448. Extraintestinal Pathogenic Escherichia coli (ExPEC) Pneumonia in Cancer Patients
Session: Poster Session: Hospital-acquired and Transplant Infections
Friday, October 30, 2009: 12:00 AM
Room: Poster Hall A
Background: Escherichia. coli is the most common isolated Gram negative bacilli in patients with bacteremia and constitutes a serious threat to compromised such as cancer patients. The virulence factors (VFs) of E. coli and the characteristics of the disease have not been studied.
Methods: E. coli isolates recovered from respiratory samples from cancer patients (July 07-June 08) were analyzed using established PCR assays for detection of ExPEC (≥2 of the following VFs: papA or papC, afa, sfa, iutA and kpsii). The clinical characteristics of the disease, laboratory and radiologic findings as well as outcome were collected.
Results: E. coli were recovered from 33 patients. Only 21 fulfilled the IDSA/ATS definition of HAP or HCAP (7 from BAL, 12 from sputum and 2 from tracheostomy aspirate). The mean age was 65 years old with a 2:1 male to female ratio. Four patients had hematologic malignancies and 81% had a solid tumor (35% lung cancer). Nine patients had polymicrobial infections and only one patient had E. coli bacteremia. Radiological imaging showed consolidations in 85% of the cases. Average APACHE II score was 13. Nine cases required ICU care and two (9.5%) of them died secondary to the infection. Of the 21 E. coli isolates recovered, only 10 (50%) met the criteria for ExPEC. The iutA gene that encodes aerobactin receptor was the only virulence factor identified in the fatal cases.
Conclusion: E. coli pneumonia in cancer patients is uncommon. It usually affects elderly patients. Our E. coli isolates have less virulence factors identified than E. coli isolates infecting non-cancer patients.
Javier Adachi, MD, Dept. of Infectious Diseases, Infection Control and Employee Health, The University of Texas M. D. Anderson Cancer Center, Houston, TX, Nadim Ajami, BS, The University of Texas Health Science Center at Houston, Houston, TX, Herbert DuPont, MD, FIDSA, St. Luke's Episcopal Hospital and Kelsey Research Foundation and Kelsey-Seybold Clinic, Houston, TX, Zhi-Dong Jiang, MD, PhD, University of Texas at Houston, School of Public Health, Houston, TX, Jeffrey Tarrand, MD, M.D. Anderson Cancer Center, Houston, TX, Karen Vigil, MD, The University of Texas M. D. Anderson Cancer Center, Houston, TX and  K. J. Vigil, None..
J. A. Adachi, None..
N. Ajami, None..
J. Tarrand, None..
Z. Jiang, None. 
H. L. DuPont,
Salix Pharmaceutical Company Role(s): Consultant, Received: Research Grant, Speaker Honorarium.
Romark Institute for Medical Research Role(s): Consultant, Received: Consulting Fee.
Optimer Pharmaceuticals and IOMAI Corporation Role(s): Research Relationship, Received: Research Grant.
McNeil Consumer Healthcare and Merck Vaccine Division Role(s): Consultant, Speaker's Bureau, Received: Speaker Honorarium, Consulting Fee.