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Updated: Jun 28, 2026

Visualizing Bacteria in Nematodes using Fluorescent Microscopy
Published on: October 19, 2012
Nematode-bacteria interactions in bovine parasitic otitis
Makoto Enoki Caracciolo1,2, Erika Verissimo Villela3, Leandro Dos Santos Machado4
1Laboratório de Helmintologia Romero Lascasas Porto, Departamento de Microbiologia, Imunologia e Parasitologia, Universidade do Estado do Rio de Janeiro - UERJ, Rio de Janeiro, RJ, Brasil.
Bovine parasitic otitis is complex, involving nematodes and multidrug-resistant bacteria. Nematodes may facilitate bacterial infections and biofilm formation in cattle ears, complicating treatment.
Area of Science:
- Veterinary Parasitology
- Bacterial Pathogenesis
- Otolaryngology
Background:
- Bovine parasitic otitis is a challenging condition with diverse causative agents including bacteria, fungi, mites, and nematodes.
- The complex interplay between these agents complicates diagnosis and effective treatment strategies in dairy cattle.
Purpose of the Study:
- To investigate the presence and association of nematodes and bacteria in the auditory canals of dairy cattle.
- To characterize the antimicrobial resistance and biofilm-forming capabilities of isolated bacteria.
- To explore the potential role of nematodes in the pathogenicity of bovine otitis.
Main Methods:
- Collection of 20 ear canal samples from dairy cattle in Brazil.
- Identification of nematodes using morphological and molecular techniques.
- Bacterial identification using mass spectrometry and molecular methods (Mycoplasma spp.).
- Antimicrobial susceptibility testing and biofilm formation assays.
- Scanning electron microscopy to visualize nematode-bacteria interactions.
Main Results:
- Nematodes Metarhabditis freitasi and M. costai identified in 75% of samples.
- Bacteria detected in 65% of cattle; Mycoplasma spp. found in 45%.
- Gram-negative bacteria and Mycoplasma spp. exclusively co-occurred with nematodes.
- Isolated bacteria exhibited multidrug resistance.
- Biofilm aggregates observed on nematode cuticles, with 13 bacterial strains showing biofilm formation ability.
Conclusions:
- Nematode-bacteria associations play a significant role in the pathogenicity of bovine parasitic otitis.
- The presence of multidrug-resistant bacteria and biofilm formation by both nematodes and bacteria presents substantial challenges for diagnosis and treatment.
- Further research into nematode-mediated bacterial migration and interaction with host tissues is warranted.
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