ABSTRACT
The genus Alistipes is mailnly isolated from the human gut microbiome and belongs to the phylum Bacteroidetes. Various species of the genus Alistipes have been isolated from samples of human feces, patients with appendicitis, abdominal cavity and rectal abscesses. Currently, this genus includes species such as Alistipes finegoldii, Alistipes putredinis, Alistipes onderdonkii, Alistipes shahii and Alistipes timonensis. Some studies have shown that Alistipes has a protective effect against certain diseases, including pancreatic cancer, Alzheimer′s disease, liver fibrosis and cardiovascular disease. Conversely, other studies have shown that Alistipes is pathogenic in some diseases such as Parkinson′s disease, colorectal cancer and depression. In addition, Alistipes has also been proved to play a paradoxical role in colitis as it can promote the development of colitis and suppress inflammation. This article was to increase the understanding about the genus Alistipes and to further summarize the relationship between Alistipes and diseases.
ABSTRACT
Catabacter hongkongensis is an anaerobic gram-positive coccobacillus that was first isolated in Hong Kong. It is infectious and causes high mortality in patients with rare but underlying diseases. Alistipes indistinctus is an anaerobic gram-negative coccobacillus. This bacterium is a common member of the human intestinal microbiota. We report a case of C. hongkongensis and A. indistinctus isolated from blood cultures of a patient with acute appendicitis. A 35-year-old female patient with no specific medical history was admitted to the hospital due to abdominal pain, vomiting, nausea, and diarrhea experienced on the day before admission. On admission, laboratory tests revealed leukocytosis, neutropenia, and elevated C–reactive protein and procalcitonin levels. Following an abdominal computed tomography showing acute appendicitis with suspected perforation, emergency surgery was performed. Growth was observed in two anaerobic blood culture bottles after four days. After further culturing of the bacteria on Brucella Blood Agar, two types of bacteria were obtained. The two bacterial isolates, one gram-positive and one gram-negative, were unable to be identified using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Thus, 16S rRNA gene sequence analysis was performed, resulting in identification of the bacteria as C. hongkongensis and A. indistinctus. The patient was administered antibiotics and discharged two days after surgery. Although MALDI-TOF MS enables fast and accurate identification of bacteria, C. hongkongensis and A. indistinctus were not listed in the spectral library, and 16S rRNA gene sequence analysis was useful for identifying the two bacteria.