Hematological Parameters and Procalcitonin as Discriminants between Bacterial Pneumonia-Induced Sepsis and Viral Sepsis Secondary to COVID-19: A Retrospective Single-Center Analysis.

Bacterial and viral sepsis induce alterations of all hematological parameters and procalcitonin is used as a biomarker of infection and disease severity. Our aim was to study the hematological patterns associated with pulmonary sepsis triggered by bacteria and Severe Acute Respiratory Syndrome-Coronavirus-type-2 (SARS-CoV-2) and to identify the discriminants between them. We performed a retrospective, observational study including 124 patients with bacterial sepsis and 138 patients with viral sepsis. Discriminative ability of hematological parameters and procalcitonin between sepsis types was tested using receiver operating characteristic (ROC) analysis. Sensitivity (Sn%), specificity (Sp%), positive and negative likelihood ratios were calculated for the identified cut-off values. Patients with bacterial sepsis were older than patients with viral sepsis (p < 0.001), with no differences regarding gender. Subsequently to ROC analysis, procalcitonin had excellent discriminative ability for bacterial sepsis diagnosis with an area under the curve (AUC) of 0.92 (cut-off value of >1.49 ng/mL; Sn = 76.6%, Sp = 94.2%), followed by RDW% with an AUC = 0.87 (cut-off value >14.8%; Sn = 80.7%, Sp = 85.5%). Leukocytes, monocytes and neutrophils had good discriminative ability with AUCs between 0.76-0.78 (p < 0.001), while other hematological parameters had fair or no discriminative ability. Lastly, procalcitonin value was strongly correlated with disease severity in both types of sepsis (p < 0.001). Procalcitonin and RDW% had the best discriminative ability between bacterial and viral sepsis, followed by leukocytes, monocytes and neutrophils. Procalcitonin is a marker of disease severity regardless of sepsis type.

Blood culture utilization and epidemiology of antimicrobial-resistant bloodstream infections before and during the COVID-19 pandemic in the Indonesian national referral hospital.

BACKGROUND: There is a paucity of data regarding blood culture utilization and antimicrobial-resistant (AMR) infections in low and middle-income countries (LMICs). In addition, there has been a concern for increasing AMR infections among COVID-19 cases in LMICs. Here, we investigated epidemiology of AMR bloodstream infections (BSI) before and during the COVID-19 pandemic in the Indonesian national referral hospital. METHODS: We evaluated blood culture utilization rate, and proportion and incidence rate of AMR-BSI caused by WHO-defined priority bacteria using routine hospital databases from 2019 to 2020. A patient was classified as a COVID-19 case if their SARS-CoV-2 RT-PCR result was positive. The proportion of resistance was defined as the ratio of the number of patients having a positive blood culture for a WHO global priority resistant pathogen per the total number of patients having a positive blood culture for the given pathogen. Poisson regression models were used to assess changes in rate over time. RESULTS: Of 60,228 in-hospital patients, 8,175 had at least one blood culture taken (total 17,819 blood cultures), giving a blood culture utilization rate of 30.6 per 1,000 patient-days. A total of 1,311 patients were COVID-19 cases. Blood culture utilization rate had been increasing before and during the COVID-19 pandemic (both p < 0.001), and was higher among COVID-19 cases than non-COVID-19 cases (43.5 vs. 30.2 per 1,000 patient-days, p < 0.001). The most common pathogens identified were K. pneumoniae (23.3%), Acinetobacter spp. (13.9%) and E. coli (13.1%). The proportion of resistance for each bacterial pathogen was similar between COVID-19 and non-COVID-19 cases (all p > 0.10). Incidence rate of hospital-origin AMR-BSI increased from 130.1 cases per 100,000 patient-days in 2019 to 165.5 in 2020 (incidence rate ratio 1.016 per month, 95%CI:1.016-1.017, p < 0.001), and was not associated with COVID-19 (p = 0.96). CONCLUSIONS: In our setting, AMR-BSI incidence and etiology were similar between COVID-19 and non-COVID-19 cases. Incidence rates of hospital-origin AMR-BSI increased in 2020, which was likely due to increased blood culture utilization. We recommend increasing blood culture utilization and generating AMR surveillance reports in LMICs to inform local health care providers and policy makers.

Fungal Bloodstream Co-infection by Trichosporon asahii in a COVID-19 Critical Patient: Case Report and Literature Review.

Opportunistic infections are serious complications in critically ill COVID-19 patients, especially co-infections with bacterial and fungal agents. Here we report a rare case of bloodstream co-infection by Trichosporon asahii, an emerging yeast, and Acinetobacterbaumannii, an opportunistic nosocomial pathogen, both multidrug resistant, in a tertiary hospital from southern Brazil. A review of the literature regarding similar cases is also included. Treatment with multiple antimicrobials failed, and the patient progressed to death four days after the diagnosis of bacteremia and fungemia.

Pathogenesis and Treatment of Cytokine Storm Induced by Infectious Diseases.

Cytokine storm is a phenomenon characterized by strong elevated circulating cytokines that most often occur after an overreactive immune system is activated by an acute systemic infection. A variety of cells participate in cytokine storm induction and progression, with profiles of cytokines released during cytokine storm varying from disease to disease. This review focuses on pathophysiological mechanisms underlying cytokine storm induction and progression induced by pathogenic invasive infectious diseases. Strategies for targeted treatment of various types of infection-induced cytokine storms are described from both host and pathogen perspectives. In summary, current studies indicate that cytokine storm-targeted therapies can effectively alleviate tissue damage while promoting the clearance of invading pathogens. Based on this premise, "multi-omics" immune system profiling should facilitate the development of more effective therapeutic strategies to alleviate cytokine storms caused by various diseases.

Adhatoda Vasica attenuates inflammatory and hypoxic responses in preclinical mouse models: potential for repurposing in COVID-19-like conditions.

BACKGROUND: COVID-19 pneumonia has been associated with severe acute hypoxia, sepsis-like states, thrombosis and chronic sequelae including persisting hypoxia and fibrosis. The molecular hypoxia response pathway has been associated with such pathologies and our recent observations on anti-hypoxic and anti-inflammatory effects of whole aqueous extract of Adhatoda Vasica (AV) prompted us to explore its effects on relevant preclinical mouse models. METHODS: In this study, we tested the effect of whole aqueous extract of AV, in murine models of bleomycin induced pulmonary fibrosis, Cecum Ligation and Puncture (CLP) induced sepsis, and siRNA induced hypoxia-thrombosis phenotype. The effect on lung of AV treated naïve mice was also studied at transcriptome level. We also determined if the extract may have any effect on SARS-CoV2 replication. RESULTS: Oral administration AV extract attenuates increased airway inflammation, levels of transforming growth factor-ß1 (TGF-ß1), IL-6, HIF-1α and improves the overall survival rates of mice in the models of pulmonary fibrosis and sepsis and rescues the siRNA induced inflammation and associated blood coagulation phenotypes in mice. We observed downregulation of hypoxia, inflammation, TGF-ß1, and angiogenesis genes and upregulation of adaptive immunity-related genes in the lung transcriptome. AV treatment also reduced the viral load in Vero cells infected with SARS-CoV2. CONCLUSION: Our results provide a scientific rationale for this ayurvedic herbal medicine in ameliorating the hypoxia-hyperinflammation features and highlights the repurposing potential of AV in COVID-19-like conditions.

Purified ß-glucans from the Shiitake mushroom ameliorates antibiotic-resistant Klebsiella pneumoniae-induced pulmonary sepsis.

Bacterial infection remains the main cause of acute respiratory distress syndrome and is a leading cause of death and disability in critically ill patients. Here we report on the use of purified ß-glucan (lentinan) extracts from Lentinus edodes (Shiitake) mushroom that can reduce infection by a multidrug-resistant clinical isolate of Klebsiella pneumoniae in a rodent pneumonia model, likely through immunomodulation. Adult male Sprague-Dawley rats were subjected to intra-tracheal administration of K. pneumoniae to induce pulmonary sepsis and randomized to three groups; vehicle control (Vehicle, n = 12), commercial lentinan (CL, n = 8) or in-house extracted lentinan (IHL, n = 8) were administered intravenously 1 h postinfection. Physiological parameters and blood gas analysis were measured, bacterial counts from bronchoalveolar-lavage (BAL) were determined, along with differential staining of white cells and measurement of protein concentration in BAL 48 h after pneumonia induction. Use of IHL extract significantly decreased BAL CFU counts. Both CL and IHL extractions reduced protein concentration in BAL. Use of IHL resulted in an improvement in physiological parameters compared to controls and CL. In conclusion, administration of lentinan to treat sepsis-induced lung injury appears safe and effective and may exert its effects in an immunomodulatory manner.

Single-cell RNA sequencing reveals the sustained immune cell dysfunction in the pathogenesis of sepsis secondary to bacterial pneumonia.

Sepsis is a leading cause of mortality in intensive care unit worldwide, it's accompanied by immune cell dysfunction induced by multiple factors. However, little is known about the specific alterations in immune cells in the dynamic pathogenesis of sepsis secondary to bacterial pneumonia. Here, we used single cell RNA sequencing (scRNA-seq) to profile peripheral blood mononuclear cells (PBMCs) in a healthy control and two patients with sepsis secondary to bacterial pneumonia, including acute, stable and recovery stage. We analyzed the quantity and function of immune cells. During disease course, interferon gamma response was upregulated; T/NK cell subtypes presented activation and exhaustion properties, which might be driven by monocytes through IL-1ß signaling pathways; The proportion of plasma cells was increased, which might be driven by NK cells through IFN signaling pathways; Additionally, interferon gamma response was upregulated to a greater degree in sepsis secondary to pneumonia induced by SARS-COV-2 compared with that induced by influenza virus and bacteria.

COVID-19 and Fatal Sepsis Caused by Hypervirulent Klebsiella pneumoniae, Japan, 2020.

A patient in Japan with coronavirus disease and hypervirulent Klebsiella pneumoniae K2 sequence type 86 infection died of respiratory failure. Bacterial and fungal co-infections caused by region-endemic pathogens, including hypervirulent K. pneumoniae in eastern Asia, should be included in the differential diagnosis of coronavirus disease patients with acutely deteriorating condition.

Unexpectedly High Frequency of Enterococcal Bloodstream Infections in Coronavirus Disease 2019 Patients Admitted to an Italian ICU: An Observational Study.

OBJECTIVES: We aimed to assess the frequency of ICU-acquired bloodstream infections in coronavirus disease 2019 patients. DESIGN: Retrospective observational study. SETTING: The emergency expansion of an ICU from eight general beds to 30 coronavirus disease 2019 beds. PARTICIPANTS: Patients with coronavirus disease 2019 admitted to the ICU of Luigi Sacco Hospital (Milan, Italy) for greater than or equal to 48 hours between February 21, 2020, and April 30, 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The frequency of bloodstream infections per 1,000 days of ICU stay was calculated in 89 coronavirus disease 2019 patients, and the cumulative probability of bloodstream infection was estimated using death and ICU discharge as competing events. Sixty patients (67.4%) experienced at least one of the 93 recorded episodes of bloodstream infection, a frequency of 87 per 1,000 days of ICU stay (95% CI, 67-112).The patients who experienced a bloodstream infection had a higher Sequential Organ Failure Assessment score upon ICU admission (9.5; interquartile range, 8-12 vs 8, interquartile range, 5-10; p = 0.042), a longer median ICU stay (15 d; interquartile range, 11-23 vs 8, interquartile range, 5-12; p < 0.001), and more frequently required invasive mechanical ventilation (98.3% vs 82.8%; p = 0.013) than those who did not. The median time from ICU admission to the first bloodstream infection episode was 10 days. Gram-positive bacteria accounted for 74 episodes (79.6%), with Enterococcus species being the most prevalent (53 episodes, 55.8%). Thirty-two isolates (27.3%) showed multidrug resistance. CONCLUSIONS: Coronavirus disease 2019 seemed to increase the frequency of bloodstream infections (particularly Enterococcus-related bloodstream infection) after ICU admission. This may have been due to enteric involvement in patients with severe coronavirus disease 2019 and/or limitations in controlling the patient-to-patient transmission of infectious agents in extremely challenging circumstances.

Low prevalence of bloodstream infection and high blood culture contamination rates in patients with COVID-19.

PURPOSE: In the management of COVID-19, knowledge is lacking on the frequency of secondary bacterial infections and on how empirical antibiotic therapy should be used. In the present study, we aimed to compare blood culture (BC) results of a COVID-19 patient cohort with two cohorts of patients without detected COVID-19. METHODS: Using a retrospective cohort study design of patients subjected to BC in six tertiary care hospitals, SARS-CoV-2 positive patients from March 1 to April 30 in 2020 (COVID-19 group) were compared to patients without confirmed SARS-CoV-2 during the same period (control group-2020) and with patients sampled March 1 to April 30 in 2019 (control group-2019). The outcomes studied were proportion of BC positivity, clinically relevant growth, and contaminant growth. RESULTS: In total 15,103 patients and 17,865 BC episodes were studied. Clinically relevant growth was detected in 197/3,027 (6.5%) BC episodes in the COVID-19 group compared to 717/6,663 (10.8%) in control group-2020 (p<0.0001) and 850/8,175 (10.4%) in control group-2019 (p<0.0001). Contamination was present in 255/3,027 (8.4%) BC episodes in the COVID-19 group compared to 330/6,663 (5.0%) in control group-2020 (p<0.0001) and 354/8,175 (4.3%) in control group-2019 (p<0.0001). CONCLUSION: In COVID-19 patients, the prevalence of bloodstream bacterial infection is low and the contamination rate of BC is high. This knowledge should influence guidelines regarding blood culture sampling and empirical antibiotic therapy in COVID-19 patients.

Secondary infections in patients hospitalized with COVID-19: incidence and predictive factors.

OBJECTIVES: The aim of our study was to describe the incidence and predictive factors of secondary infections in patients with coronavirus disease 2019 (COVID-19). METHODS: This was a cohort study of patients hospitalized with COVID-19 at IRCCS San Raffaele Hospital between 25th February and 6th April 2020 (NCT04318366). We considered secondary bloodstream infections (BSIs) or possible lower respiratory tract infections (pLRTIs) occurring 48 hours after hospital admission until death or discharge. We calculated multivariable Fine-Gray models to assess factors associated with risk of secondary infections. RESULTS: Among 731 patients, a secondary infection was diagnosed in 68 patients (9.3%); 58/731 patients (7.9%) had at least one BSI and 22/731 patients (3.0%) at least one pLRTI. The overall 28-day cumulative incidence was 16.4% (95%CI 12.4-21.0%). Most of the BSIs were due to Gram-positive pathogens (76/106 isolates, 71.7%), specifically coagulase-negative staphylococci (53/76, 69.7%), while among Gram-negatives (23/106, 21.7%) Acinetobacter baumanii (7/23, 30.4%) and Escherichia coli (5/23, 21.7%) predominated. pLRTIs were caused mainly by Gram-negative pathogens (14/26, 53.8%). Eleven patients were diagnosed with putative invasive aspergillosis. At multivariable analysis, factors associated with secondary infections were low baseline lymphocyte count (≤0.7 versus >0.7 per 109/L, subdistribution hazard ratios (sdHRs) 1.93, 95%CI 1.11-3.35), baseline PaO2/FiO2 (per 100 points lower: sdHRs 1.56, 95%CI 1.21-2.04), and intensive-care unit (ICU) admission in the first 48 hours (sdHR 2.51, 95%CI 1.04-6.05). CONCLUSIONS: Patients hospitalized with COVID-19 had a high incidence of secondary infections. At multivariable analysis, early need for ICU, respiratory failure, and severe lymphopenia were identified as risk factors for secondary infections.

Microbial cell-free DNA in plasma of patients with sepsis: a potential diagnostic methodology.

Sepsis is a life-threatening clinical condition demanding accurate and rapid diagnosis of the culprit pathogen, thereby to improve prognosis. Pathogen determination through blood culture is the gold standard for diagnosis but has limitations due to low sensitivity. Recently, circulating DNAs derived from pathogenic organisms were found in the plasma of patients with sepsis and were further proved to be more sensitive biomarkers for the diagnosis of the pathogen origin in sepsis. However, the fundamental molecular characteristics of circulating DNA in patients with sepsis remain unclear. Here, we used specific PCR and Sanger sequencing to verify the microbiology culture results via the corresponding plasma circulating DNA. We analyzed the composition and molecular characteristics of circulating DNA in septic patients using next-generation sequencing technology. We showed the presence of pathogen-derived circulating DNA in the plasma of patients with sepsis. The sizes of circulating DNA fragments derived from pathogenic bacteria showed a skewed unimodal distribution, while those derived from host cells showed a normal unimodal distribution. Lengths of fragments at peak concentration for both origins ranged from 150 bp to 200 bp, and reads mapping to pathogenic bacteria genome distributed uniformly on the reference. Our findings have improved our understanding of microbial circulating DNA in patients with sepsis as a potential methodology for the accurate diagnosis of sepsis, especially in light of an urgent need for such a diagnosis associated with the COVID-19 infection.

Comparison of clinical laboratory tests between bacterial sepsis and SARS-CoV-2-associated viral sepsis.

Sepsis is a life-threatening condition that is characterized by multiple organ dysfunction due to abnormal host response to various pathogens, like bacteria, fungi and virus. The differences between viral and bacterial sepsis are indeed of great significance to deepen the understanding of the pathogenesis of sepsis, especially under pandemics of SARS-CoV-2 infection.

Sepsis, a 2020 review for the internist.

Sepsis is an overwhelming reaction to infection that comes with high morbidity and mortality, which requires urgent interventions in order to improve outcomes. Surviving Sepsis is an international campaign that aims to improve sepsis outcomes. The 2016 guideline modifies the previous definition of sepsis and proposes some specific diagnostic and therapeutic measures, such as the protocolized use of fluid resuscitation and antibiotics. We aim to summarize the main recommendations of the 2016 guideline that are relevant to the internist and evidence-base update them to the year 2020. In the current context, this review doesn't address patients affected by SARS-COV2 induced disease.