Gram-positive infections and the use of vancomycin in 550 episodes of fever and neutropenia

MRGPRX2 and Adverse Drug Reactions

Many adverse reactions to therapeutic drugs appear to be allergic in nature, and are thought to be triggered by patient-specific Immunoglobulin E (IgE) antibodies that recognize the drug molecules and form complexes with them that activate mast cells. However, in recent years another mechanism has been proposed, in which some drugs closely associated with allergic-type events can bypass the antibody-mediated pathway and trigger mast cell degranulation directly by activating a mast cell-specific receptor called Mas-related G protein-coupled receptor X2 (MRGPRX2). This would result in symptoms similar to IgE-mediated events, but would not require immune priming. This review will cover the frequency, severity, and dose-responsiveness of allergic-type events for several drugs shown to have MRGPRX2 agonist activity. Surprisingly, the analysis shows that mild-to-moderate events are far more common than currently appreciated. A comparison with plasma drug levels suggests that MRGPRX2 mediates many of these mild-to-moderate events. For some of these drugs, then, MRGPRX2 activation may be considered a regular and predictable feature after administration of high doses.

Large-scale patterns of soil antibiotic resistome in Chinese croplands

Soil is a vital reservoir of antibiotic resistance genes (ARGs), but we still know little about their distribution in cropland soils and the main driving forces. Here we performed an investigation for ARGs patterns in 105 cropland soils (planted with maize, peanut or soybean) along a 2, 200 km transect in China using high-throughput quantitative PCR approaches. Totally, 204 ARGs were detected, with a higher diversity found in central China than that in northeast and south China. The most abundant (top 50%) and highly shared (present in >50% samples) ARGs regarded as core resistome were dominated by multidrug resistance genes such as oprJ, acrA-05 and acrA-04. Regressive analyses revealed that the relative abundance of total ARGs and core resistome both had significant relationships with mobile genetic elements (MGEs). Anthropogenic factors including the consumption of plastic films and soil properties including heavy metals showed good correlations with the diversity of ARGs. Structural equation modelling analysis further explained that anthropogenic factors were the main forces shaping the ARGs patterns. These findings highlight the importance of human activities in shaping soil antibiotic resistome in the croplands, providing potential management strategies to mitigate the dissemination of ARGs to humans via food chain.

Combinatory antibiotic treatment protects against experimental acute pancreatitis by suppressing gut bacterial translocation to pancreas and inhibiting NLRP3 inflammasome pathway

Gut bacterial translocation following impaired gut barrier is a critical determinant of initiating and aggravating acute pancreatitis (AP). Antibiotic combination (ABX; vancomycin, neomycin and polymyxin b) is capable of reducing gut bacteria, but its efficacy in AP prevention and the underlying mechanism have not been investigated yet. AP was induced in BALB/c mice by caerulein (CAE) hyperstimulation. We found that ABX supplementation attenuated the severity of AP as evidenced by reduced pancreatic oedema and myeloperoxidase activity. The protective effect was also confirmed by improved histological morphology of the pancreas and decreased pro-inflammatory markers (IL-1β, TNF-α, MCP-1) in pancreas. ABX administration inhibits the activation of colonic TLR4/NLRP3 inflammasome pathway. Subsequently, down-regulated NLRP3 resulted in decreased colonic pro-inflammation (IL-1β, IL-6, MCP-1) and enhanced gut physical barrier as evidenced by up-regulation of tight junction proteins including occludin, claudin-1 and ZO-1, as well as improved histological morphology of the colon. Together, combinatory ABX therapy inhibited the translocation of gut bacteria to pancreas and its amplification effects on pancreatic inflammation by inhibiting the pancreatic NLRP3 pathway, and inhibiting intestinal-pancreatic inflammatory responses. The current study provides the basis for potential clinical application of ABX in AP.

Bone Marrow Transplantation: A Review

The indications for bone marrow transplantation (BMT) continue to expand as supportive care improves and alternative stem cell sources have been exploited. The application of allogeneic BMT has expanded to include unrelated histocompatibility antigen-matched donors and partially matched family donors. While the results of these transplants are not as good as those with sibling donors, these alternative donors allow curative therapy to be delivered to patients with leukemia, aplastic anemia, and immunodeficiency diseases who otherwise would not be eligible for curative therapy. Autologous BMT has emerged as a curative therapy for patients with non-Hodgkin's lymphoma, Hodgkin's disease, acute myeloid leukemia, and acute lymphoblastic leukemia. In addition, dose-intensive therapy with marrow or peripheral blood stem cell support to patients with Stage II, III, and IV breast carcinoma is under intense study in single and multiple-institution studies. Important issues under active study are prophylaxis for graft-versus-host-disease, the role of marrow purging in autologous BMT, the use of cytokine and chemotherapy-mobilized peripheral blood stem cells, and control of infectious diseases. This review summarizes current results in both allogeneic and autologous bone marrow transplantation, issues in marrow graft manipulations, issues in infectious disease control, the application of gene therapy to correct genetic disease through bone marrow or peripheral blood infusion, and current concepts in post-BMT immunization.

Empirical antibiotics targeting gram-positive bacteria for the treatment of febrile neutropenic patients with cancer

BACKGROUND

The pattern of infections among neutropenic patients with cancer has shifted in the last decades to a predominance of gram-positive infections. Some of these gram-positive bacteria are increasingly resistant to beta-lactams and necessitate specific antibiotic treatment.

OBJECTIVES

To assess the effectiveness of empirical anti-gram-positive (antiGP) antibiotic treatment for febrile neutropenic patients with cancer in terms of mortality and treatment failure. To assess the rate of resistance development, further infections and adverse events associated with additional antiGP treatment.

SEARCH METHODS

For the review update we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2017, Issue 2), MEDLINE (May 2012 to 2017), Embase (May 2012 to 2017), LILACS (2012 to 2017), conference proceedings, ClinicalTrials.gov trial registry, and the references of the included studies. We contacted the first authors of all included and potentially relevant trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing one antibiotic regimen versus the same regimen with the addition of an antiGP antibiotic for the treatment of febrile neutropenic patients with cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias, and extracted all data. Risk ratios (RR) with 95% confidence intervals (CIs) were calculated. A random-effects model was used for all comparisons showing substantial heterogeneity (I2 > 50%). Outcomes were extracted by intention-to-treat and the analysis was patient-based whenever possible.

MAIN RESULTS

Fourteen trials and 2782 patients or episodes were included. Empirical antiGP antibiotics were tested at the onset of treatment in 12 studies, and for persistent fever in two studies. The antiGP treatment was a glycopeptide in nine trials. Eight studies were assessed in the overall mortality comparison and no significant difference was seen between the comparator arms, RR of 0.90 (95% CI 0.64 to 1.25; 8 studies, 1242 patients; moderate-quality data). Eleven trials assessed failure, including modifications as failures, while seven assessed overall failure disregarding treatment modifications. Failure with modifications was reduced, RR of 0.72 (95% CI 0.65 to 0.79; 11 studies, 2169 patients; very low-quality data), while overall failure was the same, RR of 1.00 (95% CI 0.79 to 1.27; 7 studies, 943 patients; low-quality data). Sensitivity analysis for allocation concealment and incomplete outcome data did not change the results. Failure among patients with gram-positive infections was reduced with antiGP treatment, RR of 0.56 (95% CI 0.38 to 0.84, 5 studies, 175 patients), although, mortality among these patients was not changed.Data regarding other patient subgroups likely to benefit from antiGP treatment were not available. Glycopeptides did not increase fungal superinfection rates and were associated with a reduction in documented gram-positive superinfections. Resistant colonisation was not documented in the studies.

AUTHORS' CONCLUSIONS

Based on very low- or low-quality evidence using the GRADE approach and overall low risk of bias, the current evidence shows that the empirical routine addition of antiGP treatment, namely glycopeptides, does not improve the outcomes of febrile neutropenic patients with cancer.

Effects of inappropriate empirical antibiotic therapy on mortality in patients with healthcare-associated methicillin-resistant Staphylococcus aureus bacteremia: a propensity-matched analysis

Background

The purported value of empirical therapy to cover methicillin-resistant Staphylococcus aureus (MRSA) has been debated for decades. The purpose of this study was to evaluate the effects of inappropriate empirical antibiotic therapy on clinical outcomes in patients with healthcare-associated MRSA bacteremia (HA-MRSAB).

Methods

A prospective, multicenter, observational study was conducted in 15 teaching hospitals in the Republic of Korea from February 2010 to July 2011. The study subjects included adult patients with HA-MRSAB. Covariate adjustment using the propensity score was performed to control for bias in treatment assignment. The predictors of in-hospital mortality were determined by multivariate logistic regression analyses.

Results

In total, 345 patients with HA-MRSAB were analyzed. The overall in-hospital mortality rate was 33.0 %. Appropriate empirical antibiotic therapy was given to 154 (44.6 %) patients. The vancomycin minimum inhibitory concentrations of the MRSA isolates ranged from 0.5 to 2 mg/L by E-test. There was no significant difference in mortality between propensity-matched patient pairs receiving inappropriate or appropriate empirical antibiotics (odds ratio [OR] = 1.20; 95 % confidence interval [CI] = 0.71–2.03). Among patients with severe sepsis or septic shock, there was no significant difference in mortality between the treatment groups. In multivariate analyses, severe sepsis or septic shock (OR = 5.45; 95 % CI = 2.14–13.87), Charlson’s comorbidity index (per 1-point increment; OR = 1.52; 95 % CI = 1.27–1.83), and prior receipt of glycopeptides (OR = 3.24; 95 % CI = 1.08–9.67) were independent risk factors for mortality.

Conclusion

Inappropriate empirical antibiotic therapy was not associated with clinical outcome in patients with HA-MRSAB. Prudent use of empirical glycopeptide therapy should be justified even in hospitals with high MRSA prevalence.

Development and validation of a clinical model to predict the presence of β-lactam resistance in viridans group streptococci causing bacteremia in neutropenic cancer patients

BACKGROUND

Concern for serious infection due to β-lactam-resistant viridans group streptococci (VGS) is a major factor driving empiric use of an anti-gram-positive antimicrobial in patients with febrile neutropenia. We sought to develop and validate a prediction model for the presence of β-lactam resistance in VGS causing bloodstream infection (BSI) in neutropenic patients.

METHODS

Data from 569 unique cases of VGS BSI in neutropenic patients from 2000 to 2010 at the MD Anderson Cancer Center were used to develop the clinical prediction model. Validation was done using 163 cases from 2011 to 2013. In vitro activity of β-lactam agents was determined for 2011-2013 VGS bloodstream isolates.

RESULTS

In vitro resistance to β-lactam agents commonly used in the empiric treatment of febrile neutropenia was observed only for VGS isolates with a penicillin minimum inhibitory concentration (MIC) of ≥ 2 µg/mL. One hundred twenty-nine of 732 patients (17%) were infected with VGS strains with a penicillin MIC ≥ 2 µg/mL. For the derivation and validation cohorts, 98% of patients infected by VGS with a penicillin MIC of ≥ 2 µg/mL had at least 1 of the following risk factors: current use of a β-lactam as antimicrobial prophylaxis, receipt of a β-lactam antimicrobial in the previous 30 days, or nosocomial VGS BSI onset. Limiting empiric anti-gram-positive therapy to neutropenic patients having at least 1 of these 3 risk factors would have reduced such use by 42%.

CONCLUSIONS

Simple clinical criteria can assist with targeting of anti-gram-positive therapy to febrile neutropenic patients at risk of serious β-lactam-resistant VGS infection.

Empirical antibiotics targeting Gram-positive bacteria for the treatment of febrile neutropenic patients with cancer

BACKGROUND

The pattern of infections among neutropenic cancer patients has shifted in the last decades to a predominance of Gram-positive infections. Some of these Gram-positive bacteria are increasingly resistant to beta-lactams and necessitate specific antibiotic treatment.

OBJECTIVES

To assess the effectiveness of empirical antiGram-positive (antiGP) antibiotic treatment for febrile neutropenic cancer patients in terms of mortality and treatment failure. To assess the rate of resistance development, further infections and adverse events associated with additional antiGP treatment.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 7), MEDLINE (1966 to 2013), EMBASE (1982 to 2013), LILACS (1982 to 2013), conference proceedings, and the references of the included studies. First authors of all included and potentially relevant trials were contacted.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing one antibiotic regimen to the same regimen with the addition of an antiGP antibiotic for the treatment of febrile neutropenic cancer patients.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias, and extracted all data. Risk ratios (RR) with 95% confidence intervals (CI) were calculated. A random-effects model was used for all comparisons showing substantial heterogeneity (I(2) > 50%). Outcomes were extracted by intention to treat and the analysis was patient-based whenever possible.

MAIN RESULTS

Thirteen trials and 2392 patients or episodes were included. Empirical antiGP antibiotics were tested at the onset of treatment in 11 studies, and for persistent fever in two studies. The antiGP treatment was a glycopeptide in nine trials. Seven studies were assessed in the overall mortality comparison and no significant difference was seen between the comparator arms, RR of 0.82 (95% CI 0.56 to 1.20, 852 patients). Ten trials assessed failure, including modifications as failures, while six assessed overall failure disregarding treatment modifications. Failure with modifications was significantly reduced, RR of 0.76 (95% CI 0.68 to 0.85, 1779 patients) while overall failure was the same, RR of 1.00 (95% CI 0.79 to 1.27, 943 patients). Sensitivity analysis for allocation concealment and incomplete outcome data did not change the results. Both mortality and failure did not differ significantly among patients with Gram-positive infections, but the number of studies in the comparisons was small. Data regarding other patient subgroups likely to benefit from antiGP treatment were not available. Glycopeptides did not increase fungal superinfection rates and were associated with a reduction in documented Gram-positive superinfections. Resistant colonisation was not documented in the studies.

AUTHORS' CONCLUSIONS

Current evidence shows that the empirical routine addition of antiGP treatment, namely glycopeptides, does not improve the outcomes of febrile neutropenic patients with cancer.

Neutropenic fever and sepsis: evaluation and management

Neutropenia remains the predominant predisposing factor for infection in most cancer patients. Bacterial and fungal infections are common in this setting. Not all neutropenic patients have the same risk of developing severe infection or serious medical complications. Although all patients with neutropenia and fever should receive prompt, empiric antibiotic therapy, low-risk patients can be effectively managed without hospitalization-often with the administration of oral antibiotics. Other patients need hospital-based therapy. The emergence of resistant microorganisms has become a significant problem in neutropenic patients. Frequent epidemiologic surveys to detect the emergence of resistant organisms are recommended. Antibiotic stewardship and Infection Control Programs are important tools in combating resistant organisms.

Daptomycin use in neutropenic patients with documented gram-positive infections

PURPOSE

The goal of this study was to describe the outcomes associated with daptomycin treatment of documented gram-positive infections in patients with neutropenia.

METHODS

All patients with neutropenia (≤500 cells/m(3)) and at least one documented gram-positive culture from 2006-2009 were identified from a retrospective, multicenter, and observational registry (Cubicin(®) Outcome Registry and Experience (CORE(®))). Investigators assessed patient outcome (cured, improved, failed, nonevaluable) at the end of daptomycin therapy. All patients were included in the safety analysis.

RESULTS

The efficacy population had 186 patients; 159 (85 %) patients had either cure (n = 108, 58 %) or improved (n = 51, 27 %) as an outcome. Success rates (cure plus improved) by the lowest WBC during daptomycin were 98/116 (84 %) for ≤100 cells/m(3) and 61/70 (87 %) for 101-499 cells/m(3), P = 0.6. Most patients had cancer; 135/186 (73 %) had hematological malignancy; 26/186 (14 %) had solid tumors, and 9 (5 %) had both. One hundred fifty-six (84 %) patients received other antibiotics before daptomycin treatment; 82 % vancomycin, of which 31 % failed vancomycin. The most common infections were bacteremia (78 %), skin and skin structure infections (8 %), and urinary tract infections/pyelonephritis (6 %). The most common pathogens were vancomycin-resistant Enterococcus faecium (47 %), methicillin-resistant Staphylococcus aureus (20 %), and coagulase-negative staphylococci (19 %). The median (min, max) initial daptomycin dose was 6 mg/kg (3.6, 8.3). The median (min, max) daptomycin duration of therapy was 14 days (1, 86). Possibly related adverse events occurred in 12/209 patients (6 %), and 13 patients (6 %) discontinued daptomycin due to adverse event.

CONCLUSIONS

The results suggest that daptomycin appeared useful and well tolerated in neutropenic patients, and the degree of neutropenia did not affect daptomycin success rates. Comparative clinical trials are needed to confirm these findings.

Evidence-based approach to treatment of febrile neutropenia in hematologic malignancies

Applying the principles of evidence-based medicine to febrile neutropenia (FN) results in a more limited set of practices than expected. Hundreds of studies over the last 4 decades have produced evidence to support the following: (1) risk stratification allows the identification of a subset of patients who may be safely managed as outpatients given the right health care environment; (2) antibacterial prophylaxis for high-risk patients who remain neutropenic for ≥ 7 days prevents infections and decreases mortality; (3) the empirical management of febrile neutropenia with a single antipseudomonal beta-lactam results in the same outcome and less toxicity than combination therapy using aminoglycosides; (4) vancomycin should not be used routinely empirically either as part of the initial regimen or for persistent fever, but rather should be added when a pathogen that requires its use is isolated; (5) empirical antifungal therapy should be added after 4 days of persistent fever in patients at high risk for invasive fungal infection (IFI); the details of the characterization as high risk and the choice of agent remain debatable; and (6) preemptive antifungal therapy in which the initiation of antifungals is postponed and triggered by the presence, in addition to fever, of other clinical findings, computed tomography (CT) results, and serological tests for fungal infection is an acceptable strategy in a subset of patients. Many practical management questions remain unaddressed.

Clinical characteristics and antibiotic susceptibility of viridans streptococcal bacteremia in children with febrile neutropenia

PURPOSE

This retrospective study was performed in order to investigate the clinical characteristics and antibiotic susceptibility of viridans streptococcal bacteremia (VSB) in febrile neutropenic children in the context of the increase in incidence and antibiotic resistance of VSB.

METHODS

We conducted this study among neutropenic children with underlying hematology/oncology diseases who were diagnosed with VSB at a single institution from April 2009 to June 2012. Clinical and laboratory characteristics of the children as well as antibiotic susceptibility of the causative viridans streptococci were evaluated.

RESULTS

Fifty-seven episodes of VSB were diagnosed in 50 children. Severe complications occurred in four children (7.0%), and a death of one child (1.8%) was attributable to VSB. Acute myeloid leukemia was the most common underlying disease (70.2% of all cases), and 71.9% of all cases received chemotherapy including high-dose cytarabine. VSB occurred at a median of 13 days (range 8-21 days) after the beginning of chemotherapy, and fever lasted for a median of 4 days (range 1-21 days). The C-reactive protein level significantly increased within a week after the occurrence of VSB (p < 0.001) and the maximum C-reactive protein level showed a positive correlation with fever duration (r = 0.362, p = 0.007). Second blood cultures were done before the use of glycopeptides in 33 children, and negative results were observed in 30 children (90.9%). Susceptibilities to cefotaxime, cefepime, and vancomycin were 58.9, 69.1, and 100%, respectively.

CONCLUSIONS

Severe complications of VSB in neutropenic febrile children were rare. We suggest glycopeptide use according to the results of blood culture and antibiotic susceptibility tests based on the susceptibility to cefepime and the microbiologic response to empirical antibiotic treatment not including glycopeptides in this study.

Cefoperazone/sulbactam versus cefoperazone plus mezlocillin: empiric therapy for febrile, neutropenic bone marrow transplant patients

We conducted a prospective, randomized trial in 132 patients undergoing bone marrow transplantation comparing cefoperazone in combination with sulbactam (S), N = 66, vs. cefoperazone plus mezlocillin (CM), N = 66, as empiric antibiotic therapy for fever and neutropenia. Overall duration of neutropenia was 3-55 (median, 13) days. Forty-one patients had positive initial cultures (S = 22 and CM = 19). Twelve of these 41 patients responded to initial study antibacterial agent treatment (S = 6 and CM = 6). Twenty-nine of 41 patients were withdrawn from study because of clinical deterioration, continued fever, or persistently positive cultures (S = 16 and CM = 13). Of the 90 patients who had culture-negative fever (S = 44 and CM = 46), 44 subjects responded with or without the addition of amphotericin B (S = 21 and CM = 23). Thirty-seven of 90 patients were withdrawn from study due to continued fever or clinical deterioration (S = 17 and CM = 20). Nine patients were withdrawn as a result of rash or diarrhea (S = 6 and CM = 3). We conclude that in patients undergoing bone marrow transplantation, there was no difference in efficacy between cefoperazone/sulbactam and the combination of cefoperazone plus mezlocillin in the empiric treatment of the febrile neutropenic patient. Since the majority of initial infections were due to gram positive bacteria, consideration should be given to broadening initial empiric antibacterial agent therapy with drugs that possess potent activity against these organisms.

Teicoplanin in gram-positive infection: microbiological aspects

The widespread use of indwelling catheters and successful antibiotic treatment of Gram-negative infections has led to an increase of Gram-positive infections in severely neutropenic patients; Staphylococcus epidermidis is predominant in these infections. The problems associated with the use of vancomycin in treating such infections can be overcome by the glycopeptide antibiotic teicoplanin. It is as effective as vancomycin, but does not cause "red man" syndrome, is uncommonly nephrotoxic, can be given as a rapid bolus once daily, and routine serum monitoring is not required. Other approaches to reducing catheter-related infections include improved training of personnel in catheter insertion and the development of new materials and methods in cannula production.

Outcome of inappropriate empirical antibiotic therapy in patients with Staphylococcus aureus bacteraemia: analytical strategy using propensity scores

Patients with Staphylococcus aureus bacteraemia (SAB) who received either inappropriate or appropriate empirical therapy were compared by using two risk stratification models: (1) a cohort study using a propensity score to adjust for confounding by empirical treatment assignment; and (2) a propensity-matched case-control study. Inappropriate empirical therapy was modelled on the basis of patient characteristics, and included in the multivariate model to adjust for confounding. For case-matching analysis, patients with inappropriate empirical therapy (cases) were matched to those with appropriate empirical therapy (controls) on the basis of the propensity score (within 0.03 on a scale of 0-1). In total, 238 patients with SAB were enrolled in the cohort study. Characteristics associated with inappropriate empirical therapy were methicillin resistance, underlying haematological malignancy, no history of colonisation with methicillin-resistant S. aureus, and a long hospital stay before SAB. These variables were included in the propensity score, which had an area under the receiver operating characteristics curve of 85%. In the cohort study, SAB-related mortality was 39% (45/117) for inappropriate empirical therapy vs. 28% (34/121) for appropriate empirical therapy (odds ratio (OR) 1.60; 95% CI 0.93-2.76). After adjustment for independent predictors for mortality and the propensity score, inappropriate empirical therapy was not associated with mortality (adjusted OR 1.39; 95% CI 0.62-3.15). In the matched case-control study (50 pairs), SAB-related mortality was 32% (16/50) for inappropriate empirical therapy and 28% (14/50) for appropriate empirical therapy (McNemar's test; p 0.85; OR 1.15; 95% CI 0.51-2.64). In conclusion, inappropriate empirical therapy resulted in only a slight tendency towards increased mortality in patients with SAB.

Update on management of infections in cancer and stem cell transplant patients

Infections are the most important causes of morbidity and mortality in patients with aggressive malignancies and those undergoing allogeneic stem cell transplantation. The introduction of new therapeutic approaches including the use of nucleoside analogs and of monoclonal antibodies to CD20 and CD52 and the increased use of matched unrelated stem cell donors has resulted in new challenges with regard to systemic viral and fungal infections. In patients with bacterial infections, emergence of resistance to formerly widely used antibiotics as well as a shift of causative pathogens towards a predominance of multi-resistant gram-positive cocci has to be taken into consideration. In high-risk neutropenic patients with fever of unknown origin, prompt empiric monotherapy with piperacillin-tazobactam, cefepime, ceftazidime, or a carbapenem is mandatory. In patients with lung infiltrates, early preemptive intervention with an antifungal active against aspergilli is recommended, whereas in patients with catheter-related, skin or soft tissue infections, preemptive addition of a glycopeptide shows a high response rate. The prompt preemptive use of ganciclovir or foscarnet in allogeneic stem cell transplant recipients can reliably be guided by serial monitoring of cytomegalovirus antigen and polymerase chain reaction monitoring.

Infectious Complications of Cancer Therapy

Advances in the management of cancer, particularly the development of new chemotherapeutic agents, have greatly improved the survival and outcome of patients with hematologic malignancies and solid tumors; overall 5-year survival rates in cancer patients have improved from 39% in the 1960s to 60% in the 1990s.1 However, infection, caused by both the underlying malignancy and cancer chemotherapy, particularly myelosuppressive chemotherapy, remains a persistent challenge.

Additional anti-Gram-positive antibiotic treatment for febrile neutropenic cancer patients

BACKGROUND

The pattern of infections among neutropenic cancer patients has shifted in the last decades to a predominance of Gram-positive infections. Some of these Gram-positive bacteria are increasingly resistant to beta-lactams and necessitate specific antibiotic treatment.

OBJECTIVES

To assess the effectiveness of empirical anti-Gram-positive (antiGP) antibiotic treatment for febrile neutropenic cancer patients in terms of mortality and treatment failure. To assess the rate of resistance development, further infections and adverse events associated with additional antiGP treatment.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2004), MEDLINE (1966 to 2004), EMBASE (January 1980 to 2004), LILACS (1982 to 2004), conference proceedings, and all references of included studies. First authors of all included and potentially relevant trials were contacted.

SELECTION CRITERIA

Randomised controlled trials comparing one antibiotic regimen to the same regimen with the addition of an antiGP antibiotic for the treatment of febrile neutropenic cancer patients.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial eligibility, methodological quality and extracted all data. Relative risks (RR) with 95% confidence intervals (CI) were calculated. A random effects model was used for all comparisons showing substantial heterogeneity (I(2 )> 50%). Outcomes were extracted by intention-to-treat and the analysis was patient-based whenever possible.

MAIN RESULTS

Thirteen trials and 2392 patients or episodes were included. Empirical antiGP antibiotics were tested at the onset of treatment in eleven studies and for persistent fever in two studies. The antiGP treatment was a glycopeptide in nine trials. Seven studies were assessed in the overall mortality comparison and no significant difference between the comparator arms was seen, RR 0.82 (95% CI 0.56 to 1.20, 852 patients). Ten trials assessed failure including modifications as failures, while six assessed overall failure, disregarding treatment modifications. Failure with modifications was significantly reduced, RR 0.76 (95% CI 0.68 to 0.85, 1779 patients) while overall failure was equal, RR 1.00, 95% CI (0.79 to 1.27, 943 patients). Both mortality and failure did not differ significantly among patients with Gram-positive infections, but comparisons were small. Data regarding other patient subgroups likely to benefit from antiGP treatment were not available. Glycopeptides did not increase fungal superinfection rates, and were associated with a reduction in documented Gram-positive superinfections. Resistant colonisation was not documented in the studies.

AUTHORS' CONCLUSIONS

Current evidence shows that the addition of antiGP treatment, namely glycopeptides, prior to documentation of a Gram-positive infection does not improve outcomes.

Role of glycopeptides as part of initial empirical treatment of febrile neutropenic patients: a meta-analysis of randomised controlled trials

We did a meta-analysis of randomised controlled trials studying glycopeptides as part of the initial empirical treatment of febrile neutropenic patients with a beta-lactam and with or without an aminoglycoside. 14 randomised controlled trials that studied 2413 patients were included in the analysis. A better outcome regarding treatment success, without modification of the initial regimen, was accomplished with the inclusion of a glycopeptide in the empirical therapy; this better outcome applied to the full set of studied patients (OR=1.63, 95% CI 1.17-2.28), as well as in three important subsets of patients--those with microbiologically documented infections (2.03, 1.39-2.97), patients with bacteraemia (1.80, 1.23-2.63), and patients with severe neutropenia, defined as a white blood cell count below 100 cells/microL (2.24, 1.15-4.39). However, mortality was not different in the compared groups (0.67, 0.42-1.05). Overall treatment success was not different if a glycopeptide was added to the antimicrobial regimen in the case of continuation of fever 72 hours or more after the start of treatment (1.02, 0.68-1.52). Also, the inclusion of a glycopeptide in the empirical regimen did not lead to a difference regarding time to defervesence. Adverse effects (4.98, 2.91-8.55), including nephrotoxicity (2.10, 1.12-3.95), were more common in the group receiving a glycopeptide as part of the empirical treatment. In conclusion, our meta-analysis suggests that there are good reasons why glycopeptides should not be routinely used as part of the initial empirical treatment of febrile neutropenic patients.

Virulence of Pseudomonas aeruginosa in a murine model of gastrointestinal colonization and dissemination in neutropenia

Pseudomonas aeruginosa bacteremia in cancer patients develops from initial gastrointestinal (GI) colonization with translocation into the bloodstream in the setting of chemotherapy-induced neutropenia and GI mucosal damage. We established a reproducible mouse model of P. aeruginosa GI colonization and systemic spread during neutropenia. Mice received 2 mg of streptomycin/ml of drinking water and 1,500 U of penicillin G/ml for 4 days and then ingested 10(7) CFU of P. aeruginosa per ml of drinking water for 5 days. After GI colonization levels were determined, cyclophosphamide (Cy) was then injected intraperitoneally (i.p.) three times every other day or an antineutrophil monoclonal antibody, RB6-8C5, was injected i.p. once. Dissemination was defined by the presence of P. aeruginosa in spleens of moribund or dead mice. In this mouse model, P. aeruginosa colonizes the GI tract and then disseminates systemically once Cy or RB6-8C5 is administered. The duration and intensity of neutropenia, related to Cy dose, was found to be a means to compare the virulence of different P. aeruginosa strains, as exhibited by comparisons of strains lacking or producing the virulence-enhancing ExoU cytotoxin. The lipopolysaccharide outer core polysaccharide and O side chains were critical in establishing GI colonization, and P. aeruginosa mutants lacking the aroA gene (necessary for synthesizing aromatic amino acids) were able to establish GI colonization but unable to disseminate. Both the colonization and dissemination phases of P. aeruginosa pathogenesis can be studied in this model, which should prove useful for evaluating pathogenesis, therapies, and associated means to control P. aeruginosa nosocomial infections.

Empirical antibiotics against Gram-positive infections for febrile neutropenia: systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

To assess the value of empirical anti-Gram-positive antibiotics for the treatment of febrile neutropenia.

METHODS

Systematic review and meta-analysis of randomized controlled trials comparing antibiotics with anti-Gram-positive spectrum to control or placebo, in addition to the same baseline antibiotic regimen in both arms. We searched MEDLINE, EMBASE, LILACS, the Cochrane Library, conference proceedings, and references. No restrictions on inclusion were imposed. Two reviewers independently applied selection criteria, carried out quality assessment, and extracted the data. Relative risks with 95% confidence intervals were pooled using the fixed effect model. The primary outcome assessed was all-cause mortality.

RESULTS

Thirteen studies met inclusion criteria, including 2392 participants. Glycopeptides were assessed in nine trials. Empirical anti-Gram-positive antibiotics were assessed for the initial treatment in 11 studies, and for persistent fever in two. No significant difference in all-cause mortality was seen [RR 0.86 (0.58-1.26), seven studies, 852 participants]. Overall failure at end of therapy occurred equally [RR 1.00 (0.79-1.27), six studies, 943 participants]. Failure associated with treatment modifications was more frequent in the control arm when empirical initial glycopeptides were assessed [RR 0.70 (0.61-0.80), five studies, 1178 participants]. Bacterial superinfections, mainly Gram-positive, were detected less frequently in the intervention arm. Adverse events were significantly more common with the additional antibiotic, and nephrotoxicity was significantly more common with additional glycopeptides [RR 1.88 (1.10-3.22), six studies, 1282 participants]. No significant heterogeneity was present in these comparisons.

CONCLUSIONS

The use of glycopeptides can be safely deferred until the documentation of a resistant Gram-positive infection.

Treatment of pediatric febrile neutropenia in the era of vancomycin-resistant microbes

PURPOSE

The increasing frequency of Gm(+) infections in febrile neutropenic (FN) patients has resulted in increased use of vancomycin (VN). Likely as a result, VN-resistant Enterococcus (VRE) has become a significant concern in FN patients. We sought to understand how the emergence of VN resistant microbes has changed the antibiotic management of pediatric FN.

METHODS

A questionnaire was distributed by e-mail to responsible investigators of the Children's Oncology Group.

RESULTS

One hundred and thirty responses were analyzed. Forty-four percent initially used monotherapy, with 82% of those using ceftazidime. Twenty-seven used VN with another agent, generally ceftazidime. After the emergence of VRE and VN-resistant staphylococcus (VRS), monotherapy increased to 58%. Ceftazidime continued to be most frequently used. There was a 57% reduction in the use of VN with 88% of centers not currently using VN in their initial treatment of FN. Forty-seven percent of the centers that continue to use VN have VRE, while 90% that have discontinued its use have VRE/VRS.

CONCLUSIONS

Ours is the first study to survey current practices in the treatment of pediatric FN and to document changes in practice patterns due to emerging antibiotic resistance patterns. We demonstrate increased use of monotherapy for FN, and a 57% decrease in the use of VN. Local considerations influence antibiotic choices with a significant difference in VRE prevalence between those centers that continue to use VN as compared to those that have discontinued it.

Nonmyeloablative bone marrow transplantation: Infectious complications in 65 recipients of HLA-identical and mismatched transplants

Infections are a common complication of allogeneic bone marrow transplantation and the leading cause of transplantation-related mortality. It had been hypothesized that transplantation following nonmyeloablative preparative regimens would result in fewer infections by causing less mucosal injury, less graft-versus-host disease, and allowing earlier immune reconstitution. We have retrospectively reviewed the infectious complications of 65 consecutive patients with advanced hematologic malignancies who underwent bone marrow transplantation using a novel preparative regimen consisting of cyclophosphamide, thymic irradiation, and in vivo T-cell depletion. Cytomegalovirus (CMV) infection occurred in 52% of cases in which the donor or recipient had evidence of prior CMV exposure. Using a strategy of preemptive therapy and secondary prophylaxis with ganciclovir, no CMV disease occurred. Infections with gram-positive bacteria predominated over the first 100 days after bone marrow transplantation. Thereafter, the relative proportion of gram-negative infections increased without a significant increase in episodes of neutropenia. The rate of bacterial infections was not influenced by relapse of the underlying malignancy. Seven patients developed infections with Aspergillus species, which was the most common infectious cause of death in these patients. Infections with viruses other than CMV (n=10) and with protozoan organisms (n=2) also occurred. The use of HLA-mismatched donors, the occurrence of grade II-IV acute graft-versus-host disease, and treatment with corticosteroids did not influence the risk of CMV or bacterial or fungal infections in patients who underwent transplantation following this preparative regimen. Overall, the incidence and spectrum of infections in this series was similar to the reported incidence of infections following conventional myeloablative allogeneic stem cell transplantation. We conclude that a quantitative T-cell deficiency in these extensively T-cell depleted patients may be a risk factor for infection, even in the absence of graft-versus-host disease.

Infectious complications in patients undergoing unrelated donor bone marrow transplantation: experience from a single institution

OBJECTIVE

To analyze the incidence and characteristics of documented infections in patients with hematologic malignancies undergoing unrelated donor bone marrow transplantation (UD-BMT).

METHODS

We studied the occurrence of infections in 22 patients with hematologic malignancies or severe aplastic anemia who underwent UD-BMT from April 1990 to December 2000. The median age was 26 years (range 13-46). Acyclovir-ganciclovir, co-trimoxazole, fluconazole-nystatin and ciprofloxacin were administered for anti-infectious prophylaxis.

RESULTS

We registered 61 infectious episodes. During the early post-transplant period, there were eight clinically documented infections (CDIs), four cases of fever of unknown origin (FUO), seven cases of bacteremia, two cases of cytomegalovirus (CMV) antigenemia, and one case of CMV disease. In the intermediate period (days 30-100 after BMT), there were nine cases of CMV antigenemia, three bacterial infections, two fungal infections, one case of disseminated toxoplasmosis, and one case of FUO. In the late period (day 100 and later), we documented 13 viral infections, eight bacterial infections, one CDI, and one case of invasive aspergillosis. Infections contributed to death in 10 of 17 patients. Citrobacter bacteremia and sepsis of unknown origin were the main causes of infectious mortality in the early period. Infection was the main cause of death in six of seven patients in the late period.

CONCLUSION

A high incidence of life-threatening infections and infection-related mortality was observed. A high rate of CMV infection in the early period, and death caused by multiresistant Gram-negative microorganisms in the late period, were the main findings in this series.

Infections in the neutropenic patient--new views of an old problem

Infection in the neutropenic patient has remained a major clinical challenge for over three decades. While diagnostic and therapeutic interventions have improved greatly during this period, increases in the number of patients with neutropenia, changes in the etiologic agents involved, and growing antibiotic resistance have continued to be problematic. The evolving etiology of infections in this patient population is reviewed by Dr. Donowitz. Presently accepted antibiotic regimens and practices are discussed, along with ongoing controversies. In Section II, Drs. Maki and Crnich discuss line-related infection, which is a major infectious source in the neutropenic. Defining true line-related bloodstream infection remains a challenge despite the fact that various methods to do so exist. Means of prevention of line related infection, diagnosis, and therapy are reviewed. Fungal infection continues to perplex the infectious disease clinician and hematologist/oncologist. Diagnosis is difficult, and many fungal infections will lead to increased mortality even with rapid diagnosis and therapy. In Section III, Dr. Pappas reviews the major fungal etiologies of infection in the neutropenic patient and the new anti-fungals that are available to treat them. Finally, Dr. Rolston reviews the possibility of outpatient management of neutropenic fever. Recognizing that neutropenics represent a heterogeneous group of patients, identification of who can be treated as an outpatient and with what antibiotics are discussed.

Empirical oral antibiotic therapy for low risk febrile cancer patients with neutropenia

For over 30 years, fever and neutropenia in cancer patients has been treated with the utmost urgency, necessitating inpatient evaluation and immediate initiation of empirical broad-spectrum parenteral (i.v.) antibiotics. This practice is based on the recognition that delays in starting antibiotic therapy in febrile neutropenic patients have been associated with life-threatening infections and sometimes fatal consequences. Over the past decade, it has become evident that neutropenic cancer patients are not a homogeneous group and that practice guidelines may vary on their risk status. In fact, attempts have been made to stratify patients into high-risk and low-risk groups and differentiate treatment options respectively. Recent studies suggest that those neutropenic cancer patients who are at low risk may even be successfully treated with oral therapy, thus opening the possibility for ambulatory or home-based management. Oral antibiotic therapy, especially if safely delivered at home, offers a number of advantages including lower cost, improved quality of life (although the impact of shifting the burden of care from the hospital to the home setting on the patient, parent or care provider needs careful assessment) and a decreased risk for nosocomial infection.

Curtailing unnecessary vancomycin usage in a hospital with high rates of methicillin resistant Staphylococcus aureus infections

AIMS

To implement and monitor the effectiveness of a strategy to curb unnecessary use of vancomycin and teicoplanin for inpatients in a teaching hospital/tertiary referral centre where 33% of S. aureus isolates (72% from ICU patients) were methicillin resistant.

METHODS

A sample of 182 vancomycin/teicoplanin inpatient prescriptions surveyed, revealed that only 31 (17%) conformed with Centre for Disease Control (CDC) guidelines. Following education (ward-rounds, bulletins) on appropriate CDC based guidelines for prescribing glycopeptides directed at relevant clinicians, 'Immediate Concurrent Feedback' (ICF) was gradually deployed throughout the hospital. This entailed review of respective inpatient records on the next working day. If the indication was deemed not to conform with our guidelines, the prescriber was issued a memo (copied to the supervising doctor). Each memo detailed the 'errant' incident, listed appropriate indications and explicitly advised desisting from such prescribing and suggested alternative therapy if necessary. Corresponding glycopeptide usage data for our hospital and others in Hong Kong were retrieved and analysed as were samples of records of our inpatients with staphylococcal septicaemia (pre and during ICF).

RESULTS

Compared with baseline values, during 2 years of ICF, inpatient prescribing of vancomycin and teicoplanin deemed to conform increased to 71% (773/1086); difference 54% (P < 0.0001, 95% CIs 47-62%). Corresponding average monthly usage (DDDs/1000 admissions) decreased from 76 (pre-ICF) to 45; mean difference 31 (P < 0.0001, 95% CIs 24, 38). Mortality from staphylococcal bacteraemia remained unchanged. No comparable changes in glycopeptide usage ensued in comparator hospitals.

CONCLUSIONS

ICF can be used safely to curb irrational overuse of vancomycin and teicoplanin in a hospital with high methicillin resistant S. aureus infection rates.

Retrospective review of febrile neutropenia in the Royal Darwin Hospital, 1994-99

BACKGROUND

Febrile neutropenia is a life-threatening complication of cytotoxic chemotherapy. Empirical antibiotic treatment should be based on predominant pathogens and epidemiological characteristics of the treated community. The aim of the present study was to review cases of febrile neutropenia at the Royal Darwin Hospital (RDH) in order to assess the appropriateness of empirical antibiotic therapy.

METHODS

A retrospective review of cases of febrile neutropenia secondary to malignancy or chemotherapy occurring at the RDH over the period 1994-99. In order to compare infections in this group with those in the wider hospital community, all positive blood cultures in the medical and intensive care units were reviewed for the same time period.

RESULTS

Thirty-six episodes of febrile neutropenia were reviewed. Staphylococcus aureus (predominantly methicillin resistant), Pseudomonas aeruginosa and Escherichia coli were the most common organisms identified. Nine patients died of their infection, four with methicillin-resistant S. aureus bacteraemia. S. aureus, E. coli, Streptococcus pneumoniae and Burkholderia pseudomallei (melioid) were the most frequently isolated organisms from blood cultures taken in the medical and intensive care units.

CONCLUSIONS

Gram-positive organisms are the predominant pathogens in febrile neutropenic episodes at the RDH. Standard empirical therapy with an extended-spectrum penicillin and an aminoglycoside remains appropriate, with the addition of vancomycin when clinical status fails to improve. When practising in the Top End, particular consideration should be given to skin integrity and scabies and testing for Strongyloides in Aboriginal patients.

Infectious complications of febrile leukopenia

It can be foreseen that in the years to come major improvements in neutropenic host infections will be achieved regarding the exact identification of risk factors, allowing better patient stratification; the application of molecular techniques to recognize pathogens; the development of effective new oral antimicrobials allowing home therapy or abbreviated hospitalization; the development of new antifungals; and the development of new effective immunomodulators and cytokines to ameliorate chemotherapy-induced neutropenia. In the years to come the threat of nosocomial infections unfortunately will not be eliminated, while the development of major new parenteral antibiotics cannot be foreseen. It is therefore the caregiver/physician himself who, by applying rational antibiotic policies and strict handwashing rules, will probably escape, for his neutropenic patient's sake, the imminent threat of multiresistant pathogens.

Management of fever in neutropenic patients

Substantial progress has been made in the management of febrile episodes in neutropenic patients, largely by the prompt administration of potent, broad-spectrum antimicrobial agents. During the past several decades, the spectrum of organisms has changed from a predominance of gram-negative pathogens to a predominance of gram-positive pathogens. In recent years, some hospitals have experienced an increase of infections caused by multi-drug-resistant pathogens. Hence, it is no longer possible to rely on standardized regimens, but antimicrobial therapy must be selected based on the predominant pathogens and antimicrobial susceptibility patterns at each institution. It is customary to initiate antifungal therapy empirically in those patients whose fever persists despite broad-spectrum antibacterial therapy. Alternatives now exist to amphotericin B, including lipid formulations of this drug, and fluconazole. It is critically important that each patient be carefully re-assessed before starting antifungal therapy, because there are many other potential causes for persistent fever, including resistant bacteria and viruses. Novel approaches to therapy include outpatient antibiotics, and use of growth factors as adjunctive therapy. There also has been a renewed interest in white blood cell transfusions. Although the prognosis for infection in neutropenic patients has improved greatly, new infectious problems have emerged that limit our successful management of these complications.

Does the empiric use of vancomycin in pediatrics increase the risk for Gram-negative bacteremia?

BACKGROUND

Gram-negative bacteremia in children, a major cause of morbidity and mortality, may in part be induced by intensive treatment procedures and nonspecific use of antibiotics. Our primary objective was to study the causal relationship between the use of vancomycin and Gram-negative bacteremia, for which this antibiotic is not specifically indicated.

METHODS

The study was conducted in a 105-bed tertiary care children's hospital in the period of 1994 to 1997. The study pertains to a cohort of children with suspected bacteremia, in whom a blood culture was performed during hospital stay. Using the bacteriologic laboratory registration system, we selected all pediatric cases with bacteriologically proved Gram-negative bacteremia (n = 105) and a random sample of 225 pediatric controls with negative blood cultures. Using logistic regression analysis we examined associations between Gram-negative bacteremia and the following factors: preceding use of antibiotics, antacids, corticosteroids, surgery, mechanical ventilation, parenteral nutrition, and invasive instrumentation; and the intensity of care assessed with the Therapeutic Intensity Scoring System (TISS 28).

RESULTS

Gram-negative bacteremia was positively associated with the use of aminoglycosides, cephalosporins, surgical interventions, central venous catheters, parenteral nutrition, antacids and dexamethasone. The strongest association was with the use of vancomycin (odds ratio, 8.1; 95% confidence interval, 3.1 to 20.9). In a multiple logistic regression model containing all above-mentioned variables, the use of vancomycin remained positively and strongly associated with Gram-negative bacteremia (odds ratio, 3.88; 95% confidence interval, 1.34 to 11.21). Further adjustments and restrictions in the analysis did not materially change these findings concerning vancomycin.

CONCLUSIONS

Among children suspected of bacteremia there are several drugs and clinical procedures influencing the risk for Gram-negative bacteremia. Empiric use of vancomycin is strongly and independently associated with Gram-negative bacteremia. The safety of using vancomycin solely on the basis of suspicion of bacteremia in children may not be warranted.

Knowledge of Centers for Disease Control and Prevention guidelines for the use of vancomycin at a large tertiary care children's hospital

OBJECTIVE

In 1994, the Centers for Disease Control and Prevention (CDC) published guidelines to encourage prudent use of vancomycin. We sought to determine whether physicians could demonstrate knowledge consistent with the guidelines.

DESIGN

Survey consisting of 18 clinical vignettes based on the CDC guidelines.

PARTICIPANTS

All residents, fellows, and attending physicians involved in pediatric inpatient services.

SETTING

Tertiary care children's hospital providing service to an inner-city population and community referral base.

MAIN OUTCOME MEASURES

Comparison of survey scores and individual responses among respondents.

RESULTS

Survey scores did not vary with level of training or whether the respondent was a pediatrician or non-pediatrician. Average scores of attending physicians, fellows, and residents were 74.1% (SD = 13.1), 77.2% (SD = 11.5), and 73.4% (SD = 10.5), respectively, and did not differ significantly. Questions incorrectly answered by more than 30% of respondents concerned the use of vancomycin as: (1) first-line treatment of Clostridium difficile colitis, (2) a topical solution for wound infection, (3) initial, empiric treatment of patients with fever and neutropenia, (4) peri-operative prophylaxis, (5) a preferred agent over beta-lactam antimicrobial agents.

CONCLUSION

Deficits in knowledge regarding appropriate vancomycin use can be localized to certain clinical settings. This observation lends optimism to the notion that targeted educational intervention may improve the appropriate use of vancomycin.

National guidelines for the judicious use of glycopeptides in Belgium

OBJECTIVE

The 'HICPAC guidelines', published in the USA in 1995 stressed the crucial role of restrictive usage of glycopeptides in the strategy to limit the emergence and spread of resistant enterococci. Because controversy still remains in Belgium on the necessity and feasability of restricting glycopeptide usage, the infectious diseases advisory board (IDAB) developed a consensus statement on the judicious use of glycopeptides in Belgium.

METHODS

The literature on the indications for glycopeptide treatment was reviewed, categorized and discussed by a working party of the IDAB.Consequently, the IDAB reached consensus on the warranted indications for glycopeptide use in Belgium.

RESULTS

The opinion of the IDAB-members is reported in a consensus statement specifying the indications for treatment and for prophylaxis with glycopeptide antimicrobials, as well as the situations where glycopeptides should not be used, taking into account the specific epidemiology of bacterial resistance, the availability of antibiotics and the common prescribing practices in Belgium.

CONCLUSIONS

The IDAB concludes that restrictive usage of glycopeptides must also be a priority in Belgium. Guidelines on the judicious use of these antibiotics adapted to the national situations must contribute to this objective.

Staphylococcus aureus, Platelets, and the Heart

Infective endocarditis (IE) caused by Staphylococcus aureus is serious, burgeoning frequency, and growing increasingly resistant to antibiotics. S. aureus IE is associated with high morbidity and mortality rates in nosocomial and community-acquired settings. S. aureus is the most common, most virulent IE etiologic pathogen. S. aureus IE pathogenesis depends upon complex interaction among the pathogen, platelets, plasma proteins, and vascular endothelial cells. S. aureus coordinates the expression of key virulence factors required for the specific pathogenic phases of IE. Platelets, now appear to play an important role in antimicrobial host defense against S. aureus IE and other endovascular infections. Platelet microbicidal proteins are believed to significantly contribute to the antimicrobial properties of platelets; however, abnormal disposition of native or prosthetic cardiac valves is an important risk factor in S. aureus IE establishment and severity. Thus, the need to define the molecular mechanisms of S. aureus pathogenesis and host defense against IE is urgent. Understanding these mechanisms will yield new approaches for the prevention and treatment of such life-threatening cardiovascular infections due to S. aureus.

Comparison of efficacy and safety of teicoplanin and vancomycin in children with antineoplastic therapy-associated febrile neutropenia and gram-positive bacteremia

To compare their efficacy and safety, teicoplanin and vancomycin were randomly administered to 32 children for 52 gram-positive bacteremias during malignancy-associated neutropenia (<1000/microl). Patients mainly suffered from hematological malignancies. Twenty-five episodes were treated with teicoplanin (10 mg x kg(-1) x d(-1)) and 21 with vancomycin (40 mg x kg(-1) x d(-1)) plus ceftazidime and netilmicin. Six episodes were treated with teicoplanin because of previous "red man" reaction to vancomycin. Staphylococci (12% Staphylococcus aureus) were isolated from 50 episodes and viridans streptococci from 2. Defervescence on 3rd-4th day occurred in 29/31 (93.5%) teicoplanin-treated and 18/21 (85.7%) vancomycin-treated episodes. All 12 teicoplanin-treated and 13/13 vancomycin-treated episodes with repeat blood cultures on 3rd-4th day showed microbiological response. Two teicoplanin-treated and 3 vancomycin-treated patients required antifungals. Mild renal insufficiency appeared in 5 vancomycin-treated patients that was corrected without drug discontinuation. While both glycopeptides exhibit equal clinical and microbiological efficacy, teicoplanin is less likely to induce allergic reactions or nephrotoxicity in children.

Viridans-group streptococcal infections in immunocompromised hosts

Viridans streptococci, a diverse group of streptococcal species, are important causes of sepsis and pneumonia in the neutropenic host and sepsis and meningitis in the neonate. The oral mucosa is the most common portal of entry. Among the factors that predispose to development of viridans streptococcal sepsis are: profound neutropenia; mucositis, especially oral mucositis; cytarabine (Ara-C) therapy, which seems to have an effect beyond its association with mucositis; young age; and trimethoprim-sulphamethoxazole or quinolone administration. Fever is usually more than 39 degrees C and prolonged for several days even though blood cultures are typically negative after 24 h of therapy. The majority of patients recover uneventfully if appropriate therapy is initiated early. However, fulminant septic shock may occasional occur at onset. Delayed shock 2 or 3 days after presentation may also occur despite administration of microbiologically effective antibiotics. In severe cases, adult respiratory distress syndrome may be manifested two or three days after the initial bacteremia. There is considerable variability among institutions, but the median death rate associated with viridans streptococcal sepsis is about 10%. Local susceptibility patterns should be used to guide initial therapy for suspected viridans streptococcal infections. Some isolates of viridans streptococci are resistant to penicillins and cephalosporins, in which case vancomycin is preferred. Recurrence during subsequent neutropenic episodes is not unusual.

Evaluation of empiric vancomycin therapy in children with fever and neutropenia

A retrospective evaluation was conducted to determine which children admitted for fever and neutropenia required empiric vancomycin therapy, and to develop a clinical pathway for appropriate treatment. Chart review identified 109 admissions of 36 pediatric oncology patients for fever and neutropenia, of which 88 were eligible for analysis. Blood cultures isolated 17 gram-positive organisms; coagulase-negative staphylococci and viridans group streptococci were cultured most frequently (82%). We concluded that previous high-dose cytarabine therapy, inflamed central access site, and hypotension or septic shock are possible indicators of febrile, neutropenic patients at high risk for gram-positive pathogen isolation. These predictors then were used to determine which children would receive empiric vancomycin therapy.

Imipenem-cilastatin versus sulbactam-cefoperazone plus amikacin in the initial treatment of febrile neutropenic cancer patients

The treatment of infectious complications in cancer patients has evolved as a consequence of the developments in the chemotherapy of cancer patients. In this prospective, randomized study, we compared imipenem-cilastatin and sulbactam-cefoperazone with amikacin in the empiric therapy of febrile neutropenic (< 1000/mm3) patients with liquids and solid tumours. Of 30 evaluable episodes, 15 were treated with imipenem-cilastatin and 15 were treated with sulbactam-cefoperazone plus amikacin. 73% of episodes were culture-positive: gram-positive pathogens accounted for 62% of the isolates. Bacteremia was the most frequent site of infection. The initial clinical response rate for both regimens was 60% (p > 0.05). No major adverse effects occurred. This study demonstrated that imipenem-cilastatin monotherapy and combination therapy of sulbactam-cefoperazone plus amikacin were equally effective empiric therapy for febrile granulocytopenic cancer patients.

Interventional antimicrobial therapy in febrile neutropenic patients

In febrile neutropenic patients, prompt empiric antimicrobial intervention is mandatory. Numerous studies have demonstrated the benefit of broad-spectrum beta-lactams active against Gram-negative aerobes as well as against streptococci and Staphylococcus aureus in this setting. With this interventional strategy, a reduction of infection-related mortality to < or = 10% of patients undergoing intensive remission induction or consolidation chemotherapy could be obtained. Thereby, subgroups of patients have been identified who require an empiric modification of antimicrobial treatment, e.g., patients with catheter-related infections, with pulmonary infiltrates, or with unexplained fever (FUO) not responding to first-line antibacterials. In two consecutive, prospectively randomized trials conducted by the German Paul Ehrlich Society it could be shown that empiric antifungal therapy is beneficial for second-line treatment in patients with persistent FUO and improves first-line treatment results in patients with lung infiltrates. The addition of glycopeptides, however, should be restricted to patients with catheter-related infections due to coagulase-negative staphylococci or with infections due to multiresistant Gram-positive pathogens.