Stenotrophomonas maltophilia Infections in Pediatric Patients - Experience at a European Center for Pediatric Hematology and Oncology

Invasive fungal infection caused by Magnusiomyces capitatus in a pediatric patient with Burkitt lymphoma: Case report and review of literature

INTRODUCTION

invasive fungal infection is a serious problem in immunosuppressed patients, particularly those with hematological or oncological diseases. Recently, more cases of emerging pathogens, such as Magnusiomyces capitatus, have been reported.

CLINICAL CASE

a 4-year-old male diagnosed with stage IV sphenoidal Burkitt lymphoma, undergoing immunosuppressive treatment and with severe neutropenia, developed sepsis of abdominal origin, requiring admission to the Intensive Care Unit. He received empirical antibiotic and antifungal therapy, with isolation of M. capitatus in blood cultures and peritoneal fluid. Despite adjusting antifungal therapy, the patient died 15 days after due to the progression of the invasive fungal infection.

DISCUSSION

M. capitatus infections are reported more frequently in immunocompromised patients. A review of pediatric cases published in the literature identified a total of 16 cases (8 males and 8 females, median age 6 years). Most cases had an underlying hemato-oncological disease and were in an immunosuppressed state. In contradistinction to what is observed in adults, only three cases (18.8 %) had received antifungal prophylaxis. M. capitatus is a dimorphic yeast that is intrinsically resistant to echinocandins and has a significant mortality rate, both in studied series and in ours (50 %).

CONCLUSIONS

a rapid and accurate diagnosis of M. capitatus infection is essential to control invasive fungal infection, which could improve patient survival.

Intratumoral Stenotrophomonas Maltophilia in Breast Cancer: Unraveling the Interplay with Hormone Receptors and Impact on Tumor Immunity

This study aimed to explore the impact of intratumoral microorganisms in conjunction with hormone receptors on the tumor microenvironment and their potential role in predicting patient prognosis. Significant bacterial variations were identified within ER, PR, HER2, and triple-negative breast cancer subtypes. Kaplan-Meier survival analysis was employed to identify bacteria associated with patient survival. Further, a humanized immune system mouse model bearing breast cancer xenografts was used to evaluate the effects of Stenotrophomonas maltophilia (SMA) on tumor growth and CD8+ T cell infiltration. Additional validation experiments included fluorescence in situ hybridization for SMA, CD8+ T cell chemotaxis, and intracellular cytokine detection. Lawsonella clevelandensis-A, Diaphorobacter nitroreducens, and SMA were identified as significant prognostic species. Notably, tumor-infiltrating immune cells, particularly CD8+ T cells, exhibited a positive association with the presence of SMA. Experimental validation with clinically isolated SMA further confirmed its positive correlation with CD8+ T cell activation. In vivo findings demonstrated that SMA inhibited tumor growth and promoted CD8+ T cell infiltration, highlighting the complex interactions between intratumoral microbiota and tumor immunity in breast cancer. These insights contribute to the understanding of microbial influences on the tumor microenvironment and suggest potential pathways for improving patient prognosis through microbiota modulation.

Stenotrophomonas maltophilia Associated Factors and Outcomes in a Neonatal Intensive Care Unit: A Retrospective Matched Case-control Study

BACKGROUND

Stenotrophomonas maltophilia is a multi-drug-resistant, hospital-acquired Gram-negative bacillus associated with significant morbidity and mortality. The objective of this study is to identify risk factors and outcomes associated with S. maltophilia isolation in a high-risk neonatal population.

METHODS

This was a retrospective matched case-control study. Cases were matched 1:2 for years of neonatal intensive care unit admission, completed weeks' gestational age and birth weight in 250-gram incremental categories.

RESULTS

A total of 15 cases and 35 controls were included in the analyses. Risk factors for S. maltophilia isolation included days of antibiotics (24 vs. 18, P = 0.036), days of broad-spectrum antibiotics (19 vs. 12 days, P = 0.027), days of meropenem (9 vs. 6 days, P = 0.018) and any meropenem exposure (100% vs. 22%, P = 0.005). Other risk factors were any corticosteroid exposure (66.7% vs. 20%, P = 0.001), days of total parenteral nutrition (55 vs. 31 days, P = 0.017) and days of invasive mechanical ventilation (28 vs. 7, P = 0.015). S. maltophilia isolation was associated with increased length of neonatal intensive care unit stay (134 vs. 69 days, P < 0.001) and mortality (33.3% vs. 0%, P = 0.001).

CONCLUSIONS

Antibiotic stewardship efforts should be made to decrease the risk of S. maltophilia isolation and associated mortality. Carbapenem over-use should be specifically addressed with institutional policies and unit-based guidelines. Additional neonatal studies are needed to confirm these findings and explore other possible risk factors.

Bloodstream infections in pediatric hematology/oncology patients: a single-center study in Wuhan

Bloodstream infections (BSIs) are a critical concern in pediatric onco-hematological patients undergoing chemotherapy or hematopoietic stem cell transplantation (HSCT), leading to a major impact on morbidity, long-term hospitalization, and mortality. We retrospectively analyzed 202 BSIs in 145 patients, consisting of 128 with hematological malignancies, one with a solid tumor, and 16 with non-malignant hematological diseases. We collected data on patient demographics, clinical characteristics, pathogen distribution, and antimicrobial pathogen susceptibility. Gram-positive infections were the most frequent at (58.4%), followed by gram-negative (41%), and fungal infections (0.5%). Particularly, the majority of these infections occurred during the induction phase of chemotherapy, where 94 (46.5%) BSI episodes were recorded, predominantly in neutropenic patients (88.3%). The consolidation phase experienced lower BSIs (11.8%); among these patients (54.1%) were non-neutropenic. BSIs observed in (23.7%) of patients in the maintenance phase, with a higher proportion (66.6%) being neutropenic. Among the 7 patients who underwent HSCT, BSIs occurred in (4.9%) cases, mainly (70%) due to neutropenia. The most prevalent pathogens were Staphylococcus epidermidis (19.8%), Staphylococcus hominis (16.3%), and Escherichia coli (8.4%). The study highlights the critical need for vigilant monitoring and customized infection management strategies to enhance patient outcomes across chemotherapy phases and HSCT.

Stenotrophomonas maltophilia Outbreak in an ICU: Investigation of Possible Routes of Transmission and Implementation of Infection Control Measures

Stenotrophomonas maltophilia, a non-fermentative, ubiquitous, gram-negative aerobic bacterium, is associated with high mortality rates, particularly in immunocompromised or debilitated patients. The prevalence rate of ICU-acquired pneumonia episodes caused by this microorganism has been found to be 2%. S. maltophilia has been identified as one of the top 10 microorganisms responsible for such infections in EU/EEA countries. This study describes an outbreak of S. maltophilia in an intensive care unit of a hospital in northern Italy. This includes an epidemiological investigation of the cases, the environmental microbiological controls carried out, a comparison of the strains by multilocus sequence typing (MLST), and the measures taken to prevent and control the outbreak. Among the seven clinical isolates of S. maltophilia analyzed herein, six demonstrated susceptibilities to trimethoprim-sulfamethoxazole. Conversely, one isolate of S. maltophilia exhibited resistance to first-line antibiotics. ST was found to be identical for six patients (ST 4), as well as in the environmental feedback on the trolley of Box 2. The analysis of the temporal and spatial progression of the outbreak has suggested that the transmission of S. maltophilia may have occurred through cross-transmission during care practices.

Stenotrophomonas maltophilia neonatal sepsis: a case report

BACKGROUND

Stenotrophomonas maltophilia is a gram-negative bacteria known for causing opportunistic and nosocomial infections in humans. S. maltophilia is an emerging pathogen of concern due to it's increasing prevalence, diverse disease spectrum, intrinsic multi-drug resistance and high mortality rates in immunocompromised individuals. S. maltophilia is a rare cause of neonatal sepsis associated with significant morbidity and mortality. The bacterium's multi-drug resistance poses a considerable challenge for treatment, with various mechanisms contributing to its resistance.

CASE PRESENTATION

We report a case involving a 40-h-old male African neonate who exhibited symptoms of neonatal sepsis. The blood culture revealed Stenotrophomonas maltophilia, which was sensitive to ciprofloxacin and gentamicin but resistant to other antibiotics. Lumbar puncture for CSF could not be done because the father declined. We treated the newborn with the empirical first-line antibiotics as per the national guideline intravenous ampicillin and gentamicin for six days, and the child recovered fully with a repeated negative blood culture.

CONCLUSIONS

This report describes a neonatal sepsis case caused by S. maltophilia, a multi-drug resistant bacteria and a rare cause of neonatal sepsis. We report that early detection of the bacterial and antimicrobial management based on local antibiogram data may be essential for successful patient's management.

Case series: Stenotrophomonas maltophilia in pediatric oncology patients

BACKGROUND

Stenotrophomonas maltophilia is a bacterial pathogen that can be fatal in hospitalized and immunocompromised patients with mortality as high as 69%. Pediatric cancer patients often have risk factors that are common for this infection, making them particularly susceptible. Managing S. maltophilia is especially challenging as it has inherent resistance to several antibiotics. Furthermore, soft tissue infections in neutropenic patients may deviate from the typical clinical presentation of S. maltophilia.

CASE DETAILS

This case series describes an in-depth examination of three cases involving immunocompromised pediatric patients with S. maltophilia infections. Each case exhibited a distinct clinical presentation, encompassing infection of the blood, lung, and skin, which highlights the variability in which S. maltophilia manifests in immunocompromised pediatric patients. These patients were treated at MD Anderson Cancer Center (MDACC) from 2020 to 2023, unfortunately resulting in fatality.

CONCLUSIONS

The study aims to provide valuable insights and guidance for the management of patients with S. maltophilia infections. Emphasizing a heightened clinical suspicion will potentially lead to early initiation of directed therapy against S. maltophilia. Timely intervention may play a pivotal role in improving patient outcomes and reduce further burden to the healthcare system.

Bloodstream Infections in Pediatric Oncology Patients: Bacterial Pathogen Distribution and Antimicrobial Susceptibility at the University Hospital Centre Zagreb, Croatia-A 5-Year Analysis

The epidemiology of bacterial pathogens causing bloodstream infections (BSIs) in pediatric hematology/oncology patients is changing and resistance to antimicrobial agents is globally spread. We retrospectively assessed demographic, clinical, and microbiologic data of BSIs during a 5-year period at a pediatric hematology/oncology unit from January 1, 2017, to December 31, 2021, at the University Hospital Centre Zagreb, Zagreb, Croatia. In 66 pediatric patients with malignancies, 93 BSI episodes were registered and 97 bacterial isolates were cultured. The Gram-positive versus Gram-negative ratio was 67 (69.1%) versus 30 (30.9%). Coagulase-negative staphylococci (48; 49.6%) were the most frequent isolates, followed by Enterobacterales (17; 17.5%) and Staphylococcus aureus (6; 6.2%). Multidrug resistance isolates included extended spectrum β-lactamase producers (n=3). Resistance rates to piperacillin/tazobactam, cefepime, and meropenem in Gram-negative isolates were 15.4%, 14.3%, and 0.0%, respectively. Gram-positive bacteria are the most common cause of BSI in our patients. Resistance rates to piperacillin/tazobactam and cefepime in Gram-negative isolates make meropenem a better choice for empirical antimicrobial treatment. As national and hospital data may differ, the surveillance of pathogen distribution and antimicrobial susceptibility in pediatric hematology/oncology wards is necessary to adjust empirical treatment accordingly.

Antibiotic resistance genes prediction via whole genome sequence analysis of Stenotrophomonas maltophilia

BACKGROUND

Stenotrophomonas maltophilia (S. maltophilia) is the first dominant ubiquitous bacterial species identified from the genus Stenotrophomonas in 1943 from a human source. S. maltophilia clinical strains are resistance to several therapies, this study is designed to investigate the whole genome sequence and antimicrobial resistance genes prediction in Stenotrophomonas maltophilia (S. maltophilia) SARC-5 and SARC-6 strains, isolated from the nasopharyngeal samples of an immunocompromised patient.

METHODS

These bacterial strains were obtained from Pakistan Institute of Medical Sciences (PIMS) Hospital, Pakistan. The bacterial genome was sequenced using a whole-genome shotgun via a commercial service that used an NGS (Next Generation Sequencing) technology called as Illumina Hiseq 2000 system for genomic sequencing. Moreover, detailed in-silico analyses were done to predict the presence of antibiotic resistance genes in S. maltophilia.

RESULTS

Results showed that S. maltophilia is a rare gram negative, rod-shaped, non sporulating bacteria. The genome assembly results in 24 contigs (>500 bp) having a size of 4668,850 bp with 65.8% GC contents. Phylogenetic analysis showed that SARC-5 and SARC-6 were closely related to S. maltophilia B111, S. maltophilia BAB-5317, S. maltophilia AHL, S. maltophilia BAB-5307, S. maltophilia RD-AZPVI_04, S. maltophilia JFZ2, S. maltophilia RD_MAAMIB_06 and lastly with S. maltophilia sp ROi7. Moreover, the whole genome sequence analysis of both SARC-5 and SARC-6 revealed the presence of four resistance genes adeF, qacG, adeF, and smeR.

CONCLUSION

Our study confirmed that S. maltophilia SARC-5 and SARC-6 are one of the leading causes of nosocomial infection which carry multiple antibiotic resistance genes.

The Prognosis of Patients Tested Positive for Stenotrophomonas maltophilia from Different Sources

Purpose

The purpose of this study was to analyze the prognosis of patients tested positive for Stenotrophomonas maltophilia (SMA) from different sources.

Methods

A retrospective study was conducted among 651 patients tested positive for SMA from January 2020 to October 2022 in the First Affiliated Hospital of Anhui Medical University. The patients were divided into seven groups by the source of SMA. Univariate and multivariate analyses were used to identify risk factors for mortality in patients tested positive for SMA from different sources.

Results

A total of 651 SMA isolates were collected from various sources, including sputum (348 isolates, 53%), bronchoalveolar lavage fluid (52, 8%), abdominal drainage fluid (76, 12%), wound secretion (66, 10%), blood (62, 10%), urine (41, 6%) and cerebrospinal fluid (6, 1%). Compared with other groups, the mortality of the patients in the bronchoalveolar lavage fluid culture group, blood culture group, and abdominal drainage fluid culture group was higher, at 40.38%, 32.26%, and 26.32%, respectively. Multivariate analysis showed that continuous renal replacement therapy was an independent risk factor for mortality in patients with SMA bloodstream infection (P=0.020, OR=6.86), and effective antimicrobial therapy after being positive for S. maltophilia isolates (P=0.002, OR=0.10) was negatively correlated with the death of patients with SMA bloodstream infection. Age ≥65 years (P= 0.043, OR=4.96), kidney disease (P=0.045, OR=4.62) and antifungal agent exposure (P=0.036, OR=5.13) were independent risk factors for mortality in patients with SMA intra-abdominal infection. Antifungal agent exposure (P=0.024, OR=0.51) and glycopeptide exposure (P=0.045, OR=0.53) were independent risk factors for mortality in patients in the sputum culture group.

Conclusion

SMA has a high rate of antimicrobial resistance and can cause multisite infection. Pulmonary infections, bloodstream infections and abdominal infections caused by SMA have high mortality, and timely standardized treatment can reduce mortality.

Antibiotic Susceptibility and Minimum Inhibitory Concentration for Stenotrophomonas maltophilia Ocular Infections

Stenotrophomonas maltophilia (S. maltophilia) is a Gram-negative, opportunistic pathogen that can lead to ocular infections, such as keratitis and endophthalmitis. The purpose of this study was to determine the antibiotic susceptibility and minimum inhibitory concentrations (MICs) of S. maltophilia isolates from ocular infections and to evaluate the differences in antibiotic MICs between keratitis and endophthalmitis isolates. The disc diffusion method revealed that S. maltophilia isolates exhibited 91% susceptibility to levofloxacin and moxifloxacin and 61% susceptibility to trimethoprim−sulfamethoxazole (TMP−SMX). The E-test indicated that S. maltophilia isolates exhibited 40%, 100%, 72%, 91%, 91%, and 93% susceptibility to ceftazidime, tigecycline, TMP−SMX, levofloxacin, gatifloxacin, and moxifloxacin, respectively. The MIC90 values of amikacin, ceftazidime, cefuroxime, tigecycline, TMP−SMX, levofloxacin, gatifloxacin, and moxifloxacin were >256, >256, >256, 3, >32, 1, 2, and 0.75 µg/mL, respectively. The geometric mean MICs of ceftazidime, TMP−SMX, levofloxacin, gatifloxacin, and moxifloxacin were significantly lower for the keratitis isolates than for the endophthalmitis isolates (p = 0.0047, 0.003, 0.0029, 0.0003, and 0.0004, respectively). Fluoroquinolones showed higher susceptibility and lower MICs for the S. maltophilia isolates when compared with other antibiotics. Fluoroquinolones can be recommended for treating S. maltophilia ocular infections. Tigecycline and TMP−SMX could be alternative antibiotics for S. maltophilia ocular infections.

Efficacy of Cefiderocol in Experimental Stenotrophomonas maltophilia Pneumonia in Persistently Neutropenic Rabbits

Stenotrophomonas maltophilia is an important cause of pneumonia in immunocompromised patients. Cefiderocol is a parenteral siderophore cephalosporin with potent in vitro activity against S. maltophilia. We evaluated the efficacy of cefiderocol in a neutropenic rabbit model of S. maltophilia pneumonia in comparison to trimethoprim-sulfamethoxazole (TMP-SMX). The cefiderocol area under the plasma drug concentration-time curve extrapolated to 8 h (AUC_0–8) was lower (423.0 ± 40.9 μg·h/mL versus 713.6 ± 40.1 μg·h/mL) and clearance higher (252.77 ± 38.9 mL/h/kg versus 142.6 ± 32.9 mL/h/kg) in infected versus noninfected rabbits. We studied a clinical bloodstream S. maltophilia isolate with an MIC of 0.03 μg/mL of cefiderocol. Time spent above the MIC of cefiderocol for the majority of S. maltophilia isolates in rabbits recapitulated the plasma concentration-time profile observed in adult humans at the licensed dose of 2 g given intravenously (i.v.). Experimental groups consisted of 120 mg/kg cefiderocol i.v. every 8 hours (q8h); TMP-SMX, 5 mg/kg i.v. Q12h, and untreated controls (UCs). Treatment was administered for 10 days. Survival in cefiderocol-treated rabbits (87%) was greater than that in TMP-SMX-treated (25%; P < 0.05) and UC (0%; P < 0.05) groups. There was no residual bacterial burden in lung tissue or bronchoalveolar lavage (BAL) fluid in the cefiderocol group. Residual bacterial burden was present in lung tissue and BAL fluid in the TMP-SMX group but was decreased in comparison to UCs (P < 0.001). Lung weights (markers of pulmonary injury) were decreased in cefiderocol-treated versus TMP-SMX (P < 0.001) and UC (P < 0.001) groups. Cefiderocol is highly active in treatment of experimental S. maltophilia pneumonia, laying the foundation for future clinical investigations against this lethal infection in immunocompromised patients.

Epidemiologic and clinical characteristics of human bocavirus infection in children hospitalized for acute respiratory tract infection in Qingdao, China

Persistent infection and prolonged shedding of human bocavirus 1 (HBoV1) in children have been reported, and the role of HBoV1 as a sole causative pathogen in acute respiratory infection (ARI) is yet to be established. While the reported prevalence of HBoV infection varies due to different detection methods and sampling criteria, determining the viral and bacterial etiology of HBoV infection using multiplex real-time PCR is yet to be reported. Herein, we aimed to further explore the pathogenicity of HBoV in patients with ARI by screening the viral and bacterial infections in children with ARI in Qingdao and comparing the epidemiological, clinical characteristics, and etiological results. Human bocavirus was identified in 28.1% of the samples, and further sequencing analysis of the detected HBoV confirmed 96.4% as HBoV1. The rate of HBoV as a single viral infection was 75%, and the rate of coinfection with bacteria was 66.1%, suggesting the need for continued monitoring of HBoV in children with ARIs. Clinical characterization suggested that HBoV infection may affect the function of organs, such as the liver, kidney, and heart, and the blood acid–base balance. Additionally, it is essential to promote awareness about the importance of disinfection and sterilization of the hospital environment and standardizing operations. The interactions between HBoV and other pathogens remain to be investigated in further detail in the future.

Clinical challenges treating Stenotrophomonas maltophilia infections: an update

Stenotrophomonas maltophilia is a non-fermenting, Gram-negative bacillus that has emerged as an opportunistic nosocomial pathogen. Its intrinsic multidrug resistance makes treating infections caused by S. maltophilia a great clinical challenge. Clinical management is further complicated by its molecular heterogeneity that is reflected in the uneven distribution of antibiotic resistance and virulence determinants among different strains, the shortcomings of available antimicrobial susceptibility tests and the lack of standardized breakpoints for the handful of antibiotics with in vitro activity against this microorganism. Herein, we provide an update on the most recent literature concerning these issues, emphasizing the impact they have on clinical management of S. maltophilia infections.