Bacteremia and fungemia in patients with neoplastic disease

Antibiotic Use in the Last Week of Life in Three Different Palliative Care Settings

The purpose of this study was to examine the frequency and types of antibiotics prescribed in the last week of life in three different palliative care settings, including an acute care hospital, tertiary palliative care unit, and three hospice units. A total of 150 consecutive patients were evaluated, 50 in each of the three settings. Twenty-nine patients (58%) in the acute hospital setting, 26 (52%) in the tertiary palliative care unit, and 11(22%) in the hospice settings were prescribed antibiotics. In the acute care and tertiary palliative care settings, the most frequent route of antibiotic administration was intravenous and, in the hospice setting, oral. We conclude that there is marked variability in the numbers and types of antibiotics prescribed in these different palliative care settings in the last week of life. The high use of intravenous antibiotics and the large number of patients who were still receiving antibiotics at the time of death indicate the need for further prospective studies.

Recurrent bacteremia: A 10-year retrospective study in combat-related burn casualties

INTRODUCTION

Surviving the first episode of bacteremia predisposes burn casualties to its recurrence. Herein, we investigate the incidence, mortality, bacteriology, and source of infection of recurrent bacteremia in military burn casualties admitted to the U.S. Army Institute of Surgical Research Burn Center over a 10year period.

METHODS

Bacteremia was defined as the growth of Gram-positive or Gram-negative organisms in a blood culture that excluded probable skin contaminants. Recurrent bacteremia was defined as a subsequent episode of bacteremia ≥7 days after the first episode. Polymicrobial bacteremia was the presence of more than one pathogen in the same blood culture. Bacteremia was attributed to UTI, pneumonia, or wound sepsis. All other bacteremias were considered non-attributable bloodstream infections. Univariate and multivariate analyses determined factors predictive of clinical outcome.

RESULTS

Out of 952 combat-related burn casualties screened, 166 cases were identified; 63% (non-recurrent) and 37% (recurrent) with median time to recurrence of 20 days. Univariate and multivariate analysis showed that the mortality rate was two and nine-fold, respectively, higher with recurrent bacteremia. Univariate analysis found that except for urinary tract infection, large burn size (>20%), 3rd degree burns, increased injuiry severity, perineal burns, and mechanical ventilator days were independent factors predictive of recurrence of bacteremia as well as increased mortality in the recurrent bacteremia cohort. Acinetobacter baumannii complex (63%) was prevalent in the non-recurrent group, while Klebsiella pneumoniae (46% vs. 30%) and Pseudomonas aeruginosa (35% vs. 26%) were prevalent in recurrent bacteremia. Half of the recurrent bacteremia cases were polymicrobial, compared to 9% in non-recurrent bacteremia. Pneumonia was prevalent in non-recurrent bacteremia (38%) and a combination of pneumonia and wound sepsis (29%) in recurrent bacteremia casualties.

CONCLUSIONS

Recurrent bacteremia increases mortality in military burn casualties. Additional research is needed to address and mitigate the underlying causes, thereby improving survival.

Prospective Evaluation of Infection Episodes in Cancer Patients in a Tertiary Care Academic Center: Microbiological Features and Risk Factors for Mortality

OBJECTIVE

We aimed to determine the frequency, type, and etiology of infections and the risk factors for infections and mortality in hospitalized cancer patients.

MATERIALS AND METHODS

We prospectively enrolled adult cancer patients hospitalized in the internal medicine wards of a tertiary care academic center between January and August 2004. Patients were followed during their hospitalization periods for neutropenia, infections, culture results, and mortality.

RESULTS

We followed 473 cancer patients with 818 hospitalization episodes and 384 infection episodes in total. Seventy-nine percent of the infections were nosocomial, and febrile neutropenia (FN) was observed in 196 (51%) of the infection episodes. Bacteremia was found in 29% of FN episodes and in 8% of nonneutropenic patients. Gram-positive bacteria were the leading cause of bacteremia in both neutropenic and nonneutropenic cases (70% and 58%, respectively). Presence of an indwelling central catheter increased bacteremia risk by 3-fold. The overall mortality rate was 17%, whereas 34% of the patients with bloodstream infections died. Presence of bacteremia and advanced disease stage increased overall mortality by 6.1-fold and 3.7-fold, respectively.

CONCLUSION

Nearly half of the cancer patients developed an infection during their hospital stays, with gram-positive bacteria being the predominant etiologic microorganisms. This demonstrates the changing trends in infections considering that, until 2004, gram-negative bacteria were the most predominant microorganisms among cancer patients in our institute.

Microbial translocation contribute to febrile episodes in adults with chemotherapy-induced neutropenia

In this study we sought to determine the contribution of microbial translocation to febrile episodes with no attributable microbiological cause (Fever of Unknown Origin, FUO) in an adult febrile neutropaenic cohort. Endotoxin concentrations were measured with the chromogenic Limulus Amoebocyte Assay and used as a direct measure of bacterial products whilst soluble CD14 (sCD14), measured with ELISA was selected as an indicator of the early host response to endotoxins. Endotoxin concentrations in this cohort were generally elevated but did not differ with the presentation of fever. Further stratification of the febrile episodes based on the microbiological findings revealed significantly (p = 0.0077) elevated endotoxin concentrations in FUO episodes compared with episodes with documented bacterial and viral findings. sCD14 concentrations were however, elevated in febrile episodes (p = 0.0066) and no association was observed between sCD14 concentration and microbiological findings. However, FUO episodes and episodes with Gram-negative bacteraemia were associated with higher median sCD14 concentrations than episodes with Gram-positive bacteraemia (p = 0.030). In conclusion, our findings suggest that in the absence of microbiological findings, microbial translocation could contribute to febrile episodes in an adult neutropaenic cohort. We further observed an association between prophylactic antibiotic use and increased plasma endotoxin concentrations (p = 0.0212).

Bloodstream infections in patients with or without cancer in a large community hospital

PURPOSE

Cancer is associated with an increased risk of acquiring bloodstream infection (BSIs). Most knowledge on pathogens and outcome are derived from specialised cancer centres. We here sought to compare causative micro-organisms in BSIs in patients with or without cancer in a 600-bed teaching community hospital.

METHODS

We analysed all positive blood cultures from adult patients between January 2005 and January 2011.

RESULTS

A total of 4,918 episodes of BSI occurred in 2,891 patients, of whom 13.4% had a diagnosis of cancer (85.5% with a solid tumour). In both patient groups, Gram-positive isolates were more prevalent (58.7 and 61.4% in patients with and without cancer, respectively) than Gram-negative isolates (31.8 and 32.3%, respectively). Amongst Gram-positive organisms, coagulase-negative staphylococci, Staphylococcus aureus and enterococci were the most frequently isolated in both patient groups; in cancer patients, twice as many BSIs were caused by Enterococcus faecalis and E. faecium. Amongst Gram-negative organisms, Escherichia coli was the most common isolate; in cancer patients, twice as many BSIs were caused by Pseudomonas aeruginosa and Enterobacter cloacae. Yeasts were grown from 3.0% of blood cultures from cancer patients compared to 1.5% of cultures from non-cancer patients. Cancer patients had a 90-day mortality of 35.8% following BSI compared to 23.5% in patients without cancer.

CONCLUSION

These data demonstrate distinct BSI pathogens and impaired outcomes in patients with cancer in the setting of a large community teaching hospital.

Viral findings in adult hematological patients with neutropenia

Background

Until recently, viral infections in patients with hematological malignancies were concerns primarily in allogeneic hematopoietic stem cell transplant (HSCT) recipients. During the last years, changed treatment regimens for non-transplanted patients with hematological malignancies have had potential to increase the incidence of viral infections in this group. In this study, we have prospectively investigated the prevalence of a broad range of respiratory viruses in nasopharyngeal aspirate (NPA) as well as viruses that commonly reactivate after allogeneic HSCT.

Methodology/Principal Findings

Patients with hematological malignancies and therapy induced neutropenia (n = 159) were screened regarding a broad range of common respiratory viruses in the nasopharynx and for viruses commonly detected in severely immunosuppressed patients in peripheral blood. Quantitative PCR was used for detection of viruses. A viral pathogen was detected in 35% of the patients. The detection rate was rather similar in blood (22%) and NPA (18%) with polyoma BK virus and rhinovirus as dominating pathogens in blood and NPA, respectively. Patients with chronic lymphocytic leukemia (CLL) (p<0.01) and patients with fever (p<0.001) were overrepresented in the virus-positive group. Furthermore, viral findings in NPA were associated with upper respiratory symptoms (URTS) (p<0.0001).

Conclusions/Significance

Both respiratory viral infections and low titers of viruses in blood from patients with neutropenia were common. Patients with CLL and patients with fever were independently associated to these infections, and viral findings in NPA were associated to URTS indicating active infection. These findings motivate further studies on viruses' impact on this patient category and their potential role as causative agents of fever during neutropenia.

Infections in Patients with Cancer: Overview

Patients with neoplastic disease are often highly susceptible to severe infections. The following factors influence the types, severity, and response to therapy of these infections: (1) Changing epidemiology of infections; (2) cancer- and/or treatment-associated neutropenia; (3) acquired immune deficiency states such as cellular immune defect; (4) recent development of new-generation diagnostic tools including widely available DNA amplification tests; (5) effective intervention for infection prevention; (6) empiric or presumptive therapy during high-risk periods; (7) availability of new classes of highly active antimicrobial drugs; (8) strategies to promote hosts’ immune response; and (9) future measures. This introductory chapter intended for the reader to become familiar with the important historical milestones in the understanding and development in the field of infectious diseases in immunosuppressed patients with an underlying neoplasms and patients undergoing hematopoietic stem cell trans­plantation.

The utility of routine surveillance blood cultures in asymptomatic hematopoietic stem cell transplant patients

INTRODUCTION

Surveillance blood cultures (BCs) are often obtained in hematopoietic stem cell transplant (HSCT) patients for earlier detection of blood stream infections (BSI). The major aim of this study was to determine the utility of the current practice of obtaining surveillance blood cultures from asymptomatic transplant patients upon admission for the preparative regimen.

METHODS

We conducted an 8-year retrospective study of all patients consecutively admitted to the hospital for a HSCT from 2000 to 2008.

RESULTS

In this retrospective analysis, surveillance BCs from 191 eligible patients were analyzed. The incidence of definitive BSIs was 0.52% (1/191) with 6 BCs from other HSCT patients growing probable contaminants. The overall incidence of positive surveillance BCs was 2.9% (7/238) for the BCs taken and 3.7% (7/191) for patients cultured with coagulase negative staphylococcus being isolated from 6 of the 7 patients. The probability of increased BSI after transplantation in patients with initial positive surveillance BCs compared with those having negative BCs, was not significant (P=0.675). No infection-related mortality was observed during the first 60 days posttransplantation in these patients.

CONCLUSIONS

The frequency of positive surveillance BCs in asymptomatic HSCT patients at the time of hospital admission for transplant seems to be extremely low. These results, if confirmed by larger studies, show the reduced utility of obtaining surveillance BC in asymptomatic patients before administration of the conditioning regimen and the need for re-evaluation of this practice.

Infectious complications in patients with acute myeloid leukemia treated according to the protocol with daunorubicin and cytarabine with or without addition of cladribine. A multicenter study by the Polish Adult Leukemia Group (PALG)

OBJECTIVES

The addition of cladribine to the standard regimen consisting of daunorubicin and cytarabine has been reported to increase the efficacy of induction therapy in acute myeloid leukemia (AML). The goal of this study was to determine the effect of this modification on the incidence and spectrum of infectious complications.

METHODS

Case report forms of 309 patients with newly diagnosed AML who had been enrolled in the prospective, randomized 'DAC-7 vs. DA-7' trial were reviewed. The frequency, etiology, localization, severity, and outcome of infections were compared for patients receiving only daunorubicin and cytarabine (DA-7) and those additionally treated with cladribine (DAC-7).

RESULTS

A total of 443 febrile episodes were reported with no significant difference between the treatment groups. A trend towards a higher frequency of bacteremias was observed among DA-7 patients compared to those in the DAC-7 group (31% vs. 21%; p=0.08). The treatment arms did not differ in terms of the distribution of the isolated Gram-positive, Gram-negative, fungal, and viral organisms. However, when bacteremias were considered, Gram-positive blood cultures tended to be more frequent in the DA-7 compared to the DAC-7 group (16% vs. 8.5%; p=0.07). This difference reached statistical significance when major blood bacteremias were analyzed separately (13% vs. 5%; p=0.02). Complete recovery from infections was observed in the majority of patients across both treatment arms and no significant difference was noted regarding infection-related mortality.

CONCLUSIONS

The addition of cladribine to standard induction chemotherapy has no impact on the incidence and spectrum of infectious complications in newly diagnosed AML patients.

Antibiotics in 30 minutes or less for febrile neutropenic patients: a quality control measure in a new hospital

Infections are the most common complication in patients receiving treatment for cancer with neutropenia being the primary risk factor for the development of an infection. In the neutropenic patient, bacteremia remains a significant cause of mortality. Although the literature reports that prompt empiric antibiotic therapy to prevent death caused by virulent organisms is the standard of care, the literature fails to identify what prompt antibiotic administration means. Door/fever-to-patient antibiotic delivery was evaluated as a quality control measure in a new children's hospital. Initially, door/fever-to-patient time was significantly delayed. Collaboration between pharmacy, hospital bed control, medical, and nursing staff resulted in many changes in practice by all groups. As a result, the goal for prompt antibiotic delivery of thirty minutes or less is now achievable.

Risk factors and outcome for breakthrough candidaemia in patients with cancer

While candidaemia that develops during systemic antifungal prophylaxis or therapy [breakthrough (BT) candidaemia] has been reported increasingly, the risk factors and outcome of BT candidaemia are not yet known definitely. We evaluated a consecutive series of cancer patients with candidaemia at Asan Medical Center during 6 years to identify risk factors and outcome in BT candidaemia comparing with non-BT candidaemia. Fifty-four episodes of candidaemia in cancer patients diagnosed during this period were reviewed retrospectively. There were 10 episodes (18.5%) of BT candidaemia in which the species distribution and frequency of catheter-related infection in the BT and non-BT groups were similar. BT candidaemia had a tendency to occur more frequently in patients with haematological than non-haematological diseases. Profound neutropenia and disseminated candidiasis were more common in the BT group; however, these differences were not statistically significant (P = 0.17 and 0.07 respectively). The duration of prior antibiotic therapy and duration of profound neutropenia (<100 mm(-3)) were identified as risk factors for BT candidaemia (P < 0.01 and 0.02 respectively) in univariate analysis and the latter was the only risk factor in multivariate analysis. The death rates due to candidaemia were 85.7% in the BT group and 42.9% in the non-BT group (P = 0.08); however, BT candidaemia alone did not increase mortality rate.

Rapid detection of Candida albicans in clinical blood samples by using a TaqMan-based PCR assay

We describe a rapid and reproducible PCR assay for quantitation of the Candida albicans ribosomal DNA (rDNA) in clinical blood samples based on the TaqMan principle (Applied Biosystems), in which a signal is generated by cleavage of a template-specific probe during amplification. We used two fluorogenic probes based on universal, fungus-specific primers, one for the detection of C. albicans species DNA and one for the detection of all Candida genus DNA. C. albicans blastoconidia mixed with whole blood in a titration experiment yielded a linear PCR signal over a range of 3 orders of magnitude. The TaqMan-based PCR assay for C. albicans exhibited a low limit of detection (5 CFU/ml of blood) and an excellent reproducibility (96 to 99%). While the C. albicans species-specific probe had 100% specificity for C. albicans, all Candida genus-specific probes cross-reacted with other organisms likely to coinfect patients with C. albicans infections. On the basis of these data, we determined the C. albicans loads with a species-specific probe from 122 blood samples from 61 hematology or oncology patients with clinically proven or suspected systemic Candida infections. Eleven positive samples exhibited a wide range of C. albicans loads, extending from 5 to 100,475 CFU/ml of blood. The sensitivity and specificity of the present assay were 100 and 97%, respectively, compared with the results of blood culture. These data indicate that the TaqMan-based PCR assay for quantitation of C. albicans with a species-specific probe provides an attractive alternative for the identification and quantitation of C. albicans rDNA in pure cultures and blood samples.

Piperacillin plus aztreonam for treatment of neutropenic fever

BACKGROUND

A combination of beta-lactam plus an aminoglycoside is the most frequently used regimen for febrile episodes in neutropenic cancer patients. However, aminoglycoside-related toxicity occasionally makes this regimen difficult to use as the first-line drug therapy. In the present study, we chose aztreonam as the alternative to aminoglycoside in combination with piperacillin for neutropenic fever in pediatric patients and we evaluated its effectiveness.

METHODS

A total of 31 febrile episodes in 16 patients with malignant neoplasms were evaluted. Piperacillin (200 mg/kg per day) plus aztreonam (150 mg/kg per day) were administered intravenously following a routine fever work-up.

RESULTS

The overall response rate was 67%. The response rate when neutrophil count was less than 100/mm3 was 63%. The side effects were mild and rare. In three patients, all of the microbiologically documented infections were caused by alpha-streptococcus, which required a change in the regimen.

CONCLUSIONS

A combination of piperacillin and aztreonam provides an effective and non-toxic regimen for first-line therapy in febrile patients with neutropenia. In contrast, the results of the present study suggest the need for caution with regard to alpha-streptococcus infections.

Detection of seven Candida species using the Light-Cycler system

Due to the limitations of classical methods for the detection of systemic fungal infections and the high mortality rates associated with these infections, it has become essential to develop a quick, sensitive and specific detection assay. By using the Idaho Technologies Light-Cycler system, a qualitative real-time PCR system has been developed for the detection of the leading causes of systemic infection within the genus Candida. The sensitivity of the assay was comparable to previously described PCR methods (1-5 c.f.u. ml(-1)) and, by the use of a single Candida probe, it was able to detect, but not differentiate between, seven species of Candida (Candida albicans, Candida dubliniensis, Candida glabrata, Candida kefyr, Candida krusei, Candida parapsilosis and Candida tropicalis). Single-round amplification on the Light-Cycler allowed rapid turn-around of clinical samples (within one working day) and it was shown to be more sensitive than classical procedures, exposing 39 possible systemic infections that were not detected by blood culture.

Hematogenous infections due to Candida parapsilosis: changing trends in fungemic patients at a comprehensive cancer center during the last four decades

This study was performed to evaluate trends in species distribution in patients' with hematogenous candidiasis at a comprehensive cancer center. The results of a retrospective analysis from January 1, 1993 to December 31, 1998 were compared with prior reports from Memorial Sloan-Kettering Cancer Center in the last forty years. In 570 total episodes since 1974, 43.9% were due to Candida albicans. During 1990's, C. parapsilosis emerged as the most frequent yeast species in the non-C. albicans group (36.1% during 1993-1998 from 20.9% 1974-1982; p < 0.01). An increase in C. krusei from 5.9% (1974-1982) to 10.5% during the recent six years (1993-1998) was also noticed. The proportion of C. tropicalis among non-albicans fungemia during 1974-1982 was 42.8%, whereas in 1993 to 1998 a marked decline in C. tropicalis hematogenous infection was observed (27.8%; p < 0.01). During 1998, the incidence of candidemia declined from 7.1% (1972-1973) and 6.5% (1982) to 3.4% (p < 0.01), and improved survival among fungemic patients (33% mortality in 1998; 77.3% during 1974-1982; p < 0.001) was encouraging. The increase in C. parapsilosis bloodstream invasion during 1990's was associated with a significant reduction in the endogenous non-albicans Candida tropicalis infection that probably resulted in part due to the common prophylaxis, and/or preemptive fluconazole given routinely in high-risk patients undergoing treatment for cancer. The widespread use of extraneous implantable and/or semi-implantable indwelling intra-vascular devices may also have played an important role in promoting (exogenous) C. parapsilosis infection. This study emphasizes the importance of periodic evaluation of candidemia, especially at centers caring for patients at risk.

Infectious morbidity in critically ill patients with cancer

Infection frequently complicates the course of cancer treatment and often adversely affects the outcome. Patients have a greater tendency for acquiring infections caused by opportunistic microorganisms. Agents with low virulence potential may lead to invasive and often life-threatening infections because of altered host immune function. The immune dysfunction may be caused by the underlying malignancy, by antineoplastic chemotherapy, or by invasive procedures during supportive care.

Prospective screening by a panfungal polymerase chain reaction assay in patients at risk for fungal infections: implications for the management of febrile neutropenia

Invasive fungal infections are a major cause of mortality in neutropenic cancer patients. To determine whether a polymerase chain reaction (PCR)-based assay enabled the identification of patients at risk for invasive fungal infections, a prospective monitoring once per week was performed during 92 neutropenic episodes in patients receiving chemotherapy for acute leukaemia or high-dose therapy followed by allogeneic or autologous stem cell transplantation, with the investigators blinded to clinical and microbiological data. PCR positivity was documented in 34 out of 92 risk episodes. All patients developing proven invasive fungal infection were found PCR positive, and PCR was found to be the earliest indicator of invasive fungal infection preceding clinical evidence by a mean of 5.75 d (range 0-14 d). In febrile neutropenic patients without a prior history of invasive fungal infection, a sensitivity of 100% and a specificity of 73% of the PCR assay for the development of proven or probable invasive fungal infection was documented. In conclusion, panfungal PCR performed prospectively once a week enabled the identification of patients at high risk for invasive fungal infections.

Improved prognosis of Pseudomonas aeruginosa bacteremia in 127 consecutive neutropenic patients with hematologic malignancies

OBJECTIVES

Although decreasing in frequency, Pseudomonas aeruginosa bacteremia is still a major challenge for neutropenic cancer patients. In patients with hematologic malignancies, the prognosis of P. aeruginosa bacteremia is particularly poor due to the prolonged and severe neutropenia, mucosal damage, and other defects in immunity related both to the underlying disease and to the cytotoxic therapy.

METHODS

To verify the outcome of P. aeruginosa bacteremia and to try to define possible prognostic factors, the authors reviewed the medical records of 127 consecutive episodes of P. aeruginosa bacteremia observed in the hematologic unit of the Verona University School of Medicine.

RESULTS

Presence of pneumonia and septic shock, persistence and severity of neutropenia, delayed and inappropriate antibiotic therapy, and unresponsive underlying disease had negative impact on clinical outcome of P. aeruginosa bacteremia.

CONCLUSIONS

With recognition of the risk factors and more careful management, the prognosis of P. aeruginosa bacteremia in neutropenic patients with hematologic malignancies has improved in recent years.

Fever and neutropenia in children with cancer in one pediatric hospital in Argentina

The authors retrospectively analyzed 863 episodes of neutropenia and fever in 635 children with cancer or hematological disease hospitalized between October 1988 and November 1994. The most frequent underlying diseases were solid tumors (45%) and acute lymphoblastic leukemia (29%). Clinical site of infection could be determined in 454 (53%) episodes. Bacteremia was documented in 114 (13%) cases. Gram-positive cocci were the microorganisms most frequently isolated (47% of the cases). Noninfectious complications could be determined in 140 (16%) episodes, and were mainly severe bleeding and metabolic impairment. The episodes were divided in two groups for comparative evaluation: group A, 404 episodes, study period 1988-1991, and group B, 459 episodes, 1992-1994. According to the results, more patients in group A than group B were younger than 1 year old and had profound neutropenia; fewer patients in group A than group B had an endovascular catheter, a higher frequency of manifest clinical site of infection at admission, and a prevalence of isolation of gram-negative bacilli. A higher percentage of patients in group B had neutropenia of more than 14 days, gram-positive cocci in culture, and lower mortality. Multivariate analysis by logistic regression in 340 patients revealed that the presence of a severe noninfectious complication, severe neutropenia, and positive blood culture correlated with high mortality rate (p < or = 0.001).

Epidemiology of infectious complications in cancer patients

Patients with underlying malignancies are at risk for a wide array of infectious diseases that cause significant morbidity and mortality. To develop a clear etiologic understanding of the infectious agents involved first requires a knowledge of the factors that predispose to infection. Neutropenia is clearly the single most important risk factor for infection in the cancer patient. However, a variety of both host and treatment-associated factors act together to predispose these patients to opportunistic infections. Approaching the individual malignancies with a knowledge of the underlying risk factors helps logically guide diagnosis and therapy. The astute clinician must also be aware of new and emerging infections in this patient population. As new pathogens are discovered and established pathogens become increasingly drug resistant, they will continue to present challenges for physicians caring for these patients in the years ahead.

Gram-negative bacteremia in non-neutropenic patients: a 3-year review

The causative organisms, clinical manifestations, factors influencing prognosis, and other epidemiological characteristics of 81 episodes of bacteremia due to gram-negative organisms, in non-neutropenic patients, were studied retrospectively during a 3-year period (1992-1994) at the Department of Internal Medicine of the University Hospital of Heraklion, Crete, Greece. The gram-negative bacteremia incidence was 2% and the overall mortality 12%. All 81 patients had fever; Escherichia coli was the most frequent organism isolated (from 47 patients--58%) and was associated with shock (9/47), disseminated intravascular coagulation (DIC) (8/47), anuria (5/47), adult respiratory distress syndrome (ARDS) (3/47), and pneumonia (1/47). Other less frequent gram-negative microorganisms were Klebsiella spp. (ten patients; 12%), Pseudomonas spp. (7; 7%), Salmonella spp. (5; 6%), Enterobacter spp. (5; 6%), Proteus spp. (3; 3.4%), Stenotrophomonas spp. (3; 3.4%), and Acinetobacter spp. (1; 1.2%). ARDS. shock, DIC, anuria, presence of central venous catheter, urinary catheter, unknown origin of infection and inappropriate treatment were significantly associated with a higher death rate. Early initiation of appropriate therapy was the most important intervention that favorably affected the outcome of gram-negative bacteremias in this patient population.

Septicemia and septic shock in pediatric patients: 140 consecutive cases on a pediatric hematology-oncology service

PURPOSE

This report describes the incidence of septic shock in pediatric hematology-oncology patients with positive blood cultures and investigates parameters of potential use in early diagnosis of gram-negative (GN) bacteremia and septic shock.

PATIENTS

In a 12-month period, 140 consecutive episodes of septicemia (135 bacterial and 5 fungal) were seen in 100 patients. The absolute neutrophil count (ANC) was > 500/microl in 89 episodes (65%).

RESULTS

Septic shock developed in patients with positive blood cultures with an overall incidence of approximately 19%. Of the 12 bacteremic patients who required transfer to the intensive care unit, 83% had a GN isolate recovered. The incidence of septic shock was not significantly lower in the group of patients with ANC > 500/microl. Low serum bicarbonate correlated with GN infection in patients with bacteremia.

CONCLUSIONS

GN organisms were the major cause of septic shock in a group of pediatric hematology-oncology patients with positive blood cultures although they were recovered less frequently than gram-positive organisms. In our study, non-neutropenic patients with indwelling catheters were at approximately the same risk for GN shock as neutropenic patients. Monitoring blood carbon dioxide content may be useful in the early diagnosis of GN infection.

Nosocomial colonization, septicemia, and Hickman/Broviac catheter-related infections in bone marrow transplant recipients. A 5-year prospective study

In this 5-year prospective study of 242 bone marrow transplantation (BMT) recipients from whom daily blood cultures via the indwelling Broviac/Hickman catheter were obtained, there was a median of 35 catheter-days during hospitalization, mean of 40 days, and total of 9,667 catheter-days which were divided almost equally between neutropenic (4,771) and non-neutropenic (4,896) days. One hundred twenty (50%) patients had a total of 161 episodes of nosocomial bacterial or candidal infections. Overall, 81 (33%) patients experienced 100 episodes of catheter-related infections and 90 (37%) patients experienced 112 episodes of septicemia, including 51 episodes of catheter-related septicemia. There was an incidence of 11.59 septicemia episodes, including 5.28 catheter-related septicemia episodes, 2.48 colonization only (without subsequent septicemia), and 2.59 exit site infections only, per 1,000 catheter-days. Over a period of a total of 6,593 afebrile days, 34 (14%) patients developed 40 episodes of colonization, a rate of 6.07 per 1,000 afebrile days, of which 16 developed into septicemia. Twenty-five patients had 1 episode each of exit site infection without bacteremia. There were 10 (4%) septicemia-related deaths, 4 of which were catheter-related; 50% of all deaths involved Pseudomonas aeruginosa. The mortality due to catheter-related septicemic episodes was not greater than that of the non-catheter-related episodes. Neutropenia was found to be a significant risk factor in our study: 76% of the septicemia episodes (85/112) and 65% of the catheter-related infectious episodes (65/100) occurred during neutropenia. There was a higher incidence of septicemic episodes during neutropenia than during non-neutropenic periods, 17.82 versus 5.51 per 1,000 days (p < 0.0001), and a higher rate of catheter-related infections during the neutropenic period, 13.62 versus 7.15 during non-neutropenic days per 1,000 days (0.001). Fourteen of 16 colonization episodes developed into septicemia during neutropenia versus 2/24 during non-neutropenic periods, a rate of 5.47 versus 0.47 per 1,000 afebrile days, respectively (p < 0.0001), and 9/10 deaths occurred during neutropenia.

Predictors of adverse outcome in cancer patients with candidemia

BACKGROUND

Many factors, including severity of illness, neutropenia, intravenous catheter management, and drug therapy may affect the outcome of candidemia in cancer patients.

METHODS

The records of all patients at M. D. Anderson Cancer Center who developed one or more positive blood cultures for Candida spp between January 1, 1988, and December 31, 1992, were retrospectively reviewed. Four hundred ninety-one episodes of candidemia were identified, for which 476 had complete medical records, which were reviewed in detail.

RESULTS

By 3-month follow-up, 52% of the patients had died. Neutropenia, higher APACHE III score, and visceral dissemination were associated with poor prognosis. Cure rates, adjusted for severity of illness, were similar for fluconazole and amphotericin B treatment. Exchange of central venous catheters was associated with a modest improvement in prognosis.

CONCLUSION

Several factors that influence the outcome of candidemia in cancer patients have been identified. These factors may be relevant for the clinical management of cancer patients with candidemia, and for the design of therapeutic trials.

Lack of utility of the lysis-centrifugation blood culture method for detection of fungemia in immunocompromised cancer patients

We retrospectively compared the utility of a fungal isolation device (Isolator) versus conventional techniques for recovering fungal organisms from blood cultures obtained from neutropenic cancer patients. Positive cultures were deemed true pathogens, possible pathogens, or contaminants according to laboratory and clinical criteria. Fifty-three patients had 66 positive blood cultures for fungi, nine on multiple occasions. In 20 episodes true pathogens were recovered, 6 from broth medium alone, 4 from the Isolator system alone, and 10 from both systems. False-negative cultures were noted in 4 of 20 (20%) cases in which broth medium was used and in 6 of 20 (30%) cases in which the Isolator system was used. Possible pathogens were detected in 4 of 66 blood culture-positive cases. Forty-two positive cultures were considered contaminants, 1 collected from standard medium and 41 of 42 (98%) which grew only in Isolators. Eleven of 18 patients with true fungal infections expired as a result of infection, while 4 of 33 patients with a contaminant expired, none from a fungal cause. We do not advocate the routine use of Isolator tubes in the evaluation of the febrile, neutropenic patient due to the high rates of false positives and of contamination.

Detection and identification of fungal pathogens in blood by using molecular probes

A PCR assay was developed for the detection and identification of Candida and Aspergillus species. The design of the oligonucleotide primer pair as well as the species-specific probes used for species identification was derived from a comparison of the sequences of the 18S rRNA genes of various fungal pathogens. The primers targeted a consensus sequence for a variety of fungal pathogens. The assay was tested for sensitivity and specificity with 134 fungal and 85 nonfungal isolates. To assess clinical applicability, 601 blood samples from four defined groups were tested: group A (n = 35), controls; groups B to D (n = 86), patients with febrile neutropenia, without fungal colonization (group B; n = 29) and with fungal colonization (group C; n = 36); and patients with documented invasive fungal infection (IFI) (group D; n = 21). The assay detected and, by species-specific hybridization, identified most of the clinically relevant Candida and Aspergillus species at 1 CFU/ml of blood. Amplification was 100% sensitive for all molds and yeasts tested, with Histoplasma capsulatum being the only non-Aspergillus species hybridizing with the Aspergillus spp. probe. None of 35 group A patients and only 3 of 65 group B and C patients were PCR positive. The sensitivity of the assay for specimens from patients with IFI (21 patients in group D) was 100% if two specimens were tested. For specificity, 3 of 189 specimens from patients at risk but with negative cultures were positive by the assay, for a specificity of 98%. PCR preceded radiological signs by a median of 4 days (range, 4 to 7 days) for 12 of 17 patients with hepatosplenic candidiasis or pulmonary aspergillosis. For the 10 patients with IFI responding to antifungal therapy, PCR assays became persistently negative after 14 days of treatment, in contrast to the case for 11 patients, who remained PCR positive while not responding to antifungal therapy. Thus, the described PCR assay allows for the highly sensitive and specific detection and identification of fungal pathogens in vitro and in vivo. Preliminary data from the screening of a selected group of patients revealed some value in the early diagnosis and monitoring of antifungal therapy.

The clinical significance of positive blood cultures in the 1990s: a prospective comprehensive evaluation of the microbiology, epidemiology, and outcome of bacteremia and fungemia in adults

To assess changes since the mid-1970s, we reviewed 843 episodes of positive blood cultures in 707 patients with septicemia. The five most common pathogens were Staphylococcus aureus, Escherichia coli, coagulase-negative staphylococci (CNS), Klebsiella pneumoniae, and Enterococcus species. Although CNS were isolated most often, only 12.4% were clinically significant. Half of all episodes were nosocomial, and a quarter had no recognized source. Leading identifiable sources included intravenous catheters, the respiratory and genitourinary tracts, and intraabdominal foci. Septicemia-associated mortality was 17.5%. Patients who received appropriate antimicrobial therapy throughout the course of infection had the lowest mortality (13.3%). Multivariate analysis showed that age (relative risk [RR], 1.80), microorganism (RR, 2.27), source of infection (RR, 2.86), predisposing factors (RR, 1.98), blood pressure (RR, 2.29), body temperature (RR, 2.04), and therapy (RR, 2.72) independently influenced outcome. Bloodstream infections in the 1990s are notable for the increased importance of CNS as both contaminants and pathogens, the proportionate increase in fungi and decrease in anaerobes as pathogens, the emergence of Mycobacterium avium complex as an important cause of bacteremia in patients with advanced human immunodeficiency virus infection, and the reduction in mortality associated with infection.

Outpatient antibiotic therapy for febrile episodes in low-risk neutropenic patients with cancer

Until recently, febrile neutropenic patients were treated with intravenous antibiotics in inpatient settings. Because of work completed in the last several years by various investigators, identification of a low-risk group of febrile, neutropenic patients has allowed successful treatment with both parenteral and oral antibiotics in an ambulatory environment. This accomplishment has been facilitated by advances in broad-spectrum antibiotics with long half-lives and stabilities, the introduction of the quinolones providing oral antipseudomonal activity, home health care, improvements in vascular access devices, and technically enhanced antibiotic delivery systems. This review focuses on the rationale of risk stratification and the progress made in treating low-risk febrile neutropenic patients as outpatients.

Outpatient antibiotic treatment in low-risk febrile neutropenic cancer patients

Traditionally febrile neutropenic patients have been treated with parenteral antibiotics in an inpatient setting; however, recent work by several investigators has demonstrated successful treatment with both parenteral and oral antibiotics in an ambulatory environment. This has been accomplished by identification of low-risk neutropenic patients, advances in broad-spectrum antibiotics with long half-lives and stabilities, the introduction of the oral quinolones, home health-care initiatives, improvements in vascular access devices, and development of technically enhanced antibiotic delivery systems. Outpatient antibiotic therapy for febrile episodes in low-risk neutropenic patients should now be considered an acceptable alternative to hospital-based treatment. This review focuses on the development and rationale of risk stratification and examines the results of various outpatient antibiotic trials recently completed.

Infections in haematological malignancies: an autopsy study of 72 cases

Autopsy material from 72 patients with haematological malignancies treated in India was reviewed. Thirty-seven patients (51%) had documented infections; 20 (27%) had bacterial infections, 14 of which were Gram-negative organisms (Pseudomonas species in 10); tuberculosis was present in 2 patients (2.7%). Twenty-one patients (29%) had systemic fungal infections; invasive pulmonary aspergillosis and gastrointestinal candidiasis were present in 10 patients each. Only 3 patients (4%) had viral infection, all of which were due to cytomegalovirus. Eleven patients (15%) had polymicrobial infections. No patient had any parasitic infection. Systemic fungal infections due to Aspergillus and Candida predominated, while Gram-negative bacterial infections were also common.

Yield of positive blood cultures in pediatric oncology patients by a new method of blood culture collection

BACKGROUND

The optimal number of blood cultures and the volume of blood for pediatric blood cultures have not been defined. In 1990 such criteria were established at our institution. We retrospectively reviewed records of all pediatric oncology patients who were admitted for febrile episodes in 1989 and in 1991 and 1992 to determine whether there was an increase in the detection of bacteremia and fungemia.

METHODS

Blood was drawn via venipuncture and central intravascular catheters and inoculated into the designated blood culture bottles. Each patient had a minimum of two separate blood draws, i.e. two separate cultures; the volume was determined by the patient's weight. In all cases < 1% of the patient's blood volume was drawn per culture. Patients' records were reviewed regarding type of malignancy, chemotherapy and neutropenia.

RESULTS

The rate of bacteremic patients increased from 12% (13 of 113) in 1989 to 22% (27 of 123) in 1991. This increase continued through 1992 with 23% (27 of 118) of patients having positive blood cultures. Gram-positive bacteria predominated throughout the study period.

CONCLUSIONS

Although factors such as more aggressive chemotherapy or a different spectrum of malignant diseases may contribute to the statistically significant increase in identification of bacteremic patients, a standardized method of blood culture collection is merited. The consistent volumes of blood per culture and the minimum of two cultures per febrile episode follow the principles of blood culture collection established for adults. The same principles should apply to pediatric patients.

Catheter-related complications of cancer therapy

Although the management of CVC-related infection appears complex and at times the literature seems to be contradictory, simple guidelines can direct the clinician in a stepwise fashion. Knowledge of the pathogenesis of each organism and the immune status of the host is crucial to decide whether catheter removal or retention is indicated. For example, in general, GNB bacteremia does not immediately prompt catheter removal in a neutropenic patient but does in a nonneutropenic host because of the gastrointestinal source of the former and a primary catheter source in the latter. In summary, as more CVCs are inserted in patients undergoing chemotherapeutic, antimicrobial, transfusional, and nutritional supportive care, novel approaches to prevention and treatment of the associated infectious complications inherent with such devices are needed. A multifaceted approach from impregnated catheters to local catheter-site antisepsis was reviewed. We may find, however, that as simple handwashing between patients is crucial to infection control, so too is a trained catheter-care team using total barrier precautions and ensuring proper local catheter maintenance critical to preventing CVC-related infections.

A comparison of aztreonam plus vancomycin and imipenem plus vancomycin as initial therapy for febrile neutropenic cancer patients

BACKGROUND

The improved efficacy of imipenem over other beta-lactam antibiotics in the treatment of febrile neutropenic patients has been attributed to its broad spectrum of activity.

METHODS

A prospective, randomized, clinical trial was performed comparing vancomycin 1 g every 12 hours plus imipenem/cilassatin 500 mg every 6 hours and the same dose of vancomycin plus aztreonam 2 g every 6 hours for empiric treatment of febrile episodes in neutropenic patients with cancer.

RESULTS

The imipenem regimen cured 76% of the 148 evaluable episodes compared with a 67% cure rate for the 152 episodes treated with the aztreonam regimen (p = 0.1). Most of the polymicrobial infections (77% or 10/13) treated with the imipenem responded, whereas only 38% (5/13) of these infections responded to the aztreonam regimen. Although the cost of the imipenem regimen was less than the cost of the aztreonam regimen, it was associated significantly more with skin rashes (12/194 vs 3/189, p = 0.02). In a multivariate analysis, a poor outcome was independently associated in both instances with the persistence of neutropenia and the presence of pneumonia (p < 0.001).

CONCLUSIONS

Overall, in a multifactorial analysis that included efficacy, toxicity, and cost, the imipenem and aztreonam regimens were comparable.

Prospective study of 288 episodes of bacteremia in neutropenic cancer patients in a single institution

Trends in causative organisms and sources of infection were studied in a series of 288 episodes of bacteremia in neutropenic cancer patients observed in a single institution from 1986 to 1993. The incidence of bacteremia increased significantly from 20 episodes per 1000 admissions in 1986 to 50 episodes per 1000 admissions in 1993 (p = 0.00001). Over the study period, a continuous increment in gram-positive bacteremia, which reached 81% of episodes in 1993 (p = 0.000001), was observed. Conversely, the incidence of gram-negative bacteremia remained stable. Coagulase-negative staphylococci and viridans group streptococci were the most commonly isolated pathogens. Bacteremia caused by coagulase-negative staphylococci increased from 3 episodes per 1000 admissions to 19 episodes per 1000 admissions (p = 0.0001), and viridans group streptococci bacteremia increased from 0 episodes per 1000 admissions to 19 episodes per 1000 admissions (p = 0.000001). The upward trend in gram-positive bacteremia appeared to be related to a significant increase in both intravascular catheters (p = 0.003) and oral mucositis (p = 0.003) as sources of infection. Specific strategies to prevent chemotherapy-induced mucositis and catheter-related bacteremia merit further investigations.

Pulmonary infiltrates in patients with haematologic malignancies: clinical usefulness of non-invasive bronchoscopic procedures

In a prospective study 90 patients with haematologic malignancies (57 acute leukaemias, 6 Hodgkin's Diseases, 15 Non-Hodgkin Lymphomas, 12 other diseases), with fever exceeding 38.4 degrees C and newly developed pulmonary infiltrates underwent bronchoscopy obtaining bronchoalveolar lavage, bronchial washings and protected brush specimen (n = 71). Pneumonias due to gram-negative bacteria (n = 38) and fungi (n = 34) were most frequent. Bronchoscopic specimens yielded 226 isolates (2 different organisms/bronchoscopy on average). 112 organisms were finally regarded as causing pneumonia. Sensitivity of bronchoscopy in diagnosing infectious episodes was 66%, but only 4 out of 13 non-infectious pulmonary infiltrates could be identified. Bronchoscopy was most effective in the diagnosis of pneumocystis carinii and herpes virus pneumonia, whereas sensitivity and specificity of detecting fungal and bacterial pneumonia were low. Empirical antimicrobial therapy was verified by evaluation of bronchoscopic samples in 25 out of 90 cases. Empirical therapy was successfully changed according to the results of invasive samplings in 34 out of 90 cases. Early identification of causative pathogens had a significant impact on survival.

Staphylococcus aureus bacteremia: a 14-year nationwide study in hematological patients with malignant disease or agranulocytosis

This retrospective nationwide study of 756 cases of S. aureus bacteremia in hematological patients, between 1977-1990, confirms that S. aureus bacteremia is disproportionately prevalent among, and a major cause of morbidity and mortality in, hematological patients. The case mortality rate attributable to S. aureus bacteremia (44%) was significantly higher than the rate (29%) found in patients without hematological disease. A decreasing mortality was, however, observed from the first to the last part of the study period (53 and 37% respectively). A logistic regression analysis showed that mortality was further dependent on age, the type of hematological disease and origin of infection/primary focus of infection. Analysis of clinical features confirmed that in comparison with other patients, S. aureus bacteremia in hematological patients more often was hospital-acquired, acquired without known portal of infection/primary focus of infection and much less frequently resulted in osteomyelitis or endocarditis. From phage typing and antibiotic susceptibility patterns no specific types of S. aureus were associated with hematological patients.

Interventional antimicrobial therapy in febrile neutropenic patients. Study Group of the Paul Ehrlich Society for Chemotherapy

In this prospective multicenter trial, treatment strategies for 1573 patients with neutropenia < 1000/microliters and fever > or = 38.5 degrees C after cytotoxic chemotherapy were compared. Patients with unexplained fever were randomized to a three-phase sequential study for different established drug regimens. If an infection could be defined microbiologically or clinically, treatment modifications were determined. In phase I, treatment for all patients consisted of acylaminopenicillin (PEN) plus aminoglycoside (AMG); or third-generation cephalosporin (CEPH) plus AMG; or PEN plus CEPH. In 800 patients with unexplained fever the response rates were: PEN/AMG (n = 258): 74.4%, CEPH/AMG (n = 252): 73.4%; PEN/CEPH (n = 290): 70.0%. Total response rate was 72.5%. In phase II, patients not responding after 3 days received PEN/CEPH/vancomycin (n = 70) or PEN/CEPH/AMG (n = 74). The respective response rates were 52.9% and 55.4%, total 54.2%. If fever did not resolve, the patients received either PEN/CEPH (n = 40) or imipenem/cilastatin (n = 59) both in combination with amphotericin-B/5-flucytosin/rifampin. The response rates were 62.5% and 79.7%, respectively (p = 0.07), total 72.7%. No significant differences between the treatment modalities compared were found. Analyzing all three phases together, 91.3% of patients with unexplained fever were cured. The response rate was also analyzed according to patients with gram-positive bacteremia (n = 183), response rate = 82.5%; gram-negative organisms (n = 145) 78.6%; fungemia (n = 51) 43.1% (p < 0.001); lung infiltrates (n = 269) 61.3% (p < 0.001); clinically documented infections (n = 198) 84.4%; and clinically and microbiologically documented infections (n = 84) 82.1%. If infections were diagnosed after at least 5 febrile days, more lung infiltrates and fungal infections occurred (p < 0.001). Leukocytes rising above 500/mu during the infection predicted better response rates (p < 0.001): in unexplained fever 97.8% vs 86.5% and lower death rates 1.5% vs 8.5%. In documented infections the response rates were then 89.9% vs 62.3% and the death rates 7.0% vs 20.5%. Therapy of neutropenic fever and infections must be adapted according to risk factors and should include early empiric antifungal therapy. The therapeutic and prophylactic use of hematopoietic growth factors to overcome neutropenia should be evaluated.

Infection in immunocompromised patients with malignant blood disorders in a district general hospital

The pattern and management of infection in immunocompromised patients over a period of 3 years in a district general hospital has been studied. A total of 222 positive cultures was obtained in 607 episodes of suspected infection all involving patients with malignant blood disorders. Febrile episodes requiring intravenous antibiotics occurred in 248 instances involving 107 patients. The pattern of organisms cultured and the responses to various antibiotic regimes are reported. The costs of antibiotic therapy are considered in the light of the overall response. Of the patients studied, 54 died, infection having a likely causative or contributory part in 21 of them (less than 10% of infective episodes). We conclude that the infective complications of these disorders, particularly in older patients, can be efficiently managed in a district general hospital when full supportive facilities are available.