Polymicrobial Foot Infection Patterns Are Common and Associated With Treatment Failure
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Published on: April 19, 2024
Neal R Barshes1,2,3, Nicholas J Clark4, Deeksha Bidare5
1Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas, USA.
Background:
That foot infections are predominately polymicrobial has long been recognized, but it is not clear if the various species co-occur randomly or in patterns. We sought nonrandom species co-occurrence patterns that might help better predict prognosis or guide antimicrobial selection.
Methods:
We analyzed tissue (bone, skin, and other soft tissue), fluid, and swab specimens collected from initial foot infection episodes during a 10-year period using a hospital registry. Nonrandom co-occurrence of microbial species was identified using simple pairwise co-occurrence rates adjusted for multiple comparisons, Markov and conditional random fields, and factor analysis. A historical cohort was used to validate pattern occurrence and identify clinical significance.
Results:
In total, 156 unique species were identified among the 727 specimens obtained from initial foot infection episodes in 694 patients. Multiple analyses suggested that Staphylococcus aureus is negatively associated with other staphylococci. Another pattern noted was the co-occurrence of alpha-hemolytic Streptococcus, Enterococcus fecalis, Klebsiella, Proteus, Enterobacter, or Escherichia coli, and absence of both Bacteroides and Corynebacterium. Patients in a historical cohort with this latter pattern had significantly higher risk-adjusted rates of treatment failure.
Conclusions:
Several nonrandom microbial co-occurrence patterns are frequently seen in foot infection specimens. One particular pattern with many Proteobacteria species may denote a higher risk for treatment failure. Staphylococcus aureus rarely co-occurs with other staphylococci.
Insights
Foot infections often involve multiple microbes. Researchers found specific microbial patterns, not random ones, which can predict treatment failure and guide antibiotic choices for better patient outcomes.
Area of Science:
- Microbiology
- Infectious Diseases
- Clinical Medicine
Background:
- Foot infections are typically polymicrobial, meaning they involve multiple types of microorganisms.
- The specific co-occurrence patterns of these microbes in foot infections are not well understood.
- Identifying these patterns could improve treatment strategies and patient prognoses.
Purpose of the Study:
- To investigate nonrandom microbial species co-occurrence patterns in foot infections.
- To determine if these patterns can predict treatment outcomes or guide antimicrobial selection.
- To understand the complex microbial communities in diabetic foot infections.
Main Methods:
- Analysis of tissue, fluid, and swab specimens from initial foot infection episodes over 10 years.
- Utilized statistical methods including pairwise co-occurrence rates, Markov and conditional random fields, and factor analysis.
- Validated identified patterns in a historical patient cohort to assess clinical significance.
Main Results:
- Identified 156 unique species across 727 specimens from 694 patients.
- Found that *Staphylococcus aureus* rarely co-occurs with other staphylococci.
- Observed a pattern involving alpha-hemolytic *Streptococcus*, *Enterococcus fecalis*, *Klebsiella*, *Proteus*, *Enterobacter*, and *Escherichia coli* with the absence of *Bacteroides* and *Corynebacterium*.
Conclusions:
- Established that microbial co-occurrence in foot infections is nonrandom.
- A specific pattern, particularly with *Proteobacteria* species, is associated with a higher risk of treatment failure.
- Understanding these microbial consortia is crucial for effective management of foot infections.
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