Characterization of the microbial community colonizing the anal and vulvar pores of helminths from the hindgut of zebras

Abstract

Scanning and transmission electron microscopy were used to examine the adherence and in situ morphology of the microbial community colonizing the anal and vulvar pores of the subfamily Cyathostominae (Nematoda: Strongylidae) from the colon of Burchell's zebra (Equus burchelli antiquorum). Two different morphological types of asporogenous rod were prominent in the microbial community. One was a thin, septate, filamentous organism (0.4 to 0.5 ,um by 2 to 3 ,um) with blunt ends, which was more prominent at the site of attachment. The other was a larger (1.8 to 2.4 ,um by 5 to 10 ,im) multicellular rod with round ends in the form of a trichome. Spiraland vibrio-shaped bacteria were also present in the thin sections. The septate filaments were shown to contain a cell spacer similar to those described in Methanospirillum hungatei. Attachment to the cuticle was by means of an amorphous electron-dense material with fibrillar appearance and not by specialized holdfast segments. Ten isolates were obtained from a habitat-simulating medium on which a homogenate from the posterior region was plated. Antibodies were raised to whole cells of five rod-shaped isolates in rabbits and fluorescein isothiocyanate labeled. Positive bright-yellow fluorescence was obtained with one of the clostridial isolates. The results are discussed with reference to other bacteria with similar morphology, the nature of this unique interrelationship between the microbial community and its parasitic host inside the equine hindgut, and the possibility of biological control of parasitic helminths.

Observations on a Novel Bacterial Pathogen of Root-Knot Nematodes (Meloidogyne spp.)

“…Finally, the BN differed from non-pathogenic, segmented filamentous bacteria with blunt ends attached externally to the cuticle in the anal or vulvar regions or the reproductive tract of cyathostomins from the hindgut of zebras. The diverse community of bacteria reported presented with different and concomitant taxa, some of which were characterized by a Gram-positive reaction, greater dimensions than that of the BN, production of septa, and/or presence of Clostridium-like endospores [34].…”