Antimicrobial Stewardship Programs in PICU Settings: A Systematic Review.

OBJECTIVES: Development of antimicrobial stewardship programs (ASPs) is strategy for prevention and management of emergence of antimicrobial-resistant organisms. In this study, we systematically reviewed the literature on antimicrobial stewardship interventions in PICUs and analyzed approaches, structure, implementation, and outcomes of the ASPs. DATA SOURCES: PubMed and Scopus databases were systematically searched for studies published from January 1, 2007, to December 31, 2020, reporting interventions on judicious use of antimicrobials in PICUs (last search performed February 28, 2021). DATA SELECTION: Studies that evaluated an intervention in a PICU setting or both in PICU and other settings and reported separate results for PICU were eligible for full-text review. Studies that had implemented stewardship in the entire hospital, including the PICU, but without presenting dedicated PICU data were excluded from the analysis. DATA EXTRACTION: The strategy of intervention, structure of ASP team, implementation, and outcomes were assessed with a checklist tool for all studies included in the analysis. Risk of bias was assessed with the Cochrane Risk-of-Bias in Nonrandomized studies of Interventions tool. DATA SYNTHESIS: Thirteen articles were found: 11 that applied ASP in PICUs, and two at hospital level. All PICU-dedicated ASPs applied a multimodal intervention combining strategies simultaneously; audit with feedback (6/11) and facility-specific clinical practice guidelines (7/11) were the most common strategies. A multidisciplinary team was formulated in all ASPs except for three biomarker-based interventions. Six of 11 studies included techniques to enhance behavior change and one implemented a behavior-based intervention. Antibiotic consumption was evaluated in all ASPs, cost in three of 11, antibiotic resistance in one of 11, length of hospitalization in six of 11, and mortality in eight of 11. All hospital-wide ASPs used audit with feedback in addition to facility-specific clinical practice guidelines and assessed antimicrobial consumption, expenditures, length of stay, and mortality. CONCLUSIONS: The prevalence of ASPs in PICUs is limited, and few programs follow all of the currently available recommendations.

Targeted Genotyping of MIS-C Patients Reveals a Potential Alternative Pathway Mediated Complement Dysregulation during COVID-19 Infection.

Complement dysregulation has been documented in adults with COVID-19 and implicated in relevant pediatric inflammatory responses against SARS-CoV-2. We propose that signatures of complement missense coding SNPs associated with dysregulation could also be identified in children with multisystem inflammatory syndrome (MIS-C). We investigated 71 pediatric patients with RT-PCR validated SARS-CoV-2 hospitalized in pediatric COVID-19 care units (November 2020-March 2021) in three major groups. Seven (7) patients suffered from MIS-C (MIS-C group), 32 suffered from COVID-19 and were hospitalized (admitted group), whereas 32 suffered from COVID-19, but were sent home. All patients survived and were genotyped for variations in the C3, C5, CFB, CFD, CFH, CFHR1, CFI, CD46, CD55, MASP1, MASP2, MBL2, COLEC11, FCN1, and FCN3 genes. Upon evaluation of the missense coding SNP distribution patterns along the three study groups, we noticed similarities, but also considerably increased frequencies of the alternative pathway (AP) associated with SNPs rs12614 CFB, rs1061170, and rs1065489 CFH in the MIS-C patients. Our analysis suggests that the corresponding substitutions potentially reduce the C3b-inactivation efficiency and promote slower and weaker AP C3bBb pre-convertase assembly on virions. Under these circumstances, the complement AP opsonization capacity may be impaired, leading to compromised immune clearance and systemic inflammation in the MIS-C syndrome.

Early initiation of the respiratory syncytial virus season in 2021-2022, Greece.

Respiratory syncytial virus (RSV) is the most common viral pathogen causing respiratory disease in the pediatric population. An unexpected sudden upsurge of RSV infections among children was observed in September 2021 in Greece. Forty-one rhinopharyngeal samples from children under the age of 2 years with confirmed RSV bronchiolitis were tested to identify the genotype(s) of the RSV strain(s). The children were hospitalized during September-November 2021 in three tertiary hospitals in northern Greece. A one-step RT-PCR which amplifies a fragment of the second hypervariable region of the G protein gene was applied. PCR products were sequenced, and phylogenetic analysis was performed. Most (80.5%) RSV cases were typed as RSV-A, with RSV-B accounting for 19.5% of cases. RSV-A and RSV-B sequences clustered within the ON1 and BA genotypes, respectively. As the same genotypes were detected in cases observed during 2016-2018 in northern Greece, it was suggested that the early upsurge of infections was not related to the emergence of novel strain(s), but it was the result of the absence of immunity among children and their mothers due to the restriction measures taken during the COVID-19 pandemic in the previous RSV season. Awareness is needed to diagnose even the out-of-season RSV infections, while molecular epidemiology plays a key role in monitoring the efficacy of currently available therapeutics and for those under development.

Emergence of ST39 carbapenem-resistant Klebsiella pneumoniae producing VIM-1 and KPC-2.

INTRODUCTION: Carbapenem-resistant Klebsiella pneumoniae (CRKP) causes life-threatening hospital-acquired infections. KPC and VIM carbapenemase production is the main molecular mechanism for carbapenem resistance. The aim of the current study was the genetic characterization of four ST39 CRKP isolates simultaneously producing VIM-1 and KPC-2, obtained in a Greek tertiary hospital. METHODS: Identification and antimicrobial susceptibility testing were performed through VITEK 2. Multiplex PCR, multiplex lateral flow immunoassay, phenotypic tests and next generation sequencing were applied. The sequence reads were de novo assembled and annotated, while antimicrobial resistance genes and plasmids were identified using bioinformatics software. Genomic comparison and core genome single-nucleotide polymorphism-based phylogenetic analysis were also performed. RESULTS: Three isolates were pandrug-resistant, and one was extensively drug-resistant; they all carried blaVIM-1 and blaKPC-2 genes and were assigned to ST39. BlaVIM-1 was integrated in a class 1 integron. They all harboured many antimicrobial resistance genes and various plasmids. The mgrB gene of all isolates was disrupted by an insertion sequence (ISKpn14). Genome comparison and phylogenetic analysis revealed that the isolates were closely related. CONCLUSION: To our knowledge this is the first report on detection of CRKP ST39 isolates simultaneously producing VIM-1 and KPC-2 in addition to colistin resistance. The knowledge of the clonal relatedness of the isolates can lead to the implementation of strict infection control measures absolutely needed to eliminate their spread.

Changes in molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae in the intensive care units of a Greek hospital, 2018-2021.

The spread of multi-drug resistant (MDR) Gram-negative bacteria, including Klebsiella pneumoniae, constitutes a global threat. The most frequent mechanism of acquired carbapenem resistance is the production of carbapenemases, especially KPC, NDM, VIM, IMP and OXA-48. We analyzed the epidemiological trend of carbapenem resistance genes of carbapenem-resistant K. pneumoniae (CRKP) strains isolated from critically ill patients in a Greek tertiary hospital. The study included 150 CRKP isolates collected from 116 (77.4%) patients hospitalized in the adult ICU and 17 (11.3%) each in the pediatric and the two neonatal ICUs between March 2018 and March 2021. Identification and antimicrobial susceptibility testing were performed using VITEK-2. A multiplex lateral flow immunoassay was used for the detection of carbapenemases, while the detection of bla VIM, bla KPC, bla NDM, bla IMP and bla OXA-48-like genes was achieved by multiplex PCR. The bla NDM was mainly detected in adults (54/116, 46.9%), while in children the most often detected gene was bla KPC (24/34, 70.6%). The predominant carbapenem resistance gene during 2018-2019 was bla KPC alone or in combination with bla VIM, reaching 44.4% in 2019, while during 2020-2021 the detection of bla NDM prevailed significantly, reaching 45.5 and 60.7% for 2020 and 2021, respectively. A shift in the molecular epidemiology of CRKP was seen during 2018-2021, which is probably associated with the recent excessive empiric use of newer antimicrobials. Surveillance studies and proper and strict implementation of infection control measures are highly needed to decrease the spread of MDR bacteria, including CRKP.

SARS-CoV-2 molecular testing in Greek hospital paediatric departments: a nationwide study.

As most children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) present with mild symptoms or they are asymptomatic, the optimal strategy for molecular testing it is not well defined. The aim of the study was to determine the extent and aetiology of molecular testing for SARS-CoV-2 in Greek paediatric departments during the first phase of the pandemic and identify possible differences in incidence, depending on the age group and geographical area. We conducted a nationwide study of molecular testing for SARS-CoV-2 of children in paediatric departments between March and June 2020. A total of 65 paediatric departments participated in the study, representing 4901 children who were tested for SARS-CoV-2 and 90 (1.8%) were positive. Most paediatric cases were associated with topical outbreaks. Adolescents 11-16 years had the highest positivity rate (3.6%) followed by children 6-10 years (1.9%). However, since the testing rate significantly differed between age groups, the modified incidence of SARS-CoV-2 infection per age group was highest in infants <1 year (19.25/105 population). Most children tested presented with fever (70.9%), respiratory (50.1%) or gastrointestinal symptoms (28.1%). Significant differences were detected between public and private hospitals regarding the positivity rate (2.34% vs. 0.39%, P-value <0.001). Significant variation in SARS-CoV-2 molecular testing positivity rate and incidence between age groups indicate discrepancies in risk factors among different age groups that shall be considered when ordering molecular testing.

Invasive Mucormycosis in Children With Malignancies: Report From the Infection Working Group of the Hellenic Society of Pediatric Hematology-Oncology.

Mucormycosis is an invasive, life-threatening fungal infection that mainly affects immunocompromised hosts. We collected data of pediatric mucormycosis cases from all 7 Greek Hematology-Oncology Departments for the years 2008-2017. Six cases of invasive mucormycosis diagnosed during treatment for malignancies were included in the study. In 4 children (66%) mucormycosis occurred within the first 20 days after diagnosis of the underlying disease. Two cases were classified as proven mucormycosis and 4 as probable. The most frequently recorded species was Rhizopus arrhizus (2 patients), followed by Mucor spp (1), and Lichtheimia spp (1). All patients received liposomal amphotericin B. Combined antifungal treatment was used in 5 cases. Surgical excision was performed in 4 cases (66%). Two patients died at 6 and 12 months after the diagnosis, respectively, 1 (17%) because of mucormycosis. Our data suggest that mucormycosis may occur early after the initiation of intensive chemotherapy in children with malignancies.

Polyclonal predominance of concurrently producing OXA-23 and OXA-58 carbapenem-resistant Acinetobacter baumannii strains in a pediatric intensive care unit.

We report a predominance (64.7%) of polyclonal carbapenem-resistant Acinetobacter baumannii (CRAB) strains concurrently producing OXA-23 and OXA-58 carbapenemases in a pediatric intensive care unit in an endemic area. This is the first report of emergence of such double-OXA CRAB strains in a single unit worldwide.

Epidemiological surveillance of multidrug-resistant gram-negative bacteria in a solid organ transplantation department.

BACKGROUND: We assessed the impact of intensified infection control measures (ICM) on colonization and infection caused by carbapenem-resistant (CR) Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii in a solid organ transplantation (SOT) department. METHODS: A quasi-experimental methodology was followed. The study was divided into three periods: pre-intervention, intervention with implementation of an ICM bundle including active surveillance program (ASP) and gradually enhanced measures, and post-ASP without ASP. The bundle included active surveillance cultures, contact precautions, hand hygiene, education of health care workers (HCWs), monitoring of compliance, and environmental cleaning. Incidence of colonization and infection caused by CR gram-negative bacteria was recorded. Molecular analysis of CR bacteria was performed for a certain period. RESULTS: During the intervention, incidence of colonization reduced from 19% to 9% (P<.001). The compliance of HCWs with contact precautions and hand hygiene also improved. Monthly incidence of infections caused by these CR bacteria increased from 2.8 to 6.9/1000 bed-days (P<.001). However, this increase did not have such a strong trend after the intervention. Most K. pneumoniae isolates, the commonest pathogen, carried the blaKPC gene. Colonization and infection rates by CR K. pneumoniae, P. aeruginosa, and A. baumannii were high among SOT recipients. CONCLUSION: In settings where CR gram-negative bacteria are endemic, colonization and infection rates by these bacteria are high among SOT recipients. Implementation of enhanced ICM in all related units of a hospital, although challenging, reduces colonization rates by CR gram-negative bacteria.

Comparison of cotrimoxazole vs. second-generation cephalosporins for prevention of urinary tract infections in children.

BACKGROUND: Antimicrobial prophylaxis is recommended for the prevention of urinary tract infections (UTI) in high-risk children. However, there is growing concern about the use of ß-lactams as prophylaxis and subsequent development of antibiotic resistance. METHODS: In this prospective, randomized, crossover controlled trial we compared cotrimoxazole (SXT) and second-generation cephalosporins (2GC) as UTI prophylaxis in children ranging in age from 1 to 60 months. Eligible patients were 1:1 randomized to receive either SXT or 2GC for the initial 6-month period (1 course), then switched to the other antimicrobial agent class for the subsequent course, with switching continuing after each course until the end of the study. Urethral orifice cultures (UOCs) were obtained at the time of switching antimicrobial prophylaxis. RESULTS: Among 97 children (mean age 13.6 months) on prophylaxis, breakthrough UTIs occurred during 13.3 % (10/75) of SXT courses and 10.3 % (8/78) of 2GC courses (p = 0.62). 2GC failed earlier than SXT (mean ± standard error: 0.81 ± 0.1 vs. 2.37 ± 0.36 months, respectively; p = 0.028). Pseudomonas aeruginosa and Enterococcus spp. were more frequently isolated after 2GC courses than after SXT courses [22.6 vs. 4.8 % (p = 0.02) and 20.7 vs. 4.8 % (p = 0.035), respectively]. Prophylaxis with 2GC significantly increased resistance to both 2GC and SXT, while SXT prophylaxis did not affect susceptibility to 2GC. CONCLUSIONS: While SXT and 2GC appear to be equally efficacious as UTI prophylaxis in children, the latter exert a broader effect on patients' flora and development of bacterial resistance, suggesting that SXT may be more appropriate for UTI prophylaxis than 2GC.

Nosocomial bloodstream infections in neurosurgery: a 10-year analysis in a center with high antimicrobial drug-resistance prevalence.

BACKGROUND: Data on nosocomial bloodstream infections (NBSI) in neurosurgery is limited. This study aimed to analyze the epidemiology, microbiology, outcome, and risk factors for death in neurosurgical patients with NBSI in a multidrug resistant setting. METHODS: Neurosurgical patients with a confirmed NBSI within the period 2003-2012 were retrospectively analyzed. NBSI was diagnosed when a pathogen was isolated from a blood sample obtained after the first 48 h of hospitalization. Patients' demographic, clinical, and microbiological data were recorded and analyzed using univariate and multivariate analysis. RESULTS: A total of 236 patients with NBSI were identified and 378 isolates were recovered from blood cultures. Incidence of NBSI was 4.3 infections/1000 bed-days. Gram-negative bacteria slightly predominated (54.5 %). The commonest bacteria were coagulase-negative staphylococci (CoNS, 26 %), Klebsiella pneumoniae (15.3 %), Pseudomonas aeruginosa (14.8 %), and Acinetobacter baumannii (13.2 %). Carbapenem resistance was found in 90 % of A. baumannii, in 66 % of P. aeruginosa, and in 22 % (2003-2007) to 77 % (2008-2012) of K. pneumoniae isolates (p < 0.05). Most CoNS and Staphylococcus aureus isolates (94 and 80 %, respectively) were methicillin-resistant. All Gram-negative isolates were sensitive to colistin and all Gram-positive isolates were sensitive to vancomycin and linezolid. Antimicrobial consumption decreased after 2007 (p < 0.05). Overall mortality was 50.4 %. In multivariate analysis, advanced age and stay in an Intermediate Care Unit (IMCU) were independent risk factors for in-hospital mortality (p < 0.05). CONCLUSIONS: Overall, high incidence of NBSI and considerable resistance of Gram-positive and particularly Gram-negative bacteria were noted in neurosurgical patients. Mortality was high with advanced age and stay in IMCU being the most important death-related factors.

Successful Treatment of Disseminated Fusariosis in a 15-Month-Old Boy With Refractory Acute Lymphoblastic Leukemia Using High-Dose Voriconazole.

BACKGROUND: Infections due to rare molds, such as Fusarium spp., cause severe and difficult-to-control diseases with increasing frequency. Data on fusariosis in children and on the use of voriconazole (VCZ), considered a drug of choice, are scarce in infants and children <2 years of age. CASE PRESENTATION: We present the first, to our knowledge, pediatric case of disseminated mycosis due to Fusarium musae in a 15-month-old boy with relapsed/refractory acute lymphoblastic leukemia, diagnostics and outcome. Herein, at this severely immunocompromised patient, after prompt diagnosis, disseminated fusariosis was successfully treated with high-dose VCZ at a final dose of 15 mg/kg of body weight twice a day. This occurred by achieving adequate drug exposures as determined by drug susceptibility testing and followed by therapeutic drug monitoring without observed toxicity. CONCLUSIONS: Appropriate diagnostic approach and timely administration of optimal antifungal therapy with VCZ were important for the successful treatment of disseminated fusariosis. Therapeutic drug monitoring, especially in <2-year-old children, is necessary to achieve sufficient drug exposure for optimal therapeutic response without toxicity.

Untargeted Blood Lipidomics Analysis in Critically Ill Pediatric Patients with Ventilator-Associated Pneumonia: A Pilot Study.

This study aims to explore the diagnostic potential of blood lipid profiles in suspected ventilator-associated pneumonia (VAP). Early detection of VAP remains challenging for clinicians due to subjective clinical criteria and the limited effectiveness of current diagnostic tests. Blood samples from 20 patients, with ages between 6 months and 15 years, were collected at days 1, 3, 6, and 12, and an untargeted lipidomics analysis was performed using a Ultra high Pressure Liquid Chromatography hyphenated with High Resolution Mass Spectrometry UPLC-HRMS (TIMS-TOF/MS) platform. Patients were stratified based on modified pediatric clinical pulmonary index score (mCPIS) into high (mCPIS ≥ 6, n = 12) and low (mCPIS < 6, n = 8) VAP suspicion groups. With the untargeted lipid profiling, we were able to identify 144 lipid species from different lipid groups such as glycerophospholipids, glycerolipids, and sphingolipids, in the blood of children with VAP. Multivariate and univariate statistical analyses revealed a distinct distribution of blood lipid profiles between the studied groups, indicating the potential utility of lipid biomarkers in discriminating VAP presence. Additionally, specific lipids were associated with pharyngeal culture results, notably the presence of Klebsiella pneumoniae and Staphylococcus aureus, underscoring the importance of lipid profiling in identifying the microbial etiology of VAP.

Off-label Use of Ceftazidime/Avibactam in Neonatal Intensive Care Unit: A Real-life Experience and Literature Review.

BACKGROUND: Multi/extensively drug-resistant bacterial infections have recently increased and new antimicrobial options are needed for difficult-to-treat infections. Ceftazidime/avibactam (CZA) has been approved for patients 3 months to 18 years of age, but real-life data on its off-label use in neonates and young infants are still scarce. MATERIALS: We report demographic, clinical and microbiologic data as well as outcome and safety of all cases of infants treated with CZA between January 1, 2021 and September 30, 2022 in a tertiary neonatal intensive care unit. We also review all neonatal cases previously reported. RESULTS: Twenty-one patients [17 males, with median gestational age 29 +2 (IQR 6 +6 ) weeks] received 31 CZA courses at a dose of 20-50 mg/kg/dose of ceftazidime q8h for suspected or proved multi/extensively drug-resistant infections. Median postnatal age at the onset of treatment was 44 days (IQR: 94 days). Twelve bacteremias, 2 urinary tract infections and 1 ventilator-acquired pneumonia were recorded. Twelve (39%) treatments were targeted, while 19 (61%) were empirically started due to known colonization with Klebsiella pneumoniae carbapenemase-producing Gram-negative bacteria. All patients had received multiple antibiotics prior and concomitantly with CZA. The most common pathogen identified at targeted administrations was carbapenem-resistant Klebsiella pneumoniae (83%). No serious adverse events attributed to the drug were detected. Twenty-one courses of CZA administration to 20 neonates with a median gestational age of 28.5 (IQR 3.5) weeks were previously reported without significant related adverse events. CONCLUSIONS: Favorable clinical and microbiologic responses in neonatal intensive care unit patients treated with CZA off-label were observed without significant and unexpected adverse events in critically ill neonates.

Antifungal Drug Usage in European Neonatal Units: A Multicenter Weekly Point Prevalence Study.

BACKGROUND: Data on antifungal prescribing in neonatal patients are limited to either single-center or single-country studies or to 1-day recording. Therefore, we assessed antifungal longitudinal usage in neonatal units (NUs) within Europe. METHODS: CALYPSO, a prospective weekly point prevalence study on antifungal drug usage in NUs in 18 hospitals (8 European countries), was conducted in 2020 during a 12-week period. All patients receiving systemic antifungals were included. Ward demographics were collected at the beginning; ward and patient data including indication, risk factors and antifungal regimen were weekly collected prospectively. RESULTS: Among 27 participating NUs, 15 (56%) practiced antifungal prophylaxis for neonates with birth weight <1000 g or <1500 g and additional risk factors. In total, 174 patients received antifungals with a median frequency per week of 10.5% ranging from 6.9% to 12.6%. Indication for antifungal prescribing was prophylaxis in 135/174 (78%) courses and treatment in 22% [39 courses (69% empirical, 10% preemptive, 21% targeted)]. Fluconazole was the most frequent systemic agent used both for prophylaxis (133/135) and treatment (15/39, 39%). Among neonates receiving prophylaxis, the most common risk factors were prematurity (119/135, 88%), mechanical ventilation (109/135, 81%) and central vascular catheters (89/135, 66%). However, gestational age <28 weeks was only recorded in 55/135 (41%) courses and birth weight <1000 g in 48/135 (35%). Most common reason for empirical treatment was late-onset sepsis; all 8 targeted courses were prescribed for invasive candidiasis. CONCLUSION: Antifungal usage in European NUs is driven by prophylaxis and empirical treatment with fluconazole being the most prescribed agent for both indications.

Use of Newer and Repurposed Antibiotics against Gram-Negative Bacteria in Neonates.

Antimicrobial resistance has become a significant public health problem globally with multidrug resistant Gram negative (MDR-GN) bacteria being the main representatives. The emergence of these pathogens in neonatal settings threatens the well-being of the vulnerable neonatal population given the dearth of safe and effective therapeutic options. Evidence from studies mainly in adults is now available for several novel antimicrobial compounds, such as new ß-lactam/ß-lactamase inhibitors (e.g., ceftazidime-avibactam, meropenem-vaborbactam, imipenem/cilastatin-relebactam), although old antibiotics such as colistin, tigecycline, and fosfomycin are also encompassed in the fight against MDR-GN infections that remain challenging. Data in the neonatal population are scarce, with few clinical trials enrolling neonates for the evaluation of the efficacy, safety, and dosing of new antibiotics, while the majority of old antibiotics are used off-label. In this article we review data about some novel and old antibiotics that are active against MDR-GN bacteria causing sepsis and are of interest to be used in the neonatal population.

Neonatal Bloodstream Infection with Ceftazidime-Avibactam-Resistant blaKPC-2-Producing Klebsiella pneumoniae Carrying blaVEB-25.

BACKGROUND: Although ceftazidime/avibactam (CAZ/AVI) has become an important option for treating adults and children, no data or recommendations exist for neonates. We report a neonatal sepsis case due to CAZ/AVI-resistant blaKPC-2-harboring Klebsiella pneumoniae carrying blaVEB-25 and the use of a customized active surveillance program in conjunction with enhanced infection control measures. METHODS: The index case was an extremely premature neonate hospitalized for 110 days that had been previously treated with multiple antibiotics. Customized molecular surveillance was implemented at hospital level and enhanced infection control measures were taken for early recognition and prevention of outbreak. Detection and identification of blaVEB-25 was performed using next-generation sequencing. RESULTS: This was the first case of a bloodstream infection caused by KPC-producing K. pneumoniae that was resistant to CAZ/AVI without the presence of a metalo-ß-lactamase in the multiplex PCR platform in a neonate. All 36 additional patients tested (12 in the same NICU and 24 from other hospital departments) carried wild-type blaVEB-1 but they did not harbor blaVEB-25. CONCLUSION: The emergence of blaVEB-25 is signal for the horizontal transfer of plasmids at hospital facilities and it is of greatest concern for maintaining a sharp vigilance for the surveillance of novel resistance mechanisms. Molecular diagnostics can guide appropriate antimicrobial therapy and the early implementation of infection control measures against antimicrobial resistance.

Evaluation of Five Host Inflammatory Biomarkers in Early Diagnosis of Ventilator-Associated Pneumonia in Critically Ill Children: A Prospective Single Center Cohort Study.

Background: Early diagnosis of ventilator-associated pneumonia (VAP) remains a challenge due to subjective clinical criteria and the low discriminative power of diagnostic tests. We assessed whether rapid molecular diagnostics in combination with Clinically Pulmonary Index Score (CPIS) scoring, microbiological surveillance and biomarker measurements of PTX-3, SP-D, s-TREM, PTX-3, IL-1ß and IL-8 in the blood or lung could improve the accuracy of VAP diagnosis and follow-up in critically ill children. Methods: A prospective pragmatic study in a Pediatric Intensive Care Unit (PICU) was conducted on ventilated critically ill children divided into two groups: high and low suspicion of VAP according to modified Clinically Pulmonary Index Score (mCPIS). Blood and bronchial samples were collected on days 1, 3, 6 and 12 after event onset. Rapid diagnostics were used for pathogen identification and ELISA for PTX-3, SP-D, s-TREM, IL-1ß and IL-8 measurements. Results: Among 20 enrolled patients, 12 had a high suspicion (mCPIS > 6), and 8 had a low suspicion of VAP (mCPIS < 6); 65% were male; and 35% had chronic disease. IL-1ß levels at day 1 correlated significantly with the number of mechanical ventilation days (rs = 0.67, p < 0.001) and the PICU stay (r = 0.66; p < 0.002). No significant differences were found in the levels of the other biomarkers between the two groups. Mortality was recorded in two patients with high VAP suspicion. Conclusions: PTX-3, SP-D, s-TREM, IL-1ß and IL-8 biomarkers could not discriminate patients with a high or low suspicion of VAP diagnosis.

Genetic Characterization of Carbapenem-Resistant Klebsiella pneumoniae Clinical Isolates in a Tertiary Hospital in Greece, 2018-2022.

BACKGROUND: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a serious public health issue. The study aimed to identify the antimicrobial resistance and accessory genes, the clonal relatedness, and the evolutionary dynamics of selected CRKP isolates recovered in an adult and pediatric intensive care unit of a tertiary hospital in Greece. METHODS: Twenty-four CRKP isolates recovered during 2018-2022 were included in the study. Next-generation sequencing was performed using the Ion Torrent PGM Platform. The identification of the plasmid content, MLST, and antimicrobial resistance genes, as well as the comparison of multiple genome alignments and the identification of core genome single-nucleotide polymorphism sites, were performed using various bioinformatics software. RESULTS: The isolates belonged to eight sequence types: 11, 15, 30, 35, 39, 307, 323, and 512. A variety of carbapenemases (KPC, VIM, NDM, and OXA-48) and resistance genes were detected. CRKP strains shared visually common genomic regions with the reference strain (NTUH-K2044). ST15, ST323, ST39, and ST11 CRKP isolates presented on average 17, 6, 16, and 866 recombined SNPs, respectively. All isolates belonging to ST15, ST323, and ST39 were classified into distinct phylogenetic branches, while ST11 isolates were assigned to a two-subclade branch. For large CRKP sets, the phylogeny seems to change approximately every seven SNPs. CONCLUSIONS: The current study provides insight into the genetic characterization of CRKP isolates in the ICUs of a tertiary hospital. Our results indicate clonal dispersion of ST15, ST323, and ST39 and highly diverged ST11 isolates.