ABSTRACT
@#Abstract: Objective To analyze the phenotype and drug resistance of Robinsoniella peoriensis strains isolated from the blood of patients with prostate cancer and to learn the epidemiological characteristics of the strains. Methods Culture medium growth characteristics analysis, Gram staining, VITEK MS mass spectrometry identification, in vitro drug susceptibility test, 16S rRNA gene sequencing were performed on the strains, and case summary analysis, historical drug sensitivity results comparison and phylogenetic tree construction were carried out. Results Four of the repeatability tests of mass spectrometry identification were R. peoriensis, and the identification accuracy was 99.9%, which was the first time that mass spectrometry analysis in China accurately detected this strain. The 16S rRNA gene sequencing confirmed that the strain was R. peoriensis, and GenBank accession number is OL826796. There are currently 18 cases of R. peoriensis related to human infection in the world, mainly including bloodstream infection, prosthetic joint infection, and postoperative wound infection. The homology of OL826796 in this case with HGUE-09/943 (GU322806.1) isolated in Spanish was 99.58%; in vitro drug susceptibility showed that OL826796 was resistant to penicillin and clindamycin, and sensitive to vancomycin, imipenem, tetracycline and metronidazole. Statistical analysis of drug susceptibility of 18 cases found that R. peoriensis could be tested for drug susceptibility by E-test method: penicillin 100% (7/7), clindamycin 70% (7/10), ampenem 0% (0/4), metronidazole 0% (0/9), meropenem 0% (0/4), vancomycin 0% (0/3). Conclusion R. peoriensis is a rare anaerobic-positive bacillus. When sterile site infection occurs, attention should be paid to timely communication with clinical reports, and penicillin and clindamycin should be used cautiously to fight infection, so as to improve the cure rate of postoperative immunocompromised patients.
ABSTRACT
Robinsoniella peoriensis has recently been identified as a Gram-positive, spore-forming, anaerobic rod originally recovered from swine manure storage pits. To date, 6 cases of R. peoriensis infection have been reported, including 2 cases of bacteremia, 1 of abdominal fluid collection, and 3 of wound infection. In the present study, we report a 76-yr-old man with R. peoriensis bacteremia who developed aspiration pneumonia. Gram staining of a purified colony revealed Gram-positive, rod-shaped bacteria. Biochemical identification using API 20 A (bioMerieux, France) indicated presence of Clostridium spp. We performed both 500-bp and full-gene sequencing of 16S rRNA of the isolate. The sequence was analyzed with MicroSeq ID 16S rRNA Library v2.0 (Applied Biosystems, USA), GenBank Basic Local Alignment Search Tool (BLAST) (http://www.ncbi.nlm.nih.gov/genbank), and EzTaxon database v2.1 (http://www.eztaxon.org). The 500-bp 16S rRNA sequence of the blood culture isolate showed 99.16-99.79% similarity with R. peoriensis and the full-gene 16S rRNA sequence showed 98.87-99.50% similarity with R. peoriensis. The organism was confirmed as R. peoriensis by using all of the mentioned databases except for MicroSeq, which did not include the RNA sequence of this bacterium. This case suggests that identification of R. peoriensis might be challenging in clinical laboratories with no access to molecular methods, as certain commercial identification systems may not identify, or may misidentify, this organism. To the best of our knowledge, this is the first report of the isolation of R. peoriensis in Korea.