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The bacteriology of gangrenous and perforated appendicitis--revisited
R S Bennion1, E J Baron, J E Thompson
1Department of Surgery, Olive View Medical Center, Los Angeles, California.
Abstract:
By using optimum sampling, transport, and culture techniques in patients with gangrenous or perforated appendicitis, we recovered than has previously been reported. Thirty patients older than 12 years with histologically documented gangrenous or perforated appendicitis had peritoneal fluid, appendiceal tissue, and abscess contents (if present) cultured. Appendiceal tissue was obtained so as to exclude the lumen. A total of 223 anaerobes and 82 aerobic or faculatative bacteria were recovered, an average of 10.2 different organisms per specimen. Twenty-one different genera and more than 40 species were encountered. Bacteroides fragilis group and Escherichia coli were isolated from almost all specimens. Within the B. fragilis group, eight species were represented. Other frequent isolates included Peptostreptococcus (80%), Pseudomonas (40% [P. aeruginosa, 23.3%, other Pseudomonas spp., 16.7%]), B. splanchnicus (40%), B. intermedius (36.7%), and Lactobacillus (36.7%). Interestingly a previously undescribed fastidious gram-negative anaerobic bacillus was isolated from nearly one half of all patients. This organism was found to have low DNA homology (by dot blot) with the known organisms most closely resembling it.
Insights
This study identified a higher number of bacteria in appendicitis cases using advanced culture methods. A novel anaerobic bacillus was discovered in nearly half of the patients studied.
Area of Science:
- Microbiology
- Infectious Diseases
Background:
- Appendicitis, particularly gangrenous or perforated forms, involves complex microbial infections.
- Understanding the polymicrobial nature of appendicitis is crucial for effective treatment.
Purpose of the Study:
- To comprehensively identify bacterial species involved in gangrenous or perforated appendicitis.
- To report the recovery of a potentially novel anaerobic bacterium from patient samples.
Main Methods:
- Samples from 30 patients (appendiceal tissue, peritoneal fluid, abscess contents) were cultured using optimized techniques.
- Appendiceal tissue was collected to exclude luminal contamination.
- Bacterial identification involved standard microbiological methods and DNA homology studies.
Main Results:
- A high yield of bacteria was recovered, averaging 10.2 organisms per specimen (223 anaerobes, 82 aerobes/facultatives).
- Common isolates included the Bacteroides fragilis group, Escherichia coli, Peptostreptococcus, and Pseudomonas species.
- A previously undescribed fastidious gram-negative anaerobic bacillus was isolated from nearly 50% of patients, showing low DNA homology to known species.
Conclusions:
- Optimized culture techniques significantly increase bacterial recovery in complicated appendicitis.
- The polymicrobial flora in appendicitis is diverse, with B. fragilis group and E. coli being predominant.
- The discovery of a novel anaerobic bacillus warrants further investigation into its role in appendicitis pathogenesis.