Causative pathogens of fever in neutropenic patients at King Chulalongkorn Memorial Hospital.

Background: Infections cause substantial morbidity and morbidity in neutropenic patients. In King Chulalongkorn Memorial Hospital, Gram-negative bacteria remained the most common causative pathogen of febrile neutropenia in all three studies conducted before 2002. However, Gram-positive bacteria have become more commonly isolated etiologic pathogens, and the incidence of fungal infection has been increasing since 2005.
Objective: Determine the infectious etiology of fever in neutropenic patients at King Chulalongkorn Memorial Hospital, Bangkok, Thailand.
Material and Method: A retrospective chart review of all medical records of febrile neutropenic patients hospitalized at Department of Medicine between January 1 and December 31, 2006 in accompanying with microbiologic, radiologic, and serologic results was analyzed.
Results: There were 125 patients (61 males and 64 females) and 172 episodes of febrile neutropenia with a mean age of 46.5 +/- 18.5 years (range: 15-81 years). The three most common primary diseases associated with neutropenia were acute myeloid leukemia, non-Hodgkin's lymphoma, and acute lymphoblastic leukemia (36.6%, 33.1%, and 10.5%). Infections could be documented microbiologically and clinically in 84 episodes (48.8%), and primary bacteremia or fungemia was the most common cause of infection (40.5%). Gram-negative bacteria were the most frequently isolated pathogens (63.9%), followed by Gram-positive bacteria (29.9%) and fungi (6.2%). Escherichia coli (46.8%) and coagulase-negative Staphylococcus (27.6%) were the most common isolates among Gram-negative and Gram-positive bacteria, respectively. Among 53 episodes (30.8%) of bloodstream infections, Gram-negative bacteria were the most commonly isolated pathogens (38 episodes, 71.7%), followed by Gram-positive bacteria (19 episodes, 35.8%) and Candida tropicalis (1 episode, 1.9%). Surprisingly, invasive mold infections were noted in eight episodes (5, 1, and 2 episodes of proven, probable, and possible infections, respectively). The overall mortality was 19.2%.
Conclusions: Although Gram-negative bacteria are the most common etiology of fever in neutropenic patients, the occurrence of infections caused by coagulase-negative Staphylococcus and molds has been increasing in comparison with the observations from previous studies in King Chulalongkorn Memorial Hospital. To authors knowledge, the present study is the first in Thailand to determine the occurrence of invasive fungal infections using the standard criteria recommended by EORTC/MSG.