FilmArray (BCID2) provides essential and timely results in bloodstream infections in small acute care hospitals without conventional microbiology services

We have evaluated the performance of FilmArray BCID2 in reactive blood cultures in a small acute care hospital compared to conventional diagnostics at a regional microbiological laboratory. This is a retrospective observational study of BactAlert reactive blood cultures (n = 160) from Helgeland Hospital, July-December 2021, analysed by BCID2 locally and conventional culture at a regional laboratory. The overall clinical and analytic sensitivity with BCID2 were 87.2% and 97.8%, respectively. The false-negative BCID2 rate was low (n = 4; 2.9%). No false-positive BCID2 results were observed. The BCID2 data were available on average 1.88 days earlier than culture-based results, due to long transport time to the regional laboratory. The BCID2 provided results to support a significantly earlier optimized targeted antibiotic treatment in 27% of the cases according to national guidelines for empirical treatment of BSI. The high clinical and analytical sensitivity, and specificity support the use of BCID2 as a robust supplement to traditional cultivation of positive blood cultures. The significant time gain to microbial identification and detection of resistance determinants suggests a great clinical importance of BCID2 in small acute care hospitals with long transport time to conventional clinical microbiology services.

Corticosteroid Dosing Level, Incidence and Profile of Bacterial Blood Stream Infections in Hospitalized COVID-19 Patients

COVID-19 patients with severe or critical symptoms are often treated with corticosteroids, per contemporary guidelines. Due to their immunosuppressive and immunomodulatory properties, corticosteroids are associated with the development of superinfections. We aimed to retrospectively assess patterns of corticosteroid use and the profiles of bacterial blood stream infections associated with exposure to different dosing levels, in a cohort of 1558 real-life adult COVID-19 patients. A total of 1391 (89.3%) patients were treated with corticosteroids, with 710 (45.6%) patients receiving low, 539 (34.6%) high and 142 (9.1%) very high corticosteroid doses. Bacteremia developed in a total of 178 (11.4%) patients. The risk of bacteremia was of similar magnitude between the no and low-dose corticosteroid treatments (p = 0.352), whereas it progressively increased with high (OR 6.18, 95% CI (2.66-14.38), p < 0.001) and very high corticosteroid doses (OR 8.12, 95% CI (3.29-20.05), p < 0.001), compared to no corticosteroid treatment. These associations persisted after multivariate adjustments and were present independently of sex, comorbidity burden, and mechanical ventilation. The profiles of individual bacterial pathogens differed depending on the used corticosteroid doses. High and very high corticosteroid doses are frequently used for real-life COVID-19 patients with severe and critical clinical presentations and are associated with a higher risk of bacteremia independently of sex, comorbidity burden, and mechanical ventilation use.

Rapid phenotypic antimicrobial susceptibility testing of Gram-negative rods directly from positive blood cultures using the novel Q-linea ASTar system

Adequate and timely antibiotic therapy is crucial for the treatment of sepsis. Innovative systems, like the Q-linea ASTar, have been developed to perform rapid antimicrobial susceptibility testing (AST) directly from positive blood cultures (BCs). We conducted a prospective study to evaluate ASTar under real-life conditions with a focus on time-to-result and impact on antimicrobial therapy. Over 2 months, all positive BCs that showed Gram-negative rods upon microscopy were tested with the ASTar and our standard procedure (VITEK 2 from short-term culture). Additionally, we included multidrug-resistant Gram-negative bacteria from our archive. Both methods were compared to broth microdilution. In total, 78 bacterial strains (51 prospective and 27 archived) were tested. ASTar covered 94% of the species encountered. The categorical and essential agreement was 95.6% and 90.7%, respectively. ASTar caused 2.4% minor, 2.0% major, and 2.4% very major errors. The categorical agreement was similar to standard procedure. The average time between BC sampling and the availability of the antibiogram for the attending physician was 28 h 49 min for ASTar and 44 h 18 min for standard procedure. ASTar correctly identified all patients who required an escalation of antimicrobial therapy and 75% of those who were eligible for de-escalation. In conclusion, ASTar provided reliable AST results and significantly shortened the time to obtain an antibiogram. However, the percentage of patients that will profit from ASTar in a low-resistance setting is limited, and it is currently unclear if a change of therapy 29 h after BC sampling will have a significant impact on the patient's prognosis.

Chimaeribacter arupi a new member of the Yersineacea family has the characteristics of a human pathogen

Chimaeribacter arupi (heterotypic synonym: "Nissabacter archeti") is a facultative anaerobic, newly described Gram-negative rod and belongs to the Yersineacea family. Here, we report the case of a 19-month-old female infant patient who presented to the emergency unit with somnolence and fever. C. arupi was isolated from a positive blood culture, taken via an implanted Broviac catheter, proving a bloodstream infection by the pathogen. The objective of this study was to utilize whole genome sequencing to assess the genes encoding potential virulence associated factors, which may play a role in host tropism, tissue invasion and the subsequent stages in the pathogenesis of a bloodstream infection with C. arupi. The genome of the isolate was completely sequenced employing Illumina MiSeq and Nanopore MinION sequencing and the presumptive virulence associated factors and antimicrobial resistance genes were investigated in more detail. Additionally, we performed metabolic profiling and susceptibility testing by microdilution. The presence of predicted TcfC-like α-Pili suggests that C. arupi is highly adapted to humans as a host. It utilizes flagellar and type IV pili-mediated motility, as well as a number of γ1-pili and a σ-pilus, which may be used to facilitate biofilm formation and adherence to host epithelia. Additionally, long polar fimbriae may aid in tissue invasion. The bacterium possesses antioxidant factors, which may enable temporary survival in phagolysosomes, and a capsule that potentially provides protection from phagocytosis. It may acquire iron ions from erythrocytes through the type 6 secretion system and hemolysins. Furthermore, the isolate exhibits beta-lactamase-mediated penicillin and aminopenicillin resistance. Based on the analysis of the whole genome, we conclude that C. arupi possesses virulence factors associated with tissue invasion and may thus be a potential opportunistic pathogen of bloodstream infections.

Distribution and Antibiotic Resistance Analysis of Blood Culture Pathogens in a Tertiary Care Hospital in China in the Past Four Years

Purpose

This study aimed to investigate the antibiotic resistance patterns and clinical distribution of blood culture-positive isolates at Suining Central Hospital between 2018 and 2021. The findings of this study can provide a basis for ensuring rational and effective use of antibiotic therapy in clinical settings.

Methods

This retrospective study analyzed the data of 3660 non-repeating strains that tested positive for clinical blood culture, collected from the microbiology laboratory of Suining Central Hospital between January 2018 and December 2021. The identification of bacterial species and their antibiotic resistance patterns were analyzed.

Results

The study found that 76.7% of the bacterial strains identified were Gram-negative bacteria, while 23.3% were Gram-positive bacteria. Escherichia coli (44.8%), Klebsiella spp. (19.2%), Staphylococcus aureus (9.2%), Enterococcus spp. (5.3%), and Enterobacter spp. were the top five bacterial ratios observed. These bacteria were detected most frequently in the Digestion Center, intensive care unit (ICU), Neurology Center, Urology Department, and Hematology Department. Among the Staphylococcus spp., methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCNS) were detected at rates of 39.3% and 71.8%, respectively. However, no vancomycin- or linezolid-resistant staphylococci were identified. Enterococcus faecalis showed higher susceptibility to most antibiotic than Enterococcus faecium, except for tetracycline. The resistance rates of E. coli and Klebsiella spp. to meropenem and imipenem were low, but the resistance rates for other antibiotic were above 40%.

Conclusion

The results of this study show a rising incidence of bacterial antibiotic resistance in positive blood culture specimens at Suining Central Hospital. Clinicians should carefully consider the importance of blood culture antibiotic susceptibility testing to ensure effective treatment. The Department of Microbiology at Suining Central Hospital should regularly analyze the distribution of pathogenic bacteria and antibiotic resistance in blood cultures to ensure the most effective treatment possible.

Blood Stream Infections in Burns: A 14-Year Cohort Analysis

BACKGROUND

Blood stream infections are a significant cause of morbidity and mortality in burns, and pathogen identification is important for treatment. This study aims to characterize the microbiology of these infections and the association between the infecting pathogen and the hospitalization course.

METHODS

We conducted a cohort study that included records of burn patients treated at the Soroka University Medical Center between 2007-2020. Statistical analysis of demographic and clinical data was performed to explore relationships between burn characteristics and outcomes. Patients with positive blood cultures were divided into four groups: Gram-positive, Gram-negative, mixed-bacterial, and fungal.

RESULTS

Of the 2029 burn patients hospitalized, 11.7% had positive blood cultures. The most common pathogens were Candida and Pseudomonas. We found significant differences in ICU admission, need for surgery, and mortality between the infected and non-infected groups (p < 0.001). Pathogen groups differed significantly mean TBSA, ICU admission, need for surgery, and mortality (p < 0.001). Multivariate analysis showed flame (OR 2.84) and electric burns (OR 4.58) were independent risk factors for ICU admission and surgical intervention (p < 0.001). Gram-negative bacterial infection was found to be an independent predictor of mortality (OR = 9.29, p < 0.001).

CONCLUSIONS

Anticipating specific pathogens which are associated with certain burn characteristics may help guide future therapy.

Evaluation of the Liquid Colony™ Produced by the FAST System for Shortening the Time of Bacterial Identification and Phenotypic Antimicrobial Susceptibility Testing and Detection of Resistance Mechanisms from Positive Blood Cultures

BACKGROUND

the aim of this study was to evaluate the performance of the Liquid Colony™ (LC) generated directly from positive blood cultures (PBCs) by the FAST System (Qvella, Richmond Hill, ON, Canada) for rapid identification (ID) and antimicrobial susceptibility testing (AST) compared with the standard of care (SOC) workflow.

METHODS

Anonymized PBCs were processed in parallel by the FAST System and FAST PBC Prep cartridge (35 min runtime) and SOC. ID was performed by MALDI-ToF mass spectrometry (Bruker, Billerica, MA, USA). AST was performed by reference broth microdilution (Merlin Diagnostika, Bornheim, Germany). Carbapenemase detection was carried out with the lateral flow immunochromatographic assay (LFIA) RESIST-5 O.O.K.N.V. (Coris, Gembloux, Belgium). Polymicrobial PBCs and samples containing yeast were excluded.

RESULTS

241 PBCs were evaluated. ID results showed 100% genus-level concordance and 97.8% species-level concordance between LC and SOC. The AST results for Gram-negative bacteria showed a categorical agreement (CA) of 99.1% (1578/1593), with minor error (mE), major error (ME), and very major error (VME) rates of 0.6% (10/1593), 0.3% (3/1122), and 0.4% (2/471), respectively. The results from Gram-positive bacteria showed a CA of 99.6% (1655/1662), with mE, ME, and VME rates of 0.3% (5/1662), 0.2% (2/1279), and 0.0% (0/378), respectively. Bias evaluation revealed acceptable results for both Gram-negatives and Gram-positives (-12.4% and -6.5%, respectively). The LC yielded the detection of 14/18 carbapenemase producers by LFIA. In terms of turnaround time, the ID, AST, and carbapenemase detection results were generally obtained one day earlier with the FAST System compared with the SOC workflow.

CONCLUSIONS

The ID, AST, and carbapenemase detection results generated with the FAST System LC were highly concordant with the conventional workflow. The LC allowed species ID and carbapenemase detection within around 1 h after blood culture positivity and AST results within approximately 24 h, which is a significant reduction in the turnaround time of the PBC workflow.

Time-series prediction and detection of potential pathogens in bloodstream infection using mcfDNA sequencing

Introduction

Next-generation sequencing of microbial cell free DNA (mcfDNA-seq) has emerged as a promising diagnostic method for blood stream infection (BSI) and offers the potential to detect pathogens before blood culture. However, its application is limited by a lack of clinical validation.

Methods

We conducted sequential mcfDNA-seq on blood samples from ICU participants at high risk of BSI due to pneumonia, or intravascular catheterization; and explored whether mcfDNA-seq could diagnose and detect pathogens in advance of blood culture positivity. Blood culture results were used as evaluation criteria.

Results

A total of 111 blood samples were collected during the seven days preceding and on the day of onset of 16 BSI episodes from 13 participants. The diagnostic and total predictive sensitivity of mcfDNA-seq were 90% and 87.5%, respectively. The proportion of pathogenic bacteria was relatively high in terms of both diagnosis and prediction. The reads per million of etiologic agents trended upwards in the days approaching the onset of BSI.

Discussion

Our work found that mcfDNA-seq has high diagnostic sensitivity and could be used to identify pathogens before the onset of BSI, which could help expand the clinical application of mcfDNA-seq.

Lesson from the COVID-19 pandemic lockdown: A major change of hospital-diagnosed bacteremia epidemiology

OBJECTIVES

When the COVID-19 pandemic reached France early in 2020, the enforced nationwide lockdown deeply altered lifestyle as well as hospital processes and modalities of care. The aim of the study was to evaluate the impact during the lockdown of the first epidemic wave on the epidemiology of bacteremia in one French University Hospital.

PATIENTS AND METHODS

Retrospective cohort study including adult patients with positive blood culture between 23^rd March to 24^th May 2020. The clinical-microbiological characteristics were compared with those of the period from 25^th March to 26^th May 2019. The data were adjusted to the number of hospitalizations (h).

RESULTS

In 2020, 189 bacteremia were diagnosed from 1939 vials (9658 hospitalizations, 10911 emergency room consultations) compared to 143 from 1976 vials (14797 hospitalizations, 16493 emergency room consultations) recorded in 2019. The incidence of bacteremia increased up to 19.7 per 1000h in 2020 vs 9.7 in 2019 (p<0.001). The main differences (2020 vs 2019) were: Staphylococcus aureus bacteremia (2.4 vs 1.0/1000h, p=0.012), polymicrobial bacteremia (2.2 vs 0.9/1000h p=0.013) and Gram-negative bacteremia (8.9 vs 4.3/1000h, p<0.01). Conversely, Streptococcus pneumoniae incidence decreased (0 vs 0.47/1000h, p=0.047). The standardized incidence ratio calculation confirmed these results.

CONCLUSION

The lockdown and the impact of the first wave of the Covid-19 pandemic on the health system resulted in increased hospital-diagnosed bacteremia and decreased pneumococcal bacteremia. Disruption and overload of ICUs, lockdown with preventive control measures, and decrease in human-to-human interaction may have been the main reasons.

[Application and Prospect of Nanopore Sequencing Technology in Etiological Diagnosis of Blood Stream Infection]

Blood stream infection (BSI),a blood-borne disease caused by microorganisms such as bacteria,fungi,and viruses,can lead to bacteremia,sepsis,and infectious shock,posing a serious threat to human life and health.Identifying the pathogen is central to the precise treatment of BSI.Traditional blood culture is the gold standard for pathogen identification,while it has limitations in clinical practice due to the long time consumption,production of false negative results,etc.Nanopore sequencing,as a new generation of sequencing technology,can rapidly detect pathogens,drug resistance genes,and virulence genes for the optimization of clinical treatment.This paper reviews the current status of nanopore sequencing technology in the diagnosis of BSI.

The utility of sepsis scores for predicting blood stream infections in extracorporeal membrane oxygenation

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is an increasingly used modality of life support with high risk for nosocomial infections. The accuracy of sepsis prediction tools in identifying blood stream infections (BSI) in this population is unknown as measurement of multiple variables commonly associated with infection are altered by the circuit.

METHODS

This study compares all blood stream infections for patients receiving ECMO between January 2012 and December 2020 to timepoints when blood cultures were negative using the Sequential Organ Failure Assessment (SOFA), Logistic Organ Dysfunction Score (LODS), American Burn Association Sepsis Criteria (ABA), Systemic Inflammatory Response Syndrome (SIRS) scores.

RESULTS

Of the 220 patients who received ECMO during the study period, 40 (18%) had 51 blood stream infections and were included in this study. Gram-positive infections composed 57% (n = 29) of infections with E. faecalis (n = 12, 24%) being the most common organism isolated. There were no significant differences in sepsis prediction scores at the time of infection compared to infection-free time points for SOFA (median (IQR) 7 (5-9) vs. 6 (5-8), p = 0.22), LODS (median (IQR) 12 (10-14) vs. 12 (10-13), p = 0.28), ABA (median (IQR) 2 (1-3) vs. 2 (1-3) p = 0.75), or SIRS (median (IQR) 3 (2-3) vs. 3 (2-3), p = 0.20).

CONCLUSIONS

Our data shows that previously published sepsis scores are elevated throughout a patient's ECMO course, and do not correlate with bacteremia. Better predictive tools are needed to determine the appropriate timing for blood cultures in this population.

Development and Assessment of a Novel Predictive Nomogram to Predict the Risk of Secondary CR-GNB Bloodstream Infections among CR-GNB Carriers in the Gastroenterology Department: A Retrospective Case-Control Study

BACKGROUND

With the number of critically ill patients increasing in gastroenterology departments (GEDs), infections associated with Carbapenem-resistant Gram-negative bacteria (CR-GNB) are of great concern in GED. However, no CR-GNB bloodstream infection (BSI) risk prediction model has been established for GED patients. Almost universally, CR-GNB colonization precedes or occurs concurrently with CR-GNB BSI. The objective of this study was to develop a nomogram that could predict the risk of acquiring secondary CR-GNB BSI in GED patients who are carriers of CR-GNB.

METHODS

We conducted a single-center retrospective case-control study from January 2020 to March 2022. Univariate and multivariable logistic regression analysis was used to identify independent risk factors of secondary CR-GNB bloodstream infections among CR-GNB carriers in the gastroenterology department. A nomogram was constructed according to a multivariable regression model. Various aspects of the established predicting nomogram were evaluated, including discrimination, calibration, and clinical utility. We assessed internal validation using bootstrapping.

RESULTS

The prediction nomogram includes the following predictors: high ECOG PS, severe acute pancreatitis, diabetes mellitus, neutropenia, a long stay in hospital, and parenteral nutrition. The model demonstrated good discrimination and good calibration.

CONCLUSIONS

With an estimate of individual risk using the nomogram developed in this study, clinicians and nurses can identify patients with a high risk of secondary CR-GNB BSI early.

Bacterial Pericarditis Caused by Campylobacter fetus subsp. fetus After Mutton Consumption

Campylobacter fetus subsp. fetus causes systemic diseases including bacteremia and meningitis. However, it rarely causes bacterial pericarditis. We present a rare case of bacterial pericarditis caused by Campylobacter fetus subsp. fetus. A man in his 60s presented with a fever and dyspnea. Electrocardiography revealed ST segment elevation in all leads except augmented vector right (aVR), and contrast-enhanced computed tomography of the chest revealed a large pericardial effusion. Campylobacter fetus subsp. fetus, appearing as curved, gull-wing-shaped gram-negative rods on microscopy, was identified on blood culture. The patient was diagnosed with acute pericarditis caused by Campylobacter fetus subsp. fetus. Further, history-taking revealed that he had consumed undercooked mutton before the onset of his illness. He recovered after treatment with antibiotics (ceftriaxone, ampicillin, and amoxicillin) for four weeks. With a blood culture revealing gull-wing shaped gram-negative rods, and the patient's history including potential contact with animals or the consumption of raw or undercooked meat, Campylobacter fetus subsp. fetus infection should be suspected.

Blood culture positivity in patients with acute appendicitis: A propensity score-matched prospective cohort study

BACKGROUND AND OBJECTIVE

The prevalence of bacteremia in acute appendicitis is unknown. We aimed to assess prevalence and predictive factors of bacteremia in adult patients with appendicitis.

METHODS

In this prospective propensity score-matched cohort study, patients were recruited as part of one single-center prospective observational study assessing appendicitis microbiology in concurrence with two randomized controlled trials on non-operative treatment of uncomplicated acute appendicitis. All patients evaluated for enrollment in these three trials between April 2017 and December 2018 with both a confirmed diagnosis of appendicitis and available blood culture on admission were included in this study. Potential predictive factors of bacteremia (age, sex, body mass index (BMI), body temperature, C-reactive protein (CRP), leukocyte count, comorbidities, symptom duration, and appendicitis severity) were assessed. Prevalence of bacteremia was determined by all available blood cultures followed by propensity score matching using sex, age, BMI, CRP, leukocyte count, and body temperature of the patients without available blood culture.

RESULTS

Out of the 815 patients with appendicitis, 271 patients had available blood culture and the prevalence of bacteremia was 12% (n = 33). Based on propensity score estimation, the prevalence of bacteremia in the whole prospective appendicitis cohort was 11.1%. Bacteremia was significantly more frequent in complicated acute appendicitis (15%; 29/189) compared with uncomplicated acute appendicitis (5%; 4/82) (p = 0.015). Male sex (p = 0.024) and higher body temperature (p = 0.0044) were associated with bacteremia.

CONCLUSIONS

Estimated prevalence of bacteremia in patients with acute appendicitis was 11.1%. Complicated appendicitis, male sex, and higher body temperature were associated with bacteremia in acute appendicitis.

Incidence and Risk Factors for Blood Stream Infection in Mechanically Ventilated COVID-19 Patients

It is widely known that blood stream infections (BSIs) in critically ill patients may affect mortality, length of stay, or the duration of mechanical ventilation. There is scarce data regarding blood stream infections in mechanically ventilated COVID-19 patients. Preliminary studies report that the number of secondary infections in COVID-9 patients may be higher. This retrospective analysis was conducted to determine the incidence of BSI. Furthermore, risk factors, mortality, and other outcomes were analyzed. The setting was an Intensive Care Unit (ICU) at a University Hospital. Patients suffering from SARS-CoV-2 infection and requiring mechanical ventilation (MV) for >48 h were eligible. The characteristics of patients who presented BSI were compared with those of patients who did not present BSI. Eighty-four patients were included. The incidence of BSI was 57%. In most cases, multidrug-resistant pathogens were isolated. Dyslipidemia was more frequent in the BSI group (p < 0.05). Moreover, BSI-group patients had a longer ICU stay and a longer duration of both mechanical ventilation and sedation (p < 0.05). Deaths were not statistically different between the two groups (73% for BSI and 56% for the non-BSI group, p > 0.05). Compared with non-survivors, survivors had lower baseline APACHE II and SOFA scores, lower D-dimers levels, a higher baseline compliance of the respiratory system, and less frequent heart failure. They received anakinra less frequently and appropriate therapy more often (p < 0.05). The independent risk factor for mortality was the APACHE II score [1.232 (1.017 to 1.493), p = 0.033].

A case of Flavonifractor plautii blood stream infection in a severe burn patient and a review of the literature

BACKGROUND

Flavonifractor plautii is a strictly anaerobic rod shaped bacterium belonging to the family of Clostridiales. It is a commensal of the human intestinal microbiota which was seldom isolated from clinical samples, therefore clinical data are scarce. To date, only four cases of F. plautii infections were described, all occurring in immunosuppressed patients.

CASE PRESENTATION

We report a case where F. plautii was isolated from the blood culture of a severe burn victim and identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

DISCUSSION

To the best of our knowledge, this is the first case of F. plautii blood stream infection described in a burn patient.

Epidemiology and etiology of blood stream infections in a Belgian burn wound center

BACKGROUND

Infections are a major cause of morbidity in burn patients. We aimed to investigate the epidemiology and antibiotic susceptibility of blood stream infections in order to gain a better understanding of their role and burden in our Burn Wound Center.

METHODS

This retrospective epidemiological investigation analyzed data derived from medical files of patients admitted to our Burn Wound Center having had at least one positive blood culture between 1 January and 31 December 2018. We focused on the prevalence of causative agents in blood stream infections in function of the time after injury and on their drug sensitivity.

RESULTS

Among the 363 patients admitted to our Burn Wound Center during the study period, 29 had at least one episode of blood stream infection. Gram-negative organisms accounted for 56,36% of the pathogens in blood stream infections, Gram-positives for 38,17%, and yeasts for 5,45%. Pseudomonas aeruginosa was the most common bacterium (20%), followed by Staphylococcus epidermidis (16.36%), Escherichia coli and Klebsiella pneumoniae (9,09% each). A third of the Gram-negative isolates were multidrug resistant. Gram-positive cocci were isolated from blood cultures at a median of 9 days after the injury, earlier than Gram-negative rods (median 15 days). The main sources of blood stream infections were the burn wounds, followed by infected catheters.

CONCLUSIONS

Multidrug resistant bacteria must be considered when selecting empirical antibiotic therapy in septic burn patients. In our center, we need to update our antibiotic guidelines, to review the hospital infection control measures and to introduce routine typing technology.

Frequency and Clinical Features of Candida Bloodstream Infection Originating in the Urinary Tract

The urinary tract is considered an uncommon source of Candida bloodstream infection (CBSI). We aimed to determine the source of CBSI in hospitalized patients, and to compare clinical and microbiological features of CBSI originating in the urinary tract (U-CBSI) and non-urinary CBSI (NU-CBSI). Of 134 patients with CBSI, 28 (20.8%) met criteria for U-CBSI, 34 (25.3%) had vascular catheter-related CBSI and 21 (15.6%) had a gastrointestinal origin. Compared to NU-CBSI patients, patients with U-CBSI were older with higher rates of dementia. Bladder catheterization for urinary retention and insertion of ureteral stents or nephrostomies were risk factors for U-CBSI. Fifty percent of U-CBSI cases occurred within 48 h of hospital admission, versus 16.9% of NU-CBSI (p < 0.0001). The mortality rate was lowest for CBSI originating in the urinary tract and highest for CBSI of undetermined origin. CBSI of undetermined origin remained associated with higher mortality in a Cox regression model that included age, Candida species, Pitt bacteremia score and neutropenia as explanatory variables. U-CBSI may be increasing in frequency, reflecting extensive use of bladder catheters and urologic procedures in elderly debilitated patients. Distinct clinical features are relevant to the diagnosis, treatment and prevention of U-CBSI.

Lower beta-1,3-D-glucan testing cut-offs increase sensitivity for non-albicans Candida species blood stream infections

PURPOSE

Fungal biomarkers support early diagnosis of invasive fungal infections. In this study, we evaluated the impact of a recent update to the manufacturer-recommended cut-off for beta-1,3-D-glucan (BDG) testing (Fujifilm Wako BDG assay) on sensitivity and specificity for the detection of candidemia. Additionally, we compared the performance with tests for Candida antigen (Ag by Serion ELISA antigen Candida, Virion\Serion) and anti-mannan antibodies (Ab by Hemkit Candida IHA, Ravo Diagnostika).

METHODS

Sera of 82 patients with candidemia, which were sampled with a maximum distance of ±14 days from the date of sampling of the corresponding positive blood cultures, were retrospectively analyzed for BDG, Ag, and Ab. Results of BDG testing were compared with results from sera of 129 patients with candidemia from a different hospital.

RESULTS

Sensitivity of BDG testing (47%) was higher than for Ag (17%) or Ab (20%). By combining Ag and Ab testing, sensitivity was raised to 32%. Lowering the cut-off of BDG from 11 pg/ml to the newly recommended cut-off of 7 pg/ml resulted in a significant increase in sensitivity (47% vs. 58%, p=0.01 and 63 % vs. 71% p<0.01). At both centers, the increase was significant in NAC but not in C. albicans candidemia. No significant effects on specificity where observed.

CONCLUSION

BDG-testing outperformed Ag and Ab testing and its combination. Lowering the BDG cut-off had no significant impact on specificity. The increase in sensitivity can be mainly attributed to a gain in sensitivity for non-albicans Candida species blood stream infections.

Stenotrophomonas maltophilia Infections in Pediatric Patients - Experience at a European Center for Pediatric Hematology and Oncology

Stenotrophomonas maltophilia is an important nosocomial pathogen in immunocom-promised individuals and characterized by intrinsic resistance to broad-spectrum antibacterial agents. Limited data exists on its clinical relevance in immunocompromised pediatric patients, particularly those with hematological or oncological disorders. In a retrospective single center cohort study in pediatric patients receiving care at a large european pediatric hematology and oncology department, ten cases of invasive S.maltophilia infections (blood stream infections (BSI), 4; BSI and pneumonia, 3, or soft tissue infection, 2; and pneumonia, 1) were identified between 2010 and 2020. Seven patients had lymphoblastic leukemia and/or were post allogeneic hematopoietic cell transplantation. Invasive S.maltophilia infections occurred in a setting of indwelling central venous catheters, granulocytopenia, defective mucocutaneous barriers, treatment with broad-spectrum antibacterial agents, and admission to the intensive care unit. Whole genome sequencing based typing revealed no genetic relationship among four individual S.maltophilia isolates. The case fatality rate and mortality at 100 days post diagnosis were 40 and 50%, respectively, and three patients died from pulmonary hemorrhage. Invasive S.maltophilia infections are an emerging cause of infectious morbidity in patients receiving care at departments of pediatric hematology and oncology and carry a high case fatality rate.

Invasive Staphylococcus aureus Infection among Patients Undergoing Elective, Posterior, Instrumented Spinal Fusion Surgeries: A Retrospective Cohort Study

Background: Post-surgical invasive Staphylococcus aureus infections among spinal fusion patients are serious complications that can worsen clinical outcomes and increase healthcare utilization. Risk of such infections at the population level remains unknown. This study assessed the post-surgical risk of invasive Staphylococcus aureus infections among patients undergoing elective posterior instrumented spinal fusion surgeries in 129 U.S. hospitals. Patients and Methods: This retrospective cohort study analyzed adult patients ≥18 years of age who underwent thoracolumbar/lumbar and cervical fusion surgeries during 2010 - 2014 using the Premier Healthcare Database, the largest hospital discharge database in the United States. Risks of blood stream infection (BSI), deep or organ/space surgical site infections (SSI) caused by Staphylococcus aureus during 90 and 180 days post-index surgery were estimated. Infections were identified based on positive culture results, related International Classification of Diseases, Ninth Revision (ICD-9) procedure codes, and specific claims information. Results: Among 11,236 patients with thoracolumbar/lumbar fusion, 90- and 180-day BSI/SSI infection risks were higher for multilevel than single level fusion (90-day, 1.52% vs. 1.07%, p = 0.05; 180-day, 1.66% vs. 1.07%, p = 0.014). Among 1,641 patients with cervical fusion, 90- and 180-day BSI/SSI infection risks were also higher in multilevel fusions but not statistically significant (90-day, 1.66% vs. 0.52%, p = 0.350; 180-day, 1.80% vs. 0.51%, p = 0.241). The risk for SSI/BSI was more than twice as high among multilevel thoracolumbar/lumbar fusion patients with more than two comorbidities than those with no comorbidity at both 90-day (2.78% vs. 1.00%, p < 0.05) and 180-day (3.01% vs. 1.10%, p < 0.05). Similar trend without statistical significance was seen in multilevel cervical fusion cohort (90-day, 2.91% vs. 1.25%, p > 0.05; 180-day, 3.88% vs. 1.41%, p > 0.05). Conclusions: The risk of BSI/SSI infection for elective posterior instrumented spinal fusions ranged between 0.5% and 2%. Higher risk was observed in multilevel thoracolumbar/lumbar surgery, with infection risk greatest in patients with more than two comorbidities. These real-world findings highlight the need for additional measures, in addition to antibiotic prophylaxis, to reduce invasive Staphylococcus aureus infections in this setting.

Association between perioperative allogeneic red blood cell transfusion and infection after clean-contaminated surgery: a retrospective cohort study

BACKGROUND

Allogeneic red blood cell (RBC) transfusion can induce immunosuppression, which can then increase the susceptibility to postoperative infection. However, studies in different types of surgery show conflicting results regarding this effect.

METHODS

In this retrospective cohort study conducted in a tertiary referral centre, we included adult patients undergoing clean-contaminated surgery from 2014 to 2018. Patients who received allogeneic RBC transfusion from preoperative Day 30 to postoperative Day 30 were included into the transfusion group. The control group was matched for the type of surgery in a 1:1 ratio. The primary outcome was infection within 30 days after surgery, which was defined by healthcare-associated infection, and identified mainly based on antibiotic regimens, microbiology tests, and medical notes.

RESULTS

Among the 8098 included patients, 1525 (18.8%) developed 1904 episodes of postoperative infection. Perioperative RBC transfusion was associated with an increased risk of postoperative infection after controlling for 27 confounders by multivariable regression analysis (odds ratio [OR]: 1.60; 95% confidence interval [CI]: 1.39-1.84; P<0.001) and propensity score weighing (OR: 1.64; 95% CI: 1.45-1.85; P<0.001) and matching (OR: 1.70; 95% CI: 1.43-2.01; P<0.001), and a dose-response relationship was observed. The transfusion group also showed higher risks of surgical site infection, pneumonia, bloodstream infection, multiple infections, intensive care admission, unplanned reoperation, prolonged postoperative length of hospital stay, and all-cause death.

CONCLUSIONS

Perioperative allogeneic RBC transfusion is associated with an increased risk of infection after clean-contaminated surgery in a dose-response manner. Close monitoring of infections and enhanced prophylactic strategies should be considered after transfusion.

Performance of Verigene Rapid Diagnostic Testing for Detection of Inpatient Pediatric Bacteremia

OBJECTIVE

Verigene blood culture panels comprise rapid diagnostic testing, which aids in early bacteremia species identification. This study determined the concordance of Verigene rapid diagnostic results compared with the Vitek reference standard in patients admitted to a children's hospital.

METHODS

This was a 3-year retrospective observational study of neonatal and pediatric patients ≤18 years admitted to a children's hospital with confirmed bacteremia for whom Verigene testing was performed. Verigene testing was conducted on cultures with reported growth on Gram stain and final organism speciation confirmed via Vitek. Percent concordance and positive percent agreement with 95% CIs were calculated for Verigene panel-identifiable organisms. Negative percent agreement with 95% CIs was calculated for non-panel organisms. Time-to-result was calculated from Gram stain reporting to both Verigene and Vitek final organism susceptibility.

RESULTS

One hundred thirty-five Gram-positive (GP) and 51 Gram-negative (GN) isolates were identified through Vitek. Verigene GP panel-detectable organisms were correctly identified 96.9% (125/129) at the genus level and 95.3% (123/129) at the species level. Overall positive percent agreement was 95.3 (CI: 90.2-98.3). Negative percent agreement was 83.3 (CI: 35.9-99.6) for the 6 non-panel GP organisms. All GN isolates were correctly identified on Verigene. Median time-to-result was 2.9 hours (IQR 2.6, 3.2) and 44.4 hours (IQR: 35.4, 52.5) for Verigene and final susceptibilities, respectively. There was a statistically significant time savings of 41.5 hours (CI: 29.8-53.2) for identification and detection of resistance markers (p < 0.0001).

CONCLUSION

Verigene concordance at our institution aligns with results from previously published studies and can be considered a reliable clinical decision-support tool.

[Clinical characteristics and risk factors of blood stream infections after orthopedic surgery]

OBJECTIVE

To analyze the clinical characteristics, risk factors, and drug resistance of pathogenic bacteria in patients with blood stream infections (BSI) after orthopedic surgery, so as to provide reference and basis for clinical diagnosis and treatment.

METHODS

A retrospective analysis was made on the clinical data of 6 348 orthopedic patients admitted for surgery between January 2017 and December 2019. There were 3 598 males and 2 750 females. Their age ranged from 18 to 98 years, with an average of 66 years. The data of patients were collected, and the risk factors of BSI were analyzed by univariate analysis and logistic regression analysis. The distribution of BSI pathogenic bacteria, the results of drug sensitivity test, the incidence of BSI in patients after orthopedic surgery in different years, and the common sites of BSI secondary infection were summarized.

RESULTS

BSI occurred in 106 (1.67%) of 6 348 patients after orthopedic surgery. There were 71 cases (66.98%) of secondary infection. The mortality of postoperative BSI patients was 1.89%, and the difference was significant when compared with that of non-postoperative BSI patients (0.24%) ( χ 2=5.313, P=0.021). The incidences of BSI in 2017, 2018, and 2019 were 1.18%, 1.53%, and 2.17%, respectively, showing an increasing trend year by year (trend χ 2=6.610, P=0.037). Statistical analysis showed that the independent risk factors for BSI after orthopedic surgery ( P<0.05) included the trauma, length of hospital stay≥14 days, emergency surgery, postoperative leukocyte counting<4×10 9/L, level of hemoglobin≤90 g/L, albumin≤30 g/L, the time of indwelling ureter>24 hours, use of deep vein catheter insertion, and merging other site infection. Blood culture showed 56 strains (52.83%) of Gram-positive bacteria, 47 strains (44.34%) of Gram-negative bacteria, and 3 strains (2.83%) of fungi. The top three pathogenic bacteria were coagulase negative Staphylococci (CNS; 36 strains, 33.96%), Escherichia coli (16 strains, 15.09%), and Staphylococcus aureus (15 strains, 14.15%). The detection rates of extended-spectum β-lactamases producing strains of Escherichia coli and Klebsiella pneumoniae were 56.25% (9/16) and 44.44% (4/9), respectively. The detection rates of methicillin-resistant strains in Staphylococcus aureus and CNS were 46.67% (7/15) and 72.22% (26/36), respectively.

CONCLUSION

Postoperative BSI in orthopedic patients is caused by multiple factors. Preventive measures should be taken according to related risk factors and perioperative risk assessment should be strengthened. Staphylococcus and Escherichia coli are the most common pathogenic bacteria in BSI after orthopedic surgery. The infection rate and drug-resistant bacteria are increasing year by year. Therefore, drug resistance monitoring should be strengthened.

Equal effect of vancomycin lock with or without heparin in treatment of central venous catheter related blood stream infections - an observational study in palliative home care

BACKGROUND

Catheter related blood stream infections is a complication in patients with central venous catheter. The aim of this study was to compare vancomycin-heparin-lock and non-heparin, high-dose vancomycin-lock as treatment in patients admitted to palliative home care. With non-heparin, high-dose vancomycin-lock a high concentration of 5 mg/mL vancomycin is attained instead of only 500 ug/mL when dissolved in heparin. The non-heparin method also has the advantage of being easier and cheaper but might entail an increased risk of clotting.

METHODS

Medical records from patients enrolled at a palliative home care unit in Stockholm between 2016 and 2018 were reviewed retrospectively. Three divisions used vancomycin-heparin-lock and the other 3 divisions used non-heparin, high-dose vancomycin-lock. Inclusion criteria were a central venous catheter related blood stream infection treated with one of the two methods for >7 days and a follow-up blood culture at the end of treatment.

RESULTS

Twenty-five patients fulfilled the inclusion criteria, 12 treated with vancomycin-heparin-lock and 13 with non-heparin, high-dose vancomycin-lock. There was no significant difference in resolved infections between the two treatments, 6 of 12 for vancomycin-heparin-lock and 10 of 13 for non-heparin, high-dose vancomycin-lock (p = .23). In the non-heparin group one central venous catheter was removed due to clotting although the infection had resolved. Overall, removal of central venous catheter was similar in the two groups (6 of 12 and 4 of 13, p = .43).

CONCLUSION

The current study does not support superiority of one treatment over the other. However, larger, randomized studies are needed, before firm conclusions can be drawn.

Rapid metagenomics for diagnosis of bloodstream and respiratory tract nosocomial infections: current status and future prospects

Introduction: Nosocomial infections represent a major problem for the health-care systems worldwide. Currently, diagnosis relies on microbiological culture, which is slow and has poor sensitivity. While waiting for a diagnosis, patients are treated with empiric broad spectrum antimicrobials, which are often inappropriate for the infecting pathogen. This results in poor patient outcomes, poor antimicrobial stewardship and increased costs for health-care systems.Areas covered: Clinical metagenomics (CMg), the application of metagenomic sequencing for the diagnosis of infection, has the potential to become a viable alternative to culture that can offer rapid results with high accuracy. In this article, we review current CMg methods for the diagnosis of nosocomial bloodstream (BSI) and lower respiratory-tract infections (LRTI).Expert opinion: CMg approaches are more accurate in LRTI compared to BSI. This is because BSIs are caused by low pathogen numbers in a high background of human cells. To overcome this, most approaches focus on cell-free DNA, but, to date, these tests are not accurate enough yet to replace blood culture. The higher pathogen numbers in LRTI samples make this a more suitable for CMg and accurate approaches have been developed, which are likely to be implemented in hospitals within the next 2-5 years.

The predictive role of Interleukin 6 in burn patients with positive blood cultures

Interleukin 6 (IL-6) is an established biomarker of inflammation with one of the earliest responses in sepsis. Serum levels can easily be measured within a few hours. The clinical significance of IL-6 in the early stage of sepsis in burned patients has not yet been confirmed. The purpose of our research was to investigate the predictive value of IL-6 for positive blood cultures in comparison to Procalcitonin (PCT), white blood cell (WBC) count, body temperature and the Sequential Organ Failure Assessment (SOFA) score in the presence of suspected sepsis in burn patients. In a retrospective study, we included all patients admitted to a regional burn centre in a 7-year period. Patients with a clinical suspicion of sepsis and complete laboratory tests underwent further analysis. Patients were categorized following culture results into either positive or negative bloodstream infection (BSI or non-BSI) groups. 39 of the 101 included patients had positive blood cultures (BSI). The serum IL-6 levels were significantly higher in the BSI group [1047 (339.9; 9000.5) vs. 198.5 (112.4; 702.5) ng/l; P = 0.001]. Receiver operating characteristic (ROC) curve analysis showed an AUC of 0.7 (59; 80.8%). The optimal IL-6 cut-off level was 312.8 ng/l (sensitivity 79.5%, specificity 56.5%). Other biomarkers (PCT, WBC), the maximum body temperature and increase of SOFA score were not different between the groups. IL-6 can be used to predict a positive blood culture even in the early stage of suspected sepsis in burned patients. In this context, other biomarkers (PCT, WBC) and body temperature are of limited clinical utility.

Selective Host Cell Death by Staphylococcus aureus: A Strategy for Bacterial Persistence

Host cell death programs are fundamental processes that shape cellular homeostasis, embryonic development, and tissue regeneration. Death signaling and downstream host cell responses are not only critical to guide mammalian development, they often act as terminal responses to invading pathogens. Here, we briefly review and contrast how invading pathogens and specifically Staphylococcus aureus manipulate apoptotic, necroptotic, and pyroptotic cell death modes to establish infection. Rather than invading host cells, S. aureus subverts these cells to produce diffusible molecules that cause death of neighboring hematopoietic cells and thus shapes an immune environment conducive to persistence. The exploitation of cell death pathways by S. aureus is yet another virulence strategy that must be juxtaposed to mechanisms of immune evasion, autophagy escape, and tolerance to intracellular killing, and brings us closer to the true portrait of this pathogen for the design of effective therapeutics and intervention strategies.

Association between lymphopenia at one month post-transplant and infectious outcomes or death in heart transplant recipients

BACKGROUND

Cell-mediated immunity is a specific target of several medications used to prevent or treat rejection in orthotopic heart transplantation. Low absolute lymphocyte count (ALC) has potential to be a useful and accessible clinical indicator of overall infection risk. Though some studies have demonstrated this association in other transplant populations, it has not been assessed in heart transplant recipients.

METHODS

A single-center retrospective cohort study examined adult heart transplant recipients transplanted between 2000 and 2018. The exposure of interest was ALC less than 0.75 x10 3cells/µL at one month post-transplant and the primary endpoint was a composite outcome of infection (including cytomegalovirus [CMV], herpes simplex I/II or varicella zoster virus [HSV/VZV], blood stream infection [BSI], invasive fungal infection [IFI]) or death occurring after one month and before one year post-transplant. A multivariable Cox proportional hazards model was created to control for confounders identified using clinical judgment and statistical criteria.

RESULTS

Of 375 subjects analyzed, 101 (27%) developed the composite outcome (61 CMV, 3 HSV/VZV, 19 BSI, 10 IFI, 8 deaths). Lymphopenia (ALC<0.75 x10 3cells/µL) at one month was associated with a greater than two fold higher rate of the composite outcome (hazard ratio 2.26, 95% confidence interval 1.47-3.46, p-value <0.001) compared to patients without lymphopenia at one month. After adjustment for confounding variables, the presence of lymphopenia remained statistically significantly associated with the composite outcome (HR 1.72 95% CI 1.08-2.75, p=0.02). Conclusion: ALC measured at one month post-heart transplant is associated with an increased risk of infectious outcomes or death in the ensuing 11months. This is a simple, accessible laboratory measure.

Human Infection of Methicillin-Susceptible Staphylococcus aureus CC398: A Review

Staphylococcus aureus (SA) belonging to the clonal complex 398 (CC398) took a special place within the species due to its spread throughout the world. SA CC398 is broadly separated in two subpopulations: livestock-associated methicillin-resistant SA (MRSA) and human-associated methicillin-susceptible SA (MSSA). Here, we reviewed the global epidemiology of SA CC398 in human clinical infections and focused on MSSA CC398. The last common ancestor of SA CC398 was probably a human-adapted prophage φSa3-positive MSSA CC398 strain, but the multiple transmissions between human and animal made its evolution complex. MSSA and MRSA CC398 had different geographical evolutions. Although MSSA was present in several countries all over the world, it was mainly reported in China and in France with a prevalence about 20%. MSSA CC398 was frequently implicated in severe infections such as bloodstream infections, endocarditis, and bone joint infections whereas MRSA CC398 was mainly reported in skin and soft tissue. The spread of the MSSA CC398 clone is worldwide but with a heterogeneous prevalence. The prophage φSa3 played a crucial role in the adaptation to the human niche and in the virulence of MSSA CC398. However, the biological features that allowed the recent spread of this lineage are still far from being fully understood.

Etiological Profile and Antimicrobial Patterns in Blood Culture Specimens in a Tertiary Care Setting

Introduction Universally, blood stream infections are linked with increasing morbidity and mortality. Timely diagnosis for identification of bacterial etiology, their susceptibility pattern and choice of empiric treatment plays a vital role in management. Objective To reveal the etiological profile and antibiotic sensitivity in blood culture specimens in a tertiary care setting. Methods This descriptive study was carried out in pathology laboratory of a tertiary care hospital from August 2016 to July 2019. All the 750 blood culture bottles were processed and isolates were recognized by morphological appearance on recommended media, gram stain, and different biochemical tests using Analytic Profile Index. Antibiotic sensitivity was implemented by modified disc diffusion method as per Clinical and Laboratory Standards Institute (CLSI) principles (2019). Results Out of 750 blood samples, 212 (28.26%) were culture positive. The percentage of gram-negative bacilli (n = 105) and gram-positive cocci (n = 104) was almost same (49.52%), while candida spp. was recovered from three (1.41%) isolates. The identified gram-negative bacteria were E. coli and Acinetobacter baumannii each (19.04%), Klebsiella pneumoniae and Pseudomonas aeruginosa each (16.19%), Enterobacter cloaca (11.42%), Salmonella typhi (8.57%), Burkholderia cepacia (1.90%), and Raoultella terrigena (7.61%). Among gram-positive isolates, coagulase-negative staphylococci (79.80%), Staphylococcus aureus (6.73%), Enterococcus spp. (11.53%) and Streptococcus spp. (1.92%) were recovered. Colistin, imipenem, meropenem, and amikacin were most successful against gram-negative rods. The sensitivity to vancomycin, teicoplanin and linezolid was 100%, for gram positive organisms. Methicillin resistance was present in 84.4% Staphylococcal isolates. Conclusion Local data showing changing etiological pattern and antibiogram of isolated pathogens, along with adequate infection prevention and control measures can be useful to improve patient care, in terms of hospital stay, duration of medication and treatment cost.

An analysis of totally implantable central venous port system infections in an urban tertiary referral center

A frequent complication of central venous port systems (CVP) is infection (CVP-I), either local (CVP-LI) or a life-threatening blood stream infection (CVP-BSI). We examined the course of CVP-I including results of an antibiotic eradication attempt of CVP-BSI. We investigated adults with CVP-I from 2010 to 2018 who had to undergo port explantation or were treated by a combination of systemic antibiotics and antibiotic lock therapy (ALT). In nine years we diagnosed 206 CVP-I (CVP-LI: 52; CVP-BSI: 152). In 146 patients with CVP-I the port system was primary explanted, while 56 patients received antibiotics/ALT. 79% of Gram negative pathogens and 50% of coagulase negative staphylococci (CoNS) were eradicated. Failure of antibiotic treatment was more often associated with short time span since CVP implantation, neutropenia and polymicrobial infection. All patients with non-neoplastic disease survived, while 18/173 patients (10%) with underlying malignant disease had a fatal outcome in the same hospital stay.

Impact of Continuation of Parenteral Nutrition on Outcomes of Patients with Blood Stream Infections

Background: The impact of continuing parenteral nutrition (PN) in patients who develop blood stream infections (BSI) while receiving PN is largely unknown. Patients and Methods: Adult patients admitted to a large academic center over three consecutive years and seven months who had a positive blood culture while receiving PN were included in the study. The cohort was divided into those who had PN continued (PN-c) or discontinued (PN-dc) after the positive culture. We evaluated the effect of continuing PN on clinical outcomes by comparing a composite outcome of recurrent BSI, severe sepsis/septic shock, and death within 30 days between the two groups using a propensity score-weighting regression analysis. Results: Of 154 patients included in the study, approximately 70% of whom were surgical patients, 65 (42%) had PN discontinued whereas 89 (58%) had PN continued. Cohort characteristics were similar between the two groups including the Pitt bacteremia score and source control. There were more cases of candidemia (18% vs 6%, p = 0.03) and more cases of intra-abdominal infections (IAI; 42% vs 25%, p = 0.02) in the PN-c group compared with the PN-dc group. The most common sites of infection were endovascular and IAI in both groups. The median duration of bacteremia for both groups was one day. After applying propensity score weighting, the composite outcome of recurrent BSI, severe sepsis/septic shock, and death within 30 days was similar between the PN-dc and PN-c groups (43% and 49%, respectively; p = 0.61). Conclusions: Continuing PN in patients with bacteremia or candidemia was not associated with worse clinical outcomes.

Incidence of healthcare-associated infections in patients with fever during the first 48 hours after decannulation from veno-venous extracorporeal membrane oxygenation

INTRODUCTION

Fevers following decannulation from veno-venous extracorporeal membrane oxygenation often trigger an infectious workup; however, the yield of this workup is unknown. We investigated the incidence of post-veno-venous extracorporeal membrane oxygenation decannulation fever as well as the incidence and nature of healthcare-associated infections in this population within 48 hours of decannulation.

METHODS

All patients treated with veno-venous extracorporeal membrane oxygenation for acute respiratory failure who survived to decannulation between August 2014 and November 2018 were retrospectively reviewed. Trauma patients and bridge to lung transplant patients were excluded. The highest temperature and maximum white blood cell count in the 24 hours preceding and the 48 hours following decannulation were obtained. All culture data obtained in the 48 hours following decannulation were reviewed. Healthcare-associated infections included blood stream infections, ventilator-associated pneumonia, and urinary tract infections.

RESULTS

A total of 143 patients survived to decannulation from veno-venous extracorporeal membrane oxygenation and were included in the study. In total, 73 patients (51%) were febrile in the 48 hours following decannulation. Among this cohort, seven healthcare-associated infections were found, including five urinary tract infections, one blood stream infection, and one ventilator-associated pneumonia. In the afebrile cohort (70 patients), four healthcare-associated infections were found, including one catheter-associated urinary tract infection, two blood stream infections, and one ventilator-associated pneumonia. In all decannulated patients, the majority of healthcare-associated infections were urinary tract infections (55%). No central line-associated blood stream infections were identified in either cohort. When comparing febrile to non-febrile cohorts, there was a significant difference between pre- and post-decannulation highest temperature (p < 0.001) but not maximum white blood cell count (p = 0.66 and p = 0.714) between the two groups. Among all positive culture data, the most commonly isolated organism was Klebsiella pneumoniae (41.7%) followed by Escherichia coli (33%). Median hospital length of stay and time on extracorporeal membrane oxygenation were shorter in the afebrile group compared to the febrile group; however, this did not reach a statistical difference.

CONCLUSION

Fever is common in the 48 hours following decannulation from veno-venous extracorporeal membrane oxygenation. Differentiating infection from non-infectious fever in the post-decannulation veno-venous extracorporeal membrane oxygenation population remains challenging. In our febrile post-decannulation cohort, the incidence of healthcare-associated infections was low. The majority were diagnosed with a urinary tract infection. We believe obtaining cultures in febrile patients in the immediate decannulation period from veno-venous extracorporeal membrane oxygenation has utility, and even in the absence of other clinical suspicion, should be considered. However, based on our data, a urinalysis and urine culture may be sufficient as an initial work up to identify the source of infection.

Early detection of infectious complications during induction therapy for acute leukemia with serial C-reactive protein biomarker assessment

Febrile neutropenia (FN) and blood stream infections (BSI) are major complications of induction treatment for acute leukemia. We assessed the predictive utility of C-reactive protein (CRP), an acute phase reactant, for FN and BSI during induction. CRP levels and dynamics were analyzed in 138 consecutive patients. FN and BSI occurred in 110 (80.3%) and 10 (7.5%) patients, respectively. Median peak CRP level in the 24-hours preceding FN was 7.5 mg/dl (0.2-38.1) vs. median peak CRP level of 5.11 mg/dl (0.2-23.1, p = .009) in patients without FN. CRP levels preceding BSI were 13.1 mg/dl (6.9-27.9) vs. 6.3 mg/dl (0.16-38.14, p = .011). CRP increase prior to event (ΔCRP) was higher among patients with BSI vs. patients without BSI (p = .013). CRP was predictive for FN (p = .009) and BSI (p = .01) on ROC curve analysis and was also independently associated with FN on multivariate analysis. In conclusion, CRP is a sensitive biomarker that precedes FN and BSI.

Blood stream infections in children in the first year after liver transplantation at Wits Donald Gordon Medical Centre, South Africa

Children who undergo liver transplantation and subsequently develop BSI are at risk for adverse outcomes. Research from high-income settings contrasts the dearth of information from transplant centers in low- and middle-income countries, such as South Africa. Therefore, this study from Johannesburg aimed to describe the clinical and demographic profile of children undergoing liver transplantation, and determine the incidence and pattern of BSI and associated risk factors for BSI during the first year after liver transplant. Pediatric liver transplants performed from 2005 to 2014 were reviewed. Descriptive analyses summarized donor, recipient, and post-transplant infection characteristics. Association between BSI and sex, cause of liver failure, age, nutritional status, PELD/MELD score, graft type, biliary complications, and acute rejection was determined by Fisher's exact test; and association with length of stay by Cox proportional hazards regression analysis. Survival estimates were determined by the Kaplan-Meier method. Sixty-five children received one transplant and four had repeat transplants, totaling 69 procedures. Twenty-nine BSI occurred in 19/69 (28%) procedures, mostly due to gram-negative organisms, namely Klebsiella species. Risk for BSI was independently associated with biliary atresia (44% BSI in BA compared to 17% in non-BA transplants; P = .014) and post-operative biliary complications (55% BSI in transplants with biliary complications compared to 15% in those without; P = .0013). One-year recipient and graft survival was 78% (CI 67%-86%) and 77% (CI 65%-85%), respectively. In Johannesburg, incident BSI, mostly from gram-negative bacteria, were associated with biliary atresia and post-operative biliary complications in children undergoing liver transplantation.

Colistin-Resistant Acinetobacter Baumannii Bacteremia: A Serious Threat for Critically Ill Patients

The prevalence of acinetobacter baumannii (AB) as a cause of hospital infections has been rising. Unfortunately, emerging colistin resistance limits therapeutic options and affects the outcome. The aim of the study was to confirm our clinically-driven hypothesis that intensive care unit (ICU) patients with AB resistant-to-colistin (ABCoR) bloodstream infection (BSI) develop fulminant septic shock and die. We conducted a 28-month retrospective observational study including all patients developing AB infection on ICU admission or during ICU stay. From 622 screened patients, 31 patients with BSI sepsis were identified. Thirteen (41.9%) patients had ABCoR BSI and 18/31 (58.1%) had colistin-susceptible (ABCoS) BSI. All ABCoR BSI patients died; of them, 69% (9/13) presented with fulminant septic shock and died within the first 3 days from its onset. ABCoR BSI patients compared to ABCoS BSI patients had higher mortality (100% vs. 50%, respectively (p = 0.001)), died sooner (p = 0.006), had lower pH (p = 0.004) and higher lactate on ICU admission (p = 0.0001), and had higher APACHE II (p = 0.01) and Charlson Comorbidity Index scores (p = 0.044). In conclusion, we documented that critically ill patients with ABCoR BSI exhibit fulminant septic shock with excessive mortality. Our results highlight the emerging clinical problem of AB colistin resistance among ICU patients.

Impact of International Nosocomial Infection Control Consortium's multidimensional approach on central line-associated bloodstream infection rates in Bahrain

BACKGROUND

Central line-associated bloodstream infections are serious life-threatening infections in the intensive care unit setting.

METHODS

To analyze the impact of the International Nosocomial Infection Control Consortium (INICC) Multidimensional Approach (IMA) and INICC Surveillance Online System (ISOS) on central line-associated bloodstream infection rates in Bahrain from January 2013 to December 2016, we conducted a prospective, before-after surveillance, cohort, observational study in one intensive care unit in Bahrain. During baseline, we performed outcome and process surveillance of central line-associated bloodstream infection on 2320 intensive care unit patients, applying Centers for Disease Control and Prevention's National Healthcare Safety Network definitions. During intervention, we implemented IMA through ISOS, including (1) a bundle of infection prevention interventions, (2) education, (3) outcome surveillance, (4) process surveillance, (5) feedback on central line-associated bloodstream infection rates and consequences, and (6) performance feedback of process surveillance. Bivariate and multivariate regression analyses were performed using a logistic regression model to estimate the effect of the intervention on the central line-associated bloodstream infection rate.

RESULTS

During baseline, 672 central line days and 7 central line-associated bloodstream infections were recorded, accounting for 10.4 central line-associated bloodstream infections per 1000 central line days. During intervention, 13,020 central line days and 48 central line-associated bloodstream infections were recorded. After the second year, there was a sustained 89% cumulative central line-associated bloodstream infection rate reduction to 1.2 central line-associated bloodstream infections per 1000 central line days (incidence density rate, 0.11; 95% confidence interval 0.1-0.3; p, 0.001). The average extra length of stay of patients with central line-associated bloodstream infection was 23.3 days, and due to the reduction of central line-associated bloodstream infections, 367 days of hospitalization were saved, amounting to a reduction in hospitalization costs of US$1,100,553.

CONCLUSION

Implementing IMA was associated with a significant reduction in the central line-associated bloodstream infection rate in Bahrain.

The Impact of Integrating Rapid PCR-Based Blood Culture Identification Panel to an Established Antimicrobial Stewardship Program in the United Arab of Emirates

BACKGROUND

Studies have shown improvement in the outcome of blood stream infections (BSI) due to the use of Rapid PCR-Based Blood Culture Identification Panel (BCID) in Antimicrobial stewardship programs (ASP). There is currently no data on the use of BCID with ASP in the United Arab Emirates (UAE).

METHOD

Pre-post quasiexperimental study included hospitalized patients with BSI, their positive blood cultures on BCID were studied in 2 groups: conventional culture with ASP (AS), and BCID with ASP (BCID). The primary outcomes were time to first appropriate antimicrobial therapy, infection related length of stay (LOS), ICU admission, 14 days bacteremia recurrence and in-hospital mortality. Secondary outcomes were 30 days reinfection rate, hospital cost and ASP interventions.

RESULTS

Out of total 477 positive blood cultures, 206 (AS and BCID) with real BSI were included. The time needed for organism identification was shorter in the BCID group than in the AS group (1.3 h vs. 51 h; P = 0.0002). BCID had a shorter time to appropriate antimicrobial therapy than AS (17.8 h vs.45 h; P = 0.0004). No statistical difference was observed in mortality rate, 14 days bacteremia recurrence, ICU admission, hospital cost, LOS or ASP interventions.

CONCLUSION

Implementing BCID to ASP significantly decreased the time needed to identify the organism and time to appropriate antimicrobial therapy. Similarly, LOS and hospital cost were reduced, however, the reduction was not statistically significant.

Systematic Comparison of Four Methods for Detection of Carbapenemase-Producing Enterobacterales Directly from Blood Cultures

Early identification of infections caused by carbapenemase-producing Enterobacterales (CPE) can help to optimize patient treatment and improve outcome. In this study, protocols for rapid detection of carbapenemase production directly from positive blood cultures were developed applying a concentration and hemolysis step before a test for carbapenemase production was performed.

Early identification of infections caused by carbapenemase-producing Enterobacterales (CPE) can help to optimize patient treatment and improve outcome. In this study, protocols for rapid detection of carbapenemase production directly from positive blood cultures were developed applying a concentration and hemolysis step before a test for carbapenemase production was performed. Four different methods (three modified colorimetric assays [β-Carba, bcCarba NP, and NeoRapid Carb] and a variation of the carbapenem inactivation method [CIM] test with blood cultures [bcCIM]) were assessed on blood cultures spiked with 185 different molecularly characterized Enterobacterales isolates. The challenge collection included 81 carbapenemase-negative isolates and 104 CPEs (OXA-48 [n = 25], NDM [n = 20], KPC [n = 18], VIM [n = 25], GIM [n = 5], OXA-48-like [n = 9], and OXA-48-like plus NDM [n = 2]). The sensitivity/specificity was 99.0%/95.1% for bcCarba NP, 99.0%/91.4% for NeoRapid Carb, 100%/95.1% for β-Carba and 100%/100% for bcCIM. Weakly hydrolyzing carbapenemases (e.g., OXA-48-like) were also well detected by the assays. The time to result was 20 to 45 min for β-Carba, 2 to 3 h for bcCarba NP, 2.5 to 2 h for NeoRapid Carb, and 18 to 24 h for bcCIM. In conclusion, all assays demonstrated good detection of CPE. The protocols can be easily implemented in any clinical microbiology laboratory and could help to optimize therapy early in bloodstream infections by CPE.

Clinical Significance of Isolates Known to Be Blood Culture Contaminants in Pediatric Patients

Background and objectives: The objective of this study was to investigate the clinical significance of isolates from blood stream infection known to be blood culture contaminants in pediatric patients. Materials and Methods: Microbiological reports and medical records of all blood culture tests issued from 2002 to 2012 (n = 76,331) were retrospectively reviewed. Evaluation for potential contaminants were done by reviewing medical records of patients with the following isolates: coagulase-negative Staphylococcus, viridans group Streptococcus, Bacillus, Corynebacterium, Micrococcus, Aerococcus, and Proprionibacterium species. Repeated cultures with same isolates were considered as a single case. Cases were evaluated for their status as a pathogen. Results: Coagulase-negative Staphylococcus had clinical significance in 23.8% of all cases. Its rate of being a true pathogen was particularly high in patients with malignancy (43.7%). Viridans group Streptococcus showed clinical significance in 46.2% of all cases. Its rate of being a true pathogen was similar regardless of the underlying morbidity of the patient. The rate of being a true pathogens for remaining isolates was 27.7% for Bacillus and 19.0% for Corynebacterium species. Conclusions: Coagulase-negative Staphylococcus and viridans group Streptococcus isolates showed high probability of being true pathogens in the pediatric population, especially in patients with underlying malignancy.

Efficacy of Antimicrobial Peptide DP7, Designed by Machine-Learning Method, Against Methicillin-Resistant Staphylococcus aureus

Antimicrobial peptides (AMPs) provide a promising strategy against infections involving multidrug-resistant pathogens. In previous studies, we designed a short 12 amino acid AMP DP7, using a machine-learning method based on an amino acid activity contribution matrix. DP7 shows broad-spectrum antimicrobial activities both in vitro and in vivo. Here, we aim to investigate the efficacy of DP7 against multidrug resistant Staphylococcus aureus (S. aureus) and reveal the potential mechanisms. First, by measuring the killing kinetics of DP7 against S. aureus and comparing these results with antibiotics with different antimicrobial mechanisms, we hypothesize that DP7, in addition to its known ability to induce cell wall cation damage, can also exert a full killing effect. With FITC-conjugated or biotin-labeled DP7, we tracked DP7's attachment, membrane permeation and subsequent intracellular distribution in S. aureus. These results indicated that the possible targets of DP7 were within the bacterial cells. Transcriptome sequencing of S. aureus exposed to DP7 identified 333 differentially expressed genes (DEGs) influenced by DP7, involving nucleic acid metabolism, amino acid biosynthesis, cell wall destruction and pathogenesis, respectively, indicating the comprehensive killing efficacy of DP7. In addition, the genome sequencing results of the induced DP7 resistant strain S. aureus DP7-R revealed two-point mutations in the mprF and guaA gene. Moreover, in a murine model for MRSA blood stream infection, intravenously treating mice with DP7 showed a good protective effect on mice. In conclusion, DP7 is an effective bactericide for S. aureus, which deserves further study for clinical application and drug development.

Increased Incidence of Central Venous Catheter-Related Infection in Patients Undergoing Cytoreductive Surgery and Hyperthermic Intra-Peritoneal Chemotherapy

Background: Cytoreductive surgery (CRS) and hyperthermic intra-peritoneal chemotherapy (HIPEC) is a complex surgical intervention with associated risks. Central venous catheter (CVC) line sepsis is one of a number of potential morbidities. The aim of this study was to calculate the incidence of catheter-related infection (CRI) in a CRS and HIPEC patient population and to assess its influence on length of hospital stay. Methods: Data were collected on consecutive patients who underwent CRS HIPEC between August 2013 and October 2017. Data included patient demographics, timing of CVC insertion/removal, time spent in critical care, and CVC tip/blood culture results. Charts were reviewed for patients with both positive CVC culture and positive blood cultures to assess for evidence of catheter related infection and systemic inflammatory response syndrome (SIRS). Results: Data on 100 consecutive CRS HIPEC operations performed between August 2013 and October 2017 was analyzed. There were 11 CRIs in 100 CVCs, resulting in a CRI rate of 16.2 per 1,000 CVC days. Patients within the CRI group had a longer high-dependency unit (HDU) stay compared with the non-septic group (6 days vs. 4.07 days, p < 0.05). The CVC duration for the CRI and non-CRI group was 8.4 and 7.6 days, respectively (p = 0.12). The CRI group also had an increased total hospital length of stay (LOS; 20.8 days vs. 15.4 days, p < 0.05). On average, CRIs occurred eight days post-operative and four days post-HDU discharge. There was no association identified with longer CVC duration (p = 0.34). There has been an annual decline in CRI rates in CRS and HIPEC patients over the duration of the study period from 19.1 per 1,000 CVC days in 2016 to 8.2 per 1,000 CVC days in 2017. Conclusion: This is the first study to report on CRI rates in patients undergoing CRS and HIPEC. The CRI rate of 16.2 per 1,000 CVC days is higher than the overall national figure of 5.2 per 1,000 for CVC lines inserted in the operating room. Patients who developed line sepsis had longer HDU and longer overall hospital stay. Catheter-related infection was noted post-HDU discharge in all cases. Implementation of a CVC care bundle in the later years of the study period coincided with a reduction in CRI rates.

A New Method Aimed to Quickly Identify Pathogen and Drug Susceptibility Test Based on Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry Combined with Flow Cytometry

AIM

To discuss the significance and applied value in the rapid identification and drug susceptibility test for blood stream infection (BSI) using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) combined with flow cytometry (FCM).

METHODS

The bacteria were separated from the positive blood culture bottle using the separation gel-adsorption method system, and then applying MALDI-TOF MS combined with FCM to identify pathogen and drug susceptibility test quickly.

RESULTS

The efficiency of the separation gel-adsorption method for gram-negative bacterium, gram-positive bacteria, and fungi is 71%, 74%, and 88%, respectively. The results of identifying pathogens using MALDI-TOFMS are in agreement with results obtained using VITEK^®2 (bioMérieux, Marcy l'Etoile, France); both methods can identify 90% of bacteria to species. For fungi, MALDI-TOF MS can identify 75% fungi to species, which is superior to VITEK2, which identifies 60% fungi to species. The results of drug susceptibility test using FCM are almost identical to VITEK2; additionally, the addition of fluorescein diacetate can identify the heterogenic drug-resistant strains.

CONCLUSIONS

We can quickly identify pathogen and drug-susceptibility test based on MALDI-TOF MS combined with FCM, which is consistent with traditional methods and can shorten the report time from 36-72 hour to 3 hours. More importantly, these methods are of great significance and clinical importance for the rapid identification of BSI.

Emerging Chryseobacterium indologenes Infection in Indian Neonatal Intensive Care Units: A Case Report

Antibiotic-resistant pathogens and nosocomial infections constitute common and serious problems for neonates admitted to neonatal intensive care units worldwide. Chryseobacterium indologenes is a non-lactose-fermenting, gram-negative, health care-associated pathogen (HCAP). It is ubiquitous and intrinsically resistant to several antibiotics. Despite its low virulence, C. indologenes has been widely reported to cause life-threatening infections. Patients on chronic immunosuppressant drugs, harboring invasive devices and indwelling catheters become the nidus for C. indologenes. Typically, C. indologenes causes major health care-associated infections such as pneumonia, empyema, pyelonephritis, cystitis, peritonitis, meningitis, and bacteremia in patients harboring central venous catheters. Management of C. indologenes infection in neonates is not adequately documented owing to underreporting, particularly in India. Because of its multidrug resistance and the scant availability of data from the literature, the effective empirical treatment of C. indologenes is challenging. We present an uncommon case of bacteremia caused by C. indologenes in a preterm newborn baby with moderate respiratory distress syndrome who was successfully treated. We also provide a review of infections in the neonatal age group. Henceforth, in neonates receiving treatments involving invasive equipment use and long-term antibiotic therapy, multidrug resistant C. indologenes should be considered an HCAP.

The clinical impact of patients with bloodstream infection with different groups of Viridans group streptococci by using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)

The accuracy of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for identifying viridans group streptococcus (VGS) was improving. However, the clinical impact of identifying VGS had not been well recognized. Our study had comprehensively studied the clinical manifestations and outcome of VGS blood stream infection by using MALDI-TOF MS for identification.This retrospective study enrolled 312 adult patients with a monomicrobial blood culture positive for VGS. Blood culture was examined through MALDI-TOF MS.The most common VGS species were the Streptococcus anginosus group (38.8%) and Streptococcus mitis group (22.8%). Most species showed resistance to erythromycin (35.6%), followed by clindamycin (25.3%) and penicillin (12.5%). Skin and soft tissue infection and biliary tract infection were significantly related to S. anginosus group bacteremia (P = .001 and P = .005, respectively). S. mitis group bacteremia was related to infective endocarditis and bacteremia with febrile neutropenia (P = .005 and P < .001, respectively). Infective endocarditis was also more likely associated with S. sanguinis group bacteremia (P = .009). S. anginosus group had less resistance rate to ampicillin, erythromycin, clindamycin, and ceftriaxone (P = .019, <.001, .001, and .046, respectively). A more staying in intensive care unit, underlying solid organ malignancy, and a shorter treatment duration were independent risk factors for 30-day mortality. This study comprehensively evaluated different VGS group and their clinical manifestations, infection sources, concomitant diseases, treatments, and outcomes. Categorizing VGS into different groups by MALDI-TOF MS could help clinical physicians well understand their clinical presentations.

Neonatal Intensive Care Unit Length of Stay Reduction by Heart Rate Characteristics Monitoring

OBJECTIVE

To examine the effect of heart rate characteristics (HRC) monitoring on length of stay among very low birth weight (VLBW; <1500 g birth weight) neonates in the HeRO randomized controlled trial (RCT).

STUDY DESIGN

We performed a retrospective analysis of length of stay metrics among 3 subpopulations (all patients, all survivors, and survivors with positive blood or urine cultures) enrolled in a multicenter, RCT of HRC monitoring.

RESULTS

Among all patients in the RCT, infants randomized to receive HRC monitoring were more likely than controls to be discharged alive and prior to day 120 (83.6% vs 80.1%, P = .014). The postmenstrual age at discharge for survivors with positive blood or urine cultures was 3.2 days lower among infants randomized to receive HRC monitoring when compared with controls (P = .026). Although there were trends in other metrics toward reduced length of stay in HRC-monitored patients, none reached statistical significance.

CONCLUSIONS

HRC monitoring is associated with reduced mortality in VLBW patients and a reduction in length of stay among infected surviving VLBW infants.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00307333.

Clinical and microbiological profile of infections during induction phase of acute myeloid leukemia

BACKGROUND

The primary objective of this study is to describe clinical and microbiological profile of infections during induction phase of acute myeloid leukemia (AML).

PATIENTS AND METHODS

We reviewed the case records of 50 hospitalized patients with AML undergoing standard dose induction chemotherapy from January to December 2015.

RESULTS

Out of 50 cases, 34 were males 16 females with median age of 30 years. Most common presenting symptoms were fever followed by bleeding diathesis. The clinical sites of infections were gastrointestinal tract including oral cavity (48%), respiratory tract (4%), skin/soft tissue (4%) and genitourinary tract (4%). Clinically (58%) or microbiologically (30%) documented infections were 88%, while 12% had fever without identifiable source. Overall, in 21 episodes microorganisms were isolated. Common sites of isolates were blood stream (11), stool (8), sputum (1) and urine (1). Gram negative infections accounted for 81% of total isolates; Escherichia coli (E. coli) being the commonest. Gram positive microorganisms were isolated in 19% of which methicillin resistant staphylococcus aureus (MRSA) was the most common. Gram negative bacterial infections were associated with higher mortality.

CONCLUSION

Gastrointestinal tract is the most common clinical site of infection. Blood stream infection is the most common site for positive bacterial isolates. Gramnegative bacilli were the predominant cause of infections with E. coli being the most common pathogen isolated. Empiric antibiotic treatment for febrile neutropenia should be tailored to the locally prevalent pathogens and their susceptibility patterns.