[The microbiological and clinical analysis of bloodstream infections with identifiable sources].

Objective: To evaluate the microbial spectrum and clinical characteristics of microbiological diagnosed bloodstream infections (BSI) with identified infective sources.

Methods: The hospitalized patients microbiologically diagnosed as BSI with identified infective sources were included in this study from January 2008 to December 2009. Data were collected retrospectively and analyzed by software SPSS 17.0.

Results: In this 2-year study, 301 strains of microbes were isolated from 249 patients. There were 205 (82.33%) patients with monomicrobial BSI, while the other 44 (17.67%) patients with polymicrobial BSI. The most common identified source of bloodstream infections was lower respiratory tract infection (125, 41.5%), followed by intraabdominal infection (55, 18.3%) and intravascular devices related infection (54, 17.9%). The four most common isolated pathogens were Acinetobacter species (60, 19.9%), Escherichia coli (50, 16.6%), Pseudomonas species (35, 11.6%) and Staphylococcus Aureus (34, 11.3%). Eighty-eight (35.3%) patients died during hospitalization due to all causes, out of which 62 (24.9%) patients died owing to BSI. The patients with BSI originated from lower respiratory tract had a higher crude in-hospital case-fatality ratio than those with BSI originated from other resources (OR = 2.186; 95%CI 1.260 - 3.792; χ(2) = 7.879, P = 0.005). In the multivariate regression, age ≥ 65, invasive mechanical ventilation, reservation of central line and polymicrobial BSI during hospitalization were independent risk factors of death due to all causes.

Conclusions: Lower respiratory tract is the most common originated source of BSI with microbiological identified sources. Gram-negative bacillus taking advantage, the microbial spectrum of BSI with identified sources in our study is different from those reported before both in primary and secondary BSI. The patients with BSI originated from respiratory tract have a higher crude in-hospital case-fatality ratio.