Epidemiology of bacteremia and factors associated with multi-drug-resistant gram-negative bacteremia in hematopoietic stem cell transplant recipients

Abstract

The incidence of Gram-negative bacteremia has increased in hematopoietic stem cell transplant (HSCT) recipients. We prospectively collected data from 13 Brazilian HSCT centers to characterize the epidemiology of bacteremia occurring early post transplant, and to identify factors associated with infection due to multi-drug-resistant (MDR) Gram-negative isolates. MDR was defined as an isolate with resistance to at least two of the following: third-or fourth-generation cephalosporins, carbapenems or piperacillin-tazobactam. Among 411 HSCT, fever occurred in 333, and 91 developed bacteremia (118 isolates): 47% owing to Gram-positive, 37% owing to Gram-negative, and 16% caused by Gram-positive and Gram-negative bacteria. Pseudomonas aeruginosa (22%), Klebsiella pneumoniae (19%) and Escherichia coli (17%) accounted for the majority of Gram-negative isolates, and 37% were MDR. These isolates were recovered from 20 patients, representing 5% of all 411 HSCT and 22% of the episodes with bacteremia. By multivariate analysis, treatment with third-generation cephalosporins (odds ratio (OR) 10.65, 95% confidence interval (CI) 3. 75-30.27) and being at one of the hospitals (OR 9.47, 95% CI 2.60-34.40) were associated with infection due to MDR Gram-negative isolates. These findings may have important clinical implications in the decision of giving prophylaxis and selecting the empiric antibiotic regimen.

Etiology, clinical features and outcomes of pre-engraftment and post-engraftment bloodstream infection in hematopoietic SCT recipients

“…27 Gram-positive organisms, especially CNS, were the most frequent etiology of BSI in both periods, in agreement with other studies involving HSCT recipients. 3,5,10,28 The frequency of Gram negatives was similar in both groups, as was the rate of multidrug resistance among them. The overall rate of multidrug-resistant Gram-negative bacilli was 21%.…”

Characterization of Bacterial Infections in Allogeneic Hematopoietic Stem Cell Transplant Recipients Who Received Prophylactic Levofloxacin With Either Penicillin or Doxycycline

“…Only 1 extended-spectrum β-lactamaseproducing organism was identified in our study, whereas rates as high as 25% to 44% have been observed in allogeneic HSCT recipients at other centers. 12,21 In comparing our study data with our institutional antibiogram, we note that the rate of fluoroquinolone-resistant organisms is considerably higher in our allogeneic HSCT recipients than in our general patient population, reflecting not only their higher antimicrobial exposures but perhaps also their more extensive exposure to the inpatient hospital setting. Therefore, institutional antibiograms that are compiled from all pooled patient groups may not be as useful in guiding empiric antibiotic selection in those who undergo allogeneic HSCT and other patient groups with heavy antibiotic exposures.…”

Impact of bloodstream infections on outcome and the influence of prophylactic oral antibiotic regimens in allogeneic hematopoietic SCT recipients

“…Another finding that showed a predominance of Gram-negative BSIs in the current study was consistent with those reported by some institutions in Taiwan, 57,58 but in contrast to numerous studies that have found a predominance of Gram-positive bacteria. [1][2][3][4][5]40,55,59 Literature from other countries in general showed a trend shifting from GNB predominance to Gram-positive bacteria predominance. 3,[60][61][62][63] Changing trends of nosocomial BSIs pathogens over time, variations among institutional or geographic epidemiology of nosocomial BSIs, and variations of prophylactic antibiotics applied may account for this discrepancy.…”