267. Clinical Significance and Antimicrobial Susceptibility of Clinical Raoultella Species Isolates in Humans
Session: Poster Abstract Session: Antimicrobial Susceptibility and Resistance
Friday, October 21, 2011
Room: Poster Hall B1
Background: Raoultella species  are gram-negative, aerobic bacilli belonging to the Enterobacteriaceae family. Previous studies showed that human infections caused by Raoultella were uncommon and their prevalence, risk factors, and clinical significance were not fully understood. This study was conducted to determine risk factors, clinical significance of Raoultella infections.

Methods: We enrolled all patients with clinical Raoultella isolates in a medical center from 2001 to 2011. Clinical variables reviewed were as follows: patients demographic characteristics, comorbidities, severity of illness, onset of infection, and source of Raoultella isolates and their antibiotic susceptibilities.

Results: A total of 120 Raoultella isolates were collected during the study period. The median age of patients was 67 (range: 2-91) years old. Sixty-two isolates (51.7%) occurred in the community. Seventy-eight isolates (68%) were R. planticola and 42 isolates (32%) were R. ornithinolytica. Of 78 patients with R. planticola, 34 patients (43.6%) had symptomatic infections: pneumonia (14, 41.2%), bacteremia (8, 23.5%), skin and soft tissue infection (SSTI; 6, 17.6%), Urinary tract infection (UTI; 3, 8.8%), bone and joint infection (1, 2.9%), peritonitis (1, 2.9%), and cholangitis (1, 2.9%). Of 42 patients with R. ornithinolytica, 26 patients (62%) had symptomatic infections: pneumonia (9, 35%), UTI (5, 19%), SSTI (4, 15%), peritonitis (4. 15%), bacteremia (3, 12%) and bone and joint infection (1, 4%). Primary foci of bacteremia were as follows: 6 (54.5%) from biliary tract infection, 2 (18.2%) from pneumonia, 2 (18.2%) from primary bacteremia, and 1 (9.1%) from peritonitis. Patients with Raoultella infections had higher SOFA score (P<0.027), receipt of mechanical ventilator (P<0.032), and previous ICU stay (P<0.032) than asymptomatic carriers. All Raoultella isolates had more than 90% susceptibility to nearly all antibiotics except ampicillin and piperacilln.

Conclusion: Previously Raoultella species was a rare human pathogen. However, it has become more common. It caused a variety of illness such as pneumonia, UTI, SSTI and biliary track infection. Further study is required to determine the clinical characteristics of Raoultella infections.

Subject Category: J. Clinical practice issues

Yun-Hong Cheon, MD1, Sunjoo Kim, doctor2 and In-Gyu Bae, MD1, (1)Internal Medicine, Gyeongsang National University School of Medicine, Jinju, South Korea, (2)Gyeongsang National University Hospital, Jinju, Korea, Republic of


Y. H. Cheon, None

S. Kim, None

I. G. Bae, None

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.