Combining serum microRNAs and machine learning algorithms for diagnosing infectious fever after HSCT.

Infection post-hematopoietic stem cell transplantation (HSCT) is one of the main causes of patient mortality. Fever is the most crucial clinical symptom indicating infection. However, current microbial detection methods are limited. Therefore, timely diagnosis of infectious fever and administration of antimicrobial drugs can effectively reduce patient mortality. In this study, serum samples were collected from 181 patients with HSCT with or without infection, as well as the clinical information. And more than 80 infectious-related microRNAs in the serum were selected according to the bulk RNA-seq result and detected in the 345 time-pointed serum samples by Q-PCR. Unsupervised clustering result indicates a close association between these microRNAs expression and infection occurrence. Compared to the uninfected cohort, more than 10 serum microRNAs were identified as the combined diagnostic markers in one formula constructed by the Random Forest (RF) algorithms, with a diagnostic accuracy more than 0.90. Furthermore, correlations of serum microRNAs to immune cells, inflammatory factors, pathgens, infection tissue, and prognosis were analyzed in the infection cohort. Overall, this study demonstrates that the combination of serum microRNAs detection and machine learning algorithms holds promising potential in diagnosing infectious fever after HSCT.

Contributing Factors Affecting the Length of Hospital Stay among Febrile Patients with Omicron Reported in Suzhou.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has had global attention with regard to the urgent challenging threat to global public health. Currently, the novel Omicron variant is showing rapid transmission across the world, which appears to be more contagious than the previous variants of COVID-19. Early recognition of disease is critical for patients' prognosis. Fever is the most common symptom. We evaluated the clinical characteristics of febrile patients with COVID-19 reported in Suzhou and explored the predictors for a longer duration of hospitalization in febrile patients. METHODS: This retrospective study was carried out in 146 Omicron variant infected patients confirmed by nucleic acid tests in the Affiliated Infectious Hospital of Soochow University between February 13, 2022 and March 2, 2022. Data of febrile and afebrile laboratory-confirmed patients on hospital admission in Suzhou were collected and compared. According to the median length of stay (LOS), febrile cases were divided into short and long LOS groups. Then the predictive factors for a prolonged duration of hospitalization were analyzed using logistic regression methods. Receiver Operating Characteristic (ROC) Curve analysis was used to analyze the effectiveness of the risk factors for prolonged duration of hospitalization in febrile COVID-19 patients. RESULTS: Of the 146 discharged patients in our study, 112 patients (76.7%) caught a fever. Compared to afebrile Omicron patients, febrile patients showed a significantly longer duration of hospitalization (15.00 (5.80) vs. 13.00 (6.00), p = 0.002). Taking the median LOS (15 days) as the dividing point, 64 febrile cases were assigned to the short LOS group and the rest to the long LOS group. The long LOS group had a longer virus shedding duration than the short LOS group (18.42 ± 2.86 vs. 11.94 ± 2.50 days, p < 0.001). Compared to short LOS febrile patients, long LOS patients were older (44.88 ± 21.36 vs. 30.89 ± 17.95 years, p < 0.001) and showed a higher proportion of greater than 60 years old (33.3% vs. 9.4%, p = 0.002; Supplemental Table S2). Febrile patients with long LOS also showed a higher proportion of hypertension (25% vs. 6.3%, p = 0.005) and higher levels of cTnI (5.00 (3.00) vs. 4.00 (2.00) µg/L, p = 0.025). The multivariate analysis indicated that virus shedding duration (OR 2.369, 95% CI 1.684 - 3.333, p < 0.001) was the independent risk factor associated with long-term hospital stay in febrile patients with Omicron. Furthermore, ROC Curve analysis revealed that the area under the curve (AUC) for virus shedding duration to diagnose prolonged duration of hospitalization in febrile COVID-19 patients was 0.951 (95% CI 0.913 - 0.989). The cutoff point was set at 14.5 days. CONCLUSIONS: More than half of the non-severe patients exposed to the new Omicron variant had symptoms of fever. In total, 42.86% of the febrile patients were discharged within 15 days since hospital admission. Febrile Omicron cases took a longer duration of hospitalization compared to afebrile patients, and virus shedding duration (OR 2.369, 95% CI 1.684 - 3.333, p < 0.001) was probably a predictive factor for long-term hospital stays.

Fever and Rash.

Infectious causes of fever and rash pose a diagnostic challenge for the emergency provider. It is often difficult to discern rashes associated with rapidly progressive and life-threatening infections from benign exanthems, which comprise the majority of rashes seen in the emergency department. Physicians must also consider serious noninfectious causes of fever and rash. A correct diagnosis depends on an exhaustive history and head-to-toe skin examination as most emergent causes of fever and rash remain clinical diagnoses. A provisional diagnosis and immediate treatment with antimicrobials and supportive care are usually required prior to the return of confirmatory laboratory testing.

A comparative study on the use of procalcitonin to distinguish between central fever and infectious causes of fever.

Introduction: central fever is defined as elevated body temperature without any evidence of infection or drug reaction fever, and currently it has no definitive diagnostic criteria. The current study aims to assess the role of procalcitonin (PCT) in differentiating central fever from fever secondary to infections in patients with neurological insults. Methods: we conducted a retrospective study of patients admitted with a neurological insult (brain trauma, brain tumors and cerebrovascular accidents) in a tertiary care hospital. All patients who developed fever 48 hours after admission and had procalcitonin, C-reactive protein (CRP), and Erythrocyte sedimentation rate (ESR) done as part of fever evaluation were assessed to include in the study. Results: out of 70 patients who met inclusion criteria, 37 had infections identified and 33 had no source of infection. The mean age was 42.9 years (± 18) in the infectious group while 40.3 years (± 18.2) in the central fever group and there was male predominance in both groups. In the infectious group there were 25(67.6%) males vs. 12(32.4%) females while in non -infectious group, males vs. females were 18(54.5%) vs. 15(45.5%) and there was no difference in both group (p-value 0.26) Median procalcitonin (PCT) value was 0.09 ng/dl (IQR 0.05- 0.19) in patients with no identified cause of infection and 1.4 ng/dl (IQR 0.5-5.1) in patients with infections with a p-value of <0.001. Although CRP and ESR were low in patients with central fever as compared to those with infections, these differences did not reach statistical significance with p-value of CRP 0.18 and p-value of ESR 0.31 between two groups. Conclusion: PCT levels were low in patients with central fever and may be considered as a useful biomarker to differentiate between infectious fever from non-infectious fever in patients with brain injury. This can prevent unnecessary antibiotic use in patients without infection.

Diagnostic accuracy of DPP Fever Panel II Asia tests for tropical fever diagnosis.

BACKGROUND: Fever is the most frequent symptom in patients seeking care in South and Southeast Asia. The introduction of rapid diagnostic tests (RDTs) for malaria continues to drive patient management and care. Malaria-negative cases are commonly treated with antibiotics without confirmation of bacteraemia. Conventional laboratory tests for differential diagnosis require skilled staff and appropriate access to healthcare facilities. In addition, introducing single-disease RDTs instead of conventional laboratory tests remains costly. To overcome some of the delivery challenges of multiple separate tests, a multiplexed RDT with the capacity to diagnose a diverse range of tropical fevers would be a cost-effective solution. In this study, a multiplex lateral flow immunoassay (DPP Fever Panel II Assay) that can detect serum immunoglobulin M (IgM) and specific microbial antigens of common fever agents in Asia (Orientia tsutsugamushi, Rickettsia typhi, Leptospira spp., Burkholderia pseudomallei, Dengue virus, Chikungunya virus, and Zika virus), was evaluated. METHODOLOGY/PRINCIPAL FINDINGS: Whole blood (WB) and serum samples from 300 patients with undefined febrile illness (UFI) recruited in Vientiane, Laos PDR were tested using the DPP Fever Panel II, which consists of an Antibody panel and Antigen panel. To compare reader performance, results were recorded using two DPP readers, DPP Micro Reader (Micro Reader 1) and DPP Micro Reader Next Generation (Micro Reader 2). WB and serum samples were run on the same fever panel and read on both micro readers in order to compare results. ROC analysis and equal variance analysis were performed to inform the diagnostic validity of the test compared against the respective reference standards of each fever agent (S1 Table). Overall better AUC values were observed in whole blood results. No significant difference in AUC performance was observed when comparing whole blood and serum sample testing, except for when testing for R. typhi IgM (p = 0.04), Leptospira IgM (p = 0.02), and Dengue IgG (p = 0.03). Linear regression depicted R2 values had ~70% agreement across WB and serum samples, except when testing for leptospirosis and Zika, where the R2 values were 0.37 and 0.47, respectively. No significant difference was observed between the performance of Micro Reader 1 and Micro Reader 2, except when testing for the following pathogens: Zika IgM, Zika IgG, and B pseudomallei CPS Ag. CONCLUSIONS/SIGNIFICANCE: These results demonstrate that the diagnostic accuracy of the DPP Fever Panel II is comparable to that of commonly used RDTs. The optimal cut-off would depend on the use of the test and the desired sensitivity and specificity. Further studies are required to authenticate the use of these cut-offs in other endemic regions. This multiplex RDT offers diagnostic benefits in areas with limited access to healthcare and has the potential to improve field testing capacities. This could improve tropical fever management and reduce the public health burden in endemic low-resource areas.

From fever to action: diagnosis, treatment, and prevention of acute undifferentiated febrile illnesses.

Acute Undifferentiated Febrile Illness (AUFI) presents a clinical challenge, often characterized by sudden fever, non-specific symptoms, and potential life-threatening implications. This review highlights the global prevalence, types, challenges, and implications of AUFI, especially in tropical and subtropical regions where infectious diseases thrive. It delves into the difficulties in diagnosis, prevalence rates, regional variations, and potential causes, ranging from bacterial and viral infections to zoonotic diseases. Furthermore, it explores treatment strategies, preventive measures, and the critical role of the One Health approach in addressing AUFI. The paper also addresses the emerging zoonotic risks and ongoing outbreaks, including COVID-19, Rickettsia spp., and other novel pathogens, emphasizing their impact on AUFI diagnosis and management. Challenges in resource-limited settings are analyzed, highlighting the need for bolstered healthcare infrastructure, enhanced diagnostics, and collaborative One Health strategies. Amidst the complexity of emerging zoonotic threats, this review underscores the urgency for a multifaceted approach to mitigate the growing burden of AUFI, ensuring early diagnosis, appropriate treatment, and effective prevention strategies.

Performance of Febrile Infant Algorithms by Duration of Fever.

OBJECTIVES: To analyze the performance of commonly used blood tests in febrile infants ≤90 days of age to identify patients at low risk for invasive bacterial infection (bacterial pathogen in blood or cerebrospinal fluid) by duration of fever. METHODS: We conducted a secondary analysis of a prospective single-center registry that includes all consecutive infants ≤90 days of age with fever without a source evaluated at 1 pediatric emergency department between 2008 and 2021. We defined 3 groups based on caregiver-reported hours of fever (<2, 2-12, and ≥12) and analyzed the performance of the biomarkers and Pediatric Emergency Care Applied Research Network, American Academy of Pediatrics, and Step-by-Step clinical decision rules. RESULTS: We included 2411 infants; 76 (3.0%) were diagnosed with an invasive bacterial infection. The median duration of fever was 4 (interquartile range, 2-12) hours, with 633 (26.3%) patients with fever of <2 hours. The area under the curve was significantly lower in patients with <2 hours for absolute neutrophil count (0.562 vs 0.609 and 0.728) and C-reactive protein (0.568 vs 0.760 and 0.812), but not for procalcitonin (0.749 vs 0.780 and 0.773). Among well-appearing infants older than 21 days and negative urine dipstick with <2 hours of fever, procalcitonin ≥0.14 ng/mL showed a better sensitivity (100% with specificity 53.8%) than that of the combination of biomarkers of Step-by-Step (50.0% and 82.2%), and of the American Academy of Pediatrics and Pediatric Emergency Care Applied Research Network rules (83.3% and 58.3%), respectively. CONCLUSIONS: The performance of blood biomarkers, except for procalcitonin, in febrile young infants is lower in fever of very short duration, decreasing the accuracy of the clinical decision rules.

Utilizing Wearable Device Data for Syndromic Surveillance: A Fever Detection Approach.

Commercially available wearable devices (wearables) show promise for continuous physiological monitoring. Previous works have demonstrated that wearables can be used to detect the onset of acute infectious diseases, particularly those characterized by fever. We aimed to evaluate whether these devices could be used for the more general task of syndromic surveillance. We obtained wearable device data (Oura Ring) from 63,153 participants. We constructed a dataset using participants' wearable device data and participants' responses to daily online questionnaires. We included days from the participants if they (1) completed the questionnaire, (2) reported not experiencing fever and reported a self-collected body temperature below 38 °C (negative class), or reported experiencing fever and reported a self-collected body temperature at or above 38 °C (positive class), and (3) wore the wearable device the nights before and after that day. We used wearable device data (i.e., skin temperature, heart rate, and sleep) from the nights before and after participants' fever day to train a tree-based classifier to detect self-reported fevers. We evaluated the performance of our model using a five-fold cross-validation scheme. Sixteen thousand, seven hundred, and ninety-four participants provided at least one valid ground truth day; there were a total of 724 fever days (positive class examples) from 463 participants and 342,430 non-fever days (negative class examples) from 16,687 participants. Our model exhibited an area under the receiver operating characteristic curve (AUROC) of 0.85 and an average precision (AP) of 0.25. At a sensitivity of 0.50, our calibrated model had a false positive rate of 0.8%. Our results suggest that it might be possible to leverage data from these devices at a public health level for live fever surveillance. Implementing these models could increase our ability to detect disease prevalence and spread in real-time during infectious disease outbreaks.

Should you test for urinary tract infection in children with respiratory symptoms?

QUESTION: An 8-month-old boy presented to our clinic with a 3-day history of fever. He has had a cough and rhinorrhea since the onset of the fever, and his 4-year-old sibling has recently had cough and cold symptoms. I have heard that the presence of respiratory symptoms means that urinary tract infection (UTI) is less likely. In infants with fever and respiratory symptoms, who should have a sample collected for urinalysis for UTI? ANSWER: The approach to diagnosing febrile infants who have respiratory symptoms varies by age. Urinalysis should be done for all febrile infants younger than 2 months of age, regardless of whether they have respiratory symptoms. Clinicians should assess risk factors for UTI in every infant between 2 and 24 months of age and should not exclude the diagnosis of UTI based on respiratory symptoms alone. Use of a predictive tool to estimate the pretest probability of UTI would aid decision making about patients in this population.

Diagnostic test accuracy of procalcitonin and C-reactive protein for predicting invasive and serious bacterial infections in young febrile infants: a systematic review and meta-analysis.

BACKGROUND: Febrile infants presenting in the first 90 days of life are at higher risk of invasive and serious bacterial infections than older children. Modern clinical practice guidelines, mostly using procalcitonin as a diagnostic biomarker, can identify infants who are at low risk and therefore suitable for tailored management. C-reactive protein, by comparison, is widely available, but whether C-reactive protein and procalcitonin have similar diagnostic accuracy is unclear. We aimed to compare the test accuracy of procalcitonin and C-reactive protein in the prediction of invasive or serious bacterial infections in febrile infants. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, EMBASE, Web of Science, and The Cochrane Library for diagnostic test accuracy studies up to June 19, 2023, using MeSH terms "procalcitonin", and "bacterial infection" or "fever" and keywords "invasive bacterial infection*" and "serious bacterial infection*", without language or date restrictions. Studies were selected by independent authors against eligibility criteria. Eligible studies included participants aged 90 days or younger presenting to hospital with a fever (≥38°C) or history of fever within the preceding 48 h. The primary index test was procalcitonin, and the secondary index test was C-reactive protein. Test kits had to be commercially available, and test samples had to be collected upon presentation to hospital. Invasive bacterial infection was defined as the presence of a bacterial pathogen in blood or cerebrospinal fluid, as detected by culture or quantitative PCR; authors' definitions of serious bacterial infection were used. Data were extracted from selected studies, and the detection of invasive or serious bacterial infections was analysed with two models for each biomarker. Diagnostic accuracy was determined against internationally recognised cutoff values (0·5 ng/mL for procalcitonin, 20 mg/L for C-reactive protein) and pooled to calculate partial area under the curve (pAUC) values for each biomarker. Optimum cutoff values were identified for each biomarker. This study is registered with PROSPERO, CRD42022293284. FINDINGS: Of 734 studies derived from the literature search, 14 studies (n=7755) were included in the meta-analysis. For the detection of invasive bacterial infections, pAUC values were greater for procalcitonin (0·72, 95% CI 0·56-0·79) than C-reactive protein (0·28, 0·17-0·61; p=0·016). Optimal cutoffs for detecting invasive bacterial infections were 0·49 ng/mL for procalcitonin and 13·12 mg/L for C-reactive protein. For the detection of serious bacterial infections, procalcitonin and C-reactive protein had similar pAUC values (0·55, 0·44-0·69 vs 0·54, 0·40-0·61; p=0·92). For serious bacterial infections, the optimal cutoffs for procalcitonin and C-reactive protein were 0·17 ng/mL and 16·18 mg/L, respectively. Heterogeneity was low for studies investigating the test accuracy of procalcitonin in detecting invasive bacterial infection (I2=23·5%), high for studies investigating procalcitonin for serious bacterial infection (I2=75·5%), and moderate for studies investigating C-reactive protein for invasive bacterial infection (I2=49·5%) and serious bacterial infection (I2=28·3%). The absence of a single definition of serious bacterial infection across studies was the greatest source of interstudy variability and potential bias. INTERPRETATION: Within a large cohort of febrile infants, a procalcitonin cutoff of 0·5 ng/mL had a superior pAUC value to a C-reactive protein cutoff of 20 mg/L for identifying invasive bacterial infections. In settings without access to procalcitonin, C-reactive protein should therefore be used cautiously for the identification of invasive bacterial infections, and a cutoff value below 20 mg/L should be considered. C-reactive protein and procalcitonin showed similar test accuracy for the identification of serious bacterial infection with internationally recognised cutoff values. This might reflect the challenges involved in confirming serious bacterial infection and the absence of a universally accepted definition of serious bacterial infection. FUNDING: None.

Fever at Time of Leukemia Diagnosis in Children: Predictor of Bloodstream Infection or Catheter Removal?

PURPOSE: To assess the incidence of fever at diagnosis in children with leukemia and determine if fever at diagnosis is a predictor of bloodstream infection (BSI) or central venous access device (CVAD) removal for infection either within the first 30 days or between 30 and 90 days after CVAD insertion. MATERIALS AND METHODS: One hundred fifty-one patients with acute leukemia (July 1, 2018, to December 31, 2020) who underwent a CVAD insertion within 2 weeks of diagnosis were included. Patient data included demographic characteristics, fever at diagnosis, CVAD type, antibiotics before and/or on the day of CVAD insertion, BSI incidence, BSI rates per 1,000 catheter days, and need for catheter removal after CVAD insertion within 30 days and between 30 and 90 days. RESULTS: Patients with fever at diagnosis had a significantly higher incidence of BSI within the first 30 days after CVAD insertion (17/23) than that among patients without fever (6/23) (P = .046) at diagnosis. No statistically significant difference was observed in the incidence of BSI between 30 and 90 days after CVAD insertion between patients with fever (5/11) and those without fever at diagnosis (6/11) (P = .519). Fever at diagnosis was not a predictor of CVAD removal within 30 days (9 patients required CVAD removal; 7/9 had fever and 2/9 had no fever) (P = .181) or between 30 and 90 days (4 patients required CVAD removal; 1/4 had fever and 3/4 had no fever at diagnosis) (P = .343) after insertion. CONCLUSIONS: Fever at diagnosis in patients with leukemia is not a predictor of CVAD removal for infection.

Body Core Temperature Assessment in Emergency Care Departments.

BACKGROUND: There is concern that the values provided by devices using infrared thermometry in emergency departments (EDs) do not reflect body core temperature accurately. OBJECTIVES: Evaluation of three thermometers commonly used in the ED. METHODS: Two infrared ear thermometers and an infrared forehead thermometer were evaluated using 1) the Voltcraft IRS-350 calibration device, 2) comparing temperature values to a rectal end-exercise temperature (T-RECT) of 38.1°C in 12 participants, and 3) comparing temperature values to rectal temperature in 133 ED patients. RESULTS: Calibration across the human core temperature range revealed that the ear thermometers underestimated radiant temperature by 0.77 ± 0.39°C and 1.84 ± 0.26°C, respectively, whereas the forehead thermometer overestimated radiant temperature by 0.90 ± 0.51°C. After cycling exercise, all thermometers underestimated T-RECT (0.54 ± 0.27°C and 1.03 ± 0.48°C for the ear thermometers and 1.14 ± 0.38°C for the forehead thermometer). In the ED, the ear thermometers underestimated T-RECT by 0.31 ± 0.37°C and 0.46 ± 0.50°C, whereas the forehead thermometer exhibited a nonsignificant overestimation of 0.04 ± 0.46°C. If the threshold for fever in all systems had been set to 37.5°C instead of 38.0°C, the sensitivity and specificity of the systems for real fever (T-RECT ≥ 38°C) are, respectively, 71% and 96% (ear thermometer 1), 57% and 97% (ear thermometer 2), and 86% and 90% (forehead thermometer). CONCLUSION: We conclude that the investigated thermometers are not reliable as devices to measure radiant temperature, cannot be used to assess body core temperature during exercise, but may be used as a screening device, with 37.5°C as a threshold for fever in emergency care settings.

Respiratory viral detection in the plasma and cerebrospinal fluid (CSF) of young febrile infants.

Background: Respiratory viral infections are common in febrile infants ≤90 days. However, the detection of viruses other than enterovirus in the blood and cerebrospinal fluid (CSF) of young infants is not well defined. We sought to quantify the occurrence of respiratory viruses in the blood and CSF of febrile infants ≤90 days. Methods: We conducted a nested cohort study examining plasma and CSF samples from febrile infants 15-90 days via rtPCR. The samples were tested for respiratory viruses (respiratory syncytial virus, influenza, enterovirus, parechovirus, adenovirus, bocavirus). Clinical and laboratory data were also collected to determine the presence of serious bacterial infections (SBI). Results: Twenty-four percent (30 of 126) of infants had plasma/CSF specimens positive for a respiratory virus. Enterovirus and parechovirus were the most commonly detected respiratory viruses. Viral positivity was highest in plasma samples at 25% (27 of 107) compared with CSF samples at 15% (nine of 62). SBIs (specifically urinary tract infections) were less common in infants with a sample positive for a respiratory virus compared to those without a virus detected (3% vs. 26%, p = 0.008). Conclusions: Our findings support the use of molecular diagnostics to include the identification of parechovirus in addition to enterovirus in febrile infants ≤90 days. Additionally, these data support the utilization of blood specimens to diagnose enterovirus and parechovirus infections in febrile infants ≤90 days.

Performance of Febrile Infant Decision Tools on Hypothermic Infants Evaluated for Infection.

BACKGROUND: Given the lack of evidence-based guidelines for hypothermic infants, providers may be inclined to use febrile infant decision-making tools to guide management decisions. Our objective was to assess the diagnostic performance of febrile infant decision tools for identifying hypothermic infants at low risk of bacterial infection. METHODS: We conducted a secondary analysis of a retrospective cohort study of hypothermic (≤36.0 C) infants ≤90 days of age presenting to the emergency department or inpatient unit among 9 participating sites between September 1, 2016 and May 5, 2021. Well-appearing infants evaluated for bacterial infections via laboratory testing were included. Infants with complex chronic conditions or premature birth were excluded. Performance characteristics for detecting serious bacterial infection (SBI; urinary tract infection, bacteremia, bacterial meningitis) and invasive bacterial infection (IBI; bacteremia, bacterial meningitis) were calculated for each tool. RESULTS: Overall, 314 infants met the general inclusion criteria, including 14 cases of SBI (4.5%) and 7 cases of IBI (2.2%). The median age was 5 days, and 68.1% of the infants (214/314) underwent a full sepsis evaluation. The Philadelphia, Boston, IBI Score, and American Academy of Pediatrics Clinical Practice Guideline did not misclassify any SBI or IBI as low risk; however, they had low specificity and positive predictive value. Rochester and Pediatric Emergency Care Applied Research Network tools misclassified infants with bacterial infections. CONCLUSIONS: Several febrile infant decision tools were highly sensitive, minimizing missed SBIs and IBIs in hypothermic infants. However, the low specificity of these decision tools may lead to unnecessary testing, antimicrobial exposure, and hospitalization.

Predicting Serious Bacterial Infections Among Hypothermic Infants in the Emergency Department.

BACKGROUND: There is insufficient evidence to guide the initial evaluation of hypothermic infants. We aimed to evaluate risk factors for serious bacterial infections (SBI) among hypothermic infants presenting to the emergency department (ED). METHODS: We conducted a multicenter case-control study among hypothermic (rectal temperature <36.5°C) infants ≤90 days presenting to the ED who had a blood culture collected. Our outcome was SBI (bacteremia, bacterial meningitis, and/or urinary tract infection). We performed 1:2 matching. Historical, physical examination and laboratory covariables were determined based on the literature review from febrile and hypothermic infants and used logistic regression to identify candidate risk factors. RESULTS: Among 934 included infants, 57 (6.1%) had an SBI. In univariable analyses, the following were associated with SBI: age > 21 days, fever at home or in the ED, leukocytosis, elevated absolute neutrophil count, thrombocytosis, and abnormal urinalysis. Prematurity, respiratory distress, and hypothermia at home were negatively associated with SBI. The full multivariable model exhibited a c-index of 0.91 (95% confidence interval: 0.88-0.94). One variable (abnormal urinalysis) was selected for a reduced model, which had a c-index of 0.82 (95% confidence interval: 0.75-0.89). In a sensitivity analysis among hypothermic infants without fever (n = 22 with SBI among 116 infants), leukocytosis, absolute neutrophil count, and abnormal urinalysis were associated with SBI. CONCLUSIONS: Historical, examination, and laboratory data show potential as variables for risk stratification of hypothermic infants with concern for SBI. Larger studies are needed to definitively risk stratify this cohort, particularly for invasive bacterial infections.

An Exploratory and Qualitative Analysis of Self-Reported Evaluations for Fever.

Background: Despite the high prevalence of post-operative fever, a variety of approaches are taken as to the components of a fever evaluation, when it should be undertaken, and when empiric antibiotic agents should be started. Hypothesis: There is a lack of consensus surrounding many common components of a post-operative fever evaluation. Patients and Methods: The Surgical Infection Society membership was surveyed to determine practices surrounding evaluation of post-operative fever. Eight scenarios were posed in febrile (38.5°C), post-operative general surgery or trauma patients, with 19 possible components of work-up (physical examination, complete blood count [CBC], fungal biomarkers, lactate and procalcitonin [PCT] concentrations, cultures, imaging) and management (antibiotic agents). Each scenario was then re-considered for intensive care unit (ICU) patients (intubated/unstable hemodynamics). Agreement on a parameter (<1/4 or >3/4 of respondents) achieved consensus, positive or negative. Parameters between had equipoise; α was set at 0.05. Results: Among the examined scenarios, only CBC and physical examination received positive consensus across most scenarios. Blood/urine cultures, imaging, lactate, inflammatory biomarkers, and the empiric administration of antibiotic agents did not reach consensus; support was variable depending on the clinical scenario, illness severity, and the individual preferences of the answering clinician. The qualitative portion of the survey identified "fever threshold and duration," "clinical suspicion," and "physiologic manifestation" as the most important factors for deciding about the initiation of a fever evaluation and the potential empiric administration of antibiotic agents. Conclusions: There is consensus only for physical and examination routine laboratory work when initiating the evaluation of febrile post-operative patients. However, there are multiple components of a fever evaluation that individual respondents would select depending on the clinical scenario and severity of illness. Parameters demonstrating equipoise are potential candidates for formal guidance or pragmatic prospective trials.

A case of neonatal tsutsugamushi disease diagnosed with the aid of rickettsial macrogenomic detection.

BACKGROUND: Tsutsugamushi, also known as bush typhus, is a naturally occurring disease caused by Orientia tsutsugamushi. We reported a case of vertical mother-to-newborn transmission of Orientia tsutsugamushi infection in a newborn from Yunnan (China). CASE PRESENTATION: Decreased fetal movements were observed at 39 weeks of gestation. After birth, the newborn (female) had recurrent fever, shortness of breath, and bruising around the mouth and extremities. At 5 h 58 min of age, the newborn was admitted for fever, shortness of breath and generalized rash. The liver was palpable 3 cm below the costal margin, and the limbs showed pitting edema. There was subcutaneous bleeding. Investigations suggested heavy infection, myocardial damage, decreased platelets. Treatment with cefotaxime and ampicillin failed. The mother was hospitalized at 29 weeks of gestation with a fever for 4 consecutive days, and an ulcerated crust was found in the popliteal fossa. Due to this pregnancy history, A diagnosis of Orientia tsutsugamushi infection was suspected in our index case and confirmed by macrogenomic testing and she was treated with vancomycin and meropenem, and later azithromycin for 1 week. The newborn was discharged in good general condition, gradually normalizing body temperature, and decreasing rash and jaundice. There were no abnormalities on subsequent blood macrogenomic tests for the baby. And one month later she showed good mental health, sleep, and food intake and no fever, rash, or jaundice. CONCLUSION: Determining the cause of symptoms is the key to treating diseases, especially the rare diseases that can be misdiagnosed. SUITABLE FOR PEOPLE WITH: Infectious Diseases; Neonatology; Obstetrics.

Metagenomic next-generation sequencing, instead of procalcitonin, could guide antibiotic usage in patients with febrile acute necrotizing pancreatitis: a multicenter, prospective cohort study.

BACKGROUNDS: The effectiveness of procalcitonin-based algorithms in guiding antibiotic usage for febrile acute necrotizing pancreatitis (ANP) remains controversial. Metagenomic next-generation sequencing (mNGS) has been applied to diagnose infectious diseases. The authors aimed to evaluate the effectiveness of blood mNGS in guiding antibiotic stewardship for febrile ANP. MATERIALS AND METHODS: The prospective multicenter clinical trial was conducted at seven hospitals in China. Blood samples were collected during fever (T ≥38.5°C) from ANP patients. The effectiveness of blood mNGS, procalcitonin, and blood culture in diagnosing pancreatic infection was evaluated and compared. Additionally, the real-world utilization of antibiotics and the potential mNGS-guided antimicrobial strategy in febrile ANP were also analyzed. RESULTS: From May 2023 to October 2023, a total of 78 patients with febrile ANP were enrolled and 30 patients (38.5%) were confirmed infected pancreatic necrosis (IPN). Compared with procalcitonin and blood culture, mNGS showed a significantly higher sensitivity rate (86.7% vs. 56.7% vs. 26.7%, P <0.001). Moreover, mNGS outperformed procalcitonin (89.5 vs. 61.4%, P <0.01) and blood culture (89.5 vs. 69.0%, P <0.01) in terms of negative predictive value. Blood mNGS exhibited the highest accuracy (85.7%) in diagnosing IPN and sterile pancreatic necrosis, significantly superior to both procalcitonin (65.7%) and blood culture (61.4%). In the multivariate analysis, positive blood mNGS (OR=60.2, P <0.001) and lower fibrinogen level (OR=2.0, P <0.05) were identified as independent predictors associated with IPN, whereas procalcitonin was not associated with IPN, but with increased mortality (Odds ratio=11.7, P =0.006). Overall, the rate of correct use of antibiotics in the cohort was only 18.6% (13/70) and would be improved to 81.4% (57/70) if adjusted according to the mNGS results. CONCLUSION: Blood mNGS represents important progress in the early diagnosis of IPN, with particular importance in guiding antibiotic usage for patients with febrile ANP.