Characteristics of Respiratory Tract Infection in the Hematopoietic Stem Cell Transplantation Population

Lee, Dong Gun; Park, Sang Tae; Na, Byoung Kuk; Choi, Jung Hyun; Shin, Wan Shik; Paik, Soon Young; Shin, Ju Mi; Kang, Chun; Kim, Woo Joo; Lee, Hoan Jong; Kim, Chun Choo

Abstract

PURPOSES: The respiratory tract infection is one of the most prevalent and serious complications following hematopoietic stem cell transplantation (HSCT). Reports not only for the respiratory tract infection but, unlikely for bacteria or fungi, for the infections caused by the respiratory viruses have been rarely reported in Korea. During the winter of 2000~2001, authors wanted to know the prevalence rate of the respiratory tract infection and the kinds of causative microorganisms, especially the community respiratory viruses (CRV). Based on these data, we attempted to evaluate the clinical courses and prognosis of the patients.
METHODS
From October 2000 to February 2001, specimens were collected from the patients who visited Catholic hemopoietic stem cell transplantation center, showing symptoms and signs of respiratory tract infection after HSCT. Standard methods have been applied to isolate and identify bacterial and fungal species. Measles was diagnosed based on the typical symptoms, rash, fever, and Koplik spot. For the four different CRV (adenovirus, RSV, influenza virus, parainfluenza virus), multiplex PCR and conventional culture method were used for the identification.
RESULTS
Eighty-four specimens were collected from 66 patients for 4 month period. Average age of patients was 35+/-8 years. Sixty patients (90%) were received allogeneic HSCT. Sample collection was performed between 10 and 3,740 days (average 370 days, median 215 days) after HSCT. Forty-seven patients (71.2%) have been received immunosuppressants at the time of respiratory tract infection. Forty patients (60.6 %) were suffered lower respiratory tract infection and forty-four patients (66.7%) had community-acquired infection. Sixty microorganisms were identified from 45 patients out of total 66 patients. Identified microoganisms were bacteria accounting for 2 cases (3.4%), fungi for 11 (18.3%), tuberculosis for 5 (8.3%), and viruses for 42 (70.0%). Among viruses, 16 cases were measles (39%), 14 adenovirus (33%), 9 cytomegalovirus (21%), 2 parainfluenza virus (5%), 1 was influenza virus (2%). However, no RSV was identified. Most of patients showed good prognosis without any complications. Ten (15.2%) out of total 66 patients were expired. The direct cause of death for all 8 among 10 patients was pneumonia.
CONCLUSION
Of the respiratory tract infection fol-lowing HSCT, most common causative microorganisms were viruses - measles, adenovirus in order. No case of RSV infection was found. No epidemic must be occurred by influenza virus because only 1 case was found. Fourteen patients were infected by more than one microorganisms. Overall mortality rate was 15.2%. This study is still undergoing and once accumulated data for more than 1 year, it might be possible to work out a strategies of treatment and prevention for respiratory tract infections. We also expect that these data might be able to provide the basis of efficient infection control in HSCT unit.