Detection and DNA quantification of Enterococcus casseliflavus in a foal with septic meningitis.

The research study documents an exceptional case of an Enterococcus casseliflavus infection causing septic meningitis in a 3-month-old Hanoverian colt. After extensive genetic testing and clinical examinations, the colt was successfully treated, with the results offering novel insights into treating this specific bacterial infection in equines.

Case Description and Initial Treatment

• The Hanoverian colt was found to exhibit symptoms such as fever, lethargy, inappetence, drooping of the left ear, and stiff neck posture.
• Given these symptoms, empirical antimicrobial treatment and NSAIDs were initially initiated.

Clinical Findings

• Initial findings pointed towards various anomalies in the central nervous system (CNS).
• Endoscopy of the affected horse denoted signs of hyperemia, ecchymosis, and presence of some mucopurulent exudate in the right guttural pouch.
• Hematological evidence suggested a neutrophilic inflammation response in the colt.
• On the third day of hospitalization, severe neurological signs were observed.
• Computed tomography of the skull unveiled a broken axial side of the right mandibular condyle.
• Examination of the cerebrospinal fluid (CSF) demonstrated turbidity, xanthochromia, and presence of intracellular and extracellular cocci, all indicating septic meningitis.

Identification and Quantification of Bacterial Infection

• DNA extraction from blood and CSF samples was undertaken, with the sequenced products from a Polymerase Chain Reaction (PCR) assay of the bacterial 16S rRNA gene identifying a 99% match to Enterococcus casseliflavus.
• Microbial culture of CSF and blood samples revealed bacteria with Enterococcus spp morphology.
• The isolated strain was found to be resistant to vancomycin, which aided in the selection of an appropriate antimicrobial treatment.
• A quantitative PCR assay was used to estimate Enterococcus DNA concentrations in the CSF and blood.

Treatment and Outcome

• Treatment for Enterococcus casseliflavus meningitis was executed with administration of trimethoprim-sulfadiazine and ampicillin sodium, leading to resolution of clinical signs.
• After 12 days of targeted treatment, cultures of CSF and blood samples yielded no growth, indicating the successful eradication of the infection.

Clinical Implications

• The successful treatment of E casseliflavus meningitis in a horse is previously unreported, presenting novel insights for equine healthcare.
• Vancomycin-resistant Enterococci, like the strain in this case, can potentially cause clinical problems and have the potential to be zoonotic in nature.