Low incidence of sepsis due to viridans streptococci in a ten-year retrospective study of pediatric acute myeloid leukemia

New Perspectives on Primary Prophylaxis of Invasive Fungal Infection in Children Undergoing Hematopoietic Stem Cell Transplantation: A 10-Year Retrospective Cohort Study

Background: Allogenic hematopoietic stem cell transplantation (a-HCT) remains a therapeutic treatment for many pediatric hematological diseases. The occurrence of invasive fungal infections (IFIs) is a complication for which ECIL-8 recommends primary antifungal prophylaxis. In this study, we evaluated the impact of our local strategy of not systematically administering primary antifungal prophylaxis in children undergoing a-HCT on the occurrence and mortality of IFIs. Methods: We performed a retrospective monocentric study from 2010 to 2020. We retained all proven and probable IFIs diagnosed during the first year post a-HCT. Results: 308 patients were included. Eighteen patients developed twenty IFIs (thirteen proven, seven probable) (6.5%) among which aspergillosis (n = 10, 50%) and candidosis (n = 7, 35%) were the most frequently diagnosed infections. Only 2% of children died because of an IFI, which represents 14% of all deaths. Multivariate analysis found that age > 10 years (OR: 0.29), the use of a therapeutic antiviral treatment (OR: 2.71) and a low neutrophil count reconstitution (OR: 0.93) were significantly associated with the risk of IFI occurrence. There was also a trend of malignant underlying disease and status ≥ CR2 but it was not retained in multivariate analysis. Conclusions: IFI occurrence was not higher in our cohort than what is reported in the literature with the use of systematic antifungal prophylaxis, with a good survival rate nonetheless. Thus, a prophylaxis could be considered for children with a high risk of IFI such as those aged over 10 years.

Alarming Upward Trend in Multidrug-Resistant Bacteria in a Large Cohort of Immunocompromised Children: A Four-Year Comparative Study

Documenting bacteremia at the onset of fever in immunosuppressed children is challenging; therefore, it leads to the early administration of broad-spectrum antibiotics. We aimed to analyse the evolution of antibiotic resistance profiles of bacterial bloodstream infections (BSI) and gut colonisations in a large cohort of immunocompromised children carrying a central venous catheter, in comparison with a prior, similar study conducted in our centre from 2014 to 2017. A retrospective, observational cohort study was conducted from January 2018 to December 2021, in a tertiary centre for paediatric immuno-haematology and oncology. Empirical antibiotic therapy was adapted to the immunosuppression risk group and prior bacterial colonisation. There was a mean of 6.9 BSI/1000 patient bed days. Multidrug-resistant bacteria (MDRB) associated BSI accounted for 35/273 (12.8%). The incidence of MDRB gum/gut colonisation and MDRB associated BSI increased annually and correlated with the level of immunosuppression (p = 0.024). One third (34.7%) of the BSI episodes were not associated with neutropenia. As compared to the previous study, an alarming emergence of MDRB responsible for gut colonisations and BSI in immunosuppressed children was reported over the last four years. The degree of immunosuppression directly correlates with the risk of having an MDRB gut colonisation or MDRB BSI.

Life-threatening complications of streptococcal sepsis: a PICU contemporary series

Background

Life-threatening streptococcal sepsis nowadays represents an uncommon event in previously healthy infants and children. Critically ill patients suffering from severe streptococcal sepsis complications may present with pre-antibiotic era clinical pictures and require a timely clinical approach to achieve restitutio ad integrum.

Results

We report a series of four patient groups affected by an uncommon life-threatening streptococcal sepsis, each of them exhibiting some distinct features. Streptococcus Agalactiae sepsis was associated with cerebral thrombotic/ischaemic lesions, whereas severe cardiogenic shock was prominent in the Streptococcus Viridans group; Streptococcus Faecalis and β-hemolytic group A Streptococcus patients mostly reported lung complications.

Conclusions

Previous antibiotic treatments should not delay aggressive treatment in the intensive care setting. Early diagnostic suspicion, as well as appropriate and aggressive treatment provided within an intensive care setting are crucial for the clinical outcome.

Viridans Group Streptococci in Pediatric Leukemia and Stem Cell Transplant: Review of a Risk-stratified Guideline for Empiric Vancomycin in Febrile Neutropenia

Viridans group streptococci (VGS) are an important cause of sepsis in immunosuppressed children. We reviewed the effectiveness of risk-stratified addition of vancomycin to empiric febrile neutropenia therapy among 107 children with leukemia or undergoing an allogeneic transplant. Of 19 VGS bacteremia episodes, 78.9% were susceptible to risk-stratified antibiotics including 100% from high-risk patients. All blood cultures were flagged positive within 24 hours.

Trends in bacterial bloodstream infections and resistance in immuno-compromised patients with febrile neutropenia: a retrospective analysis

Bacterial infections remain a major cause of morbidity and mortality in immunocompromised children. From the onset of fever, an early administration of broad-spectrum antibiotics is begun; this strategy could induce emergence of multi-drug resistant bacteria (MDR). We describe the incidence and microbiological spectrum, including MDR bacteria of bacterial documented blood-stream infections (BSI) in immunocompromised children. A retrospective, descriptive study was conducted in a tertiary referral centre in France from January 2014 to December 2017. Our cohort included a large scale of patients with febrile neutropenia: haematological and oncological malignancies, haematopoietic stem cell transplantations, severe combined immunodeficiency syndromes. BSI were defined by positive blood culture samples associated with fever. Among 760 febrile neutropenia episodes in 7301 admitted patients, we identified 310 documented BSI with a mean of 7.4 BSI/1000 patient bed days. Only 2.9% BSIs were caused by MDR bacteria, none vancomycin resistant. Coagulase-negative staphylococci were identified in 49.7% BSI and Staphylococcus aureus caused 6.5% infections. Gram-negative bacilli accounted for 21.6% of isolated bacteria, Pseudomonas for 4.8%. The incidence of BSI annually decreased by 0.75% (p = 0.002).Conclusion: With a step-down strategy at 48 h of initial broad-spectrum antibiotic therapy, we reported a low number of MDR bacteria, no deaths related to BSI. What is Known: • Bacterial bloodstream infections are a leading cause of morbidity and mortality in immunocompromised children • Multi-drug resistant bacteria are emerging worldwide. What is New: • Initial broad-spectrum antibiotic therapy with a step-down strategy at 48 h: no deaths related to bloodstream infections with a low number of resistant bacteria. • Parental and nurse stewardship to decrease bloodstream infections incidence with a drop of staphylococcal infections.

Emerging neo adjuvants for harnessing therapeutic potential of M1 tumor associated macrophages (TAM) against solid tumors: Enusage of plasticity

Macrophages are a major component of the tumor microenvironment (TME) of most tumors. They are characterized by a high degree of functional plasticity which enable these cells to both promote and eliminate established tumors. Under the influence of immunosuppressive TME, tumor infiltrating iNOS+ and CD11b+ M-1 effector macrophages get polarized towards tumor associated macrophages (TAM) which are tropic to variety of tumors. Increased infiltration and density of TAM is associated with tumor progression and poor prognosis in the plethora of tumors due to their angiogenetic and tissue re-modelling nature. Importantly, TAMs are also responsible for developing endothelium anergy, a major physical barrier for majority of cancer directed immune/chemotherapies. Therefore, functional retuning/re-educating TAM to M-1 phenotypic macrophages is paramount for effective immunotherapy against established tumors. In this review, we discuss and provide comprehensive update on TAM-targeted approaches for enhancing immunity against various solid tumors.

Lack of Effectiveness of Neutropenic Diet and Social Restrictions as Anti-Infective Measures in Children With Acute Myeloid Leukemia: An Analysis of the AML-BFM 2004 Trial

PURPOSE

Although nonpharmacologic anti-infective measures are widely used in children treated for acute myeloid leukemia (AML), there is little evidence of their effectiveness.

PATIENTS AND METHODS

We analyzed infectious complications in children during intensive treatment of AML according to the AML-BFM 2004 trial and surveyed sites on institutional standards regarding recommended restrictions of social contacts (six items), pets (five items), and food (eight items). A scoring system was developed with a restriction score for each item. Multivariable Poisson regression adjusted for sex, age, weight group, risk stratification, and prophylactic antibiotics was used to estimate the impact of the restrictions on the incidence ratios of fever of unknown origin, bacteremia, pneumonia, and gastroenteritis.

RESULTS

Data on recommendations of nonpharmacologic anti-infective measures and infectious complications were available in 339 patients treated in 37 institutions. Analyses did not demonstrate a significant benefit of any of the restrictions regarding food, social contacts, and pets on the risk of fever, bacteremia, pneumonia, and gastroenteritis. In contrast, age, weight group, risk stratification, and nonabsorbable antibiotics had some influence on infections complications.

CONCLUSION

The lack of effectiveness of dietary restrictions and restrictions regarding social contacts and pets should result in reconsideration of anti-infective policies.

Viridans Group Streptococcal Infections in Children After Chemotherapy or Stem Cell Transplantation: A 10-year Review From a Tertiary Pediatric Hospital

Viridans Group Streptococci (VGS) are associated with high mortality rates in febrile neutropenia; yet there are no recent European pediatric studies to inform antimicrobial therapy. The aim of this study was to describe the characteristics, outcome, and resistance patterns of children with VGS bacteremia (VGSB) undergoing treatment of malignancy or hematopoietic stem cell transplant. Patients aged 0 to 18 years, admitted to a tertiary pediatric hemato-oncology center with VGSB, from 2003 to 2013, were included in the study. All data were collected retrospectively from medical records. A total of 54 bacteremic episodes occurred in 46 patients. The most common underlying diagnosis was relapsed acute lymphoblastic leukemia. Streptococcus mitis was the most frequent organism. A total of 30% of isolates were resistant to penicillin and 100% sensitive to vancomycin. There were 8 episodes (14.8%) of Viridans Group Streptococcal Shock Syndrome; 6 resulted in admission to intensive care and 3 of these patients died of multiorgan failure. The potentially fatal nature of VGSB is confirmed. The high risk in relapsed acute lymphoblastic leukemia is of note. Research is needed to develop risk-stratification scores that identify children at risk of Viridans Group Streptococcal Shock Syndrome to guide empirical antimicrobial therapy in febrile neutropenia.

Improvement in the Outcome of Invasive Aspergillosis in a Pediatric Hematology Department: A 10-Year Review

BACKGROUND

Invasive aspergillosis (IA) is associated with a high mortality rate despite the introduction of new antifungal agents. Several therapeutic strategies have been proposed to improve mortality rates in IA, including combination of drugs.

METHODS

Here, we report the outcome of treatments based on a combination of antifungal agents on IA, including voriconazole and liposomal amphotericin B, in a pediatric population from 2001 to 2010. Our population included children with diverse hematological diseases or with bone marrow transplantation.

RESULTS

Over a 10-year period, we diagnosed 19 cases (2,8%) of invasive pulmonary aspergillosis with an overall survival rate of 58%.

CONCLUSION

Compared with the previous study conducted from 1986 to 2000, the overall survival rate (bone marrow transplantation excluded) greatly improved (12.5% to 58%), especially for patients treated for acute leukemia.

Clinical and microbiologic outcomes of quinolone prophylaxis in children with acute myeloid leukemia

BACKGROUND

Intensifying treatment for pediatric acute myeloid leukemia (AML) has improved survival, with infections now being a leading cause of morbidity. Because quinolone prophylaxis is effective in adults with AML and in transplant populations, ciprofloxacin prophylaxis (CPx) was introduced as the standard for pediatric AML. We report here the impact of CPx in this population.

METHODS

Prevalence of fever and neutropenia, frequency and pathogen spectrum of infections, antibiotic use, supportive care and mortality before and after implementation of CPx were retrospectively compared in children with AML.

RESULTS

The cohort included 35 patients with de novo and 10 with relapsed AML, who together underwent 153 chemotherapy courses. Fever and neutropenia resulting in the use of empiric antibiotics occurred in 90% of chemotherapy courses (137/153); this was associated with proven bacteremia in 26%. The use of CPx did not change the incidence of febrile or infectious episodes, number of days of fever or antibiotic treatment or mortality. CPx was associated with a significant decrease in infections caused by Gram-negative rods (13.4% vs 4.7%) but a concomitant significant increase in bacteremia caused by viridans streptococci (12% vs 28%), resulting in no significant overall difference in the incidence of bacteremia between the 2 groups (35.9% vs 31.5%).

CONCLUSIONS

CPx neither alter the incidence of overall bacteremia nor change the pattern of fever or use of supportive care. Our experience supports further investigation into the use of extended-spectrum quinolone prophylaxis during therapy for pediatric AML.

Predictors and outcomes of viridans group streptococcal infections in pediatric acute myeloid leukemia: from the Canadian infections in AML research group

BACKGROUND

Viridans group streptococci (VGS) cause significant morbidity in children treated for acute myeloid leukemia (AML). Our goals were to determine the occurrence and impact of these infections in children treated for AML and to understand the factors that increase the risk of VGS infections and viridans streptococcal shock syndrome (VSSS) in this population.

METHODS

We conducted a retrospective, population-based cohort study that included children ≤18 years of age with de novo AML treated at 15 Canadian centers. We evaluated factors related to VGS infection and VSSS.

RESULTS

Among 341 children with AML, VGS occurred in 78 (22.9%) children over the entire course of therapy and 16 had recurrent episodes. VGS infection occurred in 97 of 1277 courses of chemotherapy (7.6%). VSSS occurred in 19.6% of these episodes and included 11 patients who required intensive care services with 2 VGS infections resulting in death. In multiple regression analysis, factors independently related to VGS included treatment on a Medical Research Council-based protocol (odds ratio (OR) 2.87, 95% confidence interval (CI) 1.53-5.39; P = 0.001), cytarabine dose per gram/m² (OR 1.04, 95% CI 1.01-1.07; P = 0.002) and prolonged neutropenia (OR 1.58, 95% CI: 0.97-2.56; P = 0.06). None of the evaluated factors were predictive of VSSS.

CONCLUSIONS

VGS infections occur in 7.6% of chemotherapy courses and remain an important cause of morbidity and even mortality in children being treated for AML. Interventions to reduce VGS need to be identified.

High frequency of streptococcal bacteraemia during childhood AML therapy irrespective of dose of cytarabine

BACKGROUND

High-dose cytarabine has been associated with a high frequency of viridans group streptococcal (VGS) bacteraemia. VGS bacteraemia causes considerable morbidity and mortality. The Nordic Society of Paediatric Haematology and Oncology (NOPHO)-AML protocols use higher cumulated doses of cytarabine and more chemotherapy series (n = 6) than other protocols with the potential increased risk of severe VGS infections.

PROCEDURE

Medical records of all Danish children enrolled on the NOPHO-AML-2004 protocol between January 2004 and September 2011 (n = 45) were retrospectively reviewed and all febrile episodes were registered.

RESULTS

Following 236 courses of chemotherapy, 112 positive blood cultures were registered. VGS were found in 38% of all positive blood cultures. Infectious episodes with VGS resulted in more days of fever and intravenous antibiotic therapy compared with infections caused by other microorganisms. VGS were involved in 45% of all episodes categorized as sepsis (n = 51) and in 67% of life-threatening bloodstream infections (n = 9). Penicillin resistance was found in 40% of the VGS strains. No significant difference was observed in the proportion of VGS isolated following courses with low-dose cytarabine versus courses with high-dose cytarabine.

CONCLUSIONS

VGS were the most commonly isolated pathogens causing the most severe infections and the majority of life-threatening infections. A substantial proportion of the strains were resistant to penicillin. The high rate of VGS seemed independent of high-dose cytarabine but was more likely caused by the intensive chemotherapy treatment leading to severe mucositis and neutropenia.

Life-threatening and fatal infections in children with acute myeloid leukemia: a report from the Children's Oncology Group

To determine among children with acute myeloid leukemia, whether the proportions of life-threatening or fatal infections differed according to the intensity of induction or type of intensification treatment. Participants were children enrolled to the Children's Cancer Group (CCG) 2891 with de novo acute myeloid leukemia. In phase 1 (induction) patients were randomized to 4 cycles of chemotherapy either administered as intensive or standard timing. In phase 2 (intensification), those achieving remission were allocated to allogeneic stem cell transplantation (SCT) if a suitable family donor was available while the remainder were randomized to autologous SCT or chemotherapy. Each infection was classified prospectively as nonlife-threatening, life-threatening, or fatal. The proportion of all infections that were considered life-threatening or fatal was higher with intensive timing compared with standard timing induction (60.3% vs. 37.3%, P<0.0001). Infections caused by Gram-positive and Gram-negative bacteria and fungi were significantly more likely to be severe during intensive compared with standard timing induction. Most molds were life-threatening or fatal. Chemotherapy intensification was not associated with less severe infections compared with SCT. Intensive timing was associated with more severe infections compared with standard timing induction. Prophylactic strategies are likely more important with intensive induction regimens.

Denaturing gradient gel electrophoresis of PCR-amplified gki genes: a new technique for tracking streptococci

Viridans group streptococci (VGS) are a well-known cause of infections in immunocompromised patients, accounting for severe morbidity and mortality. Streptococcus mitis group species (Streptococcus mitis, Streptococcus pneumoniae, Streptococcus oralis) are among the VGS most often encountered in clinical practice. Identifying the portal of entry for S. mitis group strains is crucial for interventions preventing bacterial translocation. Unfortunately, tracking the source of S. mitis group strains is dependent on a combination of extremely laborious and time-consuming cultivation and molecular techniques (enterobacterial repetitive intergenic consensus-PCR [ERIC-PCR]). To simplify this procedure, a PCR analysis with newly designed primers targeting the household gene glucose kinase (gki) was used in combination with denaturing gradient gel electrophoresis (DGGE). This gki-PCR-DGGE technique proved to be specific for S. mitis group strains. Moreover, these strains could be detected in samples comprised of highly diverse microbiota, without prior cultivation. To study the feasibility of this new approach, a pilot study was performed. This confirmed that the source of S. mitis group bacteremia in pediatric patients with acute myeloid leukemia could be tracked back to the throat in five out of six episodes of bacteremia, despite the fact that throat samples are polymicrobial samples containing multiple S. mitis group strains. In contrast, using the classical combination of cultivation techniques and ERIC-PCR, we could detect these strains in only two out of six cases, showing the superiority of the newly developed technique. The new gki-PCR-DGGE technique can track the source of S. mitis group strains in polymicrobial samples without prior cultivation. Therefore, it is a valuable tool in future epidemiological studies.

Prophylactic antibiotics reduce morbidity due to septicemia during intensive treatment for pediatric acute myeloid leukemia

BACKGROUND

The aim of this study was to determine whether antibiotic prophylaxis during periods of neutropenia reduced streptococcal (S. viridans) sepsis and overall bacterial sepsis.

METHODS

The authors reviewed outcomes of 78 evaluable patients who were consecutively treated for acute myeloid leukemia (AML) from October 2002 through January 2007. Several successive prophylactic antibiotic regimens were used. All patients received antifungal prophylaxis with oral voriconazole.

RESULTS

Oral cephalosporins did not significantly reduce the odds of bacterial sepsis (P = .81) or streptococcal (S. viridans) sepsis (P = .90) relative to no prophylaxis. Intravenous (iv) cefepime completely prevented streptococcal (S. viridans) sepsis and reduced the odds of bacterial sepsis 91% (P < .0001) relative to no prophylaxis, but resistant gram-negative bacteria emerged in 2 patients. Vancomycin with oral ciprofloxacin or a cephalosporin reduced the odds of bacterial sepsis by 93% (P < .0001) and streptococcal (S. viridans) sepsis by 99% (P < .0001). The fungal infection rate did not differ significantly between patients who did and did not receive antibiotic prophylaxis (1.0 per 1000 patient-days for both groups). The observed reduction in average hospital days per chemotherapy course for patients given vancomycin regimens or cefepime was 5.7 (P < .0001) and 4.1 (P = .0039) days, respectively. No reduction was observed with oral cephalosporins (P = .10). Furthermore, vancomycin regimens or cefepime were associated with a 20% reduction in healthcare charges (P = .0015) relative to using no antibiotics. One patient, who was on oral cefuroxime alone, died of septicemia.

CONCLUSIONS

Prophylaxis with intravenous cefepime or a vancomycin regimen, and voriconazole, reduced morbidity in children with AML, and resulted in dramatic decreases in the incidence of septicemia and hospitalization days.

Microbiologically documented infections and infection-related mortality in children with acute myeloid leukemia

The primary objective was to describe the prevalence and characteristics of microbiologically defined infections and infection-related mortality (IRM) in 492 children with acute myeloid leukemia enrolled on CCG 2961. Secondary objectives were to determine the relationship between demographic, disease-related, and therapeutic variables, and infections and IRM. Institutions documented infections prospectively. Age, ethnicity, body mass index, leukemia karyotype, treatment, and institutional size were examined for association with infection outcomes. More than 60% of children experienced such infections in each of 3 phases of chemotherapy. There were 58 infectious deaths; cumulative incidence of IRM was 11% plus or minus 2%. Thirty-one percent of infectious deaths were associated with Aspergillus, 25.9% with Candida, and 15.5% with alpha hemolytic streptococci. Age older than 16 years (hazard ratio [HR], 3.32; 95% confidence interval [CI], 1.87-5.89; P < .001), nonwhite ethnicity (HR, 1.85; 95% CI, 1.10-3.09; P = .02), and underweight status (HR, 3.06; 95% CI, 1.51-6.22; P = .002) were associated with IRM, while size of the treating institution was not. Thus, age, ethnicity, and BMI were important contributors to IRM. Fungi and Gram-positive cocci were the most common organisms associated with IRM and, in particular, Aspergillus species was the largest contributor to infectious deaths.