Streptococcus pneumoniae bacteremia in patients with cancer: disease characteristics and outcomes in the era of escalating drug resistance (1998-2002)

Invasive Bacterial Infections in Subjects with Genetic and Acquired Susceptibility and Impacts on Recommendations for Vaccination: A Narrative Review

The WHO recently endorsed an ambitious plan, “Defeating Meningitis by 2030”, that aims to control/eradicate invasive bacterial infection epidemics by 2030. Vaccination is one of the pillars of this road map, with the goal to reduce the number of cases and deaths due to Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae and Streptococcus agalactiae. The risk of developing invasive bacterial infections (IBI) due to these bacterial species includes genetic and acquired factors that favor repeated and/or severe invasive infections. We searched the PubMed database to identify host risk factors that increase the susceptibility to these bacterial species. Here, we describe a number of inherited and acquired risk factors associated with increased susceptibility to invasive bacterial infections. The burden of these factors is expected to increase due to the anticipated decrease in cases in the general population upon the implementation of vaccination strategies. Therefore, detection and exploration of these patients are important as vaccination may differ among subjects with these risk factors and specific strategies for vaccination are required. The aim of this narrative review is to provide information about these factors as well as their impact on vaccination against the four bacterial species. Awareness of risk factors for IBI may facilitate early recognition and treatment of the disease. Preventive measures including vaccination, when available, in individuals with increased risk for IBI may prevent and reduce the number of cases.

Fluoroquinolone treatment as a protective factor for 10-day mortality in Streptococcus pneumoniae bacteremia in cancer patients

To evaluate the prognostic factors in adult cancer patients with pneumococcal bacteremia, describe episode features and the phenotypic characteristics of the isolated strains. We evaluated the episodes in patients admitted to a cancer hospital between 2009 and 2015. The outcomes were defined as 48 h mortality and mortality within 10 days after the episode. The variables evaluated were: age, sex, ethnicity, ECOG, Karnofsky score, SOFA, cancer type, metastasis, chemotherapy, radiotherapy, neutropenia, previous antibiotic therapy, community or healthcare-acquired infection, comorbidities, smoking, pneumococcal vaccination, infection site, presence of fever, polymicrobial infection, antimicrobial susceptibility, serotype and treatment. 165 episodes were detected in 161 patients. The mean age was 61.3 years; solid tumors were the most prevalent (75%). 48 h and 10-day mortality were 21% (34/161) and 43% (70/161) respectively. The 48 h mortality- associated risk factors were SOFA and polymicrobial bacteremia; 10-day mortality-associated risk factors were fever, neutropenia, ECOG 3/4, SOFA and fluoroquinolones as a protective factor. Pneumococcal bacteremia presented high mortality in cancer patients, with prognosis related to intrinsic host factors and infection episodes features. Fluoroquinolone treatment, a protective factor in 10-day mortality, has potential use for IPDs and severe community-acquired pneumonia in cancer patients.

Implementing a Multidisciplinary Approach to Enhance Compliance With Guideline-Recommended Prechemotherapy Pneumococcal Vaccination in a Military-Based Medical Oncology Practice

Purpose:

Patients with cancer are at increased risk for invasive pneumococcal disease, including community-acquired pneumonia. Current Advisory Committee on Immunization Practices and National Cancer Comprehensive Network guidelines recommend pneumococcal vaccination for immunocompromised patients, including patients with cancer.

Methods:

We conducted a quality improvement (QI) project to enhance compliance with pneumococcal vaccination in patients before their chemotherapy. Baseline pneumococcal vaccination rates were gathered from July 2013 to June 2014. We reviewed the current guidelines for pneumococcal vaccinations in patients with cancer with physicians and encouraged them to prescribe the pneumococcal vaccination to patients before therapy. We also recruited our clinic nurse practitioner, who meets all patients for chemotherapy teaching, to prescribe the vaccine to patients younger than 65 years of age.

Results:

During the baseline period, of the 110 patients younger than 65 years who received chemotherapy, seven (6.4%) received the pneumococcal vaccine. Of the 90 patients (median age, 60 years; range, 20 to 86 years) who received chemotherapy during the study period, 58 were younger than 65 years, of whom three patients were already vaccinated before their diagnosis. Twenty-five (45.5%) patients were vaccinated through our QI project. We have improved our compliance with pneumococcal vaccination by 39% ( P < .001).

Conclusion:

We have improved compliance with pneumococcal vaccination in patients with cancer receiving chemotherapy in our clinic through a QI project. We found that screening is best accomplished by a single person who is able to screen all patients. This practice is now a standard of care in our clinic.

Predictors of Mortality Among U.S. Veterans With Streptococcus Pneumoniae Infections

INTRODUCTION

Serious Streptococcus pneumoniae infections, encompassing pneumonia, bacteremia, and meningitis, are a major cause of mortality. However, literature regarding mortality is often limited to invasive pneumococcal disease, excluding pneumonia. This study sought to identify predictors of mortality among adults with serious pneumococcal disease, including pneumonia and invasive pneumococcal disease.

METHODS

This was a nested case-control study of unvaccinated older Veterans with positive S. pneumoniae cultures (blood, cerebrospinal fluid, respiratory) admitted to Veterans Affairs medical centers nationally between 2002 and 2011. Patients vaccinated against pneumococcal disease were excluded. Using multivariable logistic regression, predictors of 30-day mortality were identified, including patient demographics, comorbidities during admission, and medical history within the previous year.

RESULTS

Among 9,468 patients, there were 9,730 serious pneumococcal infections; 1,764 (18.6%) resulted in death within 30 days (cases), whereas 7,966 did not (controls). Pneumonia accounted for half (49.4%, n=871) of all deaths. Mortality predictors consistent with vaccine recommendations included dialysis (during hospitalization, OR=3.35, 95% CI=2.37, 4.72), moderate to severe liver disease (during hospitalization, OR=2.47, 95% CI=1.53, 3.99; within 1 year, OR=1.49, 95% CI=1.01, 2.20), and neutropenia (during hospitalization, OR=2.67, 95% CI=1.32, 5.42). Predictors not included in current recommendations included dementia (during hospitalization, OR=1.8, 95% CI=1.23, 2.61) and neurologic disorders (during hospitalization, OR=1.86, 95% CI=1.42, 2.45; within 1 year, OR=1.28, 95% CI=1.02, 1.59).

CONCLUSIONS

Several mortality predictors among unvaccinated Veterans with serious pneumococcal disease were consistent with pneumococcal vaccine recommendations, including organ or immune system dysfunction-related conditions. Other predictors, including neurologic disorders or dementia, may warrant expanded vaccination recommendations.

Risk stacking of pneumococcal vaccination indications increases mortality in unvaccinated adults with Streptococcus pneumoniae infections

BACKGROUND

Several chronic disease states have been identified as pneumococcal vaccination indications due to their ability to increase pneumococcal disease development and subsequent mortality. However, the risk of mortality according to the number of these disease states present is unknown. We sought to determine the impact of concomitant, multiple risk factors (stacked risks) for pneumococcal disease on 30-day mortality in adults.

METHODS

This was a national case-control study of unvaccinated older Veterans (≥50years of age) admitted to Veterans Affairs medical centers from 2002 to 2011 with serious pneumococcal infections (pneumonia, bacteremia, meningitis) based on positive S. pneumoniae blood, cerebrospinal fluid, or respiratory cultures, respectively. Cases were those not alive 30days following culture, while controls were alive. Using logistic regression, we quantified risk of 30-day mortality among patients with stacked risk factors, including age ≥65years, alcohol abuse, chronic heart disease, chronic liver disease, chronic respiratory disease, diabetes mellitus, immunodeficiency, and smoking.

RESULTS

We identified 9730 serious pneumococcal infections, with an overall 30-day mortality rate of 18.6% (1764 cases, 7966 controls). Infection types included pneumonia (62%), bacteremia (26%), and bacteremic pneumonia (11%). Along with eight individual risk factors, we assessed 247 combinations of risk factors. Most cases (85%) and controls (74%) had at least two risk factors. Mortality increased as risks were stacked, up to six risk factors (one: OR 1.5, CI 1.08-2.07; two: OR 2.01, CI 1.47-2.75; three: OR 2.71, CI 1.99-3.69; four: OR 3.27, CI 2.39-4.47; five: OR 3.63, CI 2.60-5.07; six: OR 4.23, CI 2.69-6.65), with each additional risk factor increasing mortality an average of 55% (±13%).

CONCLUSIONS

Among adults ≥50years with serious pneumococcal disease, mortality risk increased approximately 55% as vaccination indications present increased. Mortality with six stacked indications was double that of two indications.

Retrospective study of prognostic factors in pediatric invasive pneumococcal disease

Streptococcus pneumoniae remains the leading causative pathogen in pediatric pneumonia and bacteremia throughout the world. The invasive pneumococcal disease (IPD) is known as isolation of S. pneumoniae from a normally sterile site (e.g., blood, cerebrospinal fluid, synovial fluid, pericardial fluid, pleural fluid, or peritoneal fluid). The aim of this study is to survey the clinical manifestations and laboratory results of IPD and identify the prognostic factors of mortality. From January 2001 to December 2006, a retrospective review of chart was performed in a teaching hospital in Taipei. The hospitalized pediatric patients with the diagnosis of pneumonia, arthritis, infectious endocarditis, meningitis or sepsis were recruited. Among them, 50 patients were pneumococcal infections proved by positive culture results or antigen tests. Clinical manifestations, laboratory data and hospitalization courses were analyzed. The median age was 3.5-year-old and there were 30 male patients (60%). Eight patients (16%) had underlying disease such as leukemia or congenital heart disease. Hemolytic uremic syndrome (HUS) was observed in ten patients and extracorporeal membrane oxygenation (ECMO) was performed in three patients. Leukocytosis, elevated C-reactive protein and AST level were noted in most of the patients. The overall mortality rate was 10%. We found that leukopenia, thrombocytopenia and high CRP level were significant predictors for mortality. In conclusion, S. pneumoniae remains an important health threat worldwide and IPD is life-threatening with high mortality rate. We found leukopenia, thrombocytopenia, and high CRP levels to be associated with mortality in pediatric IPD, and these factors are worthy of special attention at admission. Although we failed to identify a statistically significant prognostic factor in multivariate analysis due to relatively small sample size, we suggest an aggressive antibiotic treatment in patients with these factors at admission. Further large-scale studies are warranted.

Pneumococcal Vaccination Strategies. An Update and Perspective

Streptococcus pneumoniae is an important global pathogen that causes a wide range of clinical disease in children and adults. Pneumococcal pneumonia is by far the common presentation of noninvasive and invasive pneumococcal disease and affects the young, the elderly, and the immunocompromised disproportionately. Patients with chronic pulmonary diseases are also at higher risk for pneumococcal infections. Substantial progress over the century has been made in the understanding of pneumococcal immunobiology and the prevention of invasive pneumococcal disease through vaccination. Currently, two pneumococcal vaccines are available for individuals at risk of pneumococcal disease: the 23-valent pneumococcal polysaccharide vaccine (PPV23) and the 13-valent pneumococcal protein-conjugate vaccine (PCV13). The goal of pneumococcal vaccination is to stimulate effective antipneumococcal antibody and mucosal immunity response and immunological memory. Vaccination of infants and young children with pneumococcal conjugate vaccine has led to significant decrease in nasal carriage rates and pneumococcal disease in all age groups. Recent pneumococcal vaccine indication and schedule recommendations on the basis of age and risk factors are outlined in this Focused Review. As new pneumococcal vaccine recommendations are being followed, continued efforts are needed to address the vaccine efficacy in the waning immunity of the ever-aging population, the implementation of vaccines using two different vaccines under very specific schedules and their real world clinical and cost effectiveness, and the development of next generation pneumococcal vaccines.

Infections associated with solid malignancies

Although solid tumors comprise the vast majority of cancers, the incidence of serious infectious complications in this population is much less than in patients with hematologic malignancies. Most infections involving patients with solid tumors comprise two groups. First, patients acquire infections as a result of the cancer itself, due to either mass effect that interrupts normal function or destruction of the normal barriers to infection. Second, patients acquire infections as a complication of the treatments they receive, such as chemotherapy, radiation, surgery, or medical devices. Advances in the management of cancer have resulted in a gradual stepwise improvement in survival for patients with most types of solid tumors. Much of this improvement has been attributed to advances in cancer screening, diagnosis, and therapeutic modalities. In addition, improvements in the prevention, diagnosis, and treatment of infections have likely contributed to this prolonged survival. This review highlights select articles in the medical literature that shed light on the epidemiology and pathophysiology of infections in patients with solid tumors. In addition, this review focuses upon the diagnosis and treatment of these infections and their recent advances.

Pneumococcal immunization in immunocompromised hosts: where do we stand?

Immunocompromised patients are all at risk of invasive pneumococcal disease, of different degrees and timings. However, considerable progress in pneumococcal immunization over the last 30 years should benefit these patients. The 23-valent polysaccharide vaccine has been widely evaluated in these populations, but due to its low immunogenicity, its efficacy is sub-optimal, or even low. The principle of the conjugate vaccine is that, through the protein conjugation with the polysaccharide, the vaccine becomes more immunogenic, T-cell dependent, and thus providing a better early response and a boost effect. The 7-valent conjugate vaccine has been the first one to be evaluated in different immunocompromised populations. We review here the efficacy and safety of the different antipneumococcal vaccines in cancer, transplant and HIV-positive patients and propose a critical appraisal of the current guidelines.

Evaluation and Management of Bacterial and Fungal Infections Occurring in Patients with a Hematological Malignancy: A 2011 Update

Patients with a hematological malignancy are a heterogeneous patient population who are afflicted with diseases that range from rapidly fatal acute leukemia to indolent lymphoma or chronic leukemia. Treatment options for these patients range from observation to hematopoietic stem cell transplantation (HSCT), but all patients are more susceptible to infection. The problem of infection is dynamic with continued shifts in pathogenic organisms and microbial susceptibilities, new treatment regimens that further diminish immune function, and patients receiving treatment who are now older and frailer. The classic patterns of immunodeficiency for patients with a hematological malignancy include: periods of profound neutropenia, increased iatrogenic risks (i.e., central vascular catheters), and cellular immune suppression that affects HSCT recipients, patients with lymphoid malignancies, and those receiving treatment with corticosteroids or agents like alemtuzumab [1–4]. Recent advances in antimicrobial drug development, new technology, clinical trial results, and further clinical experience have enhanced the database on which to make infection prophylaxis and treatment decisions. However, the practicing clinician must remember that the majority of basic infection management principles for patients who are neutropenic remain unchanged.

Vitamin D's potential to reduce the risk of hospital-acquired infections

Health care–associated and hospital-acquired infections are two entities associated with increased morbidity and mortality. They are highly costly and constitute a great burden to the health care system. Vitamin D deficiency (< 20 ng/ml) is prevalent and may be a key contributor to both acute and chronic ill health. Vitamin D deficiency is associated with decreased innate immunity and increased risk for infections. Vitamin D can positively influence a wide variety of microbial infections.

Herein we discuss hospital-acquired infections, such as pneumonia, bacteremias, urinary tract and surgical site infections, and the potential role vitamin D may play in ameliorating them. We also discuss how vitamin D might positively influence these infections and help contain health care costs. Pending further studies, we think it is prudent to check vitamin D status at hospital admission and to take immediate steps to address existing insufficient 25-hydroxyvitamin D levels.

Risk factors and pathogenic significance of bacteremic pneumonia in adult patients with community-acquired pneumococcal pneumonia

OBJECTIVE

This study was performed to identify risk factors for the development of bacteremic pneumonia and to evaluate the impact of bacteremia on the outcome of pneumococcal pneumonia.

METHODS

Using a database from a surveillance study of community-acquired pneumococcal pneumonia, we compared data of the bacteremic group with that of the non-bacteremic group.

RESULTS

Among 981 adult patients with pneumococcal pneumonia, 114 (11.6%) patients who had documented pneumococcal bacteremia were classified into the bacteremic group. In a multivariable analysis, use of immunosuppressant drugs, younger age (<65 years), and DM were independent risk factors associated with the development of bacteremic pneumonia among patients with pneumococcal pneumonia (all P < 0.05). The mortality rate was significantly higher in the bacteremic group than in the non-bacteremic group (28.6% vs. 8.5%; P < 0.001). The multivariable analysis revealed that concomitant bacteremia was one of the significant risk factors associated with mortality (OR, 2.57; 95% CI, 1.24-5.29), along with cerebrovascular disease and presentation with septic shock (all P < 0.05).

CONCLUSIONS

Bacteremia was a common finding in pneumococcal pneumonia and was associated with a higher mortality rate. Several clinical variables may be useful for predicting bacteremic pneumonia among patients with pneumococcal pneumonia.

Infections in patients with hematologic neoplasms and hematopoietic stem cell transplantation: neutropenia, humoral, and splenic defects

Infections are common in patients with hematologic neoplasms and following allogeneic hematopoietic transplantation. Neutropenia and defects in adaptive B-cell-mediated immunity and/or lack of splenic function predispose patients to a host of diverse and often serious infections. It is important to recognize that patients who undergo treatment for hematologic neoplasms may have mixed immune defects, and their vulnerability to infection may continue to change, in part as a reflection of the dynamic developments in the practice of oncology. The main obstacle in providing targeted, evidence-based antimicrobial treatment is the unpredictable results of even the new generation of diagnostic assays. A definite diagnosis for most end-organ opportunistic diseases requires tissue samples that are seldom available. Because immune defects may coexist, empirical therapy is directed toward a wide spectrum of pathogens. Real-time information about innate and adaptive immune functions and the role of acute and chronic phase molecules may improve target-specific therapy.

Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the infectious diseases society of america

This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia. Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving. What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens. Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care-associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are the universal keys to managing neutropenic patients with fever and/or infection.

Executive Summary: Clinical Practice Guideline for the Use of Antimicrobial Agents in Neutropenic Patients with Cancer: 2010 Update by the Infectious Diseases Society of America

This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia.

Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving.

What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens.

Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care–associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are the universal keys to managing neutropenic patients with fever and/or infection.

How we treat febrile neutropenia in patients receiving cancer chemotherapy

Although improved supportive care has reduced mortality associated with febrile neutropenia, it continues to cause chemotherapy limitations, morbidity, mortality, and cost among patients with cancer.

The use of new and better antibiotics for bacterial infections in patients with leukemia

Bacterial infection is the most common complication of chemotherapy-induced neutropenia particularly in patients with hematologic malignancies. Bacterial infections predominate during the initial phases of neutropenic episodes. The spectrum of bacterial infection continues to evolve globally and locally at the institutional level, as do patterns of antimicrobial susceptibility/resistance. These trends are often associated with local treatment practices (eg, use of antimicrobial prophylaxis, open versus restricted formularies, clinical pathways and/or guidelines) and have a significant effect on the nature of empiric antimicrobial therapy. Increasing rates of resistance among gram-positive and gram-negative bacteria are posing new therapeutic challenges. These challenges can to some extent be overcome by new drug development. Many novel agents for the treatment of resistant gram-positive infections have been developed and are being evaluated in clinical trials. Newer agents for the treatment of Clostridium difficile associated diarrhea are also in the pipeline. Far fewer options to treat multi-drug resistant gram-negative infections exist, and new drug development is lagging behind. Consequently, the judicious use of currently available agents is essential. This is best achieved by the development of multidisciplinary antibiotic stewardship teams that gather baseline data, make recommendations for appropriate antimicrobial usage, and provide monitoring and feedback services to clinical care providers. Along with strict adherence to infection control policies, antimicrobial stewardship provides the best strategies for the management of infectious complications in patients with hematologic malignancies and other high-risk settings.

Clinical characteristics and outcomes of pneumococcal bacteremia in adult patients with liver cirrhosis

Few studies have assessed the clinical characteristics and outcomes of invasive pneumococcal diseases in cirrhotic patients. We reviewed the medical records of adult cirrhotic patients with pneumococcal bacteremia from January 1997 to April 2006. During this time, 62 episodes of pneumococcal bacteremia occurred in 59 patients with liver cirrhosis, 45 (76.3%) of whom were classified as Child-Pugh grade C. The most common source of infection was spontaneous bacterial peritonitis (SBP) (45.8%), followed by primary bacteremia (40.7%) and pneumonia (10.1%). The 30-day mortality rate was 16.9%, with all fatalities in patients classified as Child-Pugh grade C. The median model for end-stage liver disease score of patients who died was significantly higher than that of survivors (26.5 versus 17.0, P=0.001). Pneumococcal bacteremia in adult cirrhotic patients was more commonly associated with SBP than with pneumonia. Most cases of bacteremia and fatal outcomes occurred in patients with advanced cirrhosis.

Infections in non-myeloablative hematopoietic stem cell transplantation patients with lymphoid malignancies: spectrum of infections, predictors of outcome and proposed guidelines for fungal infection prevention

The overall risk of infections is lower in patients undergoing non-myeloablative allogeneic stem cell transplantation (NST) than in conventional stem cell transplant recipients. We sought to evaluate conditions associated with increased risk of infections after NST. In 81 patients, 187 infection episodes were noted; chronic lymphocytic leukemia (138 episodes/100 person-years) and recipients of matched unrelated donor graft (128 episodes/100 person-years) had higher risk of infection. Only half of the cytomegalovirus (CMV) infections occurred 31-100 days after transplantation. Most patients with CMV infection were non-neutropenic (100%), had lymphoma (76%), were younger (<55 years; 72%) and had received matched related donor (MRD) graft (72%). However, graft-versus-host disease (GVHD) was present in only 15% of these patients. Seven (78%) of nine invasive fungal infections (IFI) were diagnosed >100 days after NST and were associated with high mortality (78%). Most patients with IFI were also not neutropenic (100%), had received MRD graft (100%), had lymphoma (78%) and were given systemic steroids (78%); unlike CMV infection, 67% of these patients also had GVHD. On the basis of our results, we propose that NST recipients with lymphoma treated with high-dose corticosteroids for GVHD be considered for antifungal prophylaxis or pre-emptive antifungal therapy.

Bacteraemic pneumococcal pneumonia in COPD patients: better outcomes than expected

The purpose of the study was to compare the clinical characteristics and outcomes of bacteraemic pneumococcal pneumonia (BPP) in chronic obstructive pulmonary disease (COPD) and non-COPD patients. A case-control study was conducted. Cases were any adult with BPP and forced expiratory volume in 1 second (FEV(1)) <80% and FEV(1)/forced expiratory vital capacity (FVC) <70%. Controls were patients with BPP without clinical diagnosis of COPD matched 1:2 by age, gender and date of isolation. Variables included co-morbidities, serotypes, pneumonia severity index (PSI), treatment and mortality. There were 45 cases and 90 controls. No significant differences were found in Charlson scores, antibiotic treatment, serotype distribution and severity. Malignancy, shock and mechanical ventilation were less frequent in COPD patients. One patient died vs 14 controls (p = 0.02). In univariate analysis, shock, multilobar involvement, Charlson score, heart failure and absence of COPD were associated with mortality. After adjustment for the presence of shock there were no differences in mortality. BPP presents less frequently with shock and has a lower mortality rate in COPD patients than in non-COPD patients.

Bloodstream infections in haematology: risks and new challenges for prevention

Bloodstream infections are an important cause of morbidity and mortality in the haematology population, and may contribute to delayed administration of chemotherapy, increased length of hospitalisation, and increased healthcare expenditure. For gram-positive, gram-negative, anaerobic and fungal infections, specific risk factors are recognised. Unique host and environmental factors contributing to pathogenesis are acknowledged in this population. Trends in spectrum and antimicrobial susceptibility of pathogens are examined, and potential contributing factors are discussed. These include the widespread use of empiric antimicrobial therapy, increasingly intensive chemotherapeutic regimens, frequent use of central venous catheters, and local infection control practices. In addition, the risks and benefits of prophylaxis, and spectrum of endemic flora are identified as relevant factors within individual centres. Finally, challenges are presented regarding prevention, early detection, surveillance and prophylaxis. To reduce the rate and impact of bloodstream infections multifaceted and customised strategies are required within individual haematology units.

Multiple-dose granulocyte-macrophage-colony-stimulating factor plus 23-valent polysaccharide pneumococcal vaccine in patients with chronic lymphocytic leukemia: a prospective, randomized trial of safety and immunogenicity

BACKGROUND

For the current study, the authors sought to determine whether administration of multiple-dose granulocyte-macrophage-colony-stimulating factor (GM-CSF) could improve response to standard 23-valent polysaccharide pneumococcal vaccine (PPV) in patients with chronic lymphocytic leukemia (CLL).

METHODS

Patients were allocated randomly to receive PPV either alone or with 3 doses of GM-CSF (250 microg) given before or after vaccination. Serum was obtained before, 4 weeks after, and 12 weeks after vaccination for antibody determination. Thirty-two patients with CLL were given PPV. They were randomized to receive 3 doses of GM-CSF either before or after vaccination or to receive no GM-CSF.

RESULTS

A 4-fold rise in immunoglobulin G (IgG) to capsular polysaccharides from Streptococcus pneumoniae types 4, 6B, 9V, 14, 19F, and 23F occurred in <10% of patients in each of the 3 groups. There were no differences in geometric mean IgG levels in any of the 3 groups 4 weeks or 12 weeks after vaccination.

CONCLUSIONS

In patients with CLL, the response to pure polysaccharide pneumococcal vaccine was low despite immune enhancement with multiple doses of GM-CSF. In all patients, reactogenicity was minor.

Microbial spectrum and antibiotic susceptibility profile of gram-positive aerobic bacteria isolated from cancer patients

PURPOSE

Cancer patients are particularly susceptible to nosocomial infections because of their compromised immune system, and because of the nature of treatment practices they experience. Recently, a shift of the microbial spectrum of cancer patients from gram-negative to gram-positive has been demonstrated. This study analyzed the distribution and the antimicrobial resistance of gram-positive bacteria isolated from cancer patients in Egypt.

PATIENTS AND METHODS

We examined the microbial spectrum of gram-positive bacteria in patients with hematologic malignancies and solid tumors. In addition, we also studied the antimicrobial resistance of pathogens accounting for the majority of gram-positive infections in these cancer patients.

RESULTS

Most of gram-positive isolates from urinary tract (100%), respiratory tract (89.7%), and bloodstream infections (BSIs; 65.5%) were obtained from leukemic patients. All gram-positive isolates from skin infections were isolated from solid-tumor patients. In both leukemic and solid-tumor patients, gram-positive bacteria causing nosocomial BSI were mainly Coagulase-negative staphylococcus (CNS) and S. aureus, whereas gram-positive bacteria causing nosocomial RTI were mainly alpha-hemolytic streptococci and CNS. Gram-positive bacteria were not isolated from GI tract infections. S. aureus, CNS, and alpha-hemolytic streptococci demonstrated methicillin resistance (81.5%, 92.3%, and 90% resistance, respectively). S. aureus and CNS were susceptible to linezolid (15.4% and 0% resistance, respectively), and vancomycin (15.5% and 11% resistance, respectively).

CONCLUSION

This is the first study to report the emergence of vancomycin- and linezolid-resistant S. aureus in Egypt. Newer generation quinolones (moxifloxacin and gatifloxacin) were more active than older quinolones (ciprofloxacin and ofloxacin) against S. aureus and CNS, suggesting the use of newer generation quinolones in the prophylaxis of cancer patients.

Relationship between immunosuppression and intensive care unit-acquired multidrug-resistant bacteria: a case-control study

OBJECTIVE

To determine the relationship between immunosuppression and intensive care unit (ICU)-acquired multidrug-resistant (MDR) bacteria.

DESIGN

Retrospective case-control study based on prospectively collected data.

SETTING

A 30-bed medical and surgical ICU.

PATIENTS

All patients hospitalized >48 hrs in the ICU were eligible during a 2-yr period.

INTERVENTIONS

Immunosuppression was defined as active solid or hematologic malignancy, leucopenia, or chronic immunosuppressive treatment. MDR bacteria were defined as methicillin-resistant Staphylococcus aureus, ceftazidime- or imipenem-resistant Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia, and extending spectrum beta-lactamase producing Gram-negative bacilli. MDR bacteria screening (nasal, anal, and axilla swabs and tracheal aspirate in intubated patients) was performed at ICU admission and weekly. Only MDR bacteria isolated >48 hrs after ICU admission were taken into account; duplicates were excluded. Isolation measures were applied in all patients at ICU admission, in patients with MDR bacteria, and in patients with immunosuppression. Immunosuppressed patients (cases) were matched (1:1) with immunocompetent patients (controls) according to all the following criteria: age +/-5 yrs, Simplified Acute Physiology Score II +/-5, duration of ICU stay +/-3 days, and category of admission (medical/surgical). Risk factors for ICU-acquired MDR bacteria were determined using univariate and multivariate analyses.

MEASUREMENTS AND MAIN RESULTS

Of 1,065 eligible patients, nine patients were excluded for absence of MDR bacteria screening at ICU admission. One hundred thirty-three (12%) patients were immunosuppressed, and 128 (96%) of them were successfully matched. Mean time between ICU admission and first ICU-acquired MDR bacteria was 12 +/- 9 days. Incidence of MDR bacteria was significantly higher in cases than in controls (22 vs. 12 MDR bacteria/1000 ICU days, p = .004). However, immunosuppression was not independently associated with ICU-acquired MDR bacteria.Multivariate analysis identified prior antibiotic treatment and antibiotic treatment in the ICU as risk factors for ICU-acquired MDR bacteria (odds ratio [95% confidence interval] = 1.9 [1-3.6], p = .003; 11 [1.4-83], p = .02; respectively).

CONCLUSIONS

Immunosuppression is not independently associated with ICU-acquired MDR bacteria. However, infection control measures used in our ICU may have influenced this result.

Streptococcus pneumoniae infections in 47 hematopoietic stem cell transplantation recipients: clinical characteristics of infections and vaccine-breakthrough infections, 1989-2005

Streptococcus pneumoniae infections can cause serious systemic disease in patients following hematopoietic stem cell transplantation (HSCT), and the response to pneumococcal vaccine is inadequate in most HSCT recipients. We evaluated the clinical spectrum of pneumococcal disease and vaccine-breakthrough infections in HSCT recipients at our cancer center in a retrospective analysis of all consecutive episodes of S. pneumoniae infection from 1989 through 2005. During the study period, 7888 patients underwent HSCT at our center; we identified 47 HSCT recipients with 54 S. pneumoniae infections. The overall incidence of S. pneumoniae infection was 7 per 1000 HSCTs. The incidence was higher in recipients of allogeneic grafts than in recipients of autologous grafts (9 vs. 5 per 1000 HSCTs, respectively; p <or= 0.012). Thirty-two of the 47 patients (68%) had leukemia or lymphoma; 24 patients (51%) had a malignancy that was in complete remission. Seventeen patients (36%) had graft-versus-host disease, which was chronic in 16. The 54 episodes of S. pneumoniae infection occurred 433 +/- 669 days after HSCT; 5 patients (11%) had multiple episodes. Four episodes of S. pneumoniae infection occurred within 100 days following transplantation (45 +/- 49 d); 2 of these were during the pre-engraftment period and 3 were nosocomial infections. All 50 late post-transplant episodes (93%), which occurred 473 +/- 671 days following transplantation, were community-acquired infections (p < 0.00016). Thirty-three episodes (61%) presented as bacteremic pneumonia, 10 (19%) as pneumonia, and 8 (15%) as uncomplicated S. pneumoniae bacteremia alone. Logistic regression analysis showed that patients receiving systemic corticosteroids had increased risk for bacteremic pneumonia (odds ratio [OR], 11.7; 95% confidence intervals [CI], 1.371-99.280; p <or= 0.025). Patients with lymphoma (OR, 6.101; 95% CI, 1.106-33.640; p <or= 0.04) were more likely to develop pneumonia alone. In 27 episodes (93%) among 29 in which S. pneumoniae susceptibility testing was performed, the patients received concordant antimicrobials. Among the 6 patients (13%) who died of S. pneumoniae infection, 4 had S. pneumoniae bacteremic pneumonia and only 1 had chronic GVHD. Admission to a critical care unit at the onset of infection (OR, 15.5; 95% CI, 2.116-113.541; p <or= 0.007) and each unit increase in APACHE II score increase the probability of death (OR, 1.9; 95% CI, 1.181-3.054; p <or= 0.008). All 5 (11%) patients who developed vaccine-breakthrough S. pneumoniae infection (546 +/- 732 d following vaccination) had pneumonia, and in 4 patients concurrent bacteremia also occurred. A serious S. pneumoniae infection in HSCT recipients occurred more commonly in patients with lymphoma and patients receiving high-dose systemic corticosteroid therapy. It is noteworthy that there were no cases of extrapulmonary organ infection in HSCT recipients who presented with S. pneumoniae infection at our institution.

Influence of neutropenia on the course of serotype 8 pneumococcal pneumonia in mice

Polymorphoneutrophils (PMNs) are important effector cells in host defense against pneumonia. However, PMNs can also induce inflammation and tissue damage. To investigate the contribution of PMNs to host defense against pneumococcal pneumonia, we determined the effect of the PMN-depleting rat monoclonal antibody RB6-8C5 (RB6) on survival and inflammatory and cellular response in the lungs to a lethal intranasal infection with a serotype 8 pneumococcus in BALB/c mice. Control mice received rat immunoglobulin G (rIgG). Strikingly, the survival of RB6-treated mice was significantly prolonged compared to that of rIgG-treated mice. Although the numbers of CFU in the lungs were statistically similar in both groups 4, 24, and 32 h after infection, rIgG-treated mice developed higher levels of bacteremia, and histopathological examination of the lungs of infected mice revealed marked differences between RB6- and rIgG-treated mice. RB6-treated mice had focal, perivascular lesions without accompanying parenchymal inflammation, and rIgG-treated mice had diffuse, interstitial parenchymal inflammation. Lung homogenates from the rIgG-treated mice had more leukocytes and significantly more total and apoptotic PMNs as determined by fluorescence-activated cell sorter analysis with Annexin V and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling staining of lung tissue samples. Studies with a pneumolysin-deficient mutant of the serotype 8 strain we used also demonstrated the prolonged survival of RB6- compared to rIgG-treated mice. Taken together, our findings suggest that PMNs enhance the likelihood of early death and alter the pathological response to pneumococcal lung infection in BALB/c mice with serotype 8 pneumonia without significantly affecting bacterial clearance or the cytokine response.