Characteristics of an Unusual Anaerobic Pigmented Gram‐Negative Rod Isolated from Normal and Inflamed Appendices

Abstract

During our studies of the bacterial etiology of appendicitis, we often isolated a previously undescribed anaerobic gram-negative rod. This organism resembled the Bacteroides fragilis group because it was resistant to bile and because of its special-potency-disk pattern (resistant to vancomycin, kanamycin, and colistin), but unlike the B. fragilis group, this bacterium produced brown pigment on media containing hemolysed blood. The cellular fatty acid pattern, with iso-C15:0 being the predominant acid, was most closely related to the fatty acid profile of Porphyromonas species; however, this organism differed from Porphyromonas species by being bile-resistant and by not producing butyrate as a metabolic endproduct. Enzymatic activities of 31 isolates were determined with use of the API ZYM system and Rosco diagnostic tablets. These profiles were different from those of Prevotella, Porphyromonas, and related species. This organism was isolated from 40% of appendiceal tissue samples; no obvious qualitative or quantitative difference in rates of isolation from patients with inflamed or normal appendices was observed.

Gastrointestinal Microbiome Signatures of Pediatric Patients With Irritable Bowel Syndrome

“…Finally, several taxa of the genus Alistipes were associated with the phenotype of frequently recurrent abdominal pain. One example from this genus, Alistipes putredinis , resembles members of the Bacteroides fragilis group 35, 36 , and is considered to be a commonly found gut commensal microbe of the Bacteroidetes phylum 37 . This species has been isolated from inflamed and non-inflamed intestinal tissues in studies of the bacteriology of appendicitis in children 35,38 .…”

Complete genome sequence of the bile-resistant pigment-producing anaerobe Alistipes finegoldii type strain (AHN2437T)

“…This strain is one of several strains with similar properties [3] that were isolated mainly from pediatric patients with inflamed, gangrenous or non-inflamed appendices [4,5]. Though the type strain AHN2437 T resembled members of the Bacteroides fragilis group in bile-resistance and positive indole reaction, it was found, together with the type strain of Bacteroides putredinis, to form a separate phylogenetic lineage apart from authentic Bacteroides species [1].…”

Alistipes finegoldiiin Blood Cultures from Colon Cancer Patients

“…With routine tests, this organism resembled members of the Bacteroides fragilis group; however, the cellular fatty acid composition dominated by iso -C15:0 and production of brown pigment on media containing hemolyzed blood suggested that the organism was most closely related to the genus Porphyromonas ( 1 ). However, 16S rDNA sequence comparison showed highest sequence relatedness with B. putredinis, and the reclassification of B. putredinis in a novel genus, Alistipes , and the classification of the novel bacterium as A. finegoldii were proposed ( 4 ).…”

“…To the Editor: Alistipes finegoldii was previously isolated from appendiceal tissue samples in children with acute appendicitis and from perirectal and brain abscess material ( 1 , 2 ). 16S rDNA sequencing studies showed that this bacterium clustered with A. putredinis (Figure) in the Bacteroidetes group ( 4 ).…”

“…A novel bacterium was characterized from appendiceal tissues samples from children with appendicitis and in 2 cases of perirectal and brain abscesses associated with other anaerobes ( 1 ). With routine tests, this organism resembled members of the Bacteroides fragilis group; however, the cellular fatty acid composition dominated by iso -C15:0 and production of brown pigment on media containing hemolyzed blood suggested that the organism was most closely related to the genus Porphyromonas ( 1 ).…”