Longitudinal Monitoring of Abscess Microbiota in a Wild California Sea Lion Using Next-Generation Sequencing
A newly published case report in Animals highlights how next-generation sequencing can support microbial monitoring in complex wildlife infections.
The publication, “Longitudinal Monitoring of Abscess Microbiota in a Wild California Sea Lion (Zalophus californianus) Using Next-Generation Sequencing,” describes the use of MiDOG testing to track bacterial changes in a cervical abscess in a rehabilitating wild California sea lion.
The patient, an adult male California sea lion, was admitted to Marine Mammal Care Center Los Angeles with a large neck abscess. Initial MiDOG testing identified Fusobacterium gonidiaformans as the dominant bacterial organism in the lesion. Following treatment, repeat testing showed a major reduction in F. gonidiaformans, while additional bacterial species emerged as the microbial community shifted over time.
This case demonstrates how longitudinal NGS testing can provide more than a single diagnostic snapshot. By monitoring the abscess microbiota across multiple timepoints, clinicians were able to better understand how the bacterial landscape changed during the course of care.
Why This Case Matters
Wildlife and marine mammal infections can be difficult to manage. Many cases are polymicrobial, fast-changing, or complicated by organisms that may be difficult to recover through traditional culture.
In this case, MiDOG testing helped provide:
- Species-level bacterial identification in a complex abscess
- Longitudinal monitoring of microbial changes over time
- Insight into treatment response as the dominant organism decreased
- Visibility into emerging bacterial species after the initial microbial shift
- A broader molecular view to support antimicrobial decision-making
While F. gonidiaformans was successfully reduced during treatment, additional organisms later became visible as the microbial environment changed. This reinforces an important point for complex infection management: the microbial picture can evolve, especially in cases requiring extended care.
Supporting More Informed Wildlife and Marine Mammal Care
For zoo, wildlife, marine mammal, and exotics teams, complex infections often require more than one point of diagnostic information. Longitudinal testing can help clinicians evaluate how microbial communities respond to treatment and whether additional organisms may become clinically relevant over time.
In this case, NGS provided a broader view of the abscess microbiota than traditional methods alone. The findings also underscore the importance of interpreting microbial results in the full clinical context, including patient response, treatment history, and concurrent disease processes.
Although the sea lion ultimately died from complications associated with oropharyngeal squamous cell carcinoma, bacterial pneumonia, and sepsis, the abscess monitoring provided valuable insight into microbial dynamics during rehabilitation.
Advancing Diagnostic Insight in Complex Infections
This publication adds to the growing body of evidence supporting next-generation sequencing as a valuable tool in veterinary medicine, particularly when cases are complex, recurrent, polymicrobial, or difficult to characterize with conventional methods.
By helping clinicians identify organisms and monitor how microbial communities change over time, MiDOG supports a more complete understanding of infection dynamics in both companion animals and non-traditional species.