First Case of VIM-1-like-Producing Pseudomonas putida Bacteremia in an Oncohematological Pediatric Patient in Italy.

Bacterial infections caused by multidrug-resistant (MDR) Gram-negatives are of great concern worldwide, as they are frequently associated with high mortality and morbidity rates. To date, two cases of VIM-2 metallo-ß-lactamase (MBL)-producing Pseudomonas putida bacteremia have been ever reported in France and Spain between 2004 and 2010. Here, we present the first case of VIM-1-like-producing P. putida isolated in blood culture collected from an oncohematological pediatric patient admitted to Bambino Gesù Children's Hospital (IRCCS) in Rome, Italy.

The burden of central line-associated bloodstream infections in children with medical complexity.

BACKGROUND: Central line-associated bloodstream infections (CLABSI) are significant cause of complications in pediatric intensive care units (PICUs). An emerging challenge are CLABSIs in children with medical complexity (CMC) admitted to PICU. CMC are patients with chronic conditions with or without neurological impairment needing for tracheostomy and/or home mechanical or non-invasive ventilation and/or gastrostomy/jejunostomy. We evaluate CLABSI incidence in a PICU with high prevalence of CMC. METHODS: This was a retrospective study in the PICU of the Bambino Gesù Children Hospital from January 2017 to December 2020. The medical records were reviewed and demographic, clinical and microbiological data were extracted. CLABSI were defined according to the Center for Disease Control and Prevention's National Healthcare Safety Networks (NHSN) surveillance. RESULTS: A total of 101 children with 125 central lines (CLs) were included; 79/101 (78%) patients were CMC and 50/101 (50%) had a thracheostomy. CLABSI incidence was 2.75/1000 CL-days (9 cases/3269 CL-days); incidence was 0 in patients without underling conditions and 3.14/1000 in CMC (p < 0.001). CLABSI were due to gram negative bacteria in five patients, Candida spp in three and Staphylococcus hominis in one. CLs were removed in eight cases while in the later one, with CLABSI due to Pseudomonas aeruginosa, a conservative strategy was adopted cause of unavailable alternative venous access and removed at discharge with negative culture. All patients recovered. CONCLUSIONS: A target 0% CLABSI was possible in critically ill children without underling condition while a high incidence was reported in CMC and sustained by a peculiar CLABSI ecology. This ecology should be considered when a CLABSI was suspected in CMC for prompt antibiotics stewardship.

Effective Rapid Diagnosis of Bacterial and Fungal Bloodstream Infections by T2 Magnetic Resonance Technology in the Pediatric Population.

Children are prone to bloodstream infections (BSIs), the rapid and accurate diagnosis of which is an unmet clinical need. The T2MR technology is a direct molecular assay for identification of BSI pathogens, which can help to overcome the limits of blood culture (BC) such as diagnostic accuracy, blood volumes required, and turnaround time. We analyzed results obtained with the T2Bacteria (648) and T2Candida (106) panels in pediatric patients of the Bambino Gesù Children's Hospital between May 2018 and September 2020 in order to evaluate the performance of the T2Dx instrument with respect to BC. T2Bacteria and T2Candida panels showed 84.2% and 100% sensitivity with 85.9% and 94.1% specificity, respectively. The sensitivity and specificity of the T2Bacteria panel increased to 94.9% and 98.7%, respectively, when BC was negative but other laboratory data supported the molecular result. T2Bacteria sensitivity was 100% with blood volumes <2 mL in neonates and infants. T2Bacteria and T2Candida provided definitive microorganism identification in a mean time of 4.4 and 3.7 h, respectively, versus 65.7 and 125.5 h for BCs (P < 0.001). T2 panels rapidly and accurately enable a diagnosis of a pediatric BSI, even in children under 1 year of age and for very small blood volumes. These findings support their clinical use in life-threatening pediatric infections, where the time to diagnosis is of utmost importance, in order to improve survival and minimize the long-term sequalae of sepsis. The T2 technology could be further developed to include more bacteria and fungi species that are involved in the etiology of sepsis.

Clostridioides difficile Infection in Children: A 5-Year Multicenter Retrospective Study.

While there are numerous studies regarding Clostridioides difficile infection (CDI) in adults, literature on the pediatric population is scarce. Therefore, we performed a 5-year retrospective study between January 2014 and December 2018 in two referral centers in Rome, Italy. There were 359 patients tested for CDI who were enrolled: 87 resulted in positive and 272 in negative. CDI children had a higher number of previous-day hospital admissions (p = 0.024), hospitalizations (p = 0.001), and total hospital admissions (p = 0.008). Chronic comorbidities were more frequent in the CDI group (66.7% vs. 33.3%). Previous use of proton pump inhibitors and antibiotics was associated with CDI (p < 0.001). Among the antibiotics, only fluoroquinolones were significantly associated with CDI. Also, CDI children were more frequently exposed to antibiotics during the episode of hospitalization when children were tested. Our study provides an updated clinical and epidemiological analysis of children with CDI compared with a control group of children who tested negative. Further prospective studies could better define risk factors and preventive methods.

Evidence of pediatric sepsis caused by a drug resistant Lactococcus garvieae contaminated platelet concentrate.

Owing to an increasing number of infections in adults, Lactococcus (L.) garvieae has gained recognition as an emerging human pathogen, causing bacteraemia and septicaemia. In September 2020, four paediatric onco-hematologic patients received a platelet concentrate from the same adult donor at Bambino Gesù Children's Hospital IRCCS, Rome. Three of four patients experienced L. garvieae sepsis one day after transfusion. The L. garvieae pediatric isolates and the donor's platelet concentrates were retrospectively collected for whole-genome sequencing and shot-gun metagenomics, respectively (Illumina HiSeq). By de novo assembly of the L. garvieae genomes, we found that all three pediatric isolates shared a 99.9% identity and were characterized by 440 common SNPs. Plasmid pUC11C (conferring virulence properties) and the temperate prophage Plg-Tb25 were detected in all three strains. Core SNP genome-based maximum likelihood and Bayesian trees confirmed their phylogenetic common origin and revealed their relationship with L. garvieae strains affecting cows and humans (bootstrap values >100 and posterior probabilities = 1.00). Bacterial reads obtained by the donor's platelet concentrate have been profiled with MetaPhlAn2 (v.2.7.5); among these, 29.9% belonged to Firmicutes, and 5.16% to Streptococcaceae (>97% identity with L. garvieae), confirming the presence of L. garvieae in the platelet concentrate transfusion. These data showed three episodes of sepsis for the first time due to a transfusion-associated transmission of L. garvieae in three pediatric hospitalized hematology patients. This highlights the importance to implement the screening of platelet components with new human-defined pathogens for ensuring the safety of blood supply, and more broadly, for the surveillance of emerging pathogens.

Case Report: Trichosporon japonicum Fungemia in a Pediatric Patient With Refractory Acute B Cell Lymphoblastic Leukemia.

Trichosporon japonicum is a very rare opportunistic yeast causing fungal disease in humans, especially in immunocompromised hosts. Here, we describe a new case of T. japonicum isolated from the blood of a pyrexial pediatric patient with refractory acute B cell lymphoblastic leukemia and acute respiratory distress. Prompt diagnosis through early clinical suspicion and appropriate molecular microbiology analysis allowed the yeast to be accurately identified at species level. Subsequent drug susceptibility testing and focused antifungal treatment with voriconazole and amphotericin B led to a complete clinical and mycological resolution of the infection, which represents the second successful case of T. japonicum bloodstream infection described in literature to date.

Parenteral Nutrition Is One of the Most Significant Risk Factors for Nosocomial Infections in a Pediatric Cardiac Intensive Care Unit.

BACKGROUND: Nosocomial infections (NIs) are associated with significant morbidity and mortality and increased healthcare costs. We aimed to assess the NI epidemiology and associated risk factors in a pediatric cardiac intensive care unit (PCICU). MATERIALS AND METHODS: Prospective observational study on 1106 patients admitted to a PCICU from January 1, 2012, to October 31, 2013. NIs were defined and recorded weekly by a multidisciplinary team. Independent risk factors for NIs were assessed by logistic regression analysis in the overall cohort, in cardiac surgical patients, and in those who had cardiopulmonary bypass (CPB). RESULTS: Ninety-two patients (8.3%) had NIs. Overall mortality was 2% but 8.3% in children with NIs ( P < .001). The most frequent NIs were pneumonia (19.6%), bacteremia of unknown origin (16.3%), and catheter-associated bloodstream infection (14.1%) caused mainly by Staphylococcus aureus and Pseudomonas aeruginosa. In the overall cohort, independent risk factors for NIs were number of days of parenteral nutrition (PN), days of invasive and noninvasive ventilation, ward before PCICU admission, and days of PCICU stay; in the cardiac surgical patients, the risk factors were days of PN and days of invasive and noninvasive ventilation; in children who had undergone CPB, the risk factors for NIs were days of PN, delayed sternal closure, reintervention, length of CPB, younger age, and days of invasive ventilation. CONCLUSION: Mortality was significantly higher in patients with NIs. The use of PN was one of the most significant predictors for NIs in the overall cohort of PCICU patients, cardiac surgical patients, and those who required CPB.

Epidemiology and clinical outcomes of multidrug-resistant, gram-negative bloodstream infections in a European tertiary pediatric hospital during a 12-month period.

BACKGROUND: Bloodstream infections caused by multidrug-resistant, Gram-negative (MDRGN) bacteria represent a significant cause of morbidity and mortality. Prompt diagnosis and appropriate empiric treatment are the most important determinants of patient outcome. The objective of our study was to assess the epidemiology and clinical outcome of MDRGN sepsis in a tertiary-care pediatric hospital during a 12-month period. METHODS: It was a retrospective, observational study of MDRGN bacteremia including all patients <18 years of age, hospitalized during 2011, with documented bacteremia caused by Enterobacteriaceae or non-fermentative bacteria. RESULTS: Overall, 136 blood cultures in 119 patients were included. The median age of patients was 1.1 years; 86.3% of patients had an underlying disease. The cumulative incidence of Gram-negative bloodstream infections was 5.4/1000 hospital admissions and the infection rate was 0.65/1000 hospital days. Most frequently isolated strains were Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa; 67.6% of infections were hospital acquired. The percentage of multidrug-resistant (MDR) organisms among isolated species was 39%. The crude rate of mortality was 16% and sepsis-related mortality was 9.2%. The mortality rate among patients with an antibiotic-resistant isolate was 22.6%. Factors significantly associated with sepsis-related mortality were antibiotic resistance (odds ratio: 4.26, 95% confidence interval: 1.07-16.9) and hospital acquisition of infection (odds ratio: 1.13, 95% confidence interval: 1.05-1.22). CONCLUSIONS: This study demonstrates the high mortality of hospital-acquired MDRGN bacteremia in children. International networks focusing on clinical management and outcomes of MDRGN in children are required. Study of novel antibiotics active against Gram-negative bacteria should include children early in the clinical trial development programs.

Multiplex PCR allows rapid and accurate diagnosis of bloodstream infections in newborns and children with suspected sepsis.

Sepsis is a major health problem in newborns and children. Early detection of pathogens allows initiation of appropriate antimicrobial therapy that strongly correlates with positive outcomes. Multiplex PCR has the potential to rapidly identify bloodstream infections, compensating for the loss of blood culture sensitivity. In an Italian pediatric hospital, multiplex PCR (the LightCycler SeptiFast test) was compared to routine blood culture with 1,673 samples obtained from 803 children with suspected sepsis; clinical and laboratory information was used to determine the patient infection status. Excluding results attributable to contaminants, SeptiFast showed a sensitivity of 85.0% (95% confidence interval [CI] = 78.7 to 89.7%) and a specificity of 93.5% (95% CI = 92.1 to 94.7%) compared to blood culture. The rate of positive results was significantly higher with SeptiFast (14.6%) than blood culture (10.3%) (P < 0.0001), and the overall positivity rate was 16.1% when the results of both tests were combined. Staphylococcus aureus (11.6%), coagulase-negative staphylococci (CoNS) (29.6%), Pseudomonas aeruginosa (16.5%), and Klebsiella spp. (10.1%) were the most frequently detected. SeptiFast identified 97 additional isolates that blood culture failed to detect (24.7% P. aeruginosa, 23.7% CoNS, 14.4% Klebsiella spp., 14.4% Candida spp.). Among specimens taken from patients receiving antibiotic therapy, we also observed a significantly higher rate of positivity of SeptiFast than blood culture (14.1% versus 6.5%, respectively; P < 0.0001). On the contrary, contaminants were significantly more frequent among blood cultures than SeptiFast (n = 97 [5.8%] versus n = 26 [1.6%]), respectively; P < 0.0001). SeptiFast served as a highly valuable adjunct to conventional blood culture in children, adding diagnostic value and shortening the time to result (TTR) to 6 h.

MALDI-TOF mass spectrometry proteomic phenotyping of clinically relevant fungi.

Proteomics is particularly suitable for characterising human pathogens with high life cycle complexity, such as fungi. Protein content and expression levels may be affected by growth states and life cycle morphs and correlate to species and strain variation. Identification and typing of fungi by conventional methods are often difficult, time-consuming and frequently, for unusual species, inconclusive. Proteomic phenotypes from MALDI-TOF MS were employed as analytical and typing expression profiling of yeast, yeast-like species and strain variants in order to achieve a microbial proteomics population study. Spectra from 303 clinical isolates were generated and processed by standard pattern matching with a MALDI-TOF Biotyper (MT). Identifications (IDs) were compared to a reference biochemical-based system (Vitek-2) and, when discordant, MT IDs were verified with genotyping IDs, obtained by sequencing the 25-28S rRNA hypervariable D2 region. Spectra were converted into virtual gel-like formats, and hierarchical clustering analysis was performed for 274 Candida profiles to investigate species and strain typing correlation. MT provided 257/303 IDs consistent with Vitek-2 ones. However, amongst 26/303 discordant MT IDs, only 5 appeared "true". No MT identification was achieved for 20/303 isolates for incompleteness of database species variants. Candida spectra clustering agreed with identified species and topology of Candida albicans and Candida parapsilosis specific dendrograms. MT IDs show a high analytical performance and profiling heterogeneity which seems to complement or even outclass existing typing tools. This variability reflects the high biological complexity of yeasts and may be properly exploited to provide epidemiological tracing and infection dispersion patterns.

Use of microelectronic array technology for rapid identification of clinically relevant mycobacteria.

We developed a new method based on the Nanochip microelectronic array technology for identification of various clinically relevant mycobacterial species. PCR-amplified rRNA genes obtained from 270 positive Mycobacteria Growth Indicator Tube cultures were successfully tested by hybridizing them with species-selective probes, and the results agreed with those of conventional identification methods. The system is rapid and accurate and opens new perspectives in clinical diagnostics.