Nosocomial infections in leukemic and solid-tumor cancer patients: distribution, outcome and microbial spectrum of anaerobes

Aims: Nosocomial infections cause significant morbidity and mortality in cancer patients. As a result of their debilitated immune system, cancer patients are likely candidates for colonization with anaerobes. We sought to compare the distribution of nosocomial infections in neutropenic and non-neutropenic cancer patients and to calculate the associated mortality rates. Material & methods: This is the first study to demonstrate a complete microbial spectrum of anaerobes in various infection sites in hospitalized cancer patients. Results: Frequencies of bloodstream infections (BSI), respiratory tract infections (RTI), and GI tract infections (GITI) were significantly higher in neutropenic cancer patients (p < 0.01). Conversely, urinary tract infection (UTI) and skin infection (SI) rates were significantly higher in non-neutropenic cancer patients (p < 0.01). Mortalities attributed to BSI, UTI, RTI, SI, and GITI occured at the respective percentage frequencies of 12.5%, 11.5%, 10.4%, 7.7% and 4.9%. Anaerobes constituted 4.7% of total isolates, and were recovered from SI (66.3%) and GITI (33.6%), but not respiratory tract, urine, or blood. Most anaerobes (79.2%) were isolated from solid-tumor patients. The most common infection in cancer patients was RTI (55.8%), mainly in leukemic patients, followed by SI (18%), only in solid-tumor patients, GITI (9.7%), BSI (9.4%), and UTI (7.1%). The most frequent isolates of Fusobacterium necrophorum (32.7%) and Eubacterium lentum (23.8%) were mostly recovered from solid-tumor patients. These were followed by Clostridium perfringens (11.9%), Clostridium difficile (10.9%), Eubacterium limosum (5.9%), and Veillonella parvula (5%). Conclusion: Control measures are needed to minimize risks of nosocomial infection outbreaks by anaerobes. Continuous monitoring of the presence of anaerobes in various infection sites in hospitalized cancer patients is needed in order to be able to provide the best supportive care for cancer patients.