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Anaerobic infections in the surgical patient: microbial etiology and therapy
Charles E Edmiston1, Candace J Krepel, Gary R Seabrook
1Divisions of Trauma and Critical Care, Medical College of Wisconsin, Milwaukee, WI, 53226, USA. edmiston@mcw.edu
Abstract:
Anaerobic infections occur in surgical patients in part because of structural or functional defects in the host that (1) cause a breech in the normal mucosal barriers, (2) create localized vascular insufficiencies, or (3) produce an obstruction. Any or all of these events may compromise the oxidation-reduction potential within the tissues, encouraging rapid anaerobic growth. Although diverse anaerobic populations are spread throughout the gastrointestinal tract, a relatively limited number of organisms are responsible for clinical infection in the surgical patient. Many of these offending organisms express overt virulence factors that enhance microbial adherence, tissue destruction, and, in the case of Bacteroides fragilis, facilitate abscess formation. The selection of an appropriate perioperative or therapeutic agent requires a fundamental knowledge of the microbial ecology of this microbial population. The failure to consider the anaerobic flora as a component in the etiology of mixed surgical infections is associated with a high rate of perioperative and therapeutic failures.
Insights
Surgical patients develop anaerobic infections due to host defects compromising tissue oxygenation, favoring bacterial growth. Understanding anaerobic microbial ecology is crucial for effective perioperative and therapeutic strategies to prevent surgical infections.
Area of Science:
- Microbiology
- Surgical Infections
- Host-Pathogen Interactions
Background:
- Anaerobic infections are common in surgical patients, often stemming from host-related issues.
- These issues include breaches in mucosal barriers, vascular problems, or obstructions, which alter tissue oxidation-reduction potential.
- This altered environment promotes the growth of anaerobic bacteria, which are prevalent in the gastrointestinal tract.
Purpose of the Study:
- To highlight the importance of anaerobic bacteria in surgical infections.
- To emphasize the role of specific virulence factors in anaerobic pathogens like Bacteroides fragilis.
- To underscore the necessity of understanding anaerobic microbial ecology for successful treatment.
Main Methods:
- Review of existing literature on anaerobic infections in surgical settings.
- Analysis of the mechanisms by which host defects contribute to anaerobic infections.
- Examination of the virulence factors of common anaerobic pathogens.
Main Results:
- Host defects (barrier breaches, vascular insufficiency, obstruction) create favorable conditions for anaerobic growth.
- A limited number of anaerobic organisms, many with specific virulence factors, cause most clinical infections.
- Bacteroides fragilis is noted for its role in abscess formation.
Conclusions:
- Knowledge of anaerobic microbial ecology is essential for selecting appropriate perioperative and therapeutic agents.
- Failure to account for anaerobic flora in mixed surgical infections leads to poor patient outcomes.
- Addressing anaerobic components is critical for reducing perioperative and therapeutic failures.