Change in pathogens and antimicrobial resistance of pathogens causing bloodstream infection in patients with acute leukemia during six years

Abstract:

ObjectiveTo understand pathogens causing bloodstream infection(BSI) in patients with acute leukemia(AL), as well as trend of antimicrobial resistance of pathogens, and provide evidence for clinical antiinfection treatment. MethodsPathogens and antimicrobial susceptibility of pathogens isolated from blood culture of patients with AL in the department of hematology in a hospital from January 2011 to December 2016 were analyzed, distribution and antimicrobial resistance of pathogens between 2011-2013 and 2014-2016 were compared. Results229 strains of pathogens were isolated from 221 AL patients with BSI, including 68 strains(29.69%) of grampositive bacteria, 154(67.25%) gramnegative bacteria, and 7 (3.06%)fungus. Escherichia coli (E. coli) was dominant strain in both the first and second three years, followed by coagulasenegative staphylococcus (CNS) and Pseudomonas aeruginosa (P. aeruginosa). Constituent ratio of P. aeruginosa increased from 7.08% (8/113) to 12.07% (14/116), fungi increased from 1.77% (2/113) to 4.31% (5/116), difference in constituent ratio of pathogens and antimicrobial susceptibility between the first and second three years were not statistically significant (both P>0.05). Susceptibility of grampositive bacteria to vancomycin, linezolid, and quinupristin/dalfopristin were all 100%, 64.29%-69.57% of CNS and 55.56%-66.67% of Staphylococcus aureus were methicillinresistant strains. Resistance rates of E. coli and Klebsiella pneumoniae to cephalosporins were high, resistance rates to third generation cephalosporins were 25.00%-75.61%; imipenem and ertapenemresistant E. coli were detected. Resistance rates of Candida tropicalis to itraconazole and voriconazole increased from 0 in 2011-2013 to 25% in 2014-2016. All the detected fungi were susceptible to amphotericin B, ketoconazole, and nystatin. ConclusionE.coli is the major pathogen causing BSI in AL paptients, P. aeruginosa has a growing trend, proportion of fungal infection has increased, rational use of antimicrobial agents should be based on blood culture and antimicrobial susceptibility testing result.