Microbiological spectrum and susceptibility patterns of pathogens causing bacteraemia in paediatric febrile neutropenic oncology patients: comparison between two consecutive time periods with use of different antibiotic treatment protocols

Bacteremia in Children with Solid Tumors: Etiology, Antimicrobial Susceptibility, Factors Associated with Multidrug Resistance, and Mortality

This retrospective study aims to describe the etiology and resistance patterns of pathogens causing bacteremia in children with solid tumors in a tertiary pediatric hematology-oncology center in Jerusalem, Israel (2011-2019). Factors associated with multidrug-resistant (MDR) bacteremia and mortality were analyzed. A total of 228 pathogens were isolated in 126 patients; 61.0% were gram-negative rods (GNR) and 38.2% were gram-positive cocci (GPC). The most common pathogens were Klebsiella pneumoniae (19.3%), Escherichia coli (17.5%), and coagulase-negative staphylococci (16.2%). The proportion of MDR-GNR was 18.2%, while the proportion of MDR-GPC was 55.2%. In logistic regression analysis, breakthrough bacteremia on a penicillin-group antibiotic (odds ratio [OR] 5.69, [95% confidence interval 1.42-22.76], p-value = 0.014) was associated and underlying diagnosis of neuroblastoma was inversely associated (OR 0.17, [0.04-0.81], p-value = 0.026) with MDR-GNR bacteremia; while the previous hospitalizations' duration (OR 1.032/day, [1.01-1.06], p-value = 0.007) and oncologic treatment intensity (OR 2.19, [1.08-4.45, p-value = 0.03) were associated with MDR-GPC bacteremia. Shock, prolonged profound neutropenia, and pediatric intensive care unit (PICU) admission were associated with 7-day mortality; and relapsed disease, oncologic treatment intensity, prolonged profound neutropenia, and PICU admission-with 30-day mortality in the univariate analyses. Empirical antibiotic choice should be based on factors associated with MDR infections in this specific population.

Bloodstream Infections in Children With Cancer: Pathogen Distribution and Antimicrobial Susceptibility Patterns Over a 10-Year Period

Bloodstream infections (BSIs) adversely affect clinical outcome in children with cancer. Over 1 decade, this retrospective cohort study describes pathogen distribution in BSIs and antimicrobial susceptibility against empirical antibiotics frequently prescribed in children with cancer. The antibiotic efficacy was evaluated through the determination of minimal inhibitory concentrations for piperacillin-tazobactam and meropenem and by disk diffusion for remaining antibiotics. From 2004 to 2013, 398 BSIs occurred in 196 children with cancer (median age: 5.4 y), resulting in 457 bacteria. Overall, 266 (58.2%) were Gram-positive, and 191 (41.8%) were Gram-negative with a significant Gram-positive increase over time (P=0.032). Coagulase-negative staphylococci (74, 16.2%), viridans group streptococci (67, 14.7%), Escherichia coli (52, 11.4%), and Staphylococcus aureus (39, 8.5%) were the most common pathogens. Susceptibility to piperacillin-tazobactam (95.9%, P=0.419) and meropenem (98.9%, P=0.752) was stable over time, and resistance was observed among viridans group streptococci against piperacillin-tazobactam (18%) and meropenem (7%) and among Enterobacterales against piperacillin-tazobactam (3%). Vancomycin showed 98% Gram-positive activity, gentamicin 82% Gram-negative activity and ampicillin, cefotaxime, and cefuroxime were active in 50%, 72%, and 69% of pathogens, respectively, and BSI-related mortality was 0%. In conclusion, over 1 decade, we report an increase in Gram-positive BSIs, and stable, low-resistance rates against currently recommended empirical antibiotics, piperacillin-tazobactam and meropenem.

Infections in Children With Cancer: The Role of the Presence or Absence of Neutropenia

BACKGROUND

Infections in patients with cancer are a major cause of morbidity and mortality. In most cases, the presence of neutropenia renders them prone to infections to either common or opportunistic pathogens. A wide spectrum of bacterial, viral, or fungal agents is encountered in these patients.

AIM

The aim of this study was to evaluate infection types and pathogens in pediatric patients with cancer with and without neutropenia.

METHODS

A total of 37 pediatric patients with cancer (median age ± 25% quartile, 6.0 ± 2.0% years) with 70 febrile episodes were evaluated at fever's onset and 48 hours later with complete blood count, C-reactive protein, cultures of biological fluids, polymerase chain reaction, and antibody titers.

RESULTS

Of 70 infections, 30 (42.85%) were bacterial, 13 (18.57%) were viral, 3 (4.28%) were fungal, 16 (22.85%) were fever of unknown origin, 18 (25.71%) were opportunistic, and 12 (17.14%) were mixed infections. Neutropenia was detected in 42 (60.0%) of 70 febrile episodes, mainly in patients with hematological malignancies [odds ratio, 2.81 (0.96-8.22); P = 0.059]. Neutropenic patients had higher prevalence of mucocutaneous infections (47.6% vs 7.14%; P = 0.004). Herpes simplex virus 1 infections occurred only in the neutropenic group (14.3%).

CONCLUSIONS

Patients with cancer exhibited a high prevalence of bacterial (42.85%), opportunistic (25.7%), and mixed infections (17.14%). Patients with hematological malignancies and neutropenia presented higher frequency of mucocutaneous and herpes simplex virus 1 infections than the nonneutropenic ones.

Pediatric fever in neutropenia with bacteremia-Pathogen distribution and in vitro antibiotic susceptibility patterns over time in a retrospective single-center cohort study

Background

Fever in neutropenia (FN) is a potentially life-threatening complication of chemotherapy in pediatric cancer patients. The current standard of care at most institutions is emergency hospitalization and empirical initiation of broad-spectrum antibiotic therapy.

Methods

We analyzed in retrospect FN episodes with bacteremia in pediatric cancer patients in a single center cohort from 1993 to 2012. We assessed the distribution of pathogens, the in vitro antibiotic susceptibility patterns, and their trends over time.

Results

From a total of 703 FN episodes reported, we assessed 134 FN episodes with bacteremia with 195 pathogens isolated in 102 patients. Gram-positive pathogens (124, 64%) were more common than Gram-negative (71, 36%). This proportion did not change over time (p = 0.26). Coagulase-negative staphylococci (64, 32%), viridans group streptococci (42, 22%), Escherichia coli (33, 17%), Klebsiella spp. (10, 5%) and Pseudomonas aeruginosa (nine, 5%) were the most common pathogens. Comparing the in vitro antibiotic susceptibility patterns, the antimicrobial activity of ceftriaxone plus amikacin (64%; 95%CI: 56%-72%), cefepime (64%; 95%CI 56%-72%), meropenem (64%; 95%CI 56%-72), and piperacillin/tazobactam (62%; 95%CI 54%-70%), respectively, did not differ significantly. The addition of vancomycin to those regimens would have increased significantly in vitro activity to 99% for ceftriaxone plus amikacin, cefepime, meropenem, and 96% for piperacillin/tazobactam (p < 0.001).

Conclusions

Over two decades, we detected a relative stable pathogen distribution and found no relevant trend in the antibiotic susceptibility patterns. Different recommended antibiotic regimens showed comparable in vitro antimicrobial activity.

Frequency of Infectious Mortality at the End of Induction Chemotherapy in Acute Lymphoblastic Leukemia and Lymphoma Patients: Findings From a Tertiary Care Cancer Center

Background and objective

In low- and low-to-middle-income countries (LMICs), the incidence of treatment-related mortality (TRM) in patients with acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma (LBL) is up to 52%. This study aimed to determine the mortality rate at the end of the induction phase of the treatment among patients with ALL and lymphoma at a tertiary care cancer center.

Methods

This retrospective study analyzed outcomes after induction chemotherapy in pediatric patients with acute leukemia and lymphoma at a tertiary care cancer center from January 2015 to December 2016. Information regarding demographics, clinical characteristics, and laboratory investigations were extracted and reviewed.

Results

Of the total 160 patients, 110 were males, and the mean age of the sample was 4.6 +2.8 years. B-cell leukemia (pre-B-ALL) was diagnosed in 84% (n=134), while 10% (n=6) had acute T-cell leukemia (pre-T-ALL) and 6% (n=10) had lymphoma. Sixteen patients (10%) died within the defined induction period, with 14 deaths occurring due to infections and two deaths resulting from chemotherapy-related toxicity.

Conclusion

Based on our findings, there is a significant prospect of mortality from infections during induction chemotherapy in patients with pediatric hematological malignancies.

Prevalence, predictors, and mortality of bloodstream infections due to methicillin-resistant Staphylococcus aureus in patients with malignancy: systemic review and meta-analysis

BACKGROUND

Cancer patients are more likely to develop and die of bloodstream infection (BSI) than noncancer patients. Methicillin-resistant Staphylococcus aureus (MRSA), which is associated with immense mortality and economic burden worldwide, is not covered by the recommended initial antibiotic therapy for cancer patients with BSI. This systemic review was performed to estimate the global methicillin-resistant Staphylococcus aureus (MRSA) prevalence among bacteremia in patients with malignancy, and further study the predictors and mortality of cancer patients with MRSA bacteremia.

METHODS

The PubMed and EMBASE databases were searched for studies published from Jan. 2000 to Mar. 2020 that provided primary data on the prevalence, predictors, or mortality of MRSA bacteremia in cancer patients. A random-effects model meta-analysis was performed to estimate the pooled prevalence of MRSA with 95% confidence intervals (95% CIs).

RESULTS

The pooled prevalence of MRSA was 3% (95% CI 2-5%) among all bloodstream infections (BSIs) and 44% (95% CI 32-57%) among S. aureus bacteremia in cancer patients. Based on geographical stratification, the pooled prevalence was 5% in Africa (95% CI 1-14%), 1% in Americas (95% CI 1-2%), 2% in Europe (95% CI 1-4%), 4% in Western Pacific (95% CI 2-7%), 8% in South-east Asia (95% CI 4-14%) and 0% in Eastern Mediterranean (95% CI 0-3%). No significant temporal change in MRSA rates was detected in this analysis (R2 = 0.06; P = 0.24). Predictors for MRSA BSIs among cancer patients were identified by comparison with their methicillin-susceptible counterparts, and they were mainly related to healthcare-associated infections and immunosuppression. Finally, the 60-day mortality in adult cancer patients with MRSA BSIs was reported to be 12%, and the 6-month overall mortality was 43.2%, with community-onset infection, secondary BSI, and vancomycin MIC≥2 g/mL being the risk factors for mortality.

CONCLUSIONS

Although the prevalence of MRSA BSIs among cancer patients is relatively low, it did not decline over time as MRSA BSIs in the general hospital population and the high mortality rate was related to MRSA BSIs in patients with malignancy.

Pediatric Febrile Neutropenia: Change in Etiology of Bacteremia, Empiric Choice of Therapy and Clinical Outcomes

BACKGROUND

The optimal choice of initial antibiotic therapy for patients with high-risk febrile neutropenia (FN) in children is unclear and varies by the institution on the basis of local antibiograms and epidemiology of specific pathogens. The authors evaluated the appropriateness of antibiotics for the empiric treatment of FN in pediatric patients with cancer in our institution on the basis of changes in the epidemiology of organisms isolated from blood cultures (BCx).

METHODS

The authors conducted a retrospective medical record review of pediatric patients who received any oncology care (including patients with cancer and patients who had stem cell transplant) at University of Chicago Medicine Comer Children's Hospitals (March 2009 to December 2016) with a diagnosis of FN who had at least 1 BCx obtained. They reviewed pathogens isolated from BCx and determined whether they were pathogens or contaminants using the Infectious Diseases Society of America (IDSA) guidelines and the team's decision to treat. They investigated the microbiologic spectrum and susceptibility patterns of pathogens causing bacteremia in pediatric FN and whether the empiric therapy chosen may have affected clinical outcomes.

RESULTS

A total of 667 FN episodes were identified in 268 patients. BCx were negative in 497 (74.5%) and were determined to be contaminants in 27 (4%). In 143 episodes (21.5%), the BCx were positive for a pathogenic species. Polymicrobial bacteremia was identified in 25 episodes; a total of 176 pathogens were isolated. The majority of pathogens (95/176, 54%) were Gram-positive (GP), whereas 64 of 162 (36%) were Gram-negative (GN), 5 were fungal, and 4 were mycobacterial. The most common GP pathogens were viridans group streptococci (VGS) (n=34, 19.3%), coagulase-negative staphylococci (n=25, 14%), and methicillin-susceptible Staphylococcus aureus (n=12, 6.8%). Of aerobic GN bacilli, 15 (8.5%) were AmpC producers and 3 (1.7%) carried extended-spectrum beta-lactamases. There was no increase in the prevalence of multidrug-resistant GN isolates during the study period. Patients with VGS and multidrug-resistant GN bacteremia were more likely to be admitted to the pediatric intensive care unit [odds ratio (OR), 3.24; P=0.017; and OR, 2.8; P=0.07, respectively]. There were trends toward a higher prevalence of GP pathogens causing bacteremia and the emergence of VGS with decreased penicillin sensitivity. The prevalence of bacteremia with VGS was higher in acute myelogenous leukemia and neuroblastoma (OR, 2.3; P<0.01) than in patients with other solid tumors.

CONCLUSIONS

Empiric antibiotic treatment should be tailored to patients' risk for VGS and multidrug-resistant organisms. Individual hospitals should monitor the pathogens causing FN among patients with cancer to guide choice of empiric therapy.

Population pharmacokinetics of continuous-infusion ceftazidime in febrile neutropenic children undergoing HSCT: implications for target attainment for empirical treatment against Pseudomonas aeruginosa

OBJECTIVES

To conduct a population pharmacokinetic analysis of continuous-infusion ceftazidime in a retrospective cohort of paediatric HSCT patients who were empirically treated for febrile neutropenia (FN) and who underwent therapeutic drug monitoring of ceftazidime steady-state plasma concentrations (Css) for optimization of drug exposure.

METHODS

A non-parametric approach with Pmetrics was used for pharmacokinetic analysis and covariate evaluation. Monte Carlo simulations were performed to calculate the PTA of the pharmacodynamic determinant of efficacy (Css/MIC ≥4) against Pseudomonas aeruginosa with continuous-infusion ceftazidime dosages of 1-6 g daily. The Css safety threshold was arbitrarily placed at 100 mg/L and advisable dosages were used.

RESULTS

A total of 46 patients with 70 ceftazidime Css values were included. Estimated glomerular filtration rate (eGFR) and body surface area were the covariates associated with drug clearance. At the EUCAST clinical breakpoint of 8 mg/L, simulations showed that continuous-infusion ceftazidime dosages of 4-6 g daily attained optimal PTAs (>90%) across most of 16 different clinical scenarios based on four classes of eGFR (50-145, 145.1-200, 200.1-286 and 286.1-422 mL/min/1.73 m2) and body surface area (0.30-0.64, 0.65-0.88, 0.89-1.34 and 1.35-1.84 m2). In patients with body surface area 0.30-0.64 m2 and eGFR ≤200 mL/min/1.73 m2 the advisable dose of 3 g daily allowed only suboptimal PTAs (<75%). The cumulative fraction of response against MIC distribution of P. aeruginosa was >87%.

CONCLUSIONS

Continuous-infusion ceftazidime dosages ranging from 3 to 6 g daily according to different classes of eGFR and body surface area may allow optimized empirical treatment of P. aeruginosa infections in paediatric HSCT patients with FN.

Causes of Death in Childhood Acute Lymphoblastic Leukemia at Hue Central Hospital for 10 Years (2008-2018)

Aim. To analyze the common cause of death in childhood acute lymphoblastic leukemia patients. Methods and Materials. A retrospective descriptive study on children with acute lymphoblastic leukemia who died at Hue Central Hospital between 2008 and 2018. All the patients were treated with the same protocol of modified Children’s Cancer Group 1882 and 1881. Results. A total of 238 children with acute lymphoblastic leukemia who were cared for at our center were enrolled. Of these, there were 74 deaths. Among the death group, the male-to-female ratio was 2.7:1. Twenty-six (35.1%) occurred in maintenance phase, 18 (24.3%) occurred in induction phase, and 9 (12.2%) occurred in delayed intensification. Infection was responsible for deaths in 32 of 74 (43.2%) cases. Pseudomonas aeruginosa was found in 3 of 32 infected cases (9.4%) and resistance to almost all antibiotics in our hospital. Relapse, abandonment, and bleeding were documented in 20 (27.0%), 7 (9.5%), and 6 (8.1%) cases, respectively. Twenty-seven (84.3%) patients had absolute neutrophil count <500/µL. Of 32 infectious deaths, pneumonia occurred in 40.6%. Regarding 20 relapse death, bone marrow was the major site of relapse and it occurred in 13 (65%) cases. And there were 65% patients with very early relapse. Conclusions. Infection is the major cause of mortality in acute lymphoblastic leukemia patients in our study. To improve outcome, we should improve supportive care, especially prevention and control infection.

Antibiotic-Resistant Septicemia in Pediatric Oncology Patients Associated with Post-Therapeutic Neutropenic Fever

Death in cancer patients can be caused by the progression of tumors, their malignity, or other associated conditions such as sepsis, which is a multiphasic host response to a pathogen that can be significantly amplified by endogenous factors. Its incidence is continuously rising, which reflects the increasing number of sick patients at a higher risk of infection, especially those that are elderly, pediatric, or immunosuppressed. Sepsis appears to be directly associated with oncological treatment and fatal septic shock. Patients with a cancer diagnosis face a much higher risk of infections after being immunosuppressed by chemotherapy, radiotherapy, or anti-inflammatory therapy, especially caused by non-pathogenic, Gram-negative, and multidrug-resistant pathogens. There is a notorious difference between the incidence and mortality rates related to sepsis in pediatric oncologic patients between developed and developing countries: they are much higher in developing countries, where investment for diagnosis and treatment resources, infrastructure, medical specialists, cancer-related control programs, and post-therapeutic care is insufficient. This situation not only limits but also reduces the life expectancy of treated pediatric oncologic patients, and demands higher costs from the healthcare systems. Therefore, efforts must aim to limit the progression of sepsis conditions, applying the most recommended therapeutic regimens as soon as the initial risk factors are clinically evident-or even before they are, as when taking advantage of machine learning prediction systems to analyze data.

Increase in Antibiotic-Resistant Gram-Negative Bacterial Infections in Febrile Neutropenic Children

BACKGROUND

The incidence of bacteremia caused by Gram-negative bacteria has increased recently in febrile neutropenic patients with the increase of antibiotic-resistant Gram-negative bacterial infections. This study aimed to identify the distribution of causative bacteria and the proportion of antibiotic-resistant bacteria in bacteremia diagnosed in febrile neutropenic children.

MATERIALS AND METHODS

The medical records of febrile neutropenic children diagnosed with bacteremia between 2010 and 2014 were retrospectively reviewed. The causative bacteria and proportion of antibiotic-resistant bacteria were investigated and compared yearly during the study period. The clinical impact of antibiotic-resistant bacterial infections was also determined.

RESULTS

A total of 336 bacteremia episodes were identified. During the entire study period, 181 (53.9%) and 155 (46.1%) episodes were caused by Gram-negative and Gram-positive bacteria, respectively. Viridans streptococci (25.9%), Klebsiella spp. (16.7%), and Escherichia coli (16.4%) were the most frequent causative bacteria. The overall distribution of causative bacteria was not significantly different annually. Antibiotic-resistant bacteria were identified in 85 (25.3%) episodes, and the proportion of antibiotic-resistant bacteria was not significantly different annually. Extended-spectrum β-lactamase-producing E. coli and Klebsiella spp. were most common among antibiotic-resistant Gram-negative bacteria, and they accounted for 30.6% (n = 34) of the identified E. coli and K. pneumoniae. Methicillin-resistant coagulase-negative staphylococci were most common among antibiotic-resistant Gram-positive bacteria, and it accounted for 88.5% (n = 23) of the identified coagulase-negative staphylococci. Antibiotic-resistant bacterial infections, especially antibiotic-resistant Gram-negative bacterial infections, caused significantly higher mortality due to bacteremia compared with non-antibiotic-resistant bacterial infections (P < 0.001).

CONCLUSION

Recently, Gram-negative bacteria caused more bacteremia cases than Gram-positive bacteria in febrile neutropenic children, and antibiotic-resistant Gram-negative bacterial infections increased. Antibiotic-resistant bacterial infections caused poorer prognosis compared with non-antibiotic-resistant bacterial infections, and therefore, continuous surveillance for changing epidemiology of antibiotic-resistant bacterial infections and their clinical impact is necessary.

Clinical features and induction outcome of childhood acute lymphoblastic leukemia in a lower/middle income population: A multi-institutional report from Pakistan

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common cancer of childhood. Some evidence suggests differences in clinical and cytogenetic characteristics of ALL based on geographic and ethnic variations. However, data on ALL characteristics and early outcome of therapy from low/middle-income countries such as Pakistan are scanty.

PROCEDURE

A prospective, multi-institutional cohort study in Karachi enrolled 646 newly diagnosed children with ALL over 3 years. Standard forms were used to collect demographic, clinical, and laboratory data at presentation and at the end of induction.

RESULTS

Of the total, 66.1% (n = 427) were males. Median age was 6 (mean ± SE 6.87 ± 0.16; range 0.16-18) years. The most common clinical presentation was fever (88.7%). BPC-ALL was diagnosed in 78.5%, while 17.5% had T-ALL; 28.8% had a WBC >50 × 10(9) /L. With 316 patients karyotyped, hypodiploidy and hyperdiploidy were seen in 5.1% and 10.7%, respectively. Of those tested, ETV6-RUNX1 translocation was detected in 13.2%, while BCR-ABL1 translocation and MLL gene rearrangements were seen in 7.3% and 4.6%, respectively. The cumulative loss to follow up before and during induction was 12.8% (n = 83) and 11.5% (n = 74) died before or during this phase. Induction was successfully completed by only 75.6% (n = 489) of the entire cohort and 69.6% (n = 450) achieved remission.

CONCLUSION

These patients had ALL with higher risk features than that reported from developed countries. One quarter failed to complete induction chemotherapy. This suboptimal result requires further study and development of innovative interventions, particularly focusing on the causes and solutions for late referral, abandonment, and infections.

Diagnosis of bacteremia in pediatric oncologic patients by in-house real-time PCR

Background

Infections are the major cause of morbidity and mortality in children with cancer. Gaining a favorable prognosis for these patients depends on selecting the appropriate therapy, which in turn depends on rapid and accurate microbiological diagnosis. This study employed real-time PCR (qPCR) to identify the main pathogens causing bloodstream infection (BSI) in patients treated at the Pediatric Oncology Institute IOP-GRAACC-UNIFESP-Brazil. Antimicrobial resistance genes were also investigated using this methodology.

Methods

A total of 248 samples from BACTEC® blood culture bottles and 99 whole-blood samples collected in tubes containing EDTA K2 Gel were isolated from 137 patients. All samples were screened by specific Gram probes for multiplex qPCR. Seventeen sequences were evaluated using gender-specific TaqMan probes and the resistance genes bla_SHV, bla_TEM, bla_CTX, bla_KPC, bla_IMP, bla_SPM, bla_VIM, vanA, vanB and mecA were detected using the SYBR Green method.

Results

Positive qPCR results were obtained in 112 of the blood culture bottles (112/124), and 90 % agreement was observed between phenotypic and molecular microbial detection methods. For bacterial and fungal identification, the performance test showed: sensitivity 87 %; specificity 91 %; NPV 90 %; PPV 89 % and accuracy of 89 % when compared with the phenotypic method. The mecA gene was detected in 37 samples, extended-spectrum β-lactamases were detected in six samples and metallo-β-lactamase coding genes in four samples, with 60 % concordance between the two methods. The qPCR on whole blood detected eight samples possessing the mecA gene and one sample harboring the vanB gene. The bla_KPC, bla_VIM, bla_IMP and bla_SHV genes were not detected in this study.

Conclusion

Real-time PCR is a useful tool in the early identification of pathogens and antimicrobial resistance genes from bloodstream infections of pediatric oncologic patients.

Aetiology and resistance in bacteraemias among adult and paediatric haematology and cancer patients

OBJECTIVES

A knowledge of current epidemiology and resistance patterns is crucial to the choice of empirical treatment for bacteraemias in haematology and cancer patients.

METHODS

A literature review on bacteraemias in cancer patients considered papers published between January 1st 2005 and July 6th 2011. Additionally, in 2011, a questionnaire on the aetiology and resistance in bacteraemias, and empirical treatment, was sent to participants of the European Conference on Infections in Leukemia (ECIL) meetings; recipients were from 80 haematology centres.

RESULTS

For the literature review, data from 49 manuscripts were analysed. The questionnaire obtained responses from 39 centres in 18 countries. Compared with the published data, the questionnaire reported more recent data, and showed a reduction of the Gram-positive to Gram-negative ratio (55%:45% vs. 60%:40%), increased rates of enterococci (8% vs. 5%) and Enterobacteriaceae (30% vs. 24%), a decreased rate of Pseudomonas aeruginosa (5% vs. 10%), and lower resistance rates for all bacteria. Nevertheless the median rates of ESBL-producers (15-24%), aminoglycoside-resistant Gram-negatives (5-14%) and carbapenem-resistant P. aeruginosa (5-14%) were substantial, and significantly higher in South-East vs. North-West Europe.

CONCLUSIONS

The published epidemiological data on bacteraemias in haematology are scanty and mostly dated. Important differences in aetiology and resistance exist among centres. Updated analyses of the local epidemiology are mandatory to support appropriate empirical therapy.

Central venous catheter-associated bloodstream infections

BACKGROUND

To investigate the epidemiologic and microbiological aspects of long-term central vein catheter (CVC)-associated bloodstream infections (CABSI) in children <18 years old treated at the hemato-oncology unit during 1998-2008.

PATIENTS AND METHODS

The two long-term access devices used were Hickman and Port-A-Cath catheters. Information retrieved included demographic data, baseline pathologies, methods of insertion, anatomical insertion sites, duration of use, microbiological, and antibiotic susceptibility data and outcome.

RESULTS

There were 178 CABSI episodes; average number of episodes/1,000 catheter days was 4.7. More CABSI episodes were recorded among patients with Hickman catheter than in patients with Port-A-Cath catheter (5.05 vs. 3.57/1,000 catheter days, P = 0.059). The CVC was removed due to BSI in 52/178 (29.2%) episodes. Overall, 243 pathogens were isolated (144 Gram-negative, 92 Gram-positive, and 7 Candida spp). More Enterobacteriaceae spp. were isolated in CABSI in patients with Hickman catheters than in patients with Port-A-Cath catheters (35/103, 34%, vs. 10/65, 15%, P = 0.008); more coagulase-negative staphylococci were isolated in patients with Port-A-Cath catheters than in patients with Hickman catheters (25/65, 38.5%, vs. 23/103, 22.3%, P = 0.02). No differences in pathogen distribution were found between CABSI recorded for jugular versus subclavian veins, open versus close inserted-CVC or for CVC requiring removal versus those treated conservatively. No fatalities directly related to CABSI were recorded.

CONCLUSIONS

CABSI rates were higher in patients with Hickman catheters compared with those with Port-A-Cath catheters; Gram-negative organisms were the dominant etiologic agents of CABSI; CABSI in patients with Hickman catheters had different etiologies compared with patients with Port-A-Cath catheters.

A meta-analysis of antipseudomonal penicillins and cephalosporins in pediatric patients with fever and neutropenia

BACKGROUND

Antipseudomonal penicillins (APP) and antipseudomonal cephalosporins (APC) play important roles in the management of pediatric patients with fever and neutropenia (FN). Our primary objective was to describe the risk of treatment failure in children treated with an APP or APC as initial empiric therapy for FN. Our secondary objectives were to compare APP with APC and third- with fourth-generation APC as initial empiric therapy in this population.

METHODS

We performed electronic searches of Ovid Medline, EMBASE, and the Cochrane Central Register of Controlled Trials, limiting studies to prospective pediatric trials in FN in which at least 1 treatment arm consisted of an APP or APC antibiotic with or without an aminoglycoside. Data abstraction was conducted by 2 independent reviewers.

RESULTS

From 7281 reviewed articles, 41 studies comprising 51 treatment regimens were included in the meta-analysis. Treatment failure, including antibiotic modification, occurred in 34% and 41% of patients treated with APP and APC monotherapy, respectively, and 41% and 33% of patients treated with APP- and APC-aminoglycoside combination therapy, respectively. There were no statistically significant differences in treatment failure including modification, mortality, or adverse events when comparing APP with APC monotherapy, APP with APC combination therapy, or third- with fourth-generation APC therapy.

CONCLUSIONS

Our meta-analysis suggests that APP and APC monotherapy, as well as combination therapy with an aminoglycoside, are efficacious and safe therapeutic options for the empiric management of pediatric patients with FN. Specific antibiotic selection should be based on other important factors, such as cost, availability, and local epidemiologic and resistance patterns.

The use of antimicrobial agents in children with fever during chemotherapy-induced neutropenia: the importance of risk stratification

Children with fever and chemotherapy-induced or cancer-associated neutropenia should be assessed with complete history and physical examinations, undergo appropriate diagnostic studies, and promptly receive broad-spectrum empirical antimicrobial therapy. Assessment of risk for severe infection is crucial in determining the appropriate antimicrobial, route, venue, and duration of empirical antimicrobial therapy and need for prophylactic antimicrobial agents.

Evaluation of six risk factors for the development of bacteremia in children with cancer and febrile neutropenia

Febrile neutropenia is a well-known entity in children with cancer, being responsible for the high risk for infection that characterizes this population. For this reason, cancer patients are hospitalized so that they can receive prophylactic care. Risk factors have been used to classify patients at a high risk for developing bacteremia. The present study evaluates whether those risk factors (C-reactive protein, hypotension, leukemia as the cancer type, thrombocytopenia, recent chemotherapy, and acute malnutrition) apply to patients at the Unidad Nacional de Oncología Pediátrica. We evaluated 102 episodes in 88 patients, in whom risk factors and blood cultures were tested. We observed no statistical relationship between the six risk factors and bacteremia. There was also no relationship between bacteremia and the simultaneous presence of two, three, or more risk factors. A significant relationship of C-reactive protein and platelet count with other outcome factors was observed.

Piperacillin/tazobactam monotherapy versus piperacillin/tazobactam plus amikacin as initial empirical therapy for febrile neutropenia in children with acute leukemia

The purpose of this study is to compare the efficacy and safety of piperacillin/tazobactam (PIP/TAZO) versus PIP/TAZO plus amikacin in febrile neutropenic children with acute leukemia (AL). Children with AL who had febrile neutropenic episodes were randomized to treatment with PIP/TAZO versus PIP/TAZO plus amikacin. Modification was defined as addition of other antimicrobials and/or antifungal agents to the empirical therapy. Protocol failure was defined as withdrawal of the empirical regimen and introduction of other antimicrobials due to failure in controlling infection. Seventy-two febrile episodes of 42 patients with a median age of 4.5 years (3.5 months to 19 years) were evaluated. There were 37 and 35 episodes in PIP/TAZO and combination arms, respectively. Success without modification, with modification, protocol failure, duration of treatment were 45.9%, 35.1%, 18.9%, and 10 days in PIP/TAZO arm and 42.9%, 37.1%, 20%, and 12 days in combination arm, respectively (P > .05). There was no significant difference between the empirical therapy arms regarding median duration of neutropenia and defervescence of fever. Empirical therapy was substituted by other drugs in 6 and 5 episodes in PIP/TAZO and combination arms, respectively. There was no infection-related death. There was reversible increase in serum creatinine in 1 episode on the combination arm. Monotherapy with PIP/TAZO was effective and safe for initial empirical treatment of febrile neutropenic episodes in children with AL. However, local bacterial resistance patterns should be considered in daily practice. Combination of amikacin with PIP/TAZO did not improve treatment success, but it may increase nephrotoxicity.

Bacterial rRNA-targeted reverse transcription-PCR used to identify pathogens responsible for fever with neutropenia

The purpose of this study was to evaluate the clinical utility of bacterial rRNA-targeted reverse transcription-quantitative PCR (BrRNA RT-qPCR) assays for identifying the bacterial pathogens that cause fever with neutropenia in pediatric cancer patients, by comparing the bacterial detection rate of this technique with that of blood culture. One milliliter of blood was collected from pediatric patients who developed fever with neutropenia following cancer chemotherapy. BrRNA RT-qPCR was performed using 16 primer sets, each designed for a specific type of bacteria. The entire BrRNA RT-qPCR procedure took less than 5 h. Blood culture was performed at the same time, following the standard institutional procedure. Blood from 13 patients was collected during 23 febrile neutropenic episodes. Of these samples, bacteria were identified in 16 by BrRNA RT-qPCR (69.6%) and in 4 by blood culture (17.4%, P<0.001). In all 4 blood culture-positive samples, BrRNA RT-qPCR detected the same type of bacteria as that identified by culture. In 9 samples, more than 4 types of bacteria were identified simultaneously by BrRNA RT-qPCR, most of which were anaerobic bacteria known to be part of the gut flora. We conclude that BrRNA RT-qPCR could be useful in the diagnosis of fever with neutropenia, given its high bacterial detection rate, short turnaround time, and the small blood sample required compared with the standard blood culture techniques. Our findings also indicate that anaerobic intestinal bacteria, which are difficult to detect by standard culture techniques, may be responsible for some cases of febrile neutropenia.

Etiology and clinical course of febrile neutropenia in children with cancer

BACKGROUND

The etiology, clinical course, and outcome of fever and neutropenia (FN) in children with cancer using the current FN guidelines and diagnostic resources in the United States have not been well described.

PATIENTS AND METHODS

Medical records of a randomly selected FN episode per patient during 2004-2005 at a pediatric oncology center were reviewed. Patients were managed as per institutional FN guidelines and blood cultures collected in continuously read BACTEC bottles.

RESULTS

Of 337 FN episodes, infection was proven in 86 (25%) and probable in 75 (22%). In all, 177 episodes (53%) were judged fever of unknown origin (FUO). Bacteremia accounted for most (41) of the proven bacterial episodes, with viridans streptococci (13), Pseudomonas spp. (6) and Escherichia coli (6) the most frequently isolated organisms. The median time to positivity of blood cultures was 12 hours (range, 5.4-143.7) with 93% positive within 24 hours of incubation. Viral pathogens were identified in 29 (34%) episodes. Compared with other patients, those with FUO had shorter median duration of fever (0.5 vs. 2.0 d; P<0.0001) and hospitalization (3 vs. 6 d; P<0.0001), longer median duration since last chemotherapy (6.0 vs. 4.0 d; P=0.01), and were less likely to have a diagnosis of acute myelogenous leukemia (11% vs. 22%; P=0.009) or develop a clinical complication (5.1% vs. 24.4%; P<0.0001).

CONCLUSIONS

Despite currently available diagnostic resources, the majority of patients with FN have FUO marked by a low rate of clinical complications and no infection-related mortality. Emergence of viridans streptococci as the most common blood isolate has affected FN treatment recommendations. Study findings will help further development of strategies for risk stratified management of fever with neutropenia in pediatric patients.

Secular trends in pediatric bloodstream infections over a 20-year period at a tertiary care hospital in Germany

OBJECTIVE

Over the last 20 years, a number of medical innovations with impact on the incidence of bacterial and fungal bloodstream infections (BSIs) in children have been developed and implemented. Although appropriate empirical antimicrobial therapy is a prerequisite to the successful treatment of BSIs, to date, epidemiological data on long-term microbiological trends in BSIs of hospitalized children have not been available.

METHODS

Two cohorts of pediatric patients who were hospitalized in a single-center tertiary care hospital in Germany over a 20-year time span (period A from 1985 to 1995 vs. period B from 1997 to 2006) were retrospectively analyzed and compared with respect to the epidemiology and microbiology of BSIs.

RESULTS

A total of 1,646 cases of monomicrobial BSIs were detected. The rate of positive blood culture results dropped from 4.5% in period A to 2.0% in period B. The proportion of gram-positive vs. gram-negative pathogens recovered from blood cultures remained stable. Among gram-positive pathogens, an increase in enterococci (3.3% vs. 8.2%) and in coagulase-negative staphylococci (CoNS) (22.9 vs. 28.2%) was observed. In contrast, BSIs caused by Staphylococcus aureus (16.4% vs. 11.7%), Streptococcus agalactiae (4.9% vs. 2.1%), Haemophilus influenzae (7.3% vs. 0.7%), and Neisseria meningitidis (1.9% vs. 0.5%) diminished. In analyzing subgroups, an increase of enterococcal and CoNS infections was noted among patients with immunosuppression and neonatal early-onset sepsis (EOS), while a decrease was found among late-onset sepsis (LOS) cases with S. viridans. Notably, aminopenicillin-resistant enterococci and aminopenicillin- and fluoroquinolone-resistant Enterobacteriaceae all increased over time, while the overall resistance pattern was still favorable. The overall mortality rate of BSIs decreased (5.2% vs. 2.6%).

CONCLUSIONS

Over the 20-year study period, the spectrum of specific microorganisms among BSIs shifted, with opportunistic pathogens becoming predominant. Despite an increase in the proportion of antibiotic-resistant organisms, however, the mortality rate decreased.

Outcome of gram negative infection in immunocompromised children

BACKGROUND

Gram negative infection is an important cause of mortality in patients receiving chemotherapy for malignant disease or as conditioning for stem cell transplantation. The risk of infection is thought to be greatest in those patients who are neutropenic and it is routine for these patients to receive broad spectrum antibiotic therapy when febrile. This study evaluates the outcome of gram negative infection in a mixed haematology/oncology population in a single institution.

PROCEDURE

All episodes of laboratory proven gram negative infection in patients receiving chemotherapy between January 2004 and March 2006 were included. A retrospective case-note based analysis was carried out to identify diagnosis, treatment, neutrophil count at time of infection, antibiotic therapy and clinical outcome.

RESULTS

One hundred six episodes of gram negative infection in 72 patients were identified. Sixty-seven percent of these were in patients receiving chemotherapy for malignant disease, 33% were in patients undergoing stem cell transplantation. Overall ICU admission rate was 13% and mortality was 6%. Coliforms, Pseudomonas and Klebsiella were the commonest isolates, and ICU admission and mortality rates were higher with Pseudomonas and Klebsiella infection than coliforms. After stem cell transplantation most episodes of gram negative infection occurred in non-neutropenic patients, while the reverse was true after chemotherapy.

CONCLUSION

Gram negative infection remains a significant cause of both ICU admission and mortality. Gram negative infection is largely confined to neutropenic periods after chemotherapy but not after stem cell transplantation. The isolation of Pseudomonas or Klebsiella confers a higher chance of both ICU admission and death.

Assessment of febrile neutropenia episodes in children with acute leukemia treated with BFM protocols

The authors overviewed 239 febrile neutropenia (FN) episodes in 82 pediatric leukemia cases treated with BFM treatment protocols. FN was observed mostly during consolidation therapy. Mucositis was the most identified focus; gram-negative microorganisms were the most identified pathogens. Five patients developed invasive fungal infections. Fever resolved after mean 5.3 days and mean antibiotic administration time was 12.7 days. Addition of G-CSF to antimicrobial therapy shortened the duration of neutropenia, but it did not affect duration of fever resolution and antibiotic administration. The duration of neutropenia, fever resolution, and antibiotic administration was significantly longer in children with acute myeloid leukemia. The authors conclude that children with acute leukemia have severe prolonged neutropenia and are in high risk. In these patients, prediction of the risk of bacteremia based on clinical and laboratory features is important for immediate empiric broad-spectrum antimicrobial therapy and for higher survival rate.

Current approaches for risk stratification of infectious complications in pediatric oncology

Infections are serious complications of cytoreductive therapy in pediatric cancer patients presenting with febrile neutropenia. It is standard of care to initiate empirical intravenous broad-spectrum antibiotics until the fever and neutropenia resolve. However, it might be effective and safe to allow for early hospital discharge in certain subgroups of patients. Two strategies for risk stratification of pediatric cancer patients with regard to infectious complications are discussed in this review: (1) clinical risk parameters and laboratory measures to assist therapeutic management at presentation with fever in neutropenia, and (2) investigations of individual genetic susceptibility factors to tailor potential prophylactic approaches. Given the data available from a significant number of small studies, a large prospective non-inferiority trial is essential to assess low-risk clinical factors and additional laboratory or genetic markers for their predictive value.

Internal obturator muscle abscess caused by Klebsiella pneumoniae

Obturator internus muscle abscess is an infrequent form of pyomyositis. To date, this disease has been described almost exclusively in children and young adults, and in most cases the causative agents are Gram-positive bacteria. We present the first report of obturator internus muscle abscess caused by a highly antibiotic resistant Klebsiella pneumoniae, in an elderly diabetic patient. Once considered very rare, Gram-negative pyomyositis is increasingly reported, and is an important concern in diabetic patients. Since pyomyositis can easily be missed if not considered, physicians should become familiar with this condition, and consider it in the differential diagnosis of septic diabetic patients.

Experience with the use of piperacillin-tazobactam in pediatric non-renal solid organ transplantation

Bacterial infection remains a major problem after solid organ transplantation (SOT), especially in children. Piperacillin-tazobactam (Pip-Tazo) is a beta-lactam-antibiotic combination with a broad spectrum of activity including gram-positive cocci as well as gram-negative rods, non-fermentative and anaerobic bacteria. The aim of this retrospective study was to critically review our experience with Pip-Tazo as perioperative prophylactic agent in pediatric non-renal SOT. Between 1993 and 2003 Pip-Tazo was used as initial perioperative prophylaxis in 45 pediatric patients who underwent a total of 49 transplants (36 liver-, seven cardiac-, two lung-, and four small bowel-) at our department. Median age of the children was 7.9 (range 0.5-18.1) years. A total of 34 rejection episodes following 27 transplants were diagnosed. During first hospitalization 44 infectious episodes were observed. Bacteria were responsible for 22 episodes including sepsis (n = 10), pneumonia (n = 5), wound infection (n = 4), urinary tract infection (n = 1), and clostridial colitis (n = 2). The isolated organisms were gram-positive cocci (n = 12), gram-negative rods (n = 3), non-fermentative bacilli (n = 4), and anaerobes (n = 3). Ten episodes were caused by Pip-Tazo resistant bacteria. Twenty-one of these infections were observed following antirejection therapy with pulse steroids. At later time points nine infectious episodes were successfully treated with a second course of Pip-Tazo. During follow up, eight patients died. Six deceased perioperatively: five from infection including aspergillosis (n = 4) and Pneumocystis jiroveci pneumonia (n = 1) and cerebrovascular bleeding (n = 1) and two children later on. At present 37 children (82%) are alive with well functioning graft after a median follow up of 39.2 (range 0.6-123.5) months. No severe side effects caused by Pip-Tazo were observed in any of the children. Pip-Tazo may be a suitable single agent for perioperative prophylaxis in pediatric non-renal solid organs recipients, however, a prospective comparative study is needed to make final conclusions.