Predictive Factors of Severe Sepsis and Septic Shock in Patients with Hematological Malignancies and Pseudomonas Infections.

Pseudomonas aeruginosa is a leading cause of nosocomial infections usually associated with high mortality. The aim of this study was to determine the predictive factors of severe sepsis or septic shock in patients with hematological malignancies and pseudomonas infections.

This study was conducted in a teaching hospital (Aziza Othmana University Hospital, Tunis, Tunisia) to evaluate the clinical profile of infections due to Pseudomonas species and to determine risk factors for severe sepsis or septic shock defined according to the criteria of the ACCP/SCCM. Pearson test was used for univariate analysis, and logistic regression for multivariate analysis.

Between 2004 and 2009,a total of 73 pseudomonas isolates (70 P, aeruginosa) was collected in 60 patients : 47 with acute leukemia (78%), 7 with lymphoma (12%), and 6 with others hematological disorders (10%).The median age was 29 yrs (range, 2-64). Most common sites of the isolates were from bloodstream (45%), and skin lesions (31.5%). At least 11 patients (18%) had 2 or more infections due to Pseudomonas. The most common clinical signs observed were isolated fever (18%), respiratory symptoms (15%), diarrhea (21%), and skin lesions (29%).Susceptibility to major anti-pseudomonas antibiotics revealed that isolates tested were resistant to:piperacillin/tazobactam (40%), cefatazidim (28%), ciprofloxacin (20.5%), imipenem (22%), and amikacin (22%).Severe sepsis or septic shock occurred in 49% of episodes. Crude mortality was (18%, 11 of the 60 patients) all caused by septic shock. In univariate analysis factors associated with severe sepsis or septic shock were: Isolates from more than one site (p=0.04), Absolute neutrophil count < 0.1 × 10⁹/l (p=0.003), concomitant infection with other microorganism (p=0.019), fever lasting for more than 3 days in patients with antibiotherapy (p=0.003), C-reactive protein > 100 mg/l (p <0.0001), serum lactate >2.2 mmol/l (p< 0.0001), serum bicarbonate < 19 mmol/l (p=0.002), hemoglobin level < 70g/l (p<0.0001), renal failure (p=0.006), hypophosphatemia <0.8mmol/l (p=0.003), total bilirubin > 50 μmol/l (p=0.03), and hypoproteinemia <64g/l (p<0.0001). By multivariate analysis, antibiotherapy for more than 3 days (p=0.025,OR=0.217, 95%CI:0.05-0.82), absolute neutrophil count <0.1× 10⁹/l (p=0.046,OR=170;95% CI:1-267), C-reactive protein >100 (p=0.04,OR=15,95%CI: 1,1-219,8), hemoglobin level <70g/l (p=0.037,OR=17,95%CI: 1,1- 243), and hypophosphatemia (p=0.02,OR=148,95%CI:2.2-942) remained as independent predictors of severe sepsis or septic shock.

This study revealed that several factors such as level of neutrophil count, C-reactive protein, hemoglobin level, severe hypophosphatemia, and antibiotherapy > 72 h before microbiological documentation may play a significant and independent role for the development of severe sepsis/septic shock and increase mortality of Pseudomonas infections in patients with hematological malignancies.

No relevant conflicts of interest to declare.