Treatment of multidrug-resistant Gram-negative bloodstream infections in critically ill patients: an update.

PURPOSE OF REVIEW: This review describes the latest information in the management of bloodstream infections caused by multidrug-resistant Gram-negative bacilli (MDRGNB) in critically ill patients. RECENT FINDINGS: The prevalence of bloodstream infections due to MDRGNB is high, and they pose a significant risk in critically ill patients. Recently, novel antimicrobial agents, including new ß-lactam/ß-lactamase inhibitor combinations and cefiderocol, have been introduced for treating these infections. Concurrently, updated guidelines have been issued to aid in treatment decisions. Prompt diagnosis and identification of resistance patterns are crucial for initiating effective antibiotic therapy. Current studies, especially with observational design, and with limited sample sizes and patients with bacteremia, suggest that the use of these new antibiotics is associated with improved outcomes in critically ill patients with MDRGNB bloodstream infections. SUMMARY: For critically ill patients with bloodstream infections caused by MDRGNB, the use of newly developed antibiotics is recommended based on limited observational evidence. Further randomized clinical trials are necessary to determine the most effective antimicrobial therapies among the available options.

Bacteriemia asociada a catéteres venosos centrales no tunelizados en niños en hemodiálisis crónica / Bacteremia associated with non-tunneled central venous catheters in children undergoing chronic hemodialysis

Introducción. La infección asociada a catéter venoso central (CVC) es la principal complicación que presentan los pacientes en hemodiálisis en los que se usa este tipo de acceso. Objetivo. Estimar la incidencia de bacteriemia asociada a CVC no tunelizado, analizar la frecuencia de agentes causales y explorar factores de riesgo asociados en niños en hemodiálisis. Población y métodos. Estudio retrospectivo realizado en niños en hemodiálisis por CVC no tunelizado entre el 1 junio de 2015 y el 30 de junio de 2019. Para evaluar factores de riesgo predictores de bacteriemia asociada a CVC, se realizó regresión logística. Los factores de riesgo independiente se expresaron con odds ratio con sus respectivos intervalos de confianza del 95 %. Se consideró estadísticamente significativo un valor de p <0,05. Resultados. En este estudio se incluyeron 121 CVC no tunelizados. La incidencia de bacteriemia fue de 3,15 por 1000 días de catéter. El microorganismo aislado con mayor frecuencia fue Staphylococcus epidermidis (16 casos, 51,5 %). La infección previa del catéter fue el único factor de riesgo independiente encontrado para el desarrollo de bacteriemia asociada a CVC no tunelizado (OR: 2,84; IC95%: 1,017,96; p = 0,04). Conclusiones. El uso prolongado de los CVC no tunelizados para hemodiálisis crónica se asoció con una incidencia baja de bacteriemia. Los gérmenes grampositivos predominaron como agentes causales. La presencia de infección previa del CVC aumentó en casi 3 veces el riesgo de bacteriemia asociada a CVC en nuestra población pediátrica en hemodiálisis.

Introduction. Central venous catheter (CVC)-related infection is the main complication observed in patients undergoing hemodialysis with this type of venous access. Objective. To estimate the incidence of non-tunneled CVC-related bacteremia, analyze the frequency ofcausative agents, and explore associated risk factors in children undergoing hemodialysis. Population and methods. Retrospective study in children receiving hemodialysis via a non-tunneled CVC between June 1 st, 2015 and June 30 th, 2019. A logistic regression was carried out to assess risk factors that were predictors of CVC-related bacteremia. Independent risk factors were described as odds ratios with their corresponding 95% confidence interval (CI). A value of p < 0.05 was considered statistically significant. Results. A total of 121 non-tunneled CVCs were included in this study. The incidence of bacteremia was 3.15 per 1000 catheter-days. The most commonly isolated microorganism was Staphylococcus epidermidis(16 cases, 51.5%). Prior catheter infection was the only independent risk factor for the development of bacteremia associated with non-tunneled CVC (OR: 2.84, 95% CI: 1.01­7.96, p = 0.04). Conclusions. Prolonged use of non-tunneled CVCs for chronic hemodialysis was associated with a low incidence of bacteremia. Gram-positive microorganisms prevailed among causative agents. A prior CVC infection almost trebled the risk for CVC-related bacteremia in our pediatric population receiving hemodialysis.

Gastrointestinal endoscopy 30-day-associated bacteremia: Nonoutbreak 5-year review in an inner-city, tertiary-care hospital.

BACKGROUND: Gastrointestinal endoscopic procedures (GIEP's) are an essential part of patient care both diagnostically and therapeutically. Post-GIEP infections may be higher than previously reported and may not have been accurately captured in the past. The aim of this study was to determine the incidence and associated factors of bacteremia associated with GIEP's. METHODS: This is retrospective study of GIEPs performed over a five-year period (2018-2022) at an academic medical center. Electronic health records (EHR) identified GIEPs and positive blood cultures within 30 days of procedure. Statistical analysis was performed using non-parametric testing to compare variables due to the small number of positive blood cultures. RESULTS: EHR identified 18,986 GIEP's and 52 true and unique bacteremia out of 17,093 blood cultures during the five-year study period. The highest rate of positive blood culture of 2.84% (18/ 634) was associated with ERCP and the lowest 0.08% (7/ 9029) was associated with colonoscopy. DISCUSSION: Our study showed a reflection of the endemic rate of bacteremia post GIEP's. Our study cannot differentiate endogenous infection versus contaminated (exogenous) endoscopes. ERCP procedures are disproportionately associated with higher incidence of bacteremia. CONCLUSIONS: Clinical surveillance in non-outbreak settings is essential for estimating GIEP related infections. It should be combined with endoscopic reprocessing audits for appropriate prevention of GIEP associated infections.

Seven-day antibiotic therapy for Enterobacterales bacteremia in high-risk neutropenic patients: toward a new paradigm.

PURPOSE: Data on short courses of antibiotic therapy for Enterobacterales bacteremia in high-risk neutropenic patients are limited. The aim of the study was to describe and compare the frequency of bacteremia relapse, 30-day overall and infection-related mortality, Clostridiodes difficile infection and length of hospital stay since bacteremia among those who received antibiotic therapy for 7 or 14 days. METHODS: This is a multicenter, prospective, observational cohort study in adult high-risk neutropenic patients with hematologic malignancies or hematopoietic stem cell transplant and monomicrobial Enterobacterales bacteremia. They received appropriate empirical antibiotic therapy, had a clinical response within 7 days, and infection source control. Clinical, epidemiological and outcomes variables were compared based on 7 or 14 days of AT. RESULTS: Two hundred patients were included (100, 7-day antibiotic therapy; 100, 14-day antibiotic therapy). Escherichia coli was the pathogen most frequently isolated (47.5%), followed by Klebsiella sp. (40.5%). Among those patients that received 7-day vs. 14-day antibiotic course, a clinical source of bacteremia was found in 54% vs. 57% (p = 0.66), multidrug-resistant Enterobacterales isolates in 28% vs. 30% (p = 0.75), and 40% vs. 47% (p = 0.31) received combined empirical antibiotic therapy. Overall mortality was 3% vs. 1% (p = 0.62), in no case related to infection; bacteremia relapse was 7% vs. 2% (p = 0.17), and length of hospital stay since bacteremia had a median of 9 days (IQR: 7-15) vs. 14 days (IQR: 13-22) (p = < 0.001). CONCLUSIONS: These data suggest that seven-day antibiotic therapy might be adequate for patients with high-risk neutropenia and Enterobacterales bacteremia, who receive appropriate empirical therapy, with clinical response and infection source control.

[Detection of microorganisms and resistance genes from positive blood cultures using the FilmArray® BCID2 panel: Experience in a pediatric hospital]. / Detección de microorganismos y genes de resistencia en hemocultivos positivos mediante FilmArray® panel BCID2: experiencia en un hospital pediátrico.

The rapid identification of microorganisms that cause bacteremia and their possible resistance markers are extremely important for the timely initiation of effective antibiotic therapy. The FilmArray® panel BCID2 (an automated rapid multiplex PCR assay) detects microorganisms and resistance genes from positive blood cultures within one hour. The aim of this study was to compare the results obtained from the FilmArray® Panel BCID2 and conventional culture in pediatric patients, as well as the reporting times of both methods. Sixty (60) FilmArray® results were included in the analysis. BCID2 showed high agreement with culture in the identification of microorganisms in monomicrobial bacteremias. However, in polymicrobial blood cultures, BCID2 detected a greater number of microorganisms compared to conventional culture, specifically,1 Staphylococcus aureus, 3 Staphylococcus epidermidis, 1 Enterococcus faecium, 2 Klebsiella oxytoca, 1 Acinetobacter calcoaceticus-baumannii complex, 1 Bacteroides fragilis and 1 Haemophilus influenzae. Furthermore, 88.3% (95%CI: 78.7-94.8) of the FilmArray® results coincided with conventional culture, while in polymicrobial bacteremias, BCID2 detected a greater number of microorganisms with respect to conventional culture [70% (95%CI: 39.3-91.5)]. The agreement of resistance genes was good with a few exceptions (one ESBL was not detected by FilmArray® and one S. aureus strain was characterized as methicillin-resistant by BCID2 and methicillin-sensitive by culture). When comparing the time elapsing since the blood culture was reported as positive up to the results were obtained, BCID2 had a median of 2h 50min (IQR of 1 h 58min to 9h 27min) while the conventional culture had a median of 45h 20min (IQR of 24h 57min to 63h 50min).

Impact of Vancomycin trough levels monitoring on uncomplicated methilcillin-resistant Staphylococcus aureus bacteremia in chronic kidney disease on hemodialysis, retrospective cohort.

BACKGROUND: CKD patients on hemodialysis (HD) with Staphylococcus aureus (SA) bacteremia present high morbidity, mortality and increased risk of MRSA. Vancomycin is the antibiotic of choice in these cases, it has a narrow therapeutic margin and inadequate dosage generates a risk of toxicity, therefore, the recommendation is to dosage it through serum levels. METHODS: This is a retrospective cohort study in 3 hospitals of third level of complexity in the city of Medellin in which there were differences in the measurement and implementation of vancomycin25 dosage based on trough levels (VL) in patients with chronic kidney disease on hemodialysis (CKD- HD) with uncomplicated bacteremia based infection by methilcillin-resistant Staphyloccocus aureus (MRSA). The primary outcome was the composite of hospital mortality, clinical response (fever, hemodynamic instability and altered consciousness), complications associated with bacteremia, or bacteriological response failure (positive cultures at first week follow-up) at 7 days. The composite variables were analyzed individually as secondary outcomes. RESULTS: The main unadjusted outcome (OR 1.3, CI 0.6 - 2.7) and adjusted for age, Charlson index, loading dose, initial dose, dosing frequency and MIC to vancomycin (OR 1.2, CI 0.5 - 2.7). Regarding adjusted secondary outcomes: clinical response (OR 1.4 CI 0.3 - 5.8), death (OR 1.3 CI 0.3 - 4.6) and complications (OR 0.9, CI 0.37 - 2.2). CONCLUSIONS: We conclude that the measurement of trough levels in patients with HD-CKD does not modify the composite outcome. The main limitation is the sample size and type of study, randomized control trials may be required to confirm the results presented.

[Mortality in bacterial pneumonia due to pneumococcus]. / Mortalidad en neumonía bacteriémica por neumococo.

INTRODUCTION: Despite improvements in health care, pneumonia-associated mortality remains high. The objective of this study was to analyze the factors associated with mortality in bacteremic pneumonia caused by pneumococcus. METHODS: Retrospective cohort study in adult patients with pneumonia diagnosis and isolation of pneumococcus in blood cultures, between January 2012 and May 2021, was carried out. Clinical and laboratory variables, radiological involvement, evolution and mortality during hospitalization were analyzed. The group of deceased patients was compared with that of survivors. RESULTS: 152 patients were included. Median age: 58 years; men: 58.9%; 33% presented a CURB-65 > than 2 at admission. Overall mortality: 34% (n=52). Deceased patients were more tachypneic on admission (respiratory rate 26 vs. 22; p=0.003), presented sensory alteration more frequently (58% vs. 14%; p< 0.001), PaO2/fraction of inspired oxygen ratio < 250 (58% vs. 22%; p<0.001), bilateral radiological compromise (50% vs. 32%; p=0.03), needed mechanical ventilation (50% vs 12%; p< 0.001), higher blood creatinine values (1.6 vs. 1.15; p=0.01), lower white blood cell count (10 900 vs 17 400; p=0.002), a lower glucose dosage (111 vs. 120; p=0.01), and fewer days of hospital stay (6 vs. 9; p=0.015). In logistic regression model, significant differences were maintained in the following factors associated with mortality: mechanical ventilation (OR=3.54), altered mental status (OR=5.95), chest X-ray with bilateral compromise (OR 3.20) and PAFI less than 250 (OR=3.62). CONCLUSION: In our series, the factors related to mortality, despite the presence of bacteremia, do not differ from those published in the literature and which are part of the different prognostic scores used in routine practice.

Introducción: A pesar de las mejoras en los cuidados de la salud, la mortalidad asociada a neumonía continúa siendo alta. El objetivo de este estudio fue analizar los factores asociados a mortalidad en neumonía bacteriémica por neumococo. Métodos: Estudio de cohorte retrospectiva en pacientes adultos con diagnóstico de neumonía y neumococo aislado en hemocultivos, entre enero 2012 y mayo 2021. Se analizaron: variables clínicas y de laboratorio, compromiso radiológico, evolución y mortalidad durante la internación. Se comparó el grupo de pacientes fallecidos con el de sobrevivientes. Resultados: Se incluyeron 152 pacientes. La mediana de edad fue de 58 años y el 58.9% fueron hombres. El 33% presentó un CURB-65 mayor a 2 al momento de internación. La mortalidad global fue 34% (n=52). Los pacientes fallecidos se encontraban más frecuentemente taquipneicos al ingreso (frecuencia respiratoria 26 vs. 22; p=0.003), presentaban más frecuentemente alteración del sensorio (58% vs. 14%; p< 0.001), PaO2/fracción inspirada de oxígeno (PAFI) < 250 (58% vs. 22%; p<0.001), compromiso radiológico bilateral (50% vs. 32%; p=0.03), necesidad de asistencia respiratoria mecánica (ARM) (50% vs. 12%; p< 0.001), mayor valor de creatinina en sangre (1.6 vs. 1.15; p=0.01), menor recuento de glóbulos blancos (10 900 vs. 17 400; p=0.002), menor valor de glucemia (111 vs. 120; p=0.01) y menos días de estancia hospitalaria (6 vs. 9; p=0.015). En el análisis de regresión logística multivariable se mantuvieron diferencias significativas en los siguientes factores asociados a mortalidad: ventilación mecánica (OR=3.54), confusión (OR=5.95), radiografía con compromiso bilateral (OR= 3.20) y PAFI < 250 (OR=3.62). Conclusión: Los factores relacionados con mortalidad, a pesar de la presencia de bacteriemia, no difieren de los publicados en la literatura y forman parte de los scores pronósticos de práctica habitual.

Susceptibility evaluation of novel beta-lactam/beta-lactamase inhibitor combinations against carbapenem-resistant Klebsiella pneumoniae from bloodstream infections in hospitalized patients in Brazil.

INTRODUCTION: Novel beta-lactam/beta-lactamase inhibitor (BIBLI) combinations are commercially available and have been used for treating carbapenem-resistant Klebsiella pneumoniae (CRKP) infections. Continuous surveillance of susceptibility profiles and resistance mechanism identification are necessary to monitor the evolution of resistance within these agents. OBJECTIVE: The purpose of this study was to evaluate the susceptibility rates of ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam in CRKP isolated from patients with bloodstream infections who underwent screening for a randomized clinical trial in Brazil. METHODS: Minimum inhibitory concentrations (MICs) were determined for meropenem, ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam using the gradient diffusion strip method. Carbapenemase genes were detected by multiplex real-time polymerase chain reaction. Klebsiella pneumoniae carbapenemase (KPC)-producing isolates showing resistance to any BLBLI and New Delhi Metallo-beta-lactamase (NDM)-producing isolates with susceptibility to any BLBLI isolates were further submitted for whole-genome sequencing. RESULTS: From a total of 69 CRKP isolates, 39 were positive for blaKPC, 19 for blaNDM and 11 for blaKPC and blaNDM. KPC-producing isolates demonstrated susceptibility rates above 94 % for all BLBLIs. Two isolates with resistance to meropenem/vaborbactam demonstrated a Gly and Asp duplication at the porin OmpK36 as well as a truncated OmpK35. All NDM-producing isolates, including KPC and NDM coproducers, demonstrated susceptibility rates to ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam of 0 %, 9.1-21.1 % and 9.1-26.3 %, respectively. Five NDM-producing isolates that presented susceptibility to BLBLIs also had porin alterations CONCLUSIONS: This study showed that, although high susceptibility rates to BLBLIs were found, KPC-2 isolates were able to demonstrate resistance probably as a result of porin mutations. Additionally, NDM-1 isolates showed susceptibility to BLBLIs in vitro.

Phenotypic and genotypic characteristics of mecA - positive oxacillin-sensitive Staphylococcus aureus isolated from patients with bloodstream infection in a tertiary hospital in Southern Brazil.

Staphylococcus aureus are extremely important microorganisms, either from an epidemiological point of view or as a pathogen, responsible for causing a series of infectious processes, whether simple, restricted to the skin, or invasive infections such as bacteremia. The emergence of Oxacillin Sensitive-Methicillin Resistant S.aureus (OS-MRSA) isolates has imposed difficulties in the treatment of patients with staphylococcal infection, as such isolates can be mistakenly classified as sensitive and lead to failure of the therapy used. Thus, the objective of this study is to evaluate the prevalence, and genotypic and phenotypic characteristics, of OS-MRSA isolates, from bloodstream infections, collected from patients admitted to a hospital in southern Brazil, as well as to evaluate the treatment used. For this, 801 unique isolates of S. aureus, collected from blood cultures, between January 2011 and December 2020 were evaluated. Of these, 96 isolates were classified as sensitive to oxacillin. The isolates were identified and had their sensitivity profile performed by manual and automated methods. The minimum inhibitory concentration for vancomycin, daptomycin, oxacillin, linezolid and teicoplanine was performed by e-test. The mecA, vanA genes, typing of the SCCmec elements, as well as the search for the icaA, tst-1 and pvl virulence genes were performed by PCR. Biofilm formation was performed using the crystal violet technique. The Sequence Type (ST), as well as the Clonal Complex (CC) of the isolates was evaluated by the RTq -PCR. The clinical characteristics of the patients were evaluated through an active search in medical records. After investigating the mecA gene, 27.1% (26/96) of the isolates were considered OS-MRSA, with SCCmec type I being the most prevalent, 46.1% (12/26). Among the evaluated isolates, 41% (9/22) were included in CC5 and ST9. As for virulence, all isolates were positive for the icaA gene and characterized as strong biofilm formers. The pvl gene was found in 92.3% (24/26) of the isolates and the toxic shock syndrome toxin was present in 61.5% of the isolates (16/26). All isolates were negative for the presence of the van A gene. As for the clinical outcome, 73% (19/26) of the patients were discharged from the hospital and 27% (7/26) died. It was possible to observe a high frequency of OS-MRSA isolates causing bloodstream infections. Furthermore, such isolates contain several virulence genes, which may contribute to a worse clinical outcome.

Rapid colorimetric polymyxin B microelution directly from positive blood bottles: because patients with serious infections should not have to wait for results of culture-based methodologies.

PURPOSE: To evaluate the performance of the rapid colorimetric polymyxin B microelution (RCPEm) in determining polymyxin B resistance directly from Enterobacterales-positive blood cultures. METHODS: A set volume of positive blood culture bottles (diluted 1:10) was inoculated into a glucose-broth-phenol red solution (NP solution), where a polymyxin B disk was previously eluted (final concentration of 3 µg/mL). Test was read each 1 h for up to 4 h. Color change from red/orange to yellow indicated resistant isolates. Results were compared to the reference method, broth microdilution (BMD), performed from colonies grown on solid media from the same blood culture bottle. RESULTS: One hundred fifty-two Enterobacterales-positive blood cultures were evaluated, 22.4% (34/152) of them resistant to polymyxin B (including 6.6% with borderline MICs). When performing directly from positive blood cultures (RCPEm-BC), specificity and sensitivity were 99.1% and 94.1%, respectively. Of note, 79.4% (27/34) of truly resistant isolates required 3 h of incubation, compared to the 18 ± 2 h incubation that microtiter plates of BMD demand before reading can be performed. CONCLUSIONS: RCPEm directly from blood cultures has great potential to be part of the routine of clinical microbiology laboratories to establish polymyxin B susceptibility, impacting outcome of patients with bloodstream infections caused by carbapenem-resistant Enterobacterales.

[Microorganisms isolated from blood cultures and resistance profile in children with cancer and high-risk febrile neutropenia. Red PINDA, Chile, 2016-2021]. / Microorganismos aislados de hemocultivos y su perfil de resistencia en niños con cáncer y neutropenia febril de alto riesgo. Red PINDA, Chile, 2016-2021.

Bacteremia is a major cause of morbidity and mortality in patients with cancer and episodes of high-risk febrile neutropenia (HRFN). OBJECTIVE: To identify the frequency of microorganisms isolated from blood cultures (BC) and their antimicrobial resistance (R) profile in children with HRFN, compared with the same data from previous studies of the same group. METHOD: Prospective, multicenter, epidemiological surveillance study of microorganisms isolated from BC in patients under 18 years of age, from 7 PINDA network hospitals, between 2016 and 2021. RESULTS: 284 episodes of HRFN with positive BC were analyzed out of 1091 enrolled episodes (26%). Median age 7.2 years [3.0-12.3]. The main isolates were gram-negative bacilli (GNB) 49.2%, gram-positive cocci (GPC) 43.8%, and fungi 3.6%. The most frequently isolated microorganisms were viridans group Streptococci (VGS) (25.8%), Escherichia coli (19.8%), Pseudomonas spp. (11.2%), Klebsiella spp. (10.9%), and coagulase negative Staphylococci (CoNS) (10.9%). There was an increase in R to third-generation cephalosporins (p = 0.011) in GNB and to oxacillin in CoNS (p = 0.00), as well as a decrease in R to amikacin in non-fermenting GNB (p = 0.02) and to penicillin in VGS (p = 0.04). CONCLUSION: VGS is the main agent isolated in BC from pediatric patients with cancer and episodes of HRFN, followed by E. coli, Pseudomonas spp., and Klebsiella spp. Having epidemiological surveillance of microorganisms isolated from BC and their antimicrobial R profile is essential to favor the rational use of antimicrobials.

Safety and Efficacy of Ethanol for Catheter Salvage and Central Line-Associated Bloodstream Infection Prophylaxis in Polyurethane Catheters in the PICU.

OBJECTIVES: Ethanol lock therapy (ELT) is a potential method of central catheter salvage following central line-associated bloodstream infection (CLABSI) although there is potential risk of catheter damage in polyurethane catheters. Further, there is limited efficacy data across the spectrum of common pediatric catheters, and published ELT protocols describe dwell times that are not feasible for critically ill children. We sought to evaluate the safety and efficacy of ELT in polyurethane catheters using brief (30 min to 2 hr) dwell times in our PICU. DESIGN: Investigational pilot study using historical control data. SETTING: PICU in quaternary care, free-standing children's hospital. INTERVENTIONS: ELT in polyurethane central venous catheters for catheter salvage. RESULTS: ELT with brief dwell times was used in 25 patients, 22 of whom were bacteremic. Ultimately 11 patients, comprising 14 catheters, were diagnosed with a primary CLABSI. The catheter salvage rate in primary CLABSI patients receiving ELT was 92% (13/14) and significantly higher than the salvage rate in patients receiving antibiotics alone (non-ELT) (62%, 39/64; mean difference 0.32, 95% CI [0.14-0.50], p = 0.03). The rate of catheter fracture in all patients receiving ELT was 8% (2/25) while the rate of fracture in the non-ELT group was 13% (8/64; mean difference -0.05, 95% CI [-0.18 to 0.09], p = 0.72). The rate of tissue plasminogen activator (tPA) use in the ELT group was 8% (2/25), whereas the rate of tPA use in the non-ELT group was significantly higher at 42% (26/64; mean difference -0.34, 95% CI [-0.49 to -0.17], p = 0.002). CONCLUSIONS: The use of ELT for catheter salvage and prophylaxis in the PICU is safe in a variety of polyurethane catheters. Dwell times ranging from 30 minutes to 2 hours were effective in sterilizing the catheters while allowing other therapies to continue. This approach may decrease the need for frequent line changes in a medically fragile pediatric population.

A machine learning model for the early diagnosis of bloodstream infection in patients admitted to the pediatric intensive care unit.

Bloodstream infection (BSI) is associated with increased morbidity and mortality in the pediatric intensive care unit (PICU) and high healthcare costs. Early detection and appropriate treatment of BSI may improve patient's outcome. Data on machine-learning models to predict BSI in pediatric patients are limited and neither study included time series data. We aimed to develop a machine learning model to predict an early diagnosis of BSI in patients admitted to the PICU. This was a retrospective cohort study of patients who had at least one positive blood culture result during stay at a PICU of a tertiary-care university hospital, from January 1st to December 31st 2019. Patients with positive blood culture results with growth of contaminants and those with incomplete data were excluded. Models were developed using demographic, clinical and laboratory data collected from the electronic medical record. Laboratory data (complete blood cell counts with differential and C-reactive protein) and vital signs (heart rate, respiratory rate, blood pressure, temperature, oxygen saturation) were obtained 72 hours before and on the day of blood culture collection. A total of 8816 data from 76 patients were processed by the models. The machine committee was the best-performing model, showing accuracy of 99.33%, precision of 98.89%, sensitivity of 100% and specificity of 98.46%. Hence, we developed a model using demographic, clinical and laboratory data collected on a routine basis that was able to detect BSI with excellent accuracy and precision, and high sensitivity and specificity. The inclusion of vital signs and laboratory data variation over time allowed the model to identify temporal changes that could be suggestive of the diagnosis of BSI. Our model might help the medical team in clinical-decision making by creating an alert in the electronic medical record, which may allow early antimicrobial initiation and better outcomes.

Comparative analysis of the antimicrobial resistance and virulence traits in ESBL-producing-Klebsiella pneumoniae ST307 strains colonizing the gastrointestinal tract and causing a fatal bloodstream infection in a leukemia patient.

Klebsiella pneumoniae is an opportunistic pathogen that can colonize the gastrointestinal tract (GIT) of humans. The mechanisms underlying the successful translocation of this pathogen to cause extra-intestinal infections remain unknown, although virulence and antimicrobial resistance traits likely play significant roles in the establishment of infections. We investigated K. pneumoniae strains isolated from GIT colonization (strains Kp_FZcol-1, Kp_FZcol-2 and Kp_FZcro-1) and from a fatal bloodstream infection (strain Kp_HM-1) in a leukemia patient. All strains belonged to ST307, carried a transferable IncF plasmid containing the blaCTX-M-15 gene (pKPN3-307 TypeA-like plasmid) and showed a multidrug-resistance phenotype. Phylogenetic analysis demonstrated that Kp_HM-1 was more closely related to Kp_FZcro-1 than to the other colonizing strains. The Kp_FZcol-2 genome showed 81 % coverage with the Kp_HM-1 246,730 bp plasmid (pKp_HM-1), lacking most of its putative virulence genes. Searching public genomes with similar coverage, we observed the occurrence of this deletion in K. pneumoniae ST307 strains recovered from human colonization and infection in different countries. Our findings suggest that strains lacking the putative virulence genes found in the pKPN3-307 TypeA plasmid are still able to colonize and infect humans, highlighting the need to further investigate the role of these genes for the adaptation of K. pneumoniae ST307 in distinct human body sites.

Pseudomonas fluorescens CRBSI outbreak: complying with the standardization of invasive procedures is a step ahead in the fight against antimicrobial resistance.

In the healthcare sector, the implementation of standardized procedures, such as those commonly employed in franchises to ensure consistent quality, remains underprioritized. Within this framework, we focus on the importance of standardized central venous catheter (CVC) insertion procedures to prevent healthcare-associated outbreaks. While antimicrobial resistance (AMR) may still not be the most prevalent problem in some institutions, its increasing significance certainly underlines the urgency of infection prevention.We aim to highlight this issue by describing and discussing an outbreak scenario of carbapenem-resistant (CR) Pseudomonas fluorescens bloodstream infections resulting from a deviation from the standardized CVC insertion procedure. This outbreak led to six episodes of catheter related bloodstream infection (CRBSI) in patients with hematologic malignancies, delaying their primary treatment. Nineteen patients were exposed, leading to an attack rate of 31.6%.

Bacteremia associated with non-tunneled central venous catheters in children undergoing chronic hemodialysis. / Bacteriemia asociada a catéteres venosos centrales no tunelizados en niños en hemodiálisis crónica.

Introduction. Central venous catheter (CVC)-related infection is the main complication observed in patients undergoing hemodialysis with this type of venous access. Objective. To estimate the incidence of non-tunneled CVC-related bacteremia, analyze the frequency of causative agents, and explore associated risk factors in children undergoing hemodialysis. Population and methods. Retrospective study in children receiving hemodialysis via a non-tunneled CVC between June 1st, 2015 and June 30th, 2019. A logistic regression was carried out to assess risk factors that were predictors of CVC-related bacteremia. Independent risk factors were described as odds ratios with their corresponding 95% confidence interval (CI). A value of p < 0.05 was considered statistically significant. Results. A total of 121 non-tunneled CVCs were included in this study. The incidence of bacteremia was 3.15 per 1000 catheter-days. The most commonly isolated microorganism was Staphylococcus epidermidis (16 cases, 51.5%). Prior catheter infection was the only independent risk factor for the development of bacteremia associated with non-tunneled CVC (OR: 2.84, 95% CI: 1.01-7.96, p = 0.04). Conclusions. Prolonged use of non-tunneled CVCs for chronic hemodialysis was associated with a low incidence of bacteremia. Gram-positive microorganisms prevailed among causative agents. A prior CVC infection almost trebled the risk for CVC-related bacteremia in our pediatric population receiving hemodialysis.

Introducción. La infección asociada a catéter venoso central (CVC) es la principal complicación que presentan los pacientes en hemodiálisis en los que se usa este tipo de acceso. Objetivo. Estimar la incidencia de bacteriemia asociada a CVC no tunelizado, analizar la frecuencia de agentes causales y explorar factores de riesgo asociados en niños en hemodiálisis. Población y métodos. Estudio retrospectivo realizado en niños en hemodiálisis por CVC no tunelizado entre el 1 junio de 2015 y el 30 de junio de 2019. Para evaluar factores de riesgo predictores de bacteriemia asociada a CVC, se realizó regresión logística. Los factores de riesgo independiente se expresaron con odds ratio con sus respectivos intervalos de confianza del 95 %. Se consideró estadísticamente significativo un valor de p <0,05. Resultados. En este estudio se incluyeron 121 CVC no tunelizados. La incidencia de bacteriemia fue de 3,15 por 1000 días de catéter. El microorganismo aislado con mayor frecuencia fue Staphylococcus epidermidis (16 casos, 51,5 %). La infección previa del catéter fue el único factor de riesgo independiente encontrado para el desarrollo de bacteriemia asociada a CVC no tunelizado (OR: 2,84; IC95%: 1,017,96; p =0,04). Conclusiones. El uso prolongado de los CVC no tunelizados para hemodiálisis crónica se asoció con una incidencia baja de bacteriemia. Los gérmenes grampositivos predominaron como agentes causales. La presencia de infección previa del CVC aumentó en casi 3 veces el riesgo de bacteriemia asociada a CVC en nuestra población pediátrica en hemodiálisis.

Predictors of Invasive Bacterial Infection in Febrile Infants Aged 2 to 6 Months in the Emergency Department.

Our goal was to identify predictors of invasive bacterial infection (ie, bacteremia and bacterial meningitis) in febrile infants aged 2-6 months. In our multicenter retrospective cohort, older age and lower temperature identified infants at low risk for invasive bacterial infection who could safely avoid routine testing.

In vitro activity of ceftazidime-avibactam against gram-negative bacteria in patients with bacteremia and skin and soft-tissue infections in Colombia 2019-2021.

OBJECTIVES: Ceftazidime-avibactam (CAZ-AVI) is an option for infections caused by MDR gram-negative bacilli. In this study, we aimed to analyze the in vitro antimicrobial activity of CAZ-AVI and other antimicrobial agents against gram-negative bacilli that were collected in Colombia between 2019 and 2021 from patients with bacteremia and skin and soft-tissue infections (SSTIs). METHODS: A total of 600 Enterobacterales and 259 P. aeruginosa strains were analyzed. The phenotypic resistance of isolates, particularly non-susceptibility to meropenem, multidrug-resistant (MDR) isolates, and difficult-to-treat (DTR) P. aeruginosa, was evaluated according to CLSI breakpoints. RESULTS: Enterobacterales had the most susceptibility to CAZ-AVI (96.5 %) and tigecycline (95 %). Tigecycline and CAZ-AVI were the antimicrobial agents with the most in vitro activity against carbapenem-resistant Enterobacterales (CRE). CAZ-AVI was the antimicrobial treatment with the most activity against P. aeruginosa. CONCLUSIONS: Tigecycline and CAZ-AVI were the antimicrobial agents with the most activity against CRE and MDR Enterobacterales. For P. aeruginosa, CAZ-AVI was the antimicrobial treatment with the most in vitro activity.

Burkholderia cepacia complex in cystic fibrosis: critical gaps in diagnosis and therapy.

Burkholderia cepacia complex (Bcc) is a bacterial group with 'natural' multi-antimicrobial resistance. This complex has generated epidemic outbreaks across the world. In people with cystic fibrosis (CF), Bcc can cause severe lung infections that lead to accelerated lung damage, which can be complicated by necrotizing pneumonia accompanied by high fevers, leucocytosis, and bacteraemia, which commonly causes fatal outcomes. Specifically, infection by Burkholderia cenocepacia is considered an exclusion criterion for lung transplantation. The species of Bcc exhibit both genetic and phenotypic hypervariability that complicate their accurate microbiological identification. Automated methods such as MALDI-TOF can err in the determination of species. Their slow growth even in selective agars and the absence of international consensuses on the optimal conditions for their isolation make early diagnosis a difficult challenge to overcome. The absence of correlations between antibiograms and clinical results has resulted in the absence of standardized cut-off values of antimicrobial susceptibility, a fact that brings a latent risk since incorrect antibiotic therapy can induce the selection of more aggressive variants that worsen the clinical picture of the host, added to the absence of a clear therapeutic guide for the eradication of pulmonary infections by Bcc in patients with CF, resulting in frequently ineffective treatments. There is an urgent need to standardize methods and diagnostic tools that would allow an early and accurate diagnosis, as well as to perform clinical studies of the effectiveness of available antibiotics to eradicate Bcc infections, which would allow us to establish standardized therapeutic schemes for Bcc-infected patients.

Carbapenem-resistant Klebsiella pneumoniae bloodstream infections in haematological malignances and hematopoietic stem cell transplantation: Clinical impact of combination therapy in a 10-year Brazilian cohort.

Bacterial bloodstream infections (BSI) are a common threat among patients with haematological malignancies (HM) and hematopoietic stem cell transplant recipients (HSCT). The purpose of this research was to describe clinical and microbiological aspects of BSI caused by carbapenem-resistant Klebsiella pneumoniae (CRKp) and assess risk factors associated with 30-day mortality in a 10-year cohort of haematological patients. A total of 65 CRKp-BSI episodes occurring in HM patients and HSCT recipients and CRKp-BSI between January 2010 and December 2019 were retrospectively studied. Acute leukemias were the most frequently observed underlying disease (87.7%) and 18 patients (27.7%) received HSCT. Mucosal barrier injury in the gastrointestinal tract was the primary cause of bacteremia (86.1%). Also, 14 individuals (21.6%) had an Invasive Fungal Disease (IFD) throughout the episode. Regarding treatment, in 31 patients (47.7%) empirical therapy was deemed appropriate, whereas 33 (50.8%) patients received a combination therapy. Microbiological data revealed that the majority of isolates (53-58%) had the Polymyxin B co-resistance phenotype, while amikacin resistance was less common (16 samples, or 24.7%). The mortality rates at 14 and 30 days were 32.3% and 36.9%, respectively. In a multivariate Cox regression analysis, prompt appropriate antibiotic administration within three days was associated with a better outcome (Adjusted Hazard Ratio [aHR]: 0.33; 95% Confidence Interval [CI]: 0.14-0.76; p = 0.01), whereas hypotension at presentation (aHR: 3.88; 95% CI: 1.40-10.74; p = 0.01) and concurrent IFD (aHR: 2.97; 95% CI: 1.20-7.37; p = 0.02) were independently associated with death within 30 days. Additionally, a favorable correlation between combination therapy and overall survival was found (aHR: 0.18; 95%CI: 0.06-0.56; p = 0.002). In conclusion, 30-day mortality CRKp-BSI was elevated and most of the isolates were polymyxin B resistant. Early appropriate antimicrobial treatment and the use of combination therapy were linked to a better outcome.