[Analysis of Pathogenic Bacterial Spectrum, Drug Resistance and Risk Factors for Mortality of Bloodstream Infection in Patients with Hematologic Diseases].

OBJECTIVE: To analyze the pathogenic bacterial spectrum, drug resistance, and risk factors associated with multidrug-resistant bacterial infection and mortality in patients with hematologic diseases complicated by bloodstream infections, so as to provide reference for rational drug use and improving prognosis. METHODS: Positive blood culture specimens of patients with hematologic diseases in two Class A tertiary hospitals of Shanxi province from January 2019 to December 2021 were retrospectively analyzed. Pathogen distribution, drug resistance and outcomes of patients with bloodstream infection were investigated, then the multivariate logistic analysis was performed to analyze the risk factors of multidrug-resistant bacterial infection and factors affecting prognosis. RESULTS: 203 strains of pathogens were identified, mainly Gram-negative bacteria (GNB) (69.46%, 141/203), of which Escherichia coli (E.coli) had the highest incidence (41.13%, 58/141), followed by Klebsiella pneumoniae (20.57%, 29/141) and Pseudomonas aeruginosa (12.77%, 18/141). Extended-spectrum beta-lactamase (ESBL)-producing E.coli and Klebsiella pneumoniae were 46.55% (27/58) and 37.93% (11/29), respectively. Carbapenem-resistant Gram-negative bacteria accounted for 10.64% (15/141). And Gram-positive bacteria accounted for 27.59% (56/203), Staphylococcus epidermidis, Streptococcus pneumoniae, and Staphylococcus aureus were the most frequently isolated pathogen among Gram-positive bacteria (14.29%, 12.50% and 10.71%, respectively), of which methicillin-resistant Staphylococcus aureus accounted for 33.33% (2/6), coagulase-negative staphylococci accounted for 87.50% (7/8), without vancomycin- or linezolid-resistant strain. Additionally, fungi accounted for 2.95% (6/203), all of which were Candida. Multidrug-resistant Gram-negative bacteria (MDR-GNB) accounted for 53.90% (76/141). Duration of neutropenia >14 days was a risk factor for developing MDR-GNB infection. The 30-day all-cause mortality was 10.84%. Multivariate logistic regression analysis showed that the significant independent risk factors for mortality were age≥60 years (P <0.01, OR =5.85, 95% CI: 1.80-19.07) and use of vasopressor drugs (P <0.01, OR =5.89, 95% CI: 1.83-18.94). CONCLUSION: The pathogenic bacteria of bloodstream infection in patients with hematological diseases are widely distributed, and the detection rate of multidrug-resistant bacteria is high. The clinicians should choose suitable antibiotics according to the results of bacterial culture and antibiotic susceptibility test.

Antibiotic choices among healthcare professionals for enterococcal bacteremia with patterns of resistance and risk factors of mortality, in settings of poor antibiotic stewardship program - a five-year retrospective cohort study.

BACKGROUND: Enterococcal bacteremia has become prevalent in the recent decade, especially in hospitalized patients. Moreover, the rise in resistance patterns against antibiotic drugs regarding enterococci infection, such as cephalosporins, ampicillin and vancomycin, is prevailing. The major driving force behind this is the incongruous use of antibiotics with a minor contribution from environmental stressors which calls for vigilant and prudent administration of evidence-based antibiotics. METHODS: A retrospective study was conducted from January 1 2017 until December 31 2021, at the tertiary care center, Dr Ziauddin Hospital in Karachi, Pakistan. RESULTS: Our research revealed ampicillin resistance in 87 (63.5%), with an estimated 25 (18.8%) mortality. Male gender 19 (76%) and vancomycin resistance 13 (52%) were associated with increased mortality. Furthermore, appropriate antibiotic therapy reduced the risk of death compared with inappropriate and excessive use of antibiotics 10 (40%) vs. 15 (60%) vs. 20 (80%) respectively. Targeted therapy with amoxicillin/clavulanic acid was associated with lower mortality 1 (4%) and higher discharge rates 34 (32.1%). On Kaplan-Meier survival, targeted therapy with amoxicillin/clavulanic acid was associated with shorter hospital stays and prolonged survival. UTI was found as the most common source of enterococcal bacteremia 57 (41.6%), followed by respiratory 21 (15.3%) and intra-abdominal 13 (9.5%). In 26 (19%) patients, no identifiable source of infection was found. CONCLUSION: Vancomycin resistance and male gender were found independent risk factors for mortality. The use of inappropriate antibiotics significantly increases mortality in these patients. The appropriate antibiotic therapy reduces the risk of death. Furthermore, overuse of antibiotics didn't reduce mortality; instead increased the financial burden and chances of developing multi-drug resistant strains of other organisms by increasing hospital stays of patients.

Clinical outcomes and epidemiological characteristics of bacteremia in the older Japanese population.

BACKGROUND: The characteristics and clinical consequences of bacteremia in older people, who are highly susceptible to infections, need to be clarified. This study aimed to determine the epidemiological characteristics, prognosis, and predictors of 7-day mortality in patients with community-acquired (CA), healthcare-associated (HCA), and hospital-onset (HO) bacteremia in older adults aged ≥65 years. METHODS: Patients aged ≥65 years with positive blood cultures between April 1, 2015, and March 31, 2018, were divided into three groups: pre-old (65-74 years), old (75-89 years), and super-old (≥90 years). Characteristics based on medical exposure, including CA, HCA, and HO, were also compared and factors related to mortality were identified. RESULTS: Overall, 1716 episodes of bacteremia were identified in 1415 patients. Of the 1211 episodes without contamination, 32.8%, 54.3%, and 12.9% occurred in pre-old, old, and super-old patients. Central line-associated bloodstream infections were more common in pre-old patients and urinary tract infections in the old and super-old. The 7-day mortality rates in the pre-old, old, and super-old groups were 7.4%, 5.8%, and 14.2% (P = 0.002), respectively. Multivariable logistic regression showed that super-old age (adjusted odds ratio, aOR: 2.09 [1.13-3.88], P = 0.019) and HO bacteremia (aOR: 1.97 [1.18-3.28], P = 0.010) were independent risk factors for 7-day mortality. Infectious disease consultation had a protective effect on 7-day mortality (aOR: 0.59 [0.35-0.99], P = 0.047). CONCLUSIONS: The epidemiology of bacteremia differs among older people; thus, they should not be treated as a single entity. A careful approach is needed for the optimal management of bacteremia in these vulnerable patients.

Predictive value of C-reactive protein, procalcitonin, and interleukin-6 on 30-day mortality in patients with bloodstream infections / Valor predictivo de la proteína C reactiva, procalcitonina e interleucina-6 en la mortalidad a los 30 días en pacientes con infecciones del torrente sanguíneo

Background We aimed to assess the predictive performance of C-reactive protein (hsCRP), procalcitonin (PCT), and interleukin-6 (IL-6) at different times points of bloodstream infections (BSI) management. Methods The cases were collected from January 2020 to June 2021 in the First Affiliated Hospital of Xinjiang Medical University (n=185). We collected patients’ records of hsCRP, PCT, and IL-6 serum levels and calculated the clearance of these biomarkers on day 1, day 3, and day 5 (hsCRP-1, hsCRP-3, hsCRP-5, so do PCT, and IL-6). We analyzed these predictive performances for 30-day mortality with ROC and Logistic regression. The correlation between biomarkers and their clearance rates was performed by a rank correlation method. Results The 30-day mortality was 11.35% (21/185). Serial serum hsCRP-3, IL-6-3, PCT-1, PCT-3, and PCT-5 were statistically higher in BSI mortality than survivors. Significant predictive ability was found for 30-day mortality with blood culture (BC) reported fungi (OR, 0.033; 95% CI: 0.002–0.535) and PCT-5 (OR, 1.045; 95% CI: 1.013–1.078) levels, respectively. The AUC of PCT-5 levels for 30-day mortality was 0.784 (95% CI 0.678–0.949), and the cut-off value was 5.455ng/mL. Conclusions PCT-5 is more valuable for the prognosis of 30-day mortality in patients with BSI compared to the other inflammatory biomarkers (AU)

Antecedentes Nuestro objetivo fue evaluar el rendimiento predictivo de la proteína C reactiva (hsCRP), procalcitonina (PCT) e interleucina-6 (IL-6) en distintos momentos del tratamiento de pacientes con infecciones del torrente sanguíneo. Métodos Los casos se recogieron entre enero de 2020 y junio de 2021 en el Primer Hospital Afiliado de la Universidad Médica de Xinjiang (n = 185). Los valores de los niveles séricos de hsCRP, PCT e IL-6 se obtuvieron de los registros de los pacientes y calculamos la depuración de estos biomarcadores en el día 1, el día 3 y el día 5 (hsCRP-1, hsCRP-3, hsCRP-5, PCT e IL-6). Analizamos estos rendimientos predictivos para la mortalidad a 30 días con ROC y regresión logística. La correlación entre los biomarcadores y sus tasas de eliminación se realizó mediante un método de correlación de rangos. Resultados La mortalidad a 30 días fue de 11,35% (21/185). Los valores séricos seriados de hsCRP-3, IL-6-3, PCT-1, PCT-3 y PCT-5 fueron estadísticamente más elevados en los pacientes fallecidos de infecciones del torrente sanguíneo que en los supervivientes. Se halló una capacidad predictiva significativa para la mortalidad por hongos (OR, 0,033; IC 95%: 0,002-0,535) y el valor de PCT-5 (OR, 1.045; IC 95%: 1.013-1.078), respectivamente. El AUC de los niveles de PCT-5 para la mortalidad a 30 días fue de 0,784 (IC 95%: 0,678-0,949), y el valor de corte fue de 5.455 ng/mL. Conclusiones La PCT-5 fue un parámetro de más valor para el pronóstico de mortalidad a 30 días en pacientes con infecciones del torrente sanguíneo en comparación con los demás biomarcadores inflamatorios (AU)

The association of infectious diseases consultation and 30-day mortality rates among veterans with enterococcal bacteraemia: a propensity score-matched retrospective cohort study.

OBJECTIVES: Infectious disease consultation (IDC) has been associated with improved outcomes in several infections, but the benefit of IDC among patients with enterococcal bacteraemia has not been fully evaluated. METHODS: We performed a 1:1 propensity score-matched retrospective cohort study evaluating all patients with enterococcal bacteraemia at 121 Veterans Health Administration acute-care hospitals from 2011 to 2020. The primary outcome was 30-day mortality. We performed conditional logistic regression to calculate the OR to determine the independent association of IDC and 30-day mortality adjusted for vancomycin susceptibility and the primary source of bacteraemia. RESULTS: A total of 12,666 patients with enterococcal bacteraemia were included; 8400 (63.3%) had IDC, and 4266 (36.7%) did not have IDC. Two thousand nine hundred seventy-two patients in each group were included after propensity score matching. Conditional logistic regression revealed that IDC was associated with a significantly lower 30-day mortality rate compared with patients without IDC (OR = 0.56; 95% CI, 0.50-0.64). The association of IDC was observed irrespective of vancomycin susceptibility, and when the primary source of bacteraemia was a urinary tract infection, or from an unknown primary source. IDC was also associated with higher appropriate antibiotic use, blood culture clearance documentation, and the use of echocardiography. DISCUSSION: Our study suggests that IDC was associated with improved care processes and 30-day mortality rates among patients with enterococcal bacteraemia. IDC should be considered for patients with enterococcal bacteraemia.

Mortalidad en niños con bacteriemia por Stenotrophomonas maltophilia: revisión sistemática / Mortality in children with Stenotrophomonas maltophilia-related bacteremia: A systematic review

Introducción: En los niños, la bacteriemia por Stenotrophomonas maltophilia es considerada una complicación severa y asociada a una elevada mortalidad. Con el objetivo de conocer la mortalidad asociada a esa condición, se realizó una revisión sistemática de la literatura. Material y métodos: Se aplicó una estrategia de búsqueda bibliográfica con las palabras clave: bacteriemia por Stenotrophomonas maltophilia, niños y adolescentes como únicos filtros. Se informan la mediana y los valores intercuartílicos de la frecuencia de la mortalidad reportada por los estudios incluidos. Resultados: Se identificaron 165 estudios potencialmente útiles. De ellos, se seleccionaron finalmente, 9 estudios para ser incluidos. La incidencia de mortalidad a consecuencia de una bacteriemia por S.maltophilia fue del 25%; Q25: 11­Q75: 36; rango: 6,06 a 40,6. Consideraciones finales: La bacteriemia por Sm tuvo un alto porcentaje de mortalidad en especial en pacientes con patología subyacente y uso de procedimientos invasivos y el uso inadecuado de antibióticos empíricos (AU)

Introduction: In children, Stenotrophomonas maltophilia-related bacteremia is considered a severe complication associated with high mortality. With the aim to determine the mortality associated with this condition, a systematic review of the literature was conducted. Material and methods: A literature search strategy was applied using the keywords: bacteremia due to Stenotrophomonas maltophilia, children, and adolescents as the only filters. The median and interquartile ranges of the mortality rates described in the studies included are reported. Results: A total of 165 potentially useful studies were identified, of which nine were finally selected to be included in the analysis. The incidence of S.maltophilia bacteremia-related mortality was 25%; Q25: 11­Q75: 36; range: 6.06 to 40.6. Final considerations: S.maltophilia-related bacteremia was associated with a high mortality rate especially in patients with an underlying disease, when invasive procedures were performed, and when emperical antibiotics were inadequately used (AU)

Unresolved issues in the epidemiology and diagnosis of bacteremia: an opinion paper / Cuestiones no resueltas en la epidemiología y el diagnóstico de la bacteriemia: un documento de opinión

Bacteremia is an important cause of morbidity and mortality worldwide and, despite the diagnostic and therapeutic advances of the last decades, the evidence supporting many diagnostic aspects of bacteremia is scarce. Information on the epidemiological evolution of this entity is limited and many methodological aspects of blood culture collection and analysis are under discussion. Furthermore, the recommendations of the main scientific societies on many of these aspects are variable and, in many cases, have not been updated recently.In this scenario, we have arranged a series of questions on different aspects of bacteremia and reviewed the literature trying to find proper answers for them. We offer our opinion on the topics where the evidence was weak.The topics covered include epidemiological aspects of bacteremia, indications for blood culture extraction, methods for obtaining and incubating samples, or ways of transmitting results from the microbiology laboratory.We do not intend to summarize the current clinical practice guidelines, nor will we deal with the therapeutic management of this entity. The aim of this paper is to review the current perspective on the diagnosis of bacteremia with a critical approach, to point out the gaps in the literature, to offer the opinion of a team dedicated to infectious diseases and clinical microbiology, and to identify some areas of knowledge on which future studies should focus. (AU)

La bacteriemia es una causa importante de morbilidad y mortalidad en todo el mundo y, a pesar de los avances diagnósticos y terapéuticos de las últimas décadas, la evidencia que apoya muchos aspectos diagnósticos suele ser escasa. La información sobre la evolución epidemiológica de esta entidad es limitada y muchos aspectos metodológicos sobre la obtención y análisis de hemocultivos están en discusión. Además, las recomendaciones de las principales sociedades científicas sobre muchos de estos aspectos son variables y, en muchos casos, no se han actualizado recientemente.En este escenario, hemos preparado una serie de preguntas sobre diferentes aspectos de la bacteriemia y hemos revisado la literatura tratando de encontrar respuestas adecuadas para ellas. Ofrecemos nuestra opinión sobre los temas en los que la evidencia era débil.Los temas tratados incluyen los aspectos epidemiológicos de la bacteriemia, las indicaciones para la extracción de hemocultivos, los métodos de obtención e incubación de muestras o las formas de transmisión de los resultados desde el laboratorio de microbiología.No pretendemos resumir las guías de práctica clínica actuales, ni trataremos el manejo terapéutico de esta entidad. El objetivo de este trabajo es revisar la perspectiva actual sobre el diagnóstico de la bacteriemia con un enfoque crítico, señalar las carencias en la literatura, ofrecer la opinión de un equipo dedicado a las enfermedades infecciosas y a la microbiología clínica, e identificar algunas áreas de conocimiento en las que deberían centrarse futuros estudios. (AU)

Association Between Selective Decontamination of the Digestive Tract and In-Hospital Mortality in Intensive Care Unit Patients Receiving Mechanical Ventilation: A Systematic Review and Meta-analysis.

Importance: The effectiveness of selective decontamination of the digestive tract (SDD) in critically ill adults receiving mechanical ventilation is uncertain. Objective: To determine whether SDD is associated with reduced risk of death in adults receiving mechanical ventilation in intensive care units (ICUs) compared with standard care. Data Sources: The primary search was conducted using MEDLINE, EMBASE, and CENTRAL databases until September 2022. Study Selection: Randomized clinical trials including adults receiving mechanical ventilation in the ICU comparing SDD vs standard care or placebo. Data Extraction and Synthesis: Data extraction and risk of bias assessments were performed in duplicate. The primary analysis was conducted using a bayesian framework. Main Outcomes and Measures: The primary outcome was hospital mortality. Subgroups included SDD with an intravenous agent compared with SDD without an intravenous agent. There were 8 secondary outcomes including the incidence of ventilator-associated pneumonia, ICU-acquired bacteremia, and the incidence of positive cultures of antimicrobial-resistant organisms. Results: There were 32 randomized clinical trials including 24 389 participants in the analysis. The median age of participants in the included studies was 54 years (IQR, 44-60), and the median proportion of female trial participants was 33% (IQR, 25%-38%). Data from 30 trials including 24 034 participants contributed to the primary outcome. The pooled estimated risk ratio (RR) for mortality for SDD compared with standard care was 0.91 (95% credible interval [CrI], 0.82-0.99; I2 = 33.9%; moderate certainty) with a 99.3% posterior probability that SDD reduced hospital mortality. The beneficial association of SDD was evident in trials with an intravenous agent (RR, 0.84 [95% CrI, 0.74-0.94]), but not in trials without an intravenous agent (RR, 1.01 [95% CrI, 0.91-1.11]) (P value for the interaction between subgroups = .02). SDD was associated with reduced risk of ventilator-associated pneumonia (RR, 0.44 [95% CrI, 0.36-0.54]) and ICU-acquired bacteremia (RR, 0.68 [95% CrI, 0.57-0.81]). Available data regarding the incidence of positive cultures of antimicrobial-resistant organisms were not amenable to pooling and were of very low certainty. Conclusions and Relevance: Among adults in the ICU treated with mechanical ventilation, the use of SDD compared with standard care or placebo was associated with lower hospital mortality. Evidence regarding the effect of SDD on antimicrobial resistance was of very low certainty.

Effect of Selective Decontamination of the Digestive Tract on Hospital Mortality in Critically Ill Patients Receiving Mechanical Ventilation: A Randomized Clinical Trial.

Importance: Whether selective decontamination of the digestive tract (SDD) reduces mortality in critically ill patients remains uncertain. Objective: To determine whether SDD reduces in-hospital mortality in critically ill adults. Design, Setting, and Participants: A cluster, crossover, randomized clinical trial that recruited 5982 mechanically ventilated adults from 19 intensive care units (ICUs) in Australia between April 2018 and May 2021 (final follow-up, August 2021). A contemporaneous ecological assessment recruited 8599 patients from participating ICUs between May 2017 and August 2021. Interventions: ICUs were randomly assigned to adopt or not adopt a SDD strategy for 2 alternating 12-month periods, separated by a 3-month interperiod gap. Patients in the SDD group (n = 2791) received a 6-hourly application of an oral paste and administration of a gastric suspension containing colistin, tobramycin, and nystatin for the duration of mechanical ventilation, plus a 4-day course of an intravenous antibiotic with a suitable antimicrobial spectrum. Patients in the control group (n = 3191) received standard care. Main Outcomes and Measures: The primary outcome was in-hospital mortality within 90 days. There were 8 secondary outcomes, including the proportion of patients with new positive blood cultures, antibiotic-resistant organisms (AROs), and Clostridioides difficile infections. For the ecological assessment, a noninferiority margin of 2% was prespecified for 3 outcomes including new cultures of AROs. Results: Of 5982 patients (mean age, 58.3 years; 36.8% women) enrolled from 19 ICUs, all patients completed the trial. There were 753/2791 (27.0%) and 928/3191 (29.1%) in-hospital deaths in the SDD and standard care groups, respectively (mean difference, -1.7% [95% CI, -4.8% to 1.3%]; odds ratio, 0.91 [95% CI, 0.82-1.02]; P = .12). Of 8 prespecified secondary outcomes, 6 showed no significant differences. In the SDD vs standard care groups, 23.1% vs 34.6% had new ARO cultures (absolute difference, -11.0%; 95% CI, -14.7% to -7.3%), 5.6% vs 8.1% had new positive blood cultures (absolute difference, -1.95%; 95% CI, -3.5% to -0.4%), and 0.5% vs 0.9% had new C difficile infections (absolute difference, -0.24%; 95% CI, -0.6% to 0.1%). In 8599 patients enrolled in the ecological assessment, use of SDD was not shown to be noninferior with regard to the change in the proportion of patients who developed new AROs (-3.3% vs -1.59%; mean difference, -1.71% [1-sided 97.5% CI, -∞ to 4.31%] and 0.88% vs 0.55%; mean difference, -0.32% [1-sided 97.5% CI, -∞ to 5.47%]) in the first and second periods, respectively. Conclusions and Relevance: Among critically ill patients receiving mechanical ventilation, SDD, compared with standard care without SDD, did not significantly reduce in-hospital mortality. However, the confidence interval around the effect estimate includes a clinically important benefit. Trial Registration: ClinicalTrials.gov Identifier: NCT02389036.

Optimized identification of microorganisms directly from positive blood cultures by MALDI-TOF to improve antimicrobial treatment / Optimización en el proceso de identificación directamente de hemocultivos positivos por MALDI-TOF para mejorar el tratamiento antimicrobiano

Introduction. Bacteriemia is a major cause of morbidityand mortality among hospitalized patients worldwide. Earlyidentification of microorganisms from blood culture can leadto improvement of treatment and outcomes.Methods. The study was divided into two phases. Thefirst phase when a comparison of the methods was made tocheck the concordance between them, using as a reference thestandard method implemented in the laboratory. In a secondphase, both methods are combined. We used the rapid identification method and when it could not identify we used thestandard method. The microorganisms that were not identifiedby either of the two methods were identified from colony at24 hoursResults. A total of 589 microbial positive blood cultures have been included in the present study. With the rapidmethod we obtained 96% and 88% identification results forGram-negative bacilli (GNB) and Gram-positive cocci (GPC)respectively. In this study we observed that the combinationof the rapid and standard method achieved identifications of98% and 97% for GNB and GPC respectively.Conclusions. The data analysed shows that both methodscombined perform better than individually. We achieved anoptimization of the identification of microorganisms directlyfrom positive blood cultures by MALDI-TOF. This combinationidentified 98% of the microorganisms in between ten minutesto one hour and a half since the blood culture flagged positive (AU)

Introducción. La bacteriemia es una de las principalescausas de morbilidad y mortalidad entre los pacientes hospitalizados de todo el mundo. La identificación temprana de losmicroorganismos que están en la sangre, permite optimizar lostratamientos y conseguir mejores resultados.Material y métodos. El estudio se dividió en dos fases. Enla primera fase se realizó una comparación de los dos métodospara comprobar la concordancia entre ambos, tomando comoreferencia el método estándar implementado en el laboratorio.La segunda fase combinó ambos métodos para la identificación de hemocultivos positivos. Se utilizó el método de identificación rápida como primera opción y el método estándarsolo cuando no se consiguió identificar por la primera opción.Los microorganismos que no fueron identificados por ningunode los dos métodos, se identificaron directamente de la coloniacrecida a las 24 horas.Resultados. Se analizaron un total de 589 hemocultivospositivos en este estudio. Con el método rápido obtuvimos un96% y 88% de identificación de bacilos gramnegativos y cocosgrampositivos respectivamente. En este estudio observamosque la combinación del método rápido y el método estándarconsiguió identificaciones del 98% y 97% para bacilos gramnegativos y cocos grampositivos respectivamente.Conclusiones. Los datos analizados muestran que ambosmétodos combinados consiguen mejores resultados que utilizados de forma individual. Logramos una optimización de laidentificación de microorganismos directamente a partir dehemocultivos positivos por MALDI-TOF. Con esta combinaciónse identificó el 98% de los microorganismos entre los primeros10 minutos y hora y media de hemocultivo positivo. (AU)

Association of capsular polysaccharide locus 2 with prognosis of Acinetobacter baumannii bacteraemia.

Acinetobacter baumannii causes healthcare-associated infections worldwide. Capsular polysaccharide (CPS) is shown an important virulence factor of A. baumannii both in vitro and in vivo. Capsule locus 2 (KL2) for CPS is the most common KL type and is associated with carbapenem resistance. It is unclear whether KL2 is related to the clinical outcome of invasive A. baumannii infection. Here we had followed patients with A. baumannii bacteraemia prospectively between 2009 and 2014. One-third of the unduplicated blood isolates were randomly selected each year for microbiological and clinical studies. The KL2 gene cluster was identified using polymerase chain reaction. A total of 148 patients were enrolled randomly. Eighteen isolates (12.2%) carried KL2, and 130 isolates (87.8%) didn't. Compared with non-KL2 isolates, KL2 isolates had significantly higher resistance to imipenem, sulbactam, and tigecycline. Compared with the non-KL group, in the KL2 group, the hospital stay before development of bacteraemia was longer (P < 0.001), a higher percentage had pneumonia (P = 0.004), and the white blood cell count was lower (P = 0.03). Infection with KL2 A. baumannii predicted mortality (adjusted hazard ratio [aHR], 2.03; 95% confidence interval [CI], 1.09-3.78; P = 0.03), independently of the Pitt bacteraemia score (aHR, 1.34; 95% CI, 1.23-1.46; P < 0.001) and leucopenia (aHR, 2.16; 95% CI, 1.30-3.57; P = 0.003). Thrombocytopenia contributed to the effect of KL2 on mortality in bacteraemia (Sobel test P = 0.01). Large-scale studies are warranted to confirm these findings and the underlying mechanisms deserve further investigation.

Blood culture time to positivity in non-ß-hemolytic streptococcal bacteremia as a predictor of infective endocarditis-a retrospective cohort study.

Non-ß-hemolytic streptococci (NBHS) cause infective endocarditis (IE) and a short blood culture time to positivity (TTP) is associated with risk of IE in bacteremia with other pathogens. In this retrospective population-based cohort study, we investigate if TTP is associated to IE or mortality. Of 263 episodes with NBHS bacteremia, 28 represented IE and the median TTP did not differ significantly between episodes with IE (15 h) and non-IE (15 h) (p=0.51). TTP was similar among those who survived and those who died within 30 days. However, TTP significantly differed when comparing the different streptococcal groups (p<0.001).

Penicillin versus anti-staphylococcal beta-lactams for penicillin-susceptible Staphylococcus aureus blood stream infections: a retrospective cohort study.

The objective of the study is to assess the efficacy and tolerability of penicillins compared to anti-staphylococcal beta-lactams for treatment of penicillin-susceptible Staphylococcus aureus bloodstream infections (PSSA BSI). A retrospective cohort study was conducted of 140 sequential PSSA BSI presenting to a local health district (90 cases included). Penicillin susceptibility was confirmed by disc diffusion, Vitek® and Nitrocefin beta-lactamase methods. Clinical information regarding comorbidities and infection complexity was recorded. Antibiotic choice, dosage and duration were reviewed. Outcomes were compared according to the definitive treatment with either penicillin or ASBLs. The primary outcome was 30-day mortality. Secondary outcomes included renal injury, microbiological relapse and treatment tolerability. Ninety patients met inclusion criteria and were included in subsequent analysis. Of PSSA BSI, 69% were community acquired. Eighty-two percent had complex PSSA infections. The average duration of bacteraemia was 2.8 days (SD = 1.8 days). Sixty-six patients received definitive penicillin treatment, with a mean of 3.5 days of empiric antibiotics prior to penicillin. Twenty-four patients received definitive ASBL treatment (11 cefazolin, 13 flucloxacillin). There was no difference in 30-day mortality between groups (p = 1). There was no difference in renal injury (p > 0.5), hospital length of stay (p = 0.59) or microbiological relapse within 1 year (p = 0.17). Penicillin treatment was well tolerated. Our data supports penicillin as a suitable and well-tolerated alternative to ASBL in managing complex PSSA BSI.

Distance Between Home and the Admitting Hospital and Its Effect on Survival of Low Socioeconomic Status Population With Staphylococcus aureus Bacteremia.

OBJECTIVE: Bacteremia is the presence of bacteria in the bloodstream. The objective of this study was to determine the relationship between low socioeconomic status (SES) and the epidemiology, process of care, and outcomes of patients with Staphylococcus aureus bacteremia (SAB). METHODS: We conducted a multicenter, retrospective, cohort study that evaluated adult patients with SAB in 3 Los Angeles County hospitals from July 15, 2012, through May 31, 2018. We determined SES (low SES, intermediate SES, and high SES) for each patient and compared sociodemographic and epidemiologic characteristics, management of care received by patients with SAB (ie, process of care), and outcomes. We used a Cox proportional hazards model to determine predictors of 30-day mortality for each SES group. RESULTS: Of 915 patients included in the sample, 369 (40%) were in the low-SES group, 294 (32%) in the intermediate-SES group, and 252 (28%) in the high-SES group. Most significant predictors of 30-day mortality in the Cox proportional hazards model were admission to an intensive care unit (hazard ratio [HR] = 9.04; 95% CI, 4.26-19.14), Pitt bacteremia score ≥4 indicating critical illness (HR = 4.30; 95% CI, 2.49-7.44), having ≥3 comorbidities (HR = 2.05; 95% CI, 1.09-3.85), and advanced age (HR = 1.03; 95% CI, 1.01-1.05). Distance between home and admitting hospital affected mortality only in the low-SES group (HR = 1.02; 95% CI, 1.00-1.02). CONCLUSIONS: SES did not independently affect the outcome of SAB; however, the farther the patient's residence from the hospital, the greater the negative effect on survival in a low-SES population. Our findings underscore the need to develop multipronged, targeted public health efforts for populations that have transportation barriers to health care.

Time to positivity in bloodstream infection is not a prognostic marker for mortality: analysis of a prospective multicentre randomized control trial.

OBJECTIVES: Time to positivity (TTP), calculated automatically in modern blood culture systems, is considered a proxy for microbial load and has been suggested as a potential prognostic marker in bloodstream infections. In this large, multicentre, prospectively collected cohort, our primary analysis aimed to quantify the relationship between the TTP of monomicrobial blood cultures and mortality. METHODS: Data from a multicentre randomized controlled trial (RAPIDO) in bloodstream infection were analysed. Bloodstream infections were classified into 13 groups/subgroups. The relationship between mortality and TTP was assessed by logistic regression, adjusted for site, organism, and clinical variables, and linear regression was applied to examine the association between clinical variables and TTP. Robustness was assessed by sensitivity analysis. RESULTS: In total 4468 participants were included in the RAPIDO. After exclusions, 3462 were analysed, with the most common organisms being coagulase-negative staphylococci (1072 patients) and Escherichia coli (861 patients); 785 patients (22.7%) died within 28 days. We found no relationship between TTP and mortality for any groups except for streptococci (odds ratio (OR) with each hour 0.98, 95%CI 0.96-1.00) and Candida (OR 1.03, 95%CI 1.00-1.05). There was large variability between organisms and sites in TTP. Fever (geometric mean ratio (GMR) 0.95, 95%CI 0.92-0.99), age (GMR per 10 years 1.01, 95%CI 1.00-1.02), and neutrophilia were associated with TTP (GMR 1.03, 95%CI 1.02-1.04). CONCLUSIONS: Time to positivity is not associated with mortality, except in the case of Candida spp. (longer times associated with worse outcomes) and possibly streptococci (shorter times associated with worse outcomes). There was a large variation between median times across centres, limiting external validity.

Validation of the Giannella Risk Score for the Prediction of Infection by Carbapenemase-producing Enterobacteriaceae in the Pediatric Population.

BACKGROUND: Despite efforts made to prevent the spread of multi-drug-resistant bacteria, carbapenemase-producing Enterobacteriaceae (CPE) has become one of the most dangerous threat worldwide. However, data on the epidemiology of CPE and on the correlation between CPE colonization and infection are scanty. The objectives of this study were first to describe the epidemiologic characteristics of colonizations and invasive CPE infections in the pediatric population, and second, to apply the Giannella Risk Score (GRS) to the pediatric population for the assessment of the risk of invasive CPE infection in patients with already known colonization. METHODS: Pediatric patients with evidence of colonization by CPE were retrospectively enrolled. For each colonized patient, the subsequent development of an infection by CPE was then assessed for a 90-day period after the first CPE isolation; GRSs were compared between patients who had developed any type of CPE infection and those without infection. RESULTS: A total of 215 patients (113 males and 102 females) with at least 1 isolation of CPE during hospitalization were analyzed. Median age was 5.6 years [interquartile range (IQR), 1.89-12.2 years]. Overall, 28 CPE infections (13%) were documented: 23 blood stream infections and 5 complicated urinary tract infections. The 30-day mortality of invasive CPE infections was 34.8%. The GRS values in patients with any CPE infection were statistically higher than in noninfected patients: median GRS 9 (IQR, 4-12.5) versus 4 (IQR, 2-4), respectively; P < 0.0001. The analysis of the receiver operating characteristic curves identified a GRS cut-off value ≥8 as the best predictor of CPE infection. The likelihood ratio of the results was <2 and the informedness of the test had a value <0.50. CONCLUSIONS: Our study confirms that the spread of CPE is an impelling problem also in the pediatric population, with a high mortality rate of invasive infections. However, the application of the GRS appears to be poorly informative in the pediatric setting; it might sometimes help to identify patients at very low-risk of CPE infection, in whom it is reasonable to spare targeted antimicrobial treatments.

Antimicrobial Susceptibility Trends and Risk Factors for Antimicrobial Resistance in Pseudomonas aeruginosa Bacteremia: 12-Year Experience in a Tertiary Hospital in Korea.

BACKGROUND: Infections caused by multidrug-resistant Pseudomonas aeruginosa (MDRPA) have been on the rise worldwide, and delayed active antimicrobial therapy is associated with high mortality. However, few studies have evaluated increases in P. aeruginosa infections with antimicrobial resistance and risk factors for such antimicrobial resistance in Korea. Here, we analyzed changes in antimicrobial susceptibility associated with P. aeruginosa bacteremia and identified risk factors of antimicrobial resistance. METHODS: The medical records of patients with P. aeruginosa bacteremia who were admitted to a tertiary hospital between January 2009 and October 2020 were retrospectively reviewed. Antibiotic resistance rates were compared among the time periods of 2009-2012, 2013-2016, and 2017-2020 and between the intensive care unit (ICU) and non-ICU setting. Empirical antimicrobial therapy was considered concordant, if the organism was susceptible to antibiotics in vitro, and discordant, if resistant. RESULTS: During the study period, 295 patients with P. aeruginosa bacteremia were identified. The hepatobiliary tract (26.8%) was the most common primary site of infection. The rates of carbapenem-resistant P. aeruginosa (CRPA), MDRPA, and extensively drug-resistant P. aeruginosa (XDRPA) were 24.7%, 35.9%, and 15.9%, respectively. XDRPA showed an increasing trend, and CRPA, MDRPA, and XDRPA were also gradually increasing in non-ICU setting. Previous exposure to fluoroquinolones and glycopeptides and urinary tract infection were independent risk factors associated with CRPA, MDRPA, and XDRPA. Previous exposure to carbapenems was an independent risk factor of CRPA. CRPA, MDRPA, and XDRPA were associated with discordant empirical antimicrobial therapy. CONCLUSION: The identification of risk factors for antimicrobial resistance and analysis of antimicrobial susceptibility might be important for concordant empirical antimicrobial therapy in patients with P. aeruginosa bacteremia.

Clinical and bacterial characteristics of Pseudomonas aeruginosa affecting the outcome of patients with bacteraemic pneumonia.

Few studies have assessed the clinical and bacterial characteristics of Pseudomonas aeruginosa (PA) bacteraemic pneumonia (BP) episodes. This study analysed all non-duplicate PA-BP episodes from a tertiary hospital in 2013-2017. Epidemiology, clinical data, antimicrobial therapy and outcomes were recorded. Whole-genome sequencing was performed on PA blood isolates. The impact on early and late overall mortality of host, antimicrobial treatment and pathogen factors was assessed by multivariate logistic regression analysis. Of 55 PA-BP episodes, 32 (58.2%) were caused by extensively drug-resistant (XDR) PA. ST175 (32.7%) and ST235 (25.5%) were the most frequent high-risk clones. ß-Lactamases/carbapenemases were detected in 29 isolates, including blaVIM-2 (27.2%) and blaGES type (25.5%) [blaGES-5 (20.0%), blaGES-1 (3.6%) and blaGES-20 (1.8%)]. The most prevalent O-antigen serotypes were O4 (34.5%) and O11 (30.9%). Overall, an extensive virulome was identified in all isolates. Early mortality (56.4%) was independently associated with severe neutropenia (aOR = 4.64, 95% CI 1.11-19.33; P = 0.035) and inappropriate empirical antimicrobial therapy (aOR = 5.71, 95% CI 1.41-22.98; P = 0.014). Additionally, late mortality (67.3%) was influenced by septic shock (aOR = 8.85, 95% CI 2.00-39.16; P = 0.004) and XDR phenotype (aOR = 5.46, 95% CI 1.25-23.85; P = 0.024). Moreover, specific genetic backgrounds [ST235, blaGES, gyrA (T83I), parC (S87L), exoU and O11 serotype] showed significant differences in patient outcomes. Our results confirm the high mortality associated with PA-BP. Besides relevant clinical characteristics and inappropriate empirical therapy, bacteria-specific genetics factors, such as XDR phenotype, adversely affect the outcome of PA-BP.