Search Results (3)

A herd of approximately 300 Spanish meat goats in central Alabama experienced sporadic ocular, respiratory, and reproductive diseases over two years, prompting diagnostic investigation at Auburn University’s JT Vaughan Large Animal Teaching Hospital. Five representative doelings exhibiting ocular lesions were examined. Clinical signs included conjunctivitis, corneal opacity, uveitis, and, in one severe case, systemic illness. Initial treatment with topical and systemic antibiotics provided incomplete resolution, raising suspicion of infectious keratoconjunctivitis of atypical etiology. Comprehensive diagnostic testing was performed, including aerobic and Mycoplasma cultures, Giemsa staining, and molecular assays. Moraxella bovoculi was cultured; however, Giemsa staining revealed Chlamydia elementary bodies, and a FRET-qPCR with DNA sequencing confirmed high Chlamydia pecorum loads (up to 1.1 × 10⁷ copies/swab). Mycoplasma testing was negative. Extended treatment with systemic and topical oxytetracycline led to gradual clinical improvement, with C. pecorum DNA declining over 22,000-fold and becoming undetectable after five weeks. This case represents the first documented report of C. pecorum–associated keratoconjunctivitis in goats in the United States. The findings underscore the diagnostic importance of molecular assays for detecting intracellular pathogens that may be missed by culture. The protracted treatment course highlights the therapeutic challenges posed by chlamydial infections due to their intracellular persistence. Additionally, the concurrent detection of M. bovoculi suggests the potential for mixed infections influencing disease severity. These results emphasize C. pecorum as an emerging pathogen of caprine ocular disease with implications for herd health and management. Full article

Mycoplasma spp. are facultative pathogens that contribute to the pathogenesis of multiple bovine diseases, including the bovine respiratory disease complex, and have been shown to form biofilms. Biofilm formation is associated with increased antibiotic resistance in many organisms, but accurate determination of antimicrobial susceptibility in biofilms is challenging. In Mycoplasma spp., antimicrobial susceptibility is routinely determined using metabolic pH-dependent color change. However, biofilm formation can lead to reduced metabolism, making interpretation of metabolic readouts difficult. Therefore, we developed and optimized a new flow cytometry-based method for antimicrobial susceptibility testing in biofilm-forming Mycoplasma, termed the live/dead antimicrobial susceptibility test (LD-AST). The LD-AST measures the proportion of live bacteria upon exposure to antibiotics, works robustly with both planktonic and biofilm cultures, and enables the determination of the minimum bactericidal concentration (MBC) for a given antibiotic. We used two strains of Mycoplasma bovis (Donetta PG45 and Madison) and two clinical Mycoplasma bovoculi isolates (MVDL1 and MVDL2) to determine the impact of biofilm growth on antimicrobial susceptibility for gentamicin, enrofloxacin, or tetracycline. All Mycoplasma strains were susceptible to all antibiotics when cultured as planktonic cells, with MBCs in the expected range. However, three out of four strains (Donetta PG45, MVDL1, and MVDL2) were completely resistant to all three antibiotics when newly adhered biofilms were analyzed, whereas M. bovis Madison gave variable results. For mature biofilms that were cultured for 4–5 days before antibiotic exposure, results also were variable, with some strains showing an increased resistance with certain antibiotics and a decreased resistance with others. Overall, these results are consistent with earlier reports that biofilms can exhibit increased antimicrobial resistance. Full article

A randomized control trial was performed over a five-year period to assess the efficacy and antibody response induced by autogenous and commercial vaccine formulations against infectious bovine keratoconjunctivitis (IBK). Calves were randomly assigned each year to one of three arms: an autogenous vaccine treatment that included Moraxella bovis (M. bovis), Moraxella bovoculi, and Mycoplasma bovoculi antigens, a commercial M. bovis vaccine treatment, or a sham vaccine treatment that consisted only of adjuvant. A total of 1198 calves were enrolled in the study. Calves were administered the respective vaccines approximately 21 days apart, just prior to turnout on summer pastures. Treatment effects were analyzed for IBK incidence, retreatment incidence, 205-day adjusted weaning weights, and antibody response to the type IV pilus protein (pili) of M. bovis as measured by a novel indirect enzyme-linked immunosorbent screening assay (ELISA). Calves vaccinated with the autogenous formulation experienced a decreased cumulative incidence of IBK over the entire study compared to those vaccinated with the commercial and sham formulations (24.5% vs. 30.06% vs. 30.3%, respectively, p = 0.25), and had less IBK cases that required retreatment compared to the commercial and sham formulations (21.4% vs. 27.9% vs. 34.3%, respectively, p = 0.15), but these differences were not significant. The autogenous formulation induced a significantly stronger antibody response than the commercial (p = 0.022) and sham formulations (p = 0.001), but antibody levels were not significantly correlated with IBK protection (p = 0.37). Full article