease, Oomycete.

Transcriptome Analysis of the Entomopathogenic Oomycete Lagenidium giganteum Reveals Putative Virulence Factors

ABSTRACTA combination of 454 pyrosequencing and Sanger sequencing was used to sample and characterize the transcriptome of the entomopathogenic oomyceteLagenidium giganteum. More than 50,000 high-throughput reads were annotated through homology searches. Several selected reads served as seeds for the amplification and sequencing of full-length transcripts. Phylogenetic analyses inferred from full-length cellulose synthase alignments revealed thatL giganteumis nested within the peronosporalean galaxy and as such appears to have evolved from a phytopathogenic ancestor. In agreement with the phylogeny reconstructions, full-lengthL. giganteumoomycete effector orthologs, corresponding to the cellulose-binding elicitor lectin (CBEL), crinkler (CRN), and elicitin proteins, were characterized by domain organizations similar to those of pathogenicity factors of plant-pathogenic oomycetes. Importantly, theL. giganteumeffectors provide a basis for detailing the roles of canonical CRN, CBEL, and elicitin proteins in the infectious process of an oomycete known principally as an animal pathogen. Finally, phylogenetic analyses and genome mining identified members of glycoside hydrolase family 5 subfamily 27 (GH5_27) as putative virulence factors active on the host insect cuticle, based in part on the fact that GH5_27 genes are shared by entomopathogenic oomycetes and fungi but are underrepresented in nonentomopathogenic genomes. The genomic resources gathered from theL. giganteumtranscriptome analysis strongly suggest that filamentous entomopathogens (oomycetes and fungi) exhibit convergent evolution: they have evolved independently from plant-associated microbes, have retained genes indicative of plant associations, and may share similar cores of virulence factors, such as GH5_27 enzymes, that are absent from the genomes of their plant-pathogenic relatives.

Studies on Fungal Cultural Filtrates against AdultCulex quinquefasciatus(Diptera: Culicidae) a Vector of Filariasis

Entomopathogenic fungi have significant potential to control mosquito population. The culture filtrates ofFusarium oxysporum, Lagenidium giganteum, Trichophyton ajelloi,andCulicinomyces clavisporuswere evaluated against adults ofCx. quinquefasciatus. The culture filtrates were obtained by filtering the broth through Whatman-1 filter paper. These culture filtrates ofC. clavisporushave been found significantly pathogenic with LC50-2.5, LC90-7.24, and LC99-8.7 ML, respectively, after exposure of 24 h. However, the culture filtrates when were combined, in ratios 1 : 1 : 1 ofFusarium oxysporum, Lagenidium giganteum, Trichophyton ajelloithe mortalities were significantly increased. The LC50-3.71, LC90-8.12, and LC99-11.48 were significantly recorded after exposure of 10 hrs. Similarly, the culture filtrates ofT. ajelloi, Culicinomyces clavisporus,andL. giganteumhave been combined in ratios 1 : 1 : 1. Similarly the LC50-1.94, LC90-4, and LC99-6.16 ML Were recorded after exposure of 10 hrs. The results of present study show promise for the use of selected fungal metabolites for control ofCx. quinquefasciatusin the Laboratory.