A prospective study of septicaemia on a paediatric oncology unit: A three-year experience at The Royal Liverpool Children’s Hospital, Alder Hey, UK

Role of Polymerase Chain Reaction-Based Diagnosis of Respiratory Viruses in Febrile Neutropenic Patients

Background Neutropenic patients are commonly affected by respiratory infections, whereas respiratory viral infections causing high morbidity and mortality are routinely diagnosed in developing countries like India. Our study aimed to investigate the prevalence of respiratory viral infections in pediatric cancer patients with febrile neutropenia.  Methods This prospective study was performed on 45 neutropenia patients with hematological malignancies. Nasal swabs were collected and analyzed by real-time multiplex polymerase chain reaction (PCR), covering the following viruses: influenza A virus, influenza B virus, human parainfluenza virus (subtypes 1-4), human respiratory syncytial virus A and B, enterovirus, human-coronavirus (HCoV: HKU1, NL63, 229E, and OC43), human bocavirus, adenovirus, human rhinovirus, human-metapneumovirus A and B, human paraechovirus, and a bacterium Mycoplasma pneumoniae. Patients enrolled in the study since the COVID-19 pandemic was also detected for the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Results Of the 45 cases included in our study, 26 cases showed the presence of at least one positivity by PCR (57.7%): 23 patients had monoinfection with only one virus, two patients were found positive for coinfection with two viruses, and one patient was found positive for three viruses. The most detected viruses were human rhinovirus (26.9%, n=7) and coronavirus 19 (19.2%, n=5). A total of 11.5% of the patients had multiple viral infections. About 19 (42.2%) of the patients enrolled in our study had no viral pathogen detected. Conclusion We found that respiratory viruses contribute significantly to the development of neutropenic fever, as evidenced by the results of our prospective study. Individualizing infection treatment can reduce antibiotic use in immunocompromised patients. Thus, routine screening for viremia may be warranted in this clinical setting.

Severity of COVID-19 in children with cancer: Report from the United Kingdom Paediatric Coronavirus Cancer Monitoring Project

BACKGROUND

Children with cancer are frequently immunocompromised. While children are generally thought to be at less risk of severe SARS-CoV-2 infection than adults, comprehensive population-based evidence for the risk in children with cancer is unavailable. We aimed to produce evidence of the incidence and outcomes from SARS-CoV-2 in children with cancer attending all hospitals treating this population across the UK.

METHODS

Retrospective and prospective observational study of all children in the UK under 16 diagnosed with cancer through data collection from all hospitals providing cancer care to this population. Eligible patients tested positive for SARS-CoV-2 on reverse transcription polymerase chain reaction (RT-PCR). The primary end-point was death, discharge or end of active care for COVID-19 for those remaining in hospital.

RESULTS

Between 12 March 2020 and 31 July 2020, 54 cases were identified: 15 (28%) were asymptomatic, 34 (63%) had mild infections and 5 (10%) moderate, severe or critical infections. No patients died and only three patients required intensive care support due to COVID-19. Estimated incidence of hospital identified SARS-CoV-2 infection in children with cancer under 16 was 3%.

CONCLUSIONS

Children with cancer with SARS-CoV-2 infection do not appear at increased risk of severe infection compared to the general paediatric population. This is reassuring and supports the continued delivery of standard treatment.

Assessment of respiratory tract viruses in febrile neutropenic etiology in children and comparison with healthy children with upper/lower respiratory tract infection

OBJECTIVE:

This study aims to compare the frequency of respiratory viruses using real-time and multiplex polymerase chain reaction technology and nasopharyngeal swabs taken during exacerbation of patients aged 0–18 years followed for febrile neutropenia (FN) with non-FN children.

METHODS:

This prospective study included a total of 40 patients with FN and malignancies followed at Eskisehir Osmangazi University, Department of Pediatric Hematology and Oncology. The control group (n=76) consisted of age-matched patients with upper respiratory tract infections (URTIs) or lower respiratory tract infections (LRTIs) who were admitted to the emergency service due to fever.

RESULTS:

Viral agents were detected in 16 of 53 FN attacks (30.1%). The most commonly isolated viruses were coronavirus (23.7%, n=9), influenza B (18.4%, n=7), and adenovirus (18.4%, n=7). Of 76 children diagnosed with URTI with fever (52.6%) had viral agents, and only 28 of them had a single agent. The most commonly isolated virus was adenovirus (28.6%, n=14). Viral factors were found in 32 of 42 patients (76.1%) patients diagnosed with LRTI, while respiratory syncytial virus was the most common virus in 27 patients (21.7%, n=5).

CONCLUSION:

Our study results show that viral agents play an important role in the etiology of FN. This is the first study to show that viral agents play an important role in the etiology of this disease and viral factors in non-neutropenic febrile children at the same time period by detecting respiratory viruses in 30% of FN cases. More similar studies provide antiviral therapy in selected patients, as well as these studies lead to reduce the use of antimicrobial agents or allow more selective use of antibiotics and/or the earlier discontinuation of these antibiotics in febrile neutropenic children who have been shown to have viral cause of respiratory tract infection based on clinical and microbiological/molecular diagnostic criteria.

Infection characteristics and treatment of Staphylococcus aureus bacteraemia at a tertiary children's hospital

BACKGROUND

Staphylococcus aureus bacteraemia (SAB) causes considerable morbidity and mortality in children. Despite this, its epidemiology and risk factors are poorly understood, with minimal paediatric clinical trial data available to guide clinicians in management. We conducted a pilot study to characterise SAB and validate a severity classification for use in future clinical trials.

METHODS

Patients with SAB were prospectively identified at Princess Margaret Hospital for Children (Perth, Western Australia) from May 2011 to December 2013. Retrospective data were collected from clinical and laboratory records. Cases were classified based on a priori defined criteria as simple (single or contiguous, peripheral site focus) or complex (multi-site, deep tissue, no focus or sepsis) and tested against risk factors and markers of severity of infection.

RESULTS

There were 49 cases of SAB (median age 7.7 years), with classification as simple (n = 30, 61%) and complex (n = 19, 39%) respectively. There were no deaths or relapses in our cohort. Only 10% of isolates were methicillin resistant S. aureus (MRSA), and none of these were healthcare-associated. Age, gender, Indigenous status, MRSA and healthcare-associated infections were not predictive of complex infection. Pre-existing malignancy was a risk factor for complex infection (p = 0.02). Complex infections were associated with a higher median maximum C reactive protein (216 mg/L vs 50 mg/L, p = < 0.001), longer median length of stay (42 vs 10 days, p = < 0.001) and longer duration of antibiotic therapy (43 vs 34 days, p = 0.03).

DISCUSSION

This is the first attempt to categorise paediatric SAB as simple versus complex, to guide clinicians in decision making.

CONCLUSIONS

There is a wide spectrum of disease severity in paediatric SAB, with maximum CRP, length of stay, and duration of therapy greater in those with complex disease. Distinct cohorts with simple and complex courses which may be a target for future clinical trials have been described.

Comparing catheter-related bloodstream infections in pediatric and adult cancer patients

OBJECTIVE

Central venous catheters (CVCs) are essential to treatment of children with cancer. There are no studies comparing catheter-related bloodstream infections (CRBSIs) in pediatric cancer patients to those in adults, although current guidelines for management of CRBSI do not give separate guidelines for the pediatric population. In this study, we compared CRBSIs in both the pediatric and adult cancer population.

METHODS

We retrospectively reviewed the electronic medical records of 92 pediatric and 156 adult patients with CRBSI cared for at MD Anderson Cancer Center between September 2005 and March 2014.

RESULTS

We evaluated 248 patients with CRBSI. There was a significant difference in etiology of CRBSI between pediatric and adult patients (P = 0.002), with the former having less Gram-negative organisms (27 vs. 46%) and more polymicrobial infections (10 vs. 1%, P = 0.003). Pediatric patients had less hematologic malignancies (58 vs. 74%) and less neutropenia at presentation (40 vs. 54%) when compared with adult patients. Peripheral blood cultures were available in only 43% of pediatric cases. CVC was removed in 64% of pediatric cases versus 88% of adult cases (P < 0.0001).

CONCLUSION

We found higher rates of Gram-negative organisms in adults and higher rates of polymicrobial in children. Because of the low rates of peripheral blood cultures and the low rates of CVC removal, CRBSI diagnosis could be challenging in pediatrics. A modified CRBSI definition relying more on clinical criteria may be warranted.

Frequent Respiratory Viral Infections in Children with Febrile Neutropenia - A Prospective Follow-Up Study

OBJECTIVE

Febrile neutropenia is common in children undergoing chemotherapy for the treatment of malignancies. In the majority of cases, the cause of the fever is unknown. Although respiratory viruses are commonly associated with this condition, the etiologic significance of this finding remains unclear and is therefore the subject of this study.

STUDY DESIGN

Nasopharyngeal aspirates were collected during 87 episodes of febrile neutropenia in children age 0-18 years, being treated at a children's oncology unit between January 2013 and June 2014. Real-time polymerase chain reaction was used to determine the presence of 16 respiratory viruses. Follow-up samples were collected from children who tested positive for one or more respiratory viruses. Rhinoviruses were genotyped by VP4/VP2 sequencing. Fisher's exact test and Mann-Whitney U test were used for group comparisons.

RESULTS

At least one respiratory virus was detected in samples from 39 of 87 episodes of febrile neutropenia (45%), with rhinoviruses the most frequently detected. Follow-up samples were collected after a median of 28 days (range, 9-74 days) in 32 of the 39 virus-positive episodes. The respiratory viral infection had resolved in 25 episodes (78%). The same virus was detected at follow-up in one coronavirus and six rhinovirus episodes. Genotyping revealed a different rhinovirus species in two of the six rhinovirus infections.

CONCLUSION

The frequency of respiratory viral infections in this group of patients suggests an etiologic role in febrile neutropenia. However, these findings must be confirmed in larger patient cohorts.

Surveillance of bloodstream infections in pediatric cancer centers - what have we learned and how do we move on?

Pediatric patients receiving conventional chemotherapy for malignant disease face an increased risk of bloodstream infection (BSI). Since BSI may represent an acute life-threatening event in patients with profound immunosuppression, and show further negative impact on quality of life and anticancer treatment, the prevention of BSI is of paramount importance to improve and guarantee patients' safety during intensive treatment. The great majority of all pediatric cancer patients (about 85%) have a long-term central venous access catheter in use (type Broviac or Port; CVAD). Referring to the current surveillance definitions a significant proportion of all BSI in pediatric patients with febrile neutropenia is categorized as CVAD-associated BSI. This state of the art review summarizes the epidemiology and the distinct pathogen profile of BSI in pediatric cancer patients from the perspective of infection surveillance. Problems in executing the current surveillance definition in this patient population are discussed and a new concept for the surveillance of BSI in pediatric cancer patients is outlined.

Candida albicans Inhibits Pseudomonas aeruginosa Virulence through Suppression of Pyochelin and Pyoverdine Biosynthesis

Bacterial-fungal interactions have important physiologic and medical ramifications, but the mechanisms of these interactions are poorly understood. The gut is host to trillions of microorganisms, and bacterial-fungal interactions are likely to be important. Using a neutropenic mouse model of microbial gastrointestinal colonization and dissemination, we show that the fungus Candida albicans inhibits the virulence of the bacterium Pseudomonas aeruginosa by inhibiting P. aeruginosa pyochelin and pyoverdine gene expression, which plays a critical role in iron acquisition and virulence. Accordingly, deletion of both P. aeruginosa pyochelin and pyoverdine genes attenuates P. aeruginosa virulence. Heat-killed C. albicans has no effect on P. aeruginosa, whereas C. albicans secreted proteins directly suppress P. aeruginosa pyoverdine and pyochelin expression and inhibit P. aeruginosa virulence in mice. Interestingly, suppression or deletion of pyochelin and pyoverdine genes has no effect on P. aeruginosa’s ability to colonize the GI tract but does decrease P. aeruginosa’s cytotoxic effect on cultured colonocytes. Finally, oral iron supplementation restores P. aeruginosa virulence in P. aeruginosa and C. albicans colonized mice. Together, our findings provide insight into how a bacterial-fungal interaction can modulate bacterial virulence in the intestine. Previously described bacterial-fungal antagonistic interactions have focused on growth inhibition or colonization inhibition/modulation, yet here we describe a novel observation of fungal-inhibition of bacterial effectors critical for virulence but not important for colonization. These findings validate the use of a mammalian model system to explore the complexities of polymicrobial, polykingdom infections in order to identify new therapeutic targets for preventing microbial disease.

Pseudomonas aeruginosa and Candida albicans are two medically important human pathogens that often co-infect or co-colonize the same human niches, such as the gut. In a normal healthy host, P. aeruginosa and C. albicans can colonize the gut without any significant pathologic sequelae. But in immunocompromised hosts, both pathogens can escape the gut and cause life-threatening disseminated infections. Yet the mechanisms and pathogenic consequences of interactions between these two pathogens within a living mammalian host are not well understood. Here, we use a mouse model of P. aeruginosa and C. albicans gut co-infection to better understand the mechanisms by which C. albicans inhibits P. aeruginosa infection. C. albicans inhibits the expression of P. aeruginosa genes that are vital for iron acquisition. Accordingly, deleting these iron acquisition genes in P. aeruginosa prevents infection. Understanding how microbes interact and antagonize each other may help us identify new potential therapeutic targets for preventing or treating infections.

Risk factors for sepsis-related death in children and adolescents with hematologic and malignant diseases

BACKGROUND

The aim of this study was to elucidate risk factors for mortality after developing sepsis in pediatric patients with hematologic and malignant disorders.

METHODS

A total of 90 patients (43 boys, 47 girls) with various hematologic and malignant diseases who experienced sepsis between June 2006 and March 2014 were enrolled. Clinical and laboratory features of 134 episodes of sepsis observed in the 90 patients were compared between those with and without sepsis-related death which was defined as death within 14 days after sepsis.

RESULTS

Age at hospitalization, sex, and type of underlying disease did not differ between patients with and without sepsis-related death. Sepsis episode-based univariate analysis identified patients with a history of relapse or in a refractory state of underlying disease (p<0.01), those with high C-reactive protein concentrations (≥50 mg/L) at the beginning of fever (p<0.01), those who had undergone hematopoietic stem cell transplantation (p<0.01), and those who were forced to change initial antibiotics (p = 0.02) because of being at high risk of sepsis-related death. The former two factors were further confirmed by multivariate analysis. More than half (52.9%) the isolates from sepsis-related death were Gram-positive cocci resistant to β-lactam antibiotics, but susceptible to vancomycin.

CONCLUSION

It was found that a history of relapse, a refractory state of underlying disease, and high C-reactive protein concentrations at the beginning of fever were significant risk factors for mortality after developing sepsis. Survival rate of patients with risk factors raised in this study might be improved by early introduction of vancomycin.

Invasive bacterial and fungal infections in paediatric patients with cancer: incidence, risk factors, aetiology and outcomes in a UK regional cohort 2009-2011

BACKGROUND

Cancer is the second most common cause of childhood deaths in the United Kingdom and infection contributes to a quarter of all cancer-related deaths. This study aimed to estimate the risk, aetiology and outcome of bloodstream bacterial and fungal infections in children with cancer within a geographically defined region in South-West London over a 3-year period.

METHODS

Web-based questionnaires were completed using case records of children with positive blood cultures admitted to five London hospitals during 2009-2011.

RESULTS

A total of 112 children with a median age of 5.4 (IQR 3.6-11.2) years had 266 significant blood cultures during 149 infection episodes. Haematological malignancy affected 68 patients (60.7%) and solid tumours 44 (39.3%). The overall bloodstream infection rate was 1.5 episodes per 1,000 days-at-risk (95% CI, 1.2-1.8) and was similar for those with haematological malignancies and solid tumours. Most episodes were attributed to central venous catheter infection (120/149, 80.5%). Coagulase-negative staphylococci were isolated in almost half the bloodstream infections (127/266; 47.7%), while Gram-negative organisms accounted for a further quarter (64/266; 24.1%). Fungal isolates from blood were uncommon (8/112 children, 7.1%) but significantly associated with neutropenia (18/149 [12.1%] vs. 1/114 [0.9%], P = 0.0004). Six children (5.4%) died, including three (2.7%; 95% CI, 0.6-7.6%) whose deaths were infection-related.

CONCLUSIONS

This study provides an updated risk estimate for bloodstream infections in children with cancer and adds to the framework for developing evidence-based guidance for management of suspected infections in this highly vulnerable group.

Antibiotic-resistant Gram-negative bacteremia in pediatric oncology patients--risk factors and outcomes

BACKGROUND

Infection with antibiotic-resistant (AR) Gram-negative (GN) bacteria is associated with increased morbidity and mortality. The aim of this study was to determine risk factors and outcomes associated with GN bacteremia with acquired resistance to antibiotics used in the empiric treatment of febrile neutropenia in pediatric oncology patients at our institution.

METHODS

All episodes of GN bacteremia in oncology patients at the Royal Children's Hospital Melbourne, from 2003 to 2010 were retrospectively reviewed. Information regarding age, diagnosis, phase of treatment, inpatient status, previous AR GN infection, treatment with inotropes or ventilatory support, admission to intensive care unit, and hospital and intensive care unit length of stay were obtained from electronic records.

RESULTS

A total of 280 episodes of GN bacteremia in 210 patients were identified. Of these, 42 episodes in 35 patients were caused by an AR GN organism. Factors independently associated with AR GN bacteremia were high-intensity chemotherapy (odds ratio 3.7, 95% confidence interval: 1.2-11.4), hospital-acquired bacteremia (odds ratio 4.3, 95% confidence interval: 2.0-9.6) and isolation of AR GN bacteria from any site within the preceding 12 months (odds ratio 9.9, 95% confidence interval: 3.8-25.5). Episodes of AR GN bacteremia were associated with longer median hospital length of stay (23.5 days versus 14.0 days; P = 0.0007), longer median intensive care unit length of stay (3.8 days versus 1.6 days; P = 0.02) and a higher rate of invasive ventilation (15% versus 5.2%; P = 0.03). No significant difference in infection-related or all-cause mortality between the 2 groups was identified.

CONCLUSIONS

In pediatric oncology patients, AR GN bacteremia is associated with an increased rate of adverse outcomes and is more likely in patients who have received high-intensity chemotherapy, have been in hospital beyond 48 hours and who have had previous AR GN infection or colonization.

Antibiotic and other lock treatments for tunnelled central venous catheter-related infections in children with cancer

BACKGROUND

The risk of developing a tunnelled central venous catheter (CVC)-related infection ranges between 0.1 and 2.3 per 1000 catheter days for children with cancer. These infections are difficult to treat with systemic antibiotics (salvage rate 24% - 66%) due to biofilm formation in the CVC. Lock treatments can achieve 100 - 1000 times higher concentrations locally without exposure to high systemic concentrations.

OBJECTIVES

Our objective was to investigate the efficacy of antibiotic and other lock treatments in the treatment of CVC-related infections in children with cancer compared to a control intervention. We also assessed adverse events of lock treatments.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, issue 3, 2011), MEDLINE/PubMed (1945 to August 2011) and EMBASE/Ovid (1980 to August 2011). In addition we searched reference lists from relevant articles and the conference proceedings of the International Society for Paediatric Oncology (SIOP) (from 2006 to 2010), American Society of Clinical Oncology (ASCO) (from 2006 to 2010), the Multinational Association of Supportive Care in Cancer (MASCC) (from 2006 to 2011), the American Society of Hematology (ASH) (from 2006 to 2010) and the International Society of Thrombosis and Haematology (ISTH) (from 2006 to 2011). We scanned the ISRCTN Register and the National Institute of Health Register for ongoing trials (www.controlled-trials.com) (August 2011).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing an antibiotic lock or other lock treatment (with or without concomitant systemic antibiotics) with a control intervention (other lock treatment with or without concomitant systemic antibiotics or systemic antibiotics alone) for the treatment of CVC-related infections in children with cancer. For the description of adverse events, cohort studies were also eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies, extracted data and performed 'Risk of bias' assessments of included studies. Analyses were performed according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

Two RCTs evaluated urokinase lock treatment with concomitant systemic antibiotics (n = 56) versus systemic antibiotics alone (n = 48), and one CCT evaluated ethanol lock treatment with concomitant systemic antibiotics (n = 15) versus systemic antibiotics alone (n = 13). No RCTs or CCTs evaluating antibiotic lock treatments were identified. All studies had methodological limitations and clinical heterogeneity between studies was present. We found no evidence of significant difference between ethanol or urokinase lock treatments with concomitant systemic antibiotics and systemic antibiotics alone regarding the number of participants cured, the number of recurrent CVC-related infections, the number of days until the first negative blood culture, the number of CVCs prematurely removed, ICU admission and sepsis. Not all studies were included in all analyses. No adverse events occurred in the five publications of cohort studies (one cohort was included in two publications) assessing this outcome; CVC malfunctioning occurred in three out of five publications of cohort studies assessing this outcome.

AUTHORS' CONCLUSIONS

No significant effect of urokinase or ethanol lock in addition to systemic antibiotics was found. However, this could be due to low power or a too-short follow-up. The cohort studies identified no adverse events; some cohort studies reported CVC malfunctioning. No RCTs or CCTs were published on antibiotic lock treatment alone. More well-designed RCTs are needed to further explore the effect of antibiotic or other lock treatments in the treatment of CVC-related infections in children with cancer.

Selective decontamination of the digestive tract: the mechanism of action is control of gut overgrowth

PURPOSE

Gut overgrowth is the pathophysiological event in the critically ill requiring intensive care. In relation to the risk of developing a clinically important outcome, gut overgrowth is defined as ≥10(5) potential pathogens including 'abnormal' aerobic Gram-negative bacilli (AGNB), 'normal' bacteria and yeasts, per mL of digestive tract secretion. Surveillance samples of throat and gut are the only samples to detect overgrowth. Gut overgrowth is the crucial event which precedes both primary and secondary endogenous infection, and a risk factor for the development of de novo resistance. Selective decontamination of the digestive tract (SDD) is an antimicrobial prophylaxis designed to control overgrowth.

METHODS

There have been 65 randomised controlled trials of SDD in 15,000 patients over 25 years and 11 meta-analyses, which are reviewed.

RESULTS AND CONCLUSIONS

These trials demonstrate that the full SDD regimen using parenteral and enteral antimicrobials reduces lower airway infection by 72 %, blood stream infection by 37 %, and mortality by 29 %. Resistance is also controlled. Parenteral cefotaxime which reaches high salivary and biliary concentrations eradicates overgrowth of 'normal' bacteria such as Staphylococcus aureus in the throat. Enteral polyenes control 'normal' Candida species. Enteral polymyxin and tobramycin, eradicate, or prevent gut overgrowth of 'abnormal' AGNB. Enteral vancomycin controls overgrowth of 'abnormal' methicillin-resistant S. aureus. SDD controls overgrowth by achieving high antimicrobial concentrations effective against 'normal' and 'abnormal' potential pathogens rather than by selectivity.

Catheter-related infections in pediatric patients with cancer

Central venous catheters (CVCs) are essential in the management of pediatric patients receiving antineoplastic therapy or bone marrow transplants, and have significantly improved their quality of life, but CVC-related infectious complications are a major source of morbidity. It has been estimated that 14-51 % of the CVCs implanted in children with malignancies may be complicated by bacteremia, and that the incidence of infections is 1.4-1.9 episodes per 1,000 CVC days. However, there are few recent data concerning the epidemiology of CVC-related infections, the prevalence of antimicrobial resistance in their etiology, or the main factors associated with an increased risk of infection by type of catheter, patient age, the type of cancer, or the presence of neutropenia. Moreover, although various new strategies have been proposed in an attempt to reduce the risk of CVC-related infections, such as catheters impregnated with antiseptics/antibiotics, lock antibiotic prophylaxis, the use of ointments at the exit site, and antithrombotic prophylaxis, their real efficacy in children has not yet been demonstrated. The management of CVC-related infections remains difficult, mainly because of the number of still open questions (including the choice of optimal antimicrobial therapy because of the increasing isolation of multiresistant bacterial strains, treatment duration, whether catheters should be removed or not, the feasibility of guidewire exchange, and the usefulness of antibiotic lock therapy) and the lack of studies of children with cancer. Only well-designed, prospective clinical trials involving pediatric cancer patients can clarify optimal prevention and treatment strategies for CVC-related infections in this population.

Glutamine prevents intestinal mucosal injury induced by cyclophosphamide in rats

PURPOSE

High doses of anticancer drugs often damage the intestinal mucosa. The purpose of the present study was to examine the effect of glutamine on mucosal damage induced by cyclophosphamide in a rat model, and to elucidate the mechanisms responsible for its protective effects.

METHOD

Rats were randomly assigned to one of the three experimental groups. Group A (control) (n = 8): intraperitoneal injection of saline, group B (n = 8): intraperitoneal injection of cyclophosphamide (300 mg/kg), group C (n = 8): intraperitoneal injection of cyclophosphamide (300 mg/kg) and oral glutamine (1.0 g/kg). After 3 days, the ileal segment was removed for morphological and the biochemical analyses. We also evaluated the level of mucosal apoptosis by the TUNEL method and enterocyte proliferation using bromodeoxyuridine (BrdU).

RESULTS

Mucosal atrophy was observed in group B but not in groups A or C. The mucosal wet weight, protein and glutathione levels were significantly decreased in group B compared with group A, and were increased significantly in group C compared with group B. While enterocyte proliferation significantly decreased and the apoptotic index significantly increased in group B compared with group A, a significant increase in the enterocyte proliferation and a significant decrease in apoptosis were observed in group C compared with group B.

CONCLUSIONS

Glutamine prevented intestinal mucosal injury induced by cyclophosphamide via increased glutathione, decreased apoptosis and increased proliferation of intestinal epithelial cells.

Epidemiology of febrile neutropenia in children with central nervous system tumor: results from a single center prospective study

Data regarding the epidemiology febrile neutropenia during chemotherapy for pediatric central nervous system neoplasia are scarce. Data retrieved from a prospective study performed from January 2002 to December 2004 at G.Gaslini Children Hospital, Genoa, Italy, where analyzed to evaluate proportions, rate for 1000 neutropenic days and etiology of fever in neutropenic children receiving gentle, standard, or peripheral blood stem cell transplant (PBSCT) therapy for central nervous system tumor. During the study duration, 243 periods of neutropenia (granulocyte count <1000/cmm), accounting for 3544 patient-days at risk, were documented in 62 children. A total of 72 febrile episodes were observed in 66 (27%) neutropenic periods, for a rate of 20.31. A primary febrile episode was observed in 10% of neutropenic periods after gentle chemotherapy, in 30% after standard chemotherapy, and in 48% after PBSCT (P<0.0001). The rate of primary febrile episodes was 6.19 after a gentle chemotherapy, 27.02 after standard treatment, and 31.02 after PBSCT (P<0.0001). In a multivariable regression model, the type of chemotherapy (gentle vs. standard and PBSCT) and the thresholds of granulocyte count at neutropenia onset (999-501/cmm and 500-101/cmm vs. ≤100/cmm) were the only factors significantly associated with the development of febrile neutropenia.

[Gut translocation septicemia in infant]

Intestinal microbiotype necessary for life is a source of complications in childhood. Bacterial translocation is responsible of endogenous septicaemia and invasive complications. We report five cases of severe invasive infections associated with diarrhoea, digestive bleeding or sepsis. Biological parameters for inflammation are highly positive, and blood cultures reveal bacterial identification: salmonella enteridis, enterobacter cloacae, campylobacter jejuni, escherichia coli or clostridium difficile. We describe the predisposing factors and susceptibility status to develop translocation: invasive diarrhoea, asplenia, gasto-intestinal disease… All invasive infections in children require etiological approach with the possibility of an endogenous septicaemia (bacterial translocation). This approach minimises the nosocomial features undercurrent in these invasive infections, and leads also to other alternative preventive measures: antibiotic association, maintaining an enteral nutrition, pre or probiotic use, specific digestive decontamination.

Involvement of endotoxin in the mortality of mice with gut-derived sepsis due to methicillin-resistant Staphylococcus aureus

MRSA causes a wide diversity of diseases, ranging from benign skin infections to life-threatening diseases, such as sepsis. However, there have been few reports of the pathophysiology and mechanisms of sepsis resulting from the gut-derived origin of MRSA. Therefore, we established a murine model of gut-derived sepsis with MRSA and factors of MRSA sepsis that cause deterioration. We separated mice into four groups according to antibiotic treatment as follows: (i) ABPC 40 mg/kg; (ii) CAZ 80 mg/kg; (iii) CAZ 80 mg/kg + endotoxin 10 microg/mouse; and (iv) saline-treated control groups. Gut-derived sepsis was induced by i.p. injection of cyclophosphamide after colonization of MRSA strain 334 in the intestine. After the induction of sepsis, significantly more CAZ-treated mice survived compared with ABPC-treated and control groups. MRSA were detected in the blood and liver among all groups. Endotoxin levels were significantly lower in the CAZ-treated group compared to other groups. Inflammatory cytokine levels in the serum were lower in the CAZ-treated group compared to other groups. Fecal culture showed a lower level of colonization of E. coli in the CAZ-treated group compared to other groups. In conclusion, we found that CAZ-treatment ameliorates infection and suppresses endotoxin level by the elimination of E. coli from the intestinal tract of mice. However, giving endotoxin in the CAZ-treated group increased mortality to almost the same level as in the ABPC-treated group. These results suggest endotoxin released from resident E. coli in the intestine is involved in clinical deterioration resulting from gut-derived MRSA sepsis.

Clonal dissemination of Staphylococcus epidermidis in an oncology ward

Coagulase-negative staphylococci (CoNS) are the main cause of catheter-related infections, especially among immunosuppressed and neutropenic patients, as well as a source of bacterial contamination in blood cultures. Using biochemical identification and pulsed-field gel electrophoresis (PFGE), we sought to identify possible clonal isolates of bacteremia in patients with central lines in an oncology ward (OW), with comparison to isolates that were recovered by venipuncture from an adult emergency room (ER). A total of 243 CoNS isolates were identified to species level from the OW (126) and ER (117), with Staphylococcus epidermidis isolates being the most common (OW, 79.4%; ER, 45.3%). PFGE demonstrated a predominant clone of S. epidermidis (major subtype A) which was 35.5 times more likely (odds ratio [OR] = 35.5; 95% confidence interval [CI] = 4.7 to 267.0; P < 0.00001) to be present in the OW versus the ER. These (CoNS or major subtype A) isolates were more frequently resistant to gentamicin (OR = 2.83; 95% CI = 1.23 to 6.53; P = 0.016) and less frequently resistant to trimethoprim-sulfamethoxazole (OR = 0.38; 95% CI = 0.18 to 0.80; P = 0.013). Subset analysis of S. epidermidis isolates 2 years after the study period showed the persistence of the clone of major subtype A within the OW. This study demonstrates the presence of a predominant clone among central line isolates from an OW that is not present in CoNS venipuncture isolates from an ER.

Taurolidine-citrate lock solution (TauroLock) significantly reduces CVAD-associated grampositive infections in pediatric cancer patients

BACKGROUND

Taurolidin/Citrate (TauroLock), a lock solution with broad spectrum antimicrobial activity, may prevent bloodstream infection (BSI) due to coagulase-negative staphylococci (CoNS or 'MRSE' in case of methicillin-resistant isolates) in pediatric cancer patients with a long term central venous access device (CVAD, Port- or/Broviac-/Hickman-catheter type).

METHODS

In a single center prospective 48-months cohort study we compared all patients receiving anticancer chemotherapy from April 2003 to March 2005 (group 1, heparin lock with 200 IU/ml sterile normal saline 0.9%; Canusal Wockhardt UK Ltd, Wrexham, Wales) and all patients from April 2005 to March 2007 (group 2; taurolidine 1.35%/Sodium Citrate 4%; TauroLock, Tauropharm, Waldbüttelbrunn, Germany).

RESULTS

In group 1 (heparin), 90 patients had 98 CVAD in use during the surveillance period. 14 of 30 (47%) BSI were 'primary Gram positive BSI due to CoNS (n = 4) or MRSE (n = 10)' [incidence density (ID); 2.30 per 1000 inpatient CVAD-utilization days].In group 2 (TauroLock), 89 patients had 95 CVAD in use during the surveillance period. 3 of 25 (12%) BSI were caused by CoNS. (ID, 0.45). The difference in the ID between the two groups was statistically significant (P = 0.004).

CONCLUSION

The use of Taurolidin/Citrate (TauroLock) significantly reduced the number and incidence density of primary catheter-associated BSI due to CoNS and MRSE in pediatric cancer patients.

Healthcare-associated infections in pediatric cancer patients: results of a prospective surveillance study from university hospitals in Germany and Switzerland

Background

Pediatric cancer patients face an increased risk of healthcare-associated infection (HAI). To date, no prospective multicenter studies have been published on this topic.

Methods

Prospective multicenter surveillance for HAI and nosocomial fever of unknown origin (nFUO) with specific case definitions and standardized surveillance methods.

Results

7 pediatric oncology centers (university facilities) participated from April 01, 2001 to August 31, 2005. During 54,824 days of inpatient surveillance, 727 HAIs and nFUOs were registered in 411 patients. Of these, 263 (36%) were HAIs in 181 patients, for an incidence density (ID) (number of events per 1,000 inpatient days) of 4.8 (95% CI 4.2 to 5.4; range 2.4 to 11.7; P < 0.001), and 464 (64%) were nFUO in 230 patients. Neutropenia at diagnosis correlated significantly with clinical severity of HAI. Of the 263 HAIs, 153 (58%) were bloodstream infections (BSI). Of the 138 laboratory-confirmed BSIs, 123 (89%) were associated with use of a long-term central venous catheter (CVAD), resulting in an overall ID of 2.8 per 1,000 utilization days (95% CI 2.3 to 3.3). The ID was significantly lower in Port-type than in Hickman-type CVADs. The death of 8 children was related to HAI, including six cases of aspergillosis. The attributable mortality was 3.0% without a significant association to neutropenia at time of NI diagnosis.

Conclusion

Our study confirmed that pediatric cancer patients are at an increased risk for specific HAIs. The prospective surveillance of HAI and comparison with cumulative multicenter results are indispensable for targeted prevention of these adverse events of anticancer treatment.

Mucosal damage and neutropenia are required for Candida albicans dissemination

Candida albicans fungemia in cancer patients is thought to develop from initial gastrointestinal (GI) colonization with subsequent translocation into the bloodstream after administration of chemotherapy. It is unclear what components of the innate immune system are necessary for preventing C. albicans dissemination from the GI tract, but we have hypothesized that both neutropenia and GI mucosal damage are critical for allowing widespread invasive C. albicans disease. We investigated these parameters in a mouse model of C. albicans GI colonization that led to systemic spread after administration of immunosuppression and mucosal damage. After depleting resident GI intestinal flora with antibiotic treatment and achieving stable GI colonization levels of C. albicans, it was determined that systemic chemotherapy with cyclophosphamide led to 100% mortality, whereas selective neutrophil depletion, macrophage depletion, lymphopenia or GI mucosal disruption alone resulted in no mortality. Selective neutrophil depletion combined with GI mucosal disruption led to disseminated fungal infection and 100% mortality ensued. GI translocation and dissemination by C. albicans was also dependent on the organism's ability to transform from the yeast to the hyphal form. This mouse model of GI colonization and fungemia is useful for studying factors of innate host immunity needed to prevent invasive C. albicans disease as well as identifying virulence factors that are necessary for fungal GI colonization and dissemination. The model may also prove valuable for evaluating therapies to control C. albicans infections.

Mixed bacterial-viral infections in septic children with leukemia

BACKGROUND

Febrile infections in children with leukemia are common. The occurrence of possible mixed bacterial-viral infections is unknown.

METHODS

We searched for viruses in leukemic children with blood culture-positive bacterial infections. The prospective multicenter survey included 156 febrile episodes in 51 children with acute leukemia. The mean follow-up time was 1.5 years per patient (27,743 patient-days at risk). Sixteen viruses were searched for from nasal swab and stool samples using virus culture, virus antigen detection, and polymerase chain reaction tests.

RESULTS

Bacterial blood cultures were positive in 19 (11%) febrile episodes among 17 children. In half of the septic episodes (11 of 19), a virus was also found. Rhinovirus and respiratory syncytial virus were the most common viruses detected.

CONCLUSIONS

Our findings suggest that invasive bacterial infections are commonly associated with viral infections in children with leukemia.