P. aeruginosa bloodstream infections among hematological patients: an old or new question?

Abstract

Pseudomonas aeruginosa is a well-known cause of severe and potentially life-threatening infections among hematological patients. A prospective epidemiological surveillance program ongoing at our Hematology Unit revealed an increase over time of P. aeruginosa bloodstream infections (BSI). Their impact on outcome and antibiotic susceptibility was analyzed. BSI which consecutively occurred at our institution during a 70-month period were evaluated and correlated with type of pathogen, status of underlying disease, neutropenia, previous antibiotic therapy, resistance to antibiotics, and outcome. During the observation period, 441 BSI were recorded. Frequency of Gram-negative BSI was higher than that of other pathogens (57.3%). Overall, 66 P. aeruginosa BSI were recorded; 22 out of 66 were multiresistant (MR P. aeruginosa). Thirty-day mortality for all BSI was 11.3%; it was 27.3% for P. aeruginosa BSI and 36.4% for MR P. aeruginosa. At multivariate analysis, only active hematological disease and P. aeruginosa BSI were associated to an increased risk of death. For MR P. aeruginosa, BSI mortality was 83.3% vs. 18.8% when empiric therapy included or not an antibiotic with in vitro activity against P. aeruginosa (p=0.011). Together with active disease, the emergence of P. aeruginosa BSI, particularly if multiresistant, was responsible for an increased risk of death among hematological patients at our institution. In this scenario, reconsidering the type of combination antibiotic therapy to be used as empiric treatment of neutropenic fever was worthwhile.

Increased risk of death with recurrent Pseudomonas aeruginosa bacteremia

“…The occurrence of primary P. aeruginosa BSI infections in the hematology population is well described [12][13][14]. High rates of corticosteroid use were also described in the P. aeruginosa primary BSI cohort described by Joo et al [15].…”

Bloodstream infections in neutropenic cancer patients: A practical update

“…In fact, P. aeruginosa, which is responsible for 15-20% of GN infections, 56 might be frequently carbapenem-resistant in some regions, as demonstrated in an Italian multicenter cohort, where 71% of strains were MDR. 32 In other regions, as reported by studies from India or South Korea, A. baumannii has emerged as a common pathogen isolated in BSIs in neutropenic patients, and it is frequently resistant to cephalosporins or carbapenems. 41,57 Resistant gram-positives…”

“…29 However, this tendency has reversed again, with GN bacteria becoming more frequent than GP in many centers. [32][33][34][35][36][37][38] According to a questionnaire survey performed among hematology centers from Europe and Israel participating in the European Conference on Infections in Leukemia (ECIL) in 2011, Enterobacteriaceae were isolated in approximately 30% (range 8-56%) of the BSIs, followed by coagulase-negative staphylococci (24%, range 7-51%). 39 The GP to GN ratio was 55% to 45%, but a large variability between hospitals and countries has been noted.…”

The emerging problem of bacterial resistance in cancer patients; proceedings of a workshop held by MASCC “Neutropenia, Infection and Myelosuppression” Study Group during the MASCC annual meeting held in Berlin on 27–29 June 2013

“…MDR is now defined as resistance to at least one antibiotic in three different classes. A recent study reported by Cattaneo et al included 441 episodes of bacteremia in neutropenic patients with HM occurring between 2004 and 2010, 66 were due to P. aeruginosa, among which 33 % were MDR [37]. Inadequate empiric treatment was associated with a mortality rate of 83 % in these cases.…”