A Study in the Clinical Characteristics of Stenotrophomonas Maltophilia Bacteremia in Hematological Patients
Authors: Bao Haiyan , Chen Jia , Wu Xiaojin , Ma Xiao , Fu Chengcheng , Miao Miao , Qiu Huiying , Sun Aining , Depei Wu 
Published: October 2019

Abstract
Introduction: Stenotrophomonas maltophilia is an important nosocomial pathogen, particularly in immunocompromised patients, especially in patients with hematologic diseases.
Methods: We reviewed the clinical characteristics and prognosis of patients with S. maltophilia bacteremia over a five-year period from January 2010 to December 2014. Species identification was performed using the automated Vitek 2 compact system (bioMe rieux).
Results: The incidence of S. maltophilia bacteremia was 25.1 per 10 000 admissions in our study. Thirty-four patients (median age: 34 years; 64.7% males) with S. maltophilia bacteremia were analyzed. The S. maltophilia bacteremia related 30-day mortality was 44.1%. Risk factors associated with mortality in patients with S. maltophilia infection in the univariate and multivariate analysis were represented in Tables I and II. In the univariate analysis, risk factors included T>39.0¡æ, septic shock, respiratory failure and non-remission after treatment for primary hematological diseases (P <0.05). In the multivariate analysis, respiratory failure and non-remission status after treatment forhematological diseases were independent prognostic factors for mortality. In vitro susceptibility was higher to ciprofloxacin(82.4%), ceftazidime(70.6%), sulbactam and cefoperazone(58.8%), which was shown in Table III.
Conclusion: Combination regimens with ciprofloxacin and ceftazidime, or sulbactam and cefoperazone could be alternative treatment. Novel antibiotics are required for treatment of S. maltophilia infection, as well as infection control practices of environmental reserves, rapid detection of pathogens, risk stratification strategy and appropriate treatment for primary hematologic malignancies, which might conjointly contribute to better survival outcome of S. maltophilia bacteremia.
Univariate analysis of prognostic factors associated with mortality from S. maltophilia bacteremia
Table 1. Factor Mortality HR 95%CI P-value Withfactor Withoutfactor T>39.0¡æ 75% 16.7% 2.490 1.318-4.704 0.005 Septic shock 90.0% 25.0% 2.544 1.473-4.393 0.001 Respiratory failure 100% 20.8% 4.672 2.366-9.225 0.000 Treatment outcome for hematological diseases Remission 10.0% 85.7% 0.247 0.116-0.526 0.000 HR, hazard ratio; CI, confidence interval; HSCT, Hematopoietic stem cell transplantation
Table 2. Multivariate analysis of prognostic factors associated with mortality from S. maltophilia bacteremia Factor HR 95%CI P-value Respiratory failure 2.688 1.297-5.569 0.008 Remission after treatment for hematological diseases 0.367 0.153-0.879 0.025 HR, hazard ratio; CI, confidence interval
Table 3. Susceptibility pattern of the 34 patients with Stenotrophomonas maltophilia bacteremia Antimicrobial agents S (%) I (%) Ceftazidime 24(70.6%) 1(2.9%) Cefoperazone 19(44.1%) 6(17.6%) Sulbactam and Cefoperazone 20(58.8%) 5(14.7%) Piperacillin 7(20.6%) 6(17.6%) Piperacillin-Tazobactam 11(32.3%) 7(20.6%) Amikacin 6(17.6%) 0(0%) Ciprofloxacin 28(82.4%) 1(2.9%) S, susceptible; I, intermediately susceptible.

Disclosures
No relevant conflicts of interest to declare.