Colonization, bloodstream infection, and mortality caused by vancomycin-resistant enterococcus early after allogeneic hematopoietic stem cell transplant

Comparison of levofloxacin and garenoxacin for antibacterial prophylaxis during neutropenia

Levofloxacin (LVFX) is widely used for antibacterial prophylaxis during neutropenia. Garenoxacin (GRNX), which has been investigated in Japan, has stronger antibacterial activity than LVFX against gram-positive bacteria; however, no studies have compared the effectiveness of LVFX and GRNX. We retrospectively analyzed 42 patients with acute leukemia and 32 patients who underwent hematopoietic cell transplantation. Thirty-one patients before September 2009 received GRNX, and subsequent 43 patients received LVFX. We compared the cumulative incidences of positive blood and stool cultures. There was no significant difference in the incidence of bacteremia between the GRNX and LVFX groups. However, while gram-negative bacteria were detected in 80% of the patients with bacteremia in the GRNX group, they were detected in only 33% of the patients with bacteremia in the LVFX group. Patients in the GRNX group more frequently experienced positive stool cultures than those in the LVFX group, and this was confirmed by a multivariate analysis. Gram-negative bacteria accounted for 100 and 67% of the stool culture results in the GRNX and LVFX groups, respectively. While both fluoroquinolones may be appropriate antibacterial prophylactic agents for neutropenia patients with hematological malignancies, vigilance for gram-negative bacterial infections should be exercised when GRNX is used as prophylaxis.

Antibacterial Resistance in Patients with Hematopoietic Stem Cell Transplantation

Recipients of hematopoietic stem cell transplantation (HSCT) are at substantial risk of bacterial, fungal, viral, and parasitic infections depending on the time elapsed since transplantation, presence of graft-versus-host disease (GVHD), and the degree of immunosuppression. Infectious complications in HSCT recipients are associated with high morbidity and mortality. Bacterial infections constitute the major cause of infectious complications, especially in the early post-transplant period. The emergence of antibacterial resistance complicates the management of bacterial infections in this patient group. Multidrug-resistant bacterial infections in this group of patients have attracted considerable interest and may lead to significant morbidity and mortality. Empirical antibacterial therapy in patients with HSCT and febrile neutropenia has a critical role for survival and should be based on local epidemiology. This review attempts to provide an overview of risk factors and epidemiology of emerging resistant bacterial infections and their management in HSCT recipients.

Colonization With Vancomycin-Resistant Enterococci and Risk for Bloodstream Infection Among Patients With Malignancy: A Systematic Review and Meta-Analysis

Background

Vancomycin-resistant enterococci (VRE) cause severe infections among patients with malignancy, and these infections are usually preceded by gastrointestinal colonization.

Methods

We searched the PubMed and EMBASE databases (up to May 26, 2016) to identify studies that reported data on VRE gastrointestinal colonization among patients with solid or hematologic malignancy.

Results

Thirty-four studies, reporting data on 8391 patients with malignancy, were included in our analysis. The pooled prevalence of VRE colonization in this population was 20% (95% confidence interval [CI], 14%–26%). Among patients with hematologic malignancy, 24% (95% CI, 16%–34%) were colonized with VRE, whereas no studies reported data solely on patients with solid malignancy. Patients with acute leukemia were at higher risk for VRE colonization (risk ratio [RR] = 1.95; 95% CI, 1.17–3.26). Vancomycin use or hospitalization within 3 months were associated with increased colonization risk (RR = 1.92, 95% CI = 1.06–3.45 and RR = 4.68, 95% CI = 1.66–13.21, respectively). Among the different geographic regions, VRE colonization rate was 21% in North America (95% CI, 13%–31%), 20% in Europe (95% CI, 9%–34%), 23% in Asia (95% CI, 13%–38%), and 4% in Oceania (95% CI, 2%–6%). More importantly, colonized patients were 24.15 (95% CI, 10.27–56.79) times more likely to develop a bloodstream infection due to VRE than noncolonized patients.

Conclusions

A substantial VRE colonization burden exists among patients with malignancy, and colonization greatly increases the risk for subsequent VRE bloodstream infection. Adherence to antimicrobial stewardship is needed, and a re-evaluation of the use of vancomycin as empiric therapy in this patient population may be warranted.

Vancomycin-Resistant Enterococcus Colonization and Bacteremia and Hematopoietic Stem Cell Transplantation Outcomes

The association between pre-hematopoietic stem cell transplantation (HSCT) vancomycin-resistant Enterococcus (VRE) colonization, HSCT-associated VRE bacteremia, and HSCT mortality is disputed. We studied 161 consecutive patients with acute leukemia who underwent HSCT at our hospital between 2006 and 2014, of whom 109 also received leukemia induction/consolidation on our unit. All inpatients had weekly VRE stool surveillance. Pre-HSCT colonization was not associated with increases in HSCT mortality but did identify a subgroup of HSCT recipients with a higher risk for VRE bacteremia and possibly bacteremia from other organisms. The major risk factor for pre-HSCT colonization was the number of hospital inpatient days between initial admission for leukemia and HSCT. One-third of evaluable patients colonized before HSCT were VRE-culture negative on admission for HSCT; these patients had an increased risk for subsequent VRE stool surveillance positivity but not VRE bacteremia. Molecular typing of VRE isolates obtained before and after HSCT showed that VRE strains frequently change. Postengraftment VRE bacteremia was associated with a much higher mortality than pre-engraftment VRE bacteremia. Pre-engraftment bacteremia from any organism was associated with an alternative donor and resulted in an increase in hospital length of stay and cost. Mortality was similar for pre-engraftment VRE bacteremia and pre-engraftment bacteremia due to other organisms, but mortality associated with post-engraftment VRE bacteremia was higher and largely explained by associated severe graft-versus-host disease and relapsed leukemia. These data emphasize the importance of distinguishing between VRE colonization before HSCT and at HSCT, between pre-engraftment and postengraftment VRE bacteremia, and between VRE bacteremia and bacteremia from other organisms.

Vancomycin-resistant Enterococcus colonization and bloodstream infection: prevalence, risk factors, and the impact on early outcomes after allogeneic hematopoietic cell transplantation in patients with acute myeloid leukemia

BACKGROUND

Screening for vancomycin-resistant Enterococcus (VRE) is performed at many transplant centers, but data on the impact of VRE colonization and bloodstream infection (BSI) on hematopoietic cell transplantation (HCT) outcomes remain conflicting.

METHODS

Consecutive adults with acute myeloid leukemia who underwent allogeneic HCT between 2004 and 2014 were retrospectively reviewed. Patients were screened by perirectal PCR swabs targeting vanA and vanB twice weekly while inpatient.

RESULTS

Of a total of 203 patients (median age 54 years), 73 (36%) were VRE colonized prior to HCT, 23 (11%) became colonized within the first 100 days, and 107 (53%) remained non-colonized through day 100 post HCT. A landmark analysis on HCT day 0 revealed no significant difference in overall survival according to pre-transplant colonization status (P=.20). However, patients with subsequent VRE colonization within the first 100 days of HCT had a significantly worse survival on both univariable (P=.04) and multivariable (P=.03) analyses. During the first 30 days post HCT, 11 (5% of total and 11% of the VRE colonized) patients developed VRE BSI. Ten (91%) of these had screened positive for VRE colonization before the bacteremia. Age ≥60 years, HCT-comorbidity index ≥3, and VRE colonization were independent risk factors for VRE BSI on multivariable analysis (P=.04, .03, .003, respectively). Only 1 (9%) patient with VRE BSI died within the first 100 days post HCT.

CONCLUSION

VRE colonization is a surrogate marker and not an independent predictor of worse outcomes post HCT. VRE BSI is associated with increased morbidity, but does not impact post-HCT survival.

Vancomycin-resistant Enterococcal Bloodstream Infections in Hematopoietic Stem Cell Transplant Recipients and Patients with Hematologic Malignancies: Impact of Daptomycin MICs of 3 to 4 mg/L

PURPOSE

Case reports of treatment failure with standard-dose daptomycin (6 mg/kg) have recently surfaced in vancomycin-resistant Enterococcus (VRE) bloodstream infection (BSI) episodes with daptomycin MICs of 3 to 4 mg/L. The clinical implications of daptomycin MICs of 3 to 4 mg/L in VRE BSIs have not been elucidated.

METHODS

We performed a single institutional retrospective analysis of adult stem cell transplant recipients and patients with hematologic malignancies diagnosed with VRE BSI from 2006 to 2014 and compared outcomes between those with daptomycin MICs of 3 to 4 mg/L those with 2 mg/L, as determined by Etest.

FINDINGS

Forty-two daptomycin-treated VRE BSI episodes, all due to Enterococcus faecium were identified; 19 episodes with daptomycin MICs of 3 to 4 mg/L and 23 episodes with a daptomycin MIC of 2 mg/L. Patients in the higher daptomycin MIC group were more likely to be male, to be stem cell transplant recipients, and to have received high-dose daptomycin treatment (>6 mg/kg). In unadjusted analyses, microbiological failure in the daptomycin MICs 3 to 4 mg/L versus 2 mg/L groups (odds ratio = 1.79, 95% CI, 0.52-6.11; P = 0.35), the median duration of bacteremia (4 days in daptomycin MICs 3-4 mg/L vs 3 days in daptomycin MIC 2 mg/L; P = 0.18) and all-cause 30-day mortality (21% in daptomycin MICs 3-4 mg/L vs 35% in daptomycin MIC 2 mg/L group; P = 0.49) were not different. In adjusted analyses, the association between higher Pitt bacteremia scores and all-cause 30-day mortality was statistically significant (P = 0.0006), whereas the association between daptomycin MICs of 3 to 4 mg/L and all-cause 30-day mortality approached statistical significance (P = 0.06).

IMPLICATIONS

Duration of bacteremia and microbiological failure rates did not differ by daptomycin MICs in VRE BSI episodes in our patients, composed of adult stem cell transplant recipients and patients with hematologic malignancies. There was a nonsignificant trend in multivariable analysis suggesting that all-cause 30-day mortality was lower in patients whose VRE bloodstream isolates were with daptomycin MICs of 3 to 4 mg/L.

Room contamination, patient colonization pressure, and the risk of vancomycin-resistant Enterococcus colonization on a unit dedicated to the treatment of hematologic malignancies and hematopoietic stem cell transplantation

BACKGROUND

Contaminated surfaces and colonization pressure are risk factors for vancomycin-resistant Enterococcus (VRE) colonization in intensive care units (ICUs). Whether these apply to modern units dedicated to the care of hematologic malignancies and hematopoietic stem cell transplant (HSCT) procedures is unknown.

METHODS

We reviewed the records of 780 consecutive admissions for acute leukemia, autologous HSCT, or allogeneic HSCT in which the patient was at risk for hospital-acquired VRE and underwent weekly surveillance. We also obtained staff and room cultures, observed staff behavior, and performed VRE molecular strain typing on selected isolates.

RESULTS

The overall rate of VRE colonization was 11.4 cases/1,000 patient days. Cultures of room surfaces revealed VRE isolates in 10% of terminally cleaned rooms. A prior VRE-colonized room occupant did not increase risk, and paired isolates from 20 patients and prior occupants were indistinguishable on molecular typing in only 1 pair. VRE colonization pressure was significantly associated with acquisition. Cultures of unit personnel and shared equipment were negative except for weighing scales. Observation of unit clinical personnel showed high compliance for hand sanitation and but less so for gowns. Conversely, ancillary staff showed poor compliance.

CONCLUSIONS

Transmission of VRE from room surfaces seems to be an infrequent event. Encouraging adherence to surveillance, disinfection, and contact isolation protocols may decrease VRE colonization rates.

Low Enteric Colonization with Multidrug-Resistant Pathogens in Soldiers Returning from Deployments- Experience from the Years 2007-2015

This assessment describes the enteric colonization of German soldiers 8–12 weeks after returning from mostly but not exclusively subtropical or tropical deployment sites with third-generation cephalosporin-resistant Enterobacteriaceae, vancomycin-resistant enterococci (VRE), and methicillin-resistant Staphylococcus aureus (MRSA). Between 2007 and 2015, 828 stool samples from returning soldiers were enriched in nonselective broth and incubated on selective agars for Enterobacteriaceae expressing extended-spectrum beta-lactamases (ESBL), VRE and MRSA. Identification and resistance testing of suspicious colonies was performed using MALDI-TOF-MS, VITEK-II and agar diffusion gradient testing (bioMérieux, Marcy-l’Étoile, France). Isolates with suspicion of ESBL were characterized by ESBL/ampC disc-(ABCD)-testing and molecular approaches (PCR, Sanger sequencing). Among the returnees, E. coli with resistance against third-generation cephalosporins (37 ESBL, 1 ESBL + ampC, 1 uncertain mechanism) were found in 39 instances (4.7%). Associated quinolone resistance was found in 46.2% of these isolates. Beta-lactamases of the bla_CTX-M group 1 predominated among the ESBL mechanisms, followed by the bla_CTX-M group 9, and bla_SHV. VRE of vanA-type was isolated from one returnee (0.12%). MRSA was not isolated at all. There was no clear trend regarding the distribution of resistant isolates during the assessment period. Compared with colonization with resistant bacteria described in civilians returning from the tropics, the colonization in returned soldiers is surprisingly low and stable. This finding, together with high colonization rates found in previous screenings on deployment, suggests a loss of colonization during the 8- to 12-week period between returning from the deployments and assessment.

Gut microbiota and hematopoietic stem cell transplantation: where do we stand?

Advances in biological techniques have potentiated great progresses in understanding the interaction between human beings and the ∼10 to 100 trillion microbes living in their gastrointestinal tract: gut microbiota (GM). In this review, we describe recent emerging data on the role of GM in hematopoietic stem cell transplantation, with a focus on immunomodulatory properties in the immune system recovery and the impact in the development of the main complications, as GvHD and infections.

Impact of vancomycin-resistant enterococci colonization in critically ill pediatric patients

BACKGROUND

We aimed to determine the frequency of vancomycin-resistant enterococci (VRE) infection occurrence in previously VRE-colonized children in a pediatric intensive care unit (PICU) and to identify associated risk factors.

METHODS

Infection control nurses have performed prospective surveillance of health care-associated infections and rectal VRE carriage in PICUs from January 2010-December 2014. This database was reviewed to obtain information about VRE-colonized and subsequently infected patients. A case-control study was performed to identify risk factors associated with VRE infection development in previously VRE-colonized patients.

RESULTS

Out of 1,134 patients admitted to the PICU, 108 (9.5%) were found to be colonized with VRE throughout the study period. Systemic VRE infections developed in 11 VRE-colonized patients (10.2%), and these included primary bloodstream infection (n = 6), urinary tract infection (n = 3), meningitis and bloodstream infection (n = 1), and meningitis (n = 1). Logistic regression analysis indicated long hospital stay (≥30 days) and glycopeptide use after detection of VRE colonization as risk factors for developing VRE infection in VRE-colonized patients (odds ratio [OR], 5.76; 95% confidence interval [CI], 1.6-15.8; P = .017 and OR, 12.8; 95% CI, 1.9-26.6; P = .012, respectively).

CONCLUSIONS

VRE colonization has important consequences in pediatric critically ill patients. Strict infection control measures should be implemented to prevent VRE colonization and thereby VRE infections. Furthermore, irrational antibiotic use and particularly glycopeptide use in VRE-colonized patients should be restricted.

Microbiome mediation of infections in the cancer setting

Infections encountered in the cancer setting may arise from intensive cancer treatments or may result from the cancer itself, leading to risk of infections through immune compromise, disruption of anatomic barriers, and exposure to nosocomial (hospital-acquired) pathogens. Consequently, cancer-related infections are unique and epidemiologically distinct from those in other patient populations and may be particularly challenging for clinicians to treat. There is increasing evidence that the microbiome is a crucial factor in the cancer patient's risk for infectious complications. Frequently encountered pathogens with observed ties to the microbiome include vancomycin-resistant Enterococcus, Enterobacteriaceae, and Clostridium difficile; these organisms can exist in the human body without disease under normal circumstances, but all can arise as infections when the microbiome is disrupted. In the cancer patient, such disruptions may result from interventions such as chemotherapy, broad-spectrum antibiotics, or anatomic alteration through surgery. In this review, we discuss evidence of the significant role of the microbiome in cancer-related infections; how a better understanding of the role of the microbiome can facilitate our understanding of these complications; and how this knowledge might be exploited to improve outcomes in cancer patients and reduce risk of infection.

Results of Four-Year Rectal Vancomycin-Resistant Enterococci Surveillance in a Pediatric Hematology-Oncology Ward: From Colonization to Infection

Objective:

To investigate the clinical impact of vancomycin-resistant enterococci (VRE) colonization in patients with hematologic malignancies and associated risk factors.

Materials and Methods:

Patients colonized and infected with VRE were identified from an institutional surveillance database between January 2010 and December 2013. A retrospective case-control study was performed to identify the risk factors associated with development of VRE infection in VRE-colonized patients.

Results:

Fecal VRE colonization was documented in 72 of 229 children (31.4%). Seven VRE-colonized patients developed subsequent systemic VRE infection (9.7%). Types of VRE infections included bacteremia (n=5), urinary tract infection (n=1), and meningitis (n=1). Enterococcus faecium was isolated in all VRE infections. Multivariate analysis revealed severe neutropenia and previous bacteremia with another pathogen as independent risk factors for VRE infection development in colonized patients [odds ratio (OR): 35.4, confidence interval (CI): 1.7-72.3, p=0.02 and OR: 20.6, CI: 1.3-48.6, p=0.03, respectively]. No deaths attributable to VRE occurred.

Conclusion:

VRE colonization has important consequences in pediatric cancer patients.

Bloodstream infections in neutropenic cancer patients: A practical update

Bloodstream infections (BSI) are among the most frequent complications in neutropenic cancer patients and, if caused by Gram-negative rods, are associated with high mortality. Thus, fever during neutropenia warrants prompt empirical antibiotic therapy which should be active against the most frequent Gram-negatives. In the last decade, there has been a worldwide increase in multidrug resistant (MDR) strains. In these cases, the traditional choices such as oral therapy, ceftazidime, cefepime, piperacillin-tazobactam, or even carbapenems, might be ineffective. Therefore novel de-escalation approach has been proposed for patients who are at high risk for infections due to MDR bacteria. It consists of starting antibiotics which cover the most probable resistant strain but it is narrowed down after 72 hours if no MDR pathogen is isolated. With increasing bacterial resistance, the benefit of fluoroquinolone prophylaxis during prolonged neutropenia remains to be confirmed. Antibiotic stewardship and infection control programs are mandatory in every cancer center.

TLR-7 activation enhances IL-22-mediated colonization resistance against vancomycin-resistant enterococcus

Antibiotic administration can disrupt the intestinal microbiota and down-regulate innate immune defenses, compromising colonization resistance against orally acquired bacterial pathogens. Vancomycin-resistant Enterococcus faecium (VRE), a major cause of antibiotic-resistant infections in hospitalized patients, thrives in the intestine when colonization resistance is compromised, achieving extremely high densities that can lead to bloodstream invasion and sepsis. Viral infections, by mechanisms that remain incompletely defined, can stimulate resistance against invading bacterial pathogens. We report that murine norovirus infection correlates with reduced density of VRE in the intestinal tract of mice with antibiotic-induced loss of colonization resistance. Resiquimod (R848), a synthetic ligand for Toll-like receptor 7 (TLR-7) that stimulates antiviral innate immune defenses, restores expression of the antimicrobial peptide Reg3γ and reestablishes colonization resistance against VRE in antibiotic-treated mice. Orally administered R848 triggers TLR-7 on CD11c(+) dendritic cells, inducing interleukin-23 (IL-23) expression followed by a burst of IL-22 secretion by innate lymphoid cells, leading to Reg3γ expression and restoration of colonization resistance against VRE. Our findings reveal that an orally bioavailable TLR-7 ligand that stimulates innate antiviral immune pathways in the intestine restores colonization resistance against a highly antibiotic-resistant bacterial pathogen.

Risks and Epidemiology of Infections After Hematopoietic Stem Cell Transplantation

Infections following HCT are frequently related to risk factors caused by the procedure itself. Neutropenia and mucositis predispose to bacterial infections. Prolonged neutropenia increases the likelihood of invasive fungal infection. GVHD and its treatment create the most important easily identifiable risk period for a variety of infectious complications, particularly mold infections. Profound, prolonged T cell immunodeficiency, present after T cell-depleted or cord blood transplants, is the main risk factor for viral problems like disseminated adenovirus disease or EBV-related posttransplant lymphoproliferative disorder.

The challenge of antibiotic resistance in haematology patients

Bacterial infections were once a major obstacle to the treatment of acute leukaemia. Improvement in management strategies, including the use of broad-spectrum antibacterial drugs targeting Gram-negative bacteria, has reduced the mortality in neutropenic patients developing blood stream infections and other severe infections. In many countries these achievements are threatened by development of multi-resistant bacteria, such as Klebsiella pneumoniae, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus. This review addresses the epidemiology, clinical importance and possible management of these multi-resistant organisms.

Clinical characteristics and risk factors of enterococcal infections in Nagasaki, Japan: a retrospective study

BACKGROUND

Enterococcus spp. are particularly important etiological agents of nosocomial infections. However, the clinical characteristics of and risk factors for enterococcal infections in clinical settings are poorly understood.

METHODS

The sample included patients with Enterococcus spp. infections detected from clinical samples at Nagasaki University Hospital between 2010 and 2011 and patients with enterococcal colonization (control patients). In this retrospective study, the risk factors for enterococcal infections were analyzed by comparing infected and control patients via multivariate logistic regression.

RESULTS

A total of 182 infected (mean age, 64.6 ± 18.2 years; 114 men) and 358 control patients (patients with enterococcal colonization) (mean age, 61.6 ± 22.4 years; 183 men) were included. Enterococcal infections were classified as intraperitoneal (n = 87), urinary tract (n = 28), or bloodstream (n = 20) infections. Cancer and hematological malignancies were the most common comorbidities in enterococcal infections. Carbapenem and vancomycin were administered to 43.8 % and 57.9 % of patients infected with Enterococcus faecalis and Enterococcus faecium, respectively. No vancomycin-resistant enterococci were isolated. Multivariate analysis identified abdominal surgery (odds ratio [OR], 2.233; 95 % confidence interval [CI], 1.529-3.261; p ≤ 0.001), structural abnormalities of the urinary tract (OR, 2.086; 95 % CI, 1.088-4.000; p = 0.027), male sex (OR, 1.504; 95 % CI, 1.032-2.190; p = 0.033), and hypoalbuminemia (OR, 0.731; 95 % CI, 0.555-0.963; p = 0.026) as independent risk factors for enterococcal infections. Multivariate analysis showed abdominal surgery (OR, 2.263; 95 % CI, 1.464-3.498; p ≤ 0.001), structural abnormalities of the urinary tract (OR, 2.634; 95 % CI, 1.194-5.362; p = 0.008), and hypoalbuminemia (OR, 0.668; 95 % CI, 0.490-0.911; p = 0.011) were independent risk factors for E. faecalis infection. Finally, immunosuppressive agent use (OR, 3.837; 95 % CI, 1.397-10.541; p = 0.009) and in situ device use (OR, 3.807; 95 % CI, 1.180-12.276; p = 0.025) were independent risk factors for E. faecium infection.

CONCLUSIONS

These findings might inform early initiation of antimicrobial agents to improve clinical success.

Surveillance of Food- and Smear-Transmitted Pathogens in European Soldiers with Diarrhea on Deployment in the Tropics: Experience from the European Union Training Mission (EUTM) Mali

Introduction. Since 2013, European soldiers have been deployed on the European Union Training Mission (EUTM) in Mali. From the beginning, diarrhea has been among the most “urgent” concerns. Diarrhea surveillance based on deployable real-time PCR equipment was conducted between December 2013 and August 2014. Material and Methods. In total, 53 stool samples were obtained from 51 soldiers with acute diarrhea. Multiplex PCR panels comprised enteroinvasive bacteria, diarrhea-associated Escherichia coli (EPEC, ETEC, EAEC, and EIEC), enteropathogenic viruses, and protozoa. Noroviruses were characterized by sequencing. Cultural screening for Enterobacteriaceae with extended-spectrum beta-lactamases (ESBL) with subsequent repetitive sequence-based PCR (rep-PCR) typing was performed. Clinical information was assessed. Results. Positive PCR results for diarrhea-associated pathogens were detected in 43/53 samples, comprising EPEC (n = 21), ETEC (n = 19), EAEC (n = 15), Norovirus (n = 10), Shigella spp./EIEC (n = 6), Cryptosporidium parvum (n = 3), Giardia duodenalis (n = 2), Salmonella spp. (n = 1), Astrovirus (n = 1), Rotavirus (n = 1), and Sapovirus (n = 1). ESBL-positive Enterobacteriaceae were grown from 13 out of 48 samples. Simultaneous infections with several enteropathogenic agents were observed in 23 instances. Symptoms were mild to moderate. There were hints of autochthonous transmission. Conclusions. Multiplex real-time PCR proved to be suitable for diarrhea surveillance on deployment. Etiological attribution is challenging in cases of detection of multiple pathogens.

The clinical impact of vancomycin-resistant Enterococcus colonization and bloodstream infection in patients undergoing autologous transplantation

BACKGROUND

Although several studies have documented adverse outcomes for vancomycin-resistant Enterococcus (VRE) colonization and infection in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients, data are inadequate for patients undergoing autologous (auto-)HSCT.

METHODS

We conducted a retrospective cohort study of 300 consecutive patients receiving an auto-HSCT between 2006 and 2014. Patients had stool cultures for VRE on admission and weekly during hospitalization.

RESULTS

Thirty-six percent of patients had VRE gastrointestinal (GI) colonization and 3% developed a VRE bloodstream infection (BSI), all of whom were colonized. VRE strain typing of BSI isolates showed that some patients shared identical patterns. Rates of colonization and BSI in colonized patients were similar to simultaneous patients undergoing allo-HSCT, except that the latter had a higher rate of colonization at admission. A diagnosis of lymphoma was associated with an increased risk of colonization. VRE BSI was associated with longer lengths of stay and possibly higher costs, but no decrease in overall survival, and colonized patients had no VRE infections during the year following discharge. Repeat stool cultures in patients subsequently undergoing allo-HSCT suggested that most, if not all, VRE-positive auto-HSCT patients lose their detectable GI colonization within a few months of discharge.

CONCLUSION

VRE colonization is frequent but carries a low risk for infection in patients undergoing auto-HSCT. However, these patients can serve as reservoirs for transmission to higher risk patients. Moreover, patients may remain colonized if proceeding to an allo-HSCT shortly after auto-HSCT, potentially increasing the risk of the allogeneic procedure.

The prevention and management of infections due to multidrug resistant organisms in haematology patients

Infections due to resistant and multidrug resistant (MDR) organisms in haematology patients and haematopoietic stem cell transplant recipients are an increasingly complex problem of global concern. We outline the burden of illness and epidemiology of resistant organisms such as gram-negative pathogens, vancomycin-resistant Enterococcus faecium (VRE), and Clostridium difficile in haematology cohorts. Intervention strategies aimed at reducing the impact of these organisms are reviewed: infection prevention programmes, screening and fluoroquinolone prophylaxis. The role of newer therapies (e.g. linezolid, daptomycin and tigecycline) for treatment of resistant and MDR organisms in haematology populations is evaluated, in addition to the mobilization of older agents (e.g. colistin, pristinamycin and fosfomycin) and the potential benefit of combination regimens.

Bacterial infections in hematopoietic stem cell transplantation recipients

PURPOSE OF REVIEW

Bacterial infections are among the most frequent complications of hematopoietic stem cell transplant (HSCT). This review describes current epidemiology and management of bacterial infections.

RECENT FINDINGS

Multidrug resistant (MDR) bacteria are increasingly frequent in HSCT recipients, but significant differences in etiology of bacterial infections and prevalence of resistant strains exist between different transplant centers. Methicillin-resistant coagulase-negative staphylococci, extended-spectrum beta-lactamase-producing Enterobacteriaceae, vancomycin-resistant enterococci and MDR Pseudomonas aeruginosa are the most relevant examples. Infection control measures are mandatory to limit the spread of resistant strains. Selective digestive decontamination is controversial and potentially associated with inducing resistance to antibiotics that might be the last treatment option, such as colistin or aminoglycosides. Empirical therapy should be individualized, and an escalation or de-escalation approach should be chosen depending on local epidemiology, colonization and clinical presentation. Antimicrobial stewardship, with the aim of improving management of bacterial infections, should be put in place in transplant units.

SUMMARY

Bacterial infections in the transplant population warrant currently particular attention to limit the negative impact of infections caused by resistant strains.

Clinical significance of methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci colonization in liver transplant recipients

BACKGROUND/AIMS

Liver transplant patients are at high risk for methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) colonization. We evaluated patients before and after liver transplant using active surveillance culture (ASC) to assess the prevalence of MRSA and VRE and to determine the effect of bacterial colonization on patient outcome.

METHODS

We performed ASC on 162 liver transplant recipients at the time of transplantation and 7 days posttransplantation to monitor the prevalence of MRSA and VRE.

RESULTS

A total of 142 patients had both nasal and rectal ASCs. Of these patients, MRSA was isolated from 12 (7.4%) at the time of transplantation (group 1a), 9 (6.9%) acquired MRSA posttransplantation (group 2a), and 121 did not test positive for MRSA at either time (group 3a). Among the three groups, group 1a patients had the highest frequency of developing a MRSA infection (p < 0.01); however, group 2a patients had the highest mortality rate associated with MRSA infection (p = 0.05). Of the 142 patients, VRE colonization was detected in 37 patients (22.8%) at the time of transplantation (group 1b), 21 patients (20%) acquired VRE posttransplantation (group 2b), and 84 patients did not test positive for VRE at either time (group 3b). Among these three groups, group 2b patients had the highest frequency of VRE infections (p < 0.01) and mortality (p = 0.04).

CONCLUSIONS

Patients that acquired VRE or MRSA posttransplantation had higher mortality rates than did those who were colonized pre-transplantation or those who never acquired the pathogens. Our findings highlight the importance of preventing the acquisition of MRSA and VRE posttransplantation to reduce infections and mortality among liver transplant recipients.

Molecular Characterization and Resistant Spectrum of Enterococci Isolated from a Haematology Unit in China

OBJECTIVES

The present study screened clinical isolates of E. faecalis and E. faecium to determine resistant spectrum and the potential virulence genes characterization among them of haematology patients.

METHODS

Clinical Enterococci isolates were obtained from a haematology unit in a tertiary care hospital in China.

RESULTS

Among 125 isolates available for the investigation, 46 were identified as E. faecium, and 79 were E. faecalis. Urine was the most common source (82, 65.6%). E. faecium isolates were more resistant than E. faecalis. Among E. faecium, maximum resistance was seen against PEN 93.5% and AMP 93.5% followed by CIP 87%. Eight vancomycin-resistant E. faecium (VREfm) isolates were obtained, positive for vanA genotype. Of 125 Enterococci isolates, 67(53.6%) were acm, and 42.4%, 25.6%, 25.6%, 24.8%, 23.2%, 20.8%, 10.4% and 7.2% of isolates were positive for esp, cylL-A, asa 1, cylL-S, cpd, cylL-L, gel-E and ace, respectively. E. faecalis isolates have more virulence genes (VGs) than E. faecium. MLST analysis of VREfm identified three different STs (ST17, ST78 and ST203).

CONCLUSION

The study provides the molecular characterization and resistant spectrum of Enterococci isolated from a haematology unit in China. Molecular analysis showed that all VREfm isolates belonged to pandemic clonal complex-17(CC17), associated with hospital-related isolates. Therefore, determining resistant spectrum and virulence characterization is crucial for the prevention and control of the spread of nosocomial infections caused by Enterococci in the haematology unit.

Empiric use of linezolid in febrile hematology and hematopoietic stem cell transplantation patients colonized with vancomycin-resistant Enterococcus spp

OBJECTIVES

We conducted a retrospective study on the impact of the empiric use of linezolid on mortality in vancomycin-resistant Enterococcus spp (VRE)-colonized hematology and hematopoietic stem cell transplantation (HSCT) patients.

METHODS

VRE-colonized inpatients for whom complete data were available (n=100) were divided into two groups: those who received empiric linezolid in the course of fever refractory to broad-spectrum antibiotics, replacing the glycopeptide utilized for the previous 48 h, and those who did not (control group). All patients were followed until hospital discharge or death. The impact of linezolid and risk factors for all-cause mortality were evaluated; variables with p<0.10 were analyzed in a multivariate model. A Kaplan-Meier survival analysis was done to compare survival among febrile patients colonized by VRE who received empiric linezolid with patients who did not receive linezolid.

RESULTS

Patients empirically prescribed linezolid were generally younger (median age 33 vs. 44 years; p=0.008) and more likely to be recipients of an allogeneic HSCT (24 (68.6%) vs. 24 (36.9%); p=0.009) than patients who did not receive the drug. Fourteen (21.5%) VRE bloodstream infections were diagnosed, all in patients who did not receive empiric linezolid (p=0.002). In-hospital mortality was comparable in empiric linezolid and non-linezolid users (19 (54.3%) vs. 27 (41.5%), respectively; p=0.293). The Kaplan-Meier survival analysis showed no significant difference in survival comparing the group that received linezolid to the group that did not (p=0.72). Graft-versus-host disease (GVHD; odds ratio (OR) 5.90, 95% confidence interval (CI) 1.46-23.79; p=0.012) and persistence of neutropenia (OR 6.93, 95% CI 1.72-27.94; p=0.0065) were independent predictors of all-cause in-hospital death in HSCT patients, and persistence of neutropenia in non-HSCT patients (OR 8.12, 95% CI 1.22-53.8; p=0.030).

CONCLUSIONS

The empiric use of linezolid in VRE-colonized hematology patients had no impact on mortality, which appeared rather to be associated with the persistence of neutropenia in general and GVHD in the HSCT group.

Risk of Vancomycin-ResistantEnterococcus(VRE) Bloodstream Infection Among Patients Colonized With VRE

Background.

Colonization with vancomycin-resistantEnterococcus(VRE) is a risk factor for subsequent VRE bloodstream infection (BSI); however, risk factors for BSI among colonized patients have not been adequately described. We sought to determine the proportion of VRE-colonized patients who subsequently develop VRE BSI and to identify risk factors for VRE BSI among these patients.

Methods.

Records of 768 patients colonized with VRE from January 2002 through June 2005 were reviewed. The proportion of patients who developed VRE BSI was calculated, and the characteristics of these patients were compared, in a 2 : 1 ratio, with those of patients who did not develop VRE BSI. To identify risk factors for VRE BSI and for death, we used univariate logistic regression analysis and then multivariate logistic regression analysis. Using pulsed-field gel electrophoresis (PFGE), we compared the isolate recovered when the patient was colonized and the isolate recovered when the patient developed VRE BSI.

Results.

Of the 768 patients colonized with VRE, 31 (4.0%) developed VRE BSI. Multivariate analysis identified the following idependent risk factors for developing VRE BSI: infection of an additional body site other than blood (adjusted odds ratio [aOR], 3.9;P= .04), admission to the hospital from a long-term care facility (aOR, 12.6;P= .04), and receipt of vancomycin (aOR, 10.6;P< .001). The independent risk factors for death among patients colonized with VRE were immunosuppression (aOR, 12.9;P= .001 ) and VRE BSI (aOR, 9.1;P= .002). Of the 31 patients who developed VRE BSI, 23 (74%) had a pair of isolates representing VRE colonization and VRE BSI. For 19 (83%) of these 23 patients, the isolate representing BSI was genetically related to the isolate representing VRE colonization: 12 pairs of isolates (52%) had identical banding patterns, 5 had closely related patterns, and 2 had possibly related patterns.

Conclusion.

Of the 768 patients colonized with VRE, 31 (4.0%) usually developed VRE BSI due to a related strain. Independent risk factors for BSI among colonized patients were admission from a long-term care facility, infection of an additional body site, and exposure to vancomycin. Independent risk factors for death were immunosuppression and VRE BSI.

Epidemiology of Vancomycin-Resistant Enterococci Among Patients on an Adult Stem Cell Transplant Unit: Observations From an Active Surveillance Program

Objective.

To use the findings of an active surveillance program to delineate the unique epidemiology of vancomycin-resistant enterococci (VRE) in a mixed population of transplant and nontransplant patients hospitalized on a single patient care unit.

Design.

Surveillance survey and case-control analysis.

Setting.

A 19-bed adult bone marrow and stem cell transplant unit at a referral and primary-care center.

Patients.

The study included patients undergoing transplantation, patients who had previously received bone marrow or stem cell transplants, and patients with other malignancies and hematological disorders who were admitted to the study unit.

Methods.

Patients not previously identified as colonized with VRE had perirectal swab specimens collected at admission and once weekly while hospitalized on the unit. The prevalence of VRE colonization at admission and the incidence throughout the hospital stay, genotypes of VRE specimens as determined by pulsed field gel electrophoresis, and risk factors related to colonization were analyzed.

Results.

There was no significant difference in the prevalence or incidence of new colonization between nontransplant patients and prior or current transplant recipients, although overall prevalence at admission was significantly higher in the prior transplant group. Preliminary genotypic analysis of VRE isolates from transplant patients suggests that a proportion of cases of newly detected VRE carriage may represent prior colonization not detected at admission, with different risk factors suggestive of a potential epidemiological distinction.

Conclusion.

Examination of epidemiological and microbiological data collected by an active surveillance program provides useful information about the epidemiology of VRE that can be applied to inform rational infection control strategies.

Risk of vancomycin-resistant enterococci bloodstream infection among patients colonized with vancomycin-resistant enterococci

BACKGROUND

Vancomycin-resistant enterococci colonization has been reported to increase the risk of developing infections, including bloodstream infections.

AIM

In this study, we aimed to share our experience with the vancomycin-resistant enterococci bloodstream infections following gastrointestinal vancomycin-resistant enterococci colonization in pediatric population during a period of 18 months.

METHOD

A retrospective cohort of children admitted to a 400-bed tertiary teaching hospital in Izmir, Turkey whose vancomycin-resistant enterococci colonization was newly detected during routine surveillances for gastrointestinal vancomycin-resistant enterococci colonization during the period of January 2009 and December 2012 were included in this study. All vancomycin-resistant enterococci isolates found within 18 months after initial detection were evaluated for evidence of infection.

FINDINGS

Two hundred and sixteen patients with vancomycin-resistant enterococci were included in the study. Vancomycin-resistant enterococci colonization was detected in 136 patients (62.3%) while they were hospitalized at intensive care units; while the remaining majority (33.0%) were hospitalized at hematology-oncology department. Vancomycin-resistant enterococci bacteremia was present only in three (1.55%) patients. All these patients were immunosuppressed due to human immunodeficiency virus (one patient) and intensive chemotherapy (two patients).

CONCLUSION

In conclusion, our study found that 1.55% of vancomycin-resistant enterococci-colonized children had developed vancomycin-resistant enterococci bloodstream infection among the pediatric intensive care unit and hematology/oncology patients; according to our findings, we suggest that immunosupression is the key point for developing vancomycin-resistant enterococci bloodstream infections.

Evaluation of routine pretransplantation screening for methicillin-resistant Staphylococcus aureus in hematopoietic cell transplant recipients

Methicillin-resistant Staphylococcus aureus (MRSA) screening guidelines for hematopoietic cell transplant (HCT) recipients are not well defined. Retrospective assessment of standardized pretransplantation MRSA screening in a large single-center cohort of HCT recipients demonstrated that colonization was uncommon, and that no colonized patients developed posttransplantation invasive complications.

Daptomycin versus linezolid for treatment of vancomycin-resistant enterococcal bacteremia: systematic review and meta-analysis

Background

Linezolid, which has bacteriostatic activity, is approved for the treatment of vancomycin-resistant enterococci (VRE) infections. Meanwhile, daptomycin exerts bactericidal activity against VRE, but is not approved for the treatment of VRE bacteremia. Only a few studies with small sample sizes have compared the effectiveness of these drugs for treatment of VRE bacteremia.

Methods

PubMed, EMBASE, and the Cochrane Library were searched for studies of VRE bacteremia treatment published before January 1, 2014. All studies reporting daptomycin and linezolid treatment outcomes simultaneously were included. The endpoints were mortality and microbiological cure. The adjusted odds ratios (aORs) of mortality in daptomycin- and linezolid-treated patients were extracted if available. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for all outcomes using a random-effects model.

Results

Thirteen studies (532 patients receiving daptomycin, 656 patients receiving linezolid) met the selection criteria. All studies had retrospective cohort designs and relatively small sample sizes. Eight studies compared the aORs of mortality in daptomycin- and linezolid-treated patients. Four studies were published as conference papers and there was significant heterogeneity among these studies (I² = 63%, p = 0.04). Daptomycin use was not associated with better microbiological cure (daptomycin vs. linezolid, OR: 0.67, 95% CI: 0.42–1.06, p = 0.09). However, mortality was higher in patients receiving daptomycin (OR: 1.43, 95% CI: 1.09–1.86, p = 0.009). Subgroup analysis of studies that reported aORs indicated that daptomycin was associated with higher mortality (OR: 1.59, 95% CI: 1.02–2.50, p = 0.04). There was no evidence of publication bias, but all enrolled studies were retrospective, had small sample sizes, and had substantial limitations.

Conclusions

Although limited data is available, the current meta-analysis shows that linezolid treatment for VRE bacteremia was associated with a lower mortality than daptomycin treatment. However, the results should be interpreted cautiously because of limitations inherent to retrospective studies and the high heterogeneity among studies. A large randomized trial is needed to confirm the present results.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0687-9) contains supplementary material, which is available to authorized users.

Infection control issues in patients with haematological malignancies in the era of multidrug-resistant bacteria

Drug-resistant Gram-negative and Gram-positive bacteria are now increasingly identified as a cause of infections in immunocompromised hosts. Bacteria identified include the multidrug-resistant (MDR) and even pandrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa, as well as carbapenem-resistant Enterobacteriaceae spp. The threat from MDR pathogens has been well-documented in the past decade with warnings about the consequences of inappropriate use of antimicrobial drugs. Resistant bacteria can substantially complicate the treatment of infections in critically ill patients and can have a substantial effect on mortality. Inappropriate antimicrobial treatment can affect morbidity, mortality, and overall health-care costs. Evidence-based data for prevention and control of MDR pathogen infections in haematology are scarce. Although not yet established a bundle of infection control and prevention measures with an anti-infective stewardship programme is an important strategy in infection control, diagnosis, and antibiotic selection with optimum regimens to ensure a successful outcome for patients.

Vancomycin-Resistant Enterococcal Bacteremia Pharmacotherapy

Objective: To review the literature on the pharmacotherapy of bloodstream infections (BSI) caused by vancomycin-resistant enterococci (VRE). Data Sources: A MEDLINE literature search was performed for the period 1946 to May 2014 using the search terms Enterococcus, enterococci, vancomycin-resistant, VRE, bacteremia, and bloodstream infection. References were also identified from selected review articles. Study Selection and Data Extraction: English-language case series, cohort studies, and meta-analyses assessing the options in the pharmacotherapy of VRE BSIs in adult patients were evaluated. Data Synthesis: Studies were identified that utilized linezolid, quinupristin/dalfopristin (Q/D), and daptomycin. In all, 8 comparative retrospective cohort studies, 2 meta-analyses of daptomycin and linezolid, and 3 retrospective comparisons of linezolid and Q/D were included for review. Mortality associated with VRE BSIs was high across studies, and the ability to determine differences in outcomes between agents was confounded by the complex nature of the patients included. Two meta-analyses comparing daptomycin with linezolid for VRE BSIs found modest advantages for linezolid, but these conclusions may be hampered by heterogeneity within the included studies. Conclusions: VRE BSIs remain a difficult-to-treat clinical situation. Differences in toxicity between the agents used to treat it are clear, but therapeutic differences are more difficult to discern. Meta-analyses suggest that a moderate advantage for linezolid over daptomycin may exist, but problems with the nature of studies that they included make definitive conclusions difficult.

Assessing outcomes of adult oncology patients treated with linezolid versus daptomycin for bacteremia due to vancomycin-resistant Enterococcus

Background

The incidence and severity of vancomycin-resistant Enterococcus blood stream infections continue to rise and is a significant burden in the healthcare setting. Literature thus far is minimal regarding treatment outcomes in patients with malignancy and vancomycin-resistant Enterococcus bacteremia. Appropriate antibiotic selection is vital to treatment success due to high rates of resistance, limited antimicrobials and mortality in this patient population. We conducted this study to determine whether treatment outcomes differed between cancer patients treated with linezolid and those treated with daptomycin for vancomycin-resistant Enterococcus bacteremia.

Methods

This single-center, retrospective study included adult patients hospitalized on the oncology service with documented vancomycin-resistant Enterococcus faecium or Enterococcus faecalis bacteremia who received at least 48 h of either linezolid or daptomycin as primary treatment.

Results

A total of 65 patients were included in the analysis. Thirty-two patients received daptomycin as primary treatment, and 33 patients received linezolid as primary treatment. Twenty-six (76.5%) patients in the linezolid cohort versus 22 (71%) patients in the daptomycin cohort achieved microbiological cure ( p = 0.6141). Median length of stay in days (30 vs. 42, p = 0.0714) and mortality (7/32 (20.6%) vs. 8/33 (25.8%), p = 0.6180) were also similar between the linezolid and daptomycin treated patients, respectively.

Conclusion

No differences in microbiological cure, length of stay or mortality were identified between the groups. This study suggests that linezolid and daptomycin are each reasonable options for treating vancomycin-resistant Enterococcus bacteremia in oncology patients. Further prospective, randomized controlled trials are needed to assess the optimal treatment for vancomycin-resistant Enterococcus bacteremia in this patient population.

Changing microbial epidemiology in hematopoietic stem cell transplant recipients: increasing resistance over a 9-year period

Infections remain important contributors to mortality in hematopoietic stem cell transplantation (HSCT).

METHOD

We studied the evolving epidemiology and trends in susceptibility of bacterial and Candida isolates at an Australian HSCT center. A total of 528 HSCTs in 508 patients were performed from April 2001 to May 2010. A total of 605 isolates were eligible for study inclusion; 318 (53%) were gram-positive, 268 (44%) were gram-negative, and 19 (3%) were Candida species.

RESULTS

The most common site for isolates was blood (380 isolates, 63%). Staphylococcus aureus was the most common gram-positive organism (n = 107, 34%), but trends to increasing coagulase-negative staphylococci (P = 0.002) and vancomycin-resistant Enterococcus (P < 0.001) were observed. Escherichia coli was the most common gram-negative isolate (n = 74, 28%). Fluoroquinolone resistance increased with widespread use of protocol fluoroquinolone prophylaxis (P = 0.001). Carbapenem resistance was found in 44% of Pseudomonas or Acinetobacter isolates. Bloodstream infection with a multidrug-resistant organism (odds ratio 3.61, 95% confidence interval: 1.40-9.32, P = 0.008) was an independent predictor of mortality at 7 days after a positive blood culture.

CONCLUSIONS

Antimicrobial resistance is an increasing problem in this vulnerable patient population, and not only has an impact on choice of empiric therapy for febrile neutropenia but also on mortality.

Bloodstream infections in patients with hematological malignancies: which is more fatal - cancer or resistant pathogens?

Background

The primary objective of this study was to report the incidence of bloodstream infections (BSIs) and clinically or microbiologically proven bacterial or fungal BSIs during neutropenic episodes in patients with hematological malignancies.

Methods

In this retrospective observational study, all patients in the hematology department older than 14 years who developed febrile neutropenia during chemotherapy for hematological cancers were evaluated. Patients were included if they had experienced at least one neutropenic episode between November 2010 and November 2012 due to chemotherapy in the hematology ward.

Results

During 282 febrile episodes in 126 patients, 66 (23%) episodes of bacteremia and 24 (8%) episodes of fungemia were recorded in 48 (38%) and 18 (14%) patients, respectively. Gram-negative bacteria caused 74% (n=49) of all bacteremic episodes. Carbapenem-resistant Gram-negative bacteria (n=6) caused 12% and 9% of Gram-negative bacteremia episodes and all bacteremia episodes, respectively. Carbapenem-resistant Gram-negative bacteria included Acinetobacter baumannii (n=4), Pseudomonas aeruginosa (n=1), and Serratia marcescens (n=1). Culture-proven invasive fungal infection occurred in 24 episodes in 18 cases during the study period, with 15 episodes in ten cases occurring in the first study year and nine episodes in eight cases in the second study year. In 13 of 18 cases (72%) with bloodstream yeast infections, previous azole exposure was recorded. Candida parapsilosis, C. glabrata, and C. albicans isolates were resistant to voriconazole and fluconazole.

Conclusion

BSIs that occur during febrile neutropenic episodes in hematology patients due to Gram-negative bacteria should be treated initially with non-carbapenem-based antipseudomonal therapy taking into consideration antimicrobial stewardship. Non-azole antifungal drugs, including caspofungin and liposomal amphotericin B, should be preferred as empirical antifungal therapy in the events of possible or probable invasive fungal infections with an absence of pulmonary findings due to increase azole resistance.

Management of febrile neutropenia in the era of bacterial resistance

Managing cancer patients with fever and neutropenia must be considered as a medical emergency since any delay in initiating appropriate empirical antibacterial therapy may result in high rates of mortality and morbidity. Emerging antibacterial resistance in bacterial pathogens infecting febrile neutropenic patients complicates management, and choosing the type of empirical antimicrobial therapy has become a challenge. To further complicate the decision process, not all neutropenic patients are in same category of susceptibility to develop severe infection. While low-risk patients may be treated with oral antibiotics in the outpatient setting, high-risk patients usually need to be admitted to hospital and receive parenteral broad-spectrum antibiotics until the neutrophil levels recover. These strategies have recently been addressed in two international guidelines from the Infectious Diseases Society of America (IDSA) and the European Conference on Infections in Leukaemia (ECIL). This review gives a brief overview of current antimicrobial resistance problems and their effects in febrile neutropenic cancer patients by summarizing the suggestions from the IDSA and ECIL guidelines.

Risk factors for vancomycin-resistant enterococcus bacteremia and its influence on survival after allogeneic hematopoietic cell transplantation

Vancomycin-resistant enterococcus (VRE) is a well-known infectious complication among immunocompromised patients. We performed a retrospective analysis to identify risk factors for the development of VRE bacteremia (VRE-B) within 15 months after allogeneic hematopoietic cell transplantation (alloHCT) and to determine its prognostic importance for other post-transplant outcomes. Eight hundred consecutive adult patients who underwent alloHCT for hematologic diseases from 1997 to 2011 were included. Seventy-six (10%) developed VRE-B at a median of 46 days post transplant. Year of transplant, higher HCT comorbidity score, a diagnosis of ALL, unrelated donor and umbilical cord blood donor were all significant risk factors on multivariable analysis for the development of VRE-B. Sixty-seven (88%) died within a median of 1.1 months after VRE-B, but only four (6%) of these deaths were attributable to VRE. VRE-B was significantly associated with worse OS (hazard ratio 4.28, 95% confidence interval 3.23-5.66, P<0.001) in multivariable analysis. We conclude that the incidence of VRE-B after alloHCT has increased over time and is highly associated with mortality, although not usually attributable to VRE infection. Rather than being the cause, this may be a marker for a complicated post-transplant course. Strategies to further enhance immune reconstitution post transplant and strict adherence to infection prevention measures are warranted.

European guidelines for empirical antibacterial therapy for febrile neutropenic patients in the era of growing resistance: summary of the 2011 4th European Conference on Infections in Leukemia

Owing to increasing resistance and the limited arsenal of new antibiotics, especially against Gram-negative pathogens, carefully designed antibiotic regimens are obligatory for febrile neutropenic patients, along with effective infection control. The Expert Group of the 4(th) European Conference on Infections in Leukemia has developed guidelines for initial empirical therapy in febrile neutropenic patients, based on: i) the local resistance epidemiology; and ii) the patient's risk factors for resistant bacteria and for a complicated clinical course. An 'escalation' approach, avoiding empirical carbapenems and combinations, should be employed in patients without particular risk factors. A 'de-escalation' approach, with initial broad-spectrum antibiotics or combinations, should be used only in those patients with: i) known prior colonization or infection with resistant pathogens; or ii) complicated presentation; or iii) in centers where resistant pathogens are prevalent at the onset of febrile neutropenia. In the latter case, infection control and antibiotic stewardship also need urgent review. Modification of the initial regimen at 72-96 h should be based on the patient's clinical course and the microbiological results. Discontinuation of antibiotics after 72 h or later should be considered in neutropenic patients with fever of unknown origin who are hemodynamically stable since presentation and afebrile for at least 48 h, irrespective of neutrophil count and expected duration of neutropenia. This strategy aims to minimize the collateral damage associated with antibiotic overuse, and the further selection of resistance.

Infection control and prevention considerations

Due to the nature of their underlying illness and treatment regimens, cancer patients are at increased risk of infection. Though the advent and widespread use of anti-infective agents has allowed for the application of ever-greater immune-suppressing therapies with successful treatment of infectious complications, prevention of infection remains the primary goal. The evolutionary changes of microorganisms, whereby resistance to anti-infective therapy is increasingly common, have facilitated a paradigm shift in the field of healthcare epidemiology. No longer is the focus on "control" of infection once established in a healthcare environment. Rather, the emphasis is on prevention of infection before it occurs. The most basic tenet of infection prevention, and the cornerstone of all well-designed infection prevention and control programs, is hand hygiene. The hands of healthcare workers provide a common potential source for transmission of infectious agents, and effective decontamination of the hands reduces the risk of transmission of infectious material to other patients. Once infection is suspected or established; however, implementation of effective control strategies is important to limit the spread of infection within a healthcare environment. This chapter outlines the basic tenets of infection prevention, principles of isolation precautions and control measures, and elements for a successful infection control and prevention program.

The emergence of vancomycin-resistant enterococcal bacteremia in hematopoietic stem cell transplant recipients

Abstract As antimicrobial resistance increases, understanding the current epidemiology of bloodstream infections (BSIs) in hematopoietic stem cell transplant (HSCT) recipients is essential to guide empirical antimicrobial therapy. We therefore reviewed microbial etiologies, timing and outcomes of BSIs in patients who were transplanted from September 2007 to December 2011. Vancomycin-resistant enterococci (VRE) were the most common pathogens in allogeneic HSCT recipients and the fourth most common after autologous transplant. VRE did not cause any of 101 BSIs in neutropenic patients who were not receiving antibacterials, but caused 32 (55%) of 58 BSIs in neutropenic patients receiving a broad-spectrum β-lactam agent (p < 0.001). Rates of septic shock and 7-day mortality were 5% and 0% for streptococcal bacteremia, 12% and 18% for VRE bacteremia, and 20% and 14% for Gram-negative bacteremia. In conclusion, VRE bacteremia was the most common BSI in allogeneic HSCT recipients, occurred primarily in neutropenic patients receiving broad-spectrum β-lactams and was associated with poor outcomes.

Improving the detection rate of vancomycin-resistant enterococci colonisation using groin swabs

Vancomycin-resistant enterococci (VRE) are nosocomial pathogens associated with significant morbidity in immunosuppressed patients. Stool culture is considered the gold standard for VRE screening. However, in a clinical environment, there are difficulties associated with the practicalities of obtaining stool samples. Groin swabs, routinely collected as part of the mandatory admissions policy for meticillin-resistant Staphylococcus aureus screening were used to detect VRE. In direct comparison, stool culture had better sensitivity to groin swabs. However, groin swabs with broth enrichment allowed earlier detection of VRE carriage in 14 patients from whom stool samples could not be obtained in a timely manner.