Michael J. Satlin

The Global Challenge of Carbapenem-Resistant Enterobacteriaceae in Transplant Recipients and Patients With Hematologic Malignancies

Carbapenem-resistant Enterobacteriaceae (CRE) are emerging global pathogens. The spread of CRE to transplant recipients and patients with hematologic malignancies has ominous implications. These patients rely on timely, active antibacterial therapy to combat gram-negative infections; however, recommended empirical regimens are not active against CRE. Approximately 3%-10% of solid organ transplant (SOT) recipients in CRE-endemic areas develop CRE infection, and the infection site correlates with the transplanted organ. Mortality rates associated with CRE infections approach 40% in SOT recipients and 65% in patients with hematologic malignancies. Given that the current antimicrobial armamentarium to combat CRE is extremely limited, a multifaceted approach that includes antimicrobial stewardship and active surveillance is needed to prevent CRE infections in immunocompromised hosts. Improving outcomes of established infections will require the use of risk factor-based prediction tools and molecular assays to more rapidly administer CRE-active therapy and the development of new antimicrobial agents with activity against CRE.

Comparative Effectiveness of Aminoglycosides, Polymyxin B, and Tigecycline for Clearance of Carbapenem-Resistant Klebsiella pneumoniae from Urine

ABSTRACT Carbapenem-resistant Klebsiella pneumoniae (CRKP) is an increasingly common cause of health care-associated urinary tract infections. Antimicrobials with in vitro activity against CRKP are typically limited to polymyxins, tigecycline, and often, aminoglycosides. We conducted a retrospective cohort study of cases of CRKP bacteriuria at New York-Presbyterian Hospital from January 2005 through June 2010 to compare microbiologic clearance rates based on the use of polymyxin B, tigecycline, or an aminoglycoside. We constructed three active antimicrobial cohorts based on the active agent used and an untreated cohort of cases that did not receive antimicrobial therapy with Gram-negative activity. Microbiologic clearance was defined as having a follow-up urine culture that did not yield CRKP. Cases without an appropriate follow-up culture or that received multiple active agents or less than 3 days of the active agent were excluded. Eighty-seven cases were included in the active antimicrobial cohorts, and 69 were included in the untreated cohort. The microbiologic clearance rate was 88% in the aminoglycoside cohort (n = 41), compared to 64% in the polymyxin B (P = 0.02; n = 25), 43% in the tigecycline (P < 0.001; n = 21), and 36% in the untreated (P < 0.001; n = 69) cohorts. Using multivariate analysis, the odds of clearance were lower for the polymyxin B (odds ratio [OR], 0.10; P = 0.003), tigecycline (OR, 0.08; P = 0.001), and untreated (OR, 0.14; P = 0.003) cohorts than for the aminoglycoside cohort. Treatment with an aminoglycoside, when active in vitro, was associated with a significantly higher rate of microbiologic clearance of CRKP bacteriuria than treatment with either polymyxin B or tigecycline.

Emergence of carbapenem-resistant Enterobacteriaceae as causes of bloodstream infections in patients with hematologic malignancies

Abstract Carbapenem-resistant Enterobacteriaceae (CRE) are increasingly prevalent pathogens. However, little is known about their emergence in patients with hematologic malignancies. We identified 18 patients with hematologic malignancies over 3.5 years who developed bloodstream infections (BSIs) caused by CRE. Fourteen BSIs were caused by Klebsiella pneumoniae, three by Enterobacter cloacae, and one was polymicrobial. Initial empirical antimicrobial therapy was active in two patients (11%), and a median of 55 h elapsed between culture collection and receipt of an active agent. Ten patients (56%) died, including nine (69%) of 13 neutropenic patients, with a median of 4 days from culture collection until death. CRE isolates were analyzed for carbapenemase production, β-lactamase genes and outer membrane porin deletions and characterized by multilocus sequence typing and pulsed-field gel electrophoresis (PFGE). Carbapenem resistance mechanisms included Klebsiella pneumoniae carbapenemase production and CTX-M-15 production with an absent outer membrane porin protein. No isolate had ≥95% homology on PFGE, indicating a heterogeneous, non-outbreak population of isolates. CRE BSIs are emerging in patients with hematologic malignancies and are associated with ineffective initial empirical therapy, long delays in administration of active antimicrobials and high mortality rates. New diagnostic, therapeutic and preventive strategies for CRE infections in this vulnerable population are needed.

Independent Risk Factors for Urinary Tract Infection and for Subsequent Bacteremia or Acute Cellular Rejection: A Single Center Report of 1166 Kidney Allograft Recipients

Background Urinary tract infection (UTI) is a frequent, serious complication in kidney allograft recipients. Methods We reviewed the records of 1166 kidney allograft recipients who received their allografts at our institution between January 2005 and December 2010 and determined the incidence of UTI during the first 3 months after transplantation (early UTI). We used Cox proportional hazards models to determine the risk factors for early UTI and whether early UTI was an independent risk factor for subsequent bacteremia or acute cellular rejection (ACR). Results UTI, defined as 105 or more bacterial colony-forming units/mL urine, developed in 247 (21%) of the 1166 recipients. Independent risk factors for the first episode of UTI were female gender (hazard ratio [HR], 2.9; 95% confidence intervals [CI], 2.2–3.7; P<0.001), prolonged use of Foley catheter (HR, 3.9; 95% CI, 2.8–5.4; P <0.001), ureteral stent (HR, 1.4; 95% CI, 1.1–1.8; P=0.01), age (HR, 1.1; 95% CI, 1.0–1.2; P=0.03), and delayed graft function (HR, 1.4; 95% CI, 1.0–1.9; P=0.06). Trimethoprim/sulfamethoxazole prophylaxis was associated with a reduced risk of UTI (HR, 0.6; 95% CI, 0.3–0.9; P=0.02). UTI was an independent risk factor for subsequent bacteremia (HR, 2.4; 95% CI, 1.2–4.8; P=0.01). Untreated UTI, but not treated UTI, was associated with an increased risk of ACR (HR, 2.8; 95% CI, 1.3–6.2; P=0.01). Conclusions Female gender, prolonged use of Foley catheter, ureteral stent, age, and delayed graft function are independent risk factors for early UTI. UTI is independently associated with the development of bacteremia, and untreated UTI is associated with subsequent ACR.

Epidemiology and outcomes of invasive fungal infections in allogeneic haematopoietic stem cell transplant recipients in the era of antifungal prophylaxis: a single-centre study with focus on emerging pathogens.

With increased use of expanded‐spectrum triazoles for antifungal prophylaxis, the epidemiology of invasive fungal infections (IFIs) after allogeneic haematopoietic stem cell transplantation (HSCT) continues to evolve. To define the contemporary epidemiology of IFIs in this population, we reviewed all European Organization for Research and Treatment of Cancer‐Mycoses Study Group proven and probable IFIs in adults transplanted from 2002 to 2011 and determined the incidence and risk factors for IFI and post‐IFI mortality. All patients received antifungal prophylaxis. Fifty‐three (14%) of 378 allogeneic HSCT recipients developed an IFI. There were 62 IFI episodes, of which aspergillosis (n = 31; 50%) and candidaemia (n = 15; 24%) were most common. Sixteen episodes (26%) were caused by other fungi, including Mucorales (n = 6; 10%) and the following uncommon pathogens: Trichosporon asahii, Arthrographis sp., Cladosporium sp., Geosmithia argillacea and Hormographiella aspergillata. Independent IFI risk factors were hospitalisation in an intensive care unit [ICU; odds ratio (OR) = 6.0], graft‐versus‐host disease (OR = 5.3), central venous catheter use (OR = 5.2) and hypoalbuminaemia (OR = 0.3 g−1 dl−1 increase in albumin). The 90‐day mortality rate after IFI was 57%. Non‐cytomegalovirus systemic viral co‐infection (OR = 3.5) and stay in an ICU (OR = 2.9) were independent risk factors for death. Despite antifungal prophylaxis, IFIs remain common after allogeneic HSCT and previously uncommon pathogens are emerging.

Human rhinovirus infections of the lower respiratory tract in hematopoietic stem cell transplant recipients.

Human rhinoviruses (HRVs) are a common cause of upper respiratory infection (URI) in hematopoietic stem cell transplant (HSCT) recipients; yet, their role in lower respiratory illness is not well understood.

Multicenter clinical and molecular epidemiological analysis of bacteremia due to Carbapenem-Resistant Enterobacteriaceae (CRE) in the CRE epicenter of the United States

ABSTRACT Although the New York/New Jersey (NY/NJ) area is an epicenter for carbapenem-resistant Enterobacteriaceae (CRE), there are few multicenter studies of CRE from this region. We characterized patients with CRE bacteremia in 2013 at eight NY/NJ medical centers and determined the prevalence of carbapenem resistance among Enterobacteriaceae bloodstream isolates and CRE resistance mechanisms, genetic backgrounds, capsular types (cps), and antimicrobial susceptibilities. Of 121 patients with CRE bacteremia, 50% had cancer or had undergone transplantation. The prevalences of carbapenem resistance among Klebsiella pneumoniae, Enterobacter spp., and Escherichia coli bacteremias were 9.7%, 2.2%, and 0.1%, respectively. Ninety percent of CRE were K. pneumoniae and 92% produced K. pneumoniae carbapenemase (KPC-3, 48%; KPC-2, 44%). Two CRE produced NDM-1 and OXA-48 carbapenemases. Sequence type 258 (ST258) predominated among KPC-producing K. pneumoniae (KPC-Kp). The wzi154 allele, corresponding to cps-2, was present in 93% of KPC-3-Kp, whereas KPC-2-Kp had greater cps diversity. Ninety-nine percent of CRE were ceftazidime-avibactam (CAZ-AVI)-susceptible, although 42% of KPC-3-Kp had an CAZ-AVI MIC of ≥4/4 μg/ml. There was a median of 47 h from bacteremia onset until active antimicrobial therapy, 38% of patients had septic shock, and 49% died within 30 days. KPC-3-Kp bacteremia (adjusted odds ratio [aOR], 2.58; P = 0.045), cancer (aOR, 3.61, P = 0.01), and bacteremia onset in the intensive care unit (aOR, 3.79; P = 0.03) were independently associated with mortality. Active empirical therapy and combination therapy were not associated with survival. Despite a decade of experience with CRE, patients with CRE bacteremia have protracted delays in appropriate therapies and high mortality rates, highlighting the need for rapid diagnostics and evaluation of new therapeutics.

Epidemiology and outcomes of carbapenem-resistant Klebsiella pneumoniae bacteriuria in kidney transplant recipients

Little is known about the epidemiology of carbapenem‐resistant Klebsiella pneumoniae (CRKP) bacteriuria following kidney transplantation. We determined the incidence of post‐transplant CRKP bacteriuria in adults who underwent kidney transplant from 2007 to 2010 at 2 New York City centers.

Impact of Prophylactic Levofloxacin on Rates of Bloodstream Infection and Fever in Neutropenic Patients with Multiple Myeloma Undergoing Autologous Hematopoietic Stem Cell Transplantation.

Few studies have evaluated the role of antibacterial prophylaxis during neutropenia in patients with multiple myeloma undergoing autologous hematopoietic stem cell transplantation (HSCT). At our center, levofloxacin prophylaxis was initiated in June 2006 in patients with myeloma who were undergoing autologous HSCT. We compared the incidence of bloodstream infection (BSI) and fever and neutropenia (FN) within 30 days of transplantation before (January 2003 to May 2006) and after (June 2006 to April 2010) the initiation of levofloxacin prophylaxis in patients undergoing autologous HSCT for myeloma. We also compared rates of BSI and FN during the same time periods in autologous HSCT recipients with lymphoma who did not receive antibacterial prophylaxis during either time period. After the initiation of levofloxacin prophylaxis, the BSI rate decreased from 41.2% (49 of 119) to 14.7% (23 of 156) and the rate of FN decreased from 91.6% to 60.9% in patients with myeloma (P < .001, for each). In contrast, rates of BSI (43.1% versus 47.3%; P = .50) and FN (98.8% versus 97.1%; P = .63) did not change in patients with lymphoma. Levofloxacin prophylaxis was independently associated with decreased odds of BSI (odds ratio, .27; 95% confidence interval, .14 to .51; P < .001) and FN (odds ratio, .18; 95% confidence interval, .09 to .36; P < .001) in multivariate analysis. Patients with myeloma had a nonsignificant increase in the risk of BSI due to levofloxacin-resistant Enterobacteriaceae (5% versus 1%, P = .08) and Clostridium difficile infection (7% versus 3%, P = .12) after the initiation of levofloxacin prophylaxis but did not have higher rates of BSI due to other resistant bacteria. Levofloxacin prophylaxis is associated with decreased risk of BSI and FN in patients with myeloma undergoing autologous HSCT.

Combination Regimens for Treatment of Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infections

ABSTRACT Previous studies reported decreased mortality in patients with carbapenemase-producing Klebsiella pneumoniae bloodstream infections (BSIs) treated with combination therapy but included carbapenem-susceptible and -intermediate isolates, as per revised CLSI breakpoints. Here, we assessed outcomes in patients with BSIs caused by phenotypically carbapenem-resistant K. pneumoniae (CRKP) according to the number of in vitro active agents received and whether an extended-spectrum beta-lactam (BL) antibiotic, including meropenem, or an extended-spectrum cephalosporin was administered. We retrospectively reviewed CRKP BSIs at two New York City hospitals from 2006 to 2013, where all isolates had meropenem or imipenem MICs of ≥4 μg/ml. Univariate and multivariable models were created to identify factors associated with mortality. Of 141 CRKP BSI episodes, 23% were treated with a single active agent (SAA), 26% were treated with an SAA plus BL, 28% were treated with multiple active agents (MAA), and 23% were treated with MAA plus BL. Ninety percent of isolates had meropenem MICs of ≥16 μg/ml. Thirty-day mortality was 33% overall and did not significantly differ across the four treatment groups in a multivariable model (P = 0.4); mortality was significantly associated with a Pitt bacteremia score of ≥4 (odds ratio [OR], 7.7; 95% confidence interval [CI], 3.2 to 18.1; P = 0.1), and immunosuppression was protective (OR, 0.4; 95% CI, 0.2 to 1.0; P = 0.04). Individual treatment characteristics were also not significantly associated with outcome, including use of SAAs versus MAA (26% versus 38%, P = 0.1) or BL versus no BL (26% versus 39%, P = 0.1). In summary, in patients with CRKP BSIs caused by isolates with high carbapenem MICs, the role of combination therapy remains unclear, highlighting the need for prospective studies to identify optimal treatment regimens.