Rapid detection of gastrointestinal pathogens using a multiplex polymerase chain reaction gastrointestinal panel and its role in antimicrobial stewardship.

OBJECTIVES: The FilmArray gastrointestinal panel (FAGIP) is widely used to detect infectious diarrhoea due to its outstanding sensitivity compared to conventional methods, but there is geographic variation, such as in the distribution of pathogens, among populations. METHODS: This was a retrospective study that analysed patients with acute diarrhoea who underwent FAGIP tests from all age groups during 2022. We compared positive rates of FAGIP between paediatric (n = 245) and adult patients (n = 242) of different origins. The targeted therapy rate and antimicrobial agent use rate were also analysed. RESULTS: Among the 487 stool samples evaluated, the overall, community-origin (CO), and nosocomial (NC) positivity rates of paediatric patients were significantly higher than those of adults (73.9 % vs. 43.0 %, p = 0.000; 76.2 % vs. 51.7 %, p = 0.000; 50.0 % vs. 19.7 %, p = 0.000). Salmonella was the most frequently detected pathogen (35.9 %) in children, while the predominant pathogen in adult patients was toxin A/B-genic Clostridioides difficile (13.2 %). There was a significantly lower antimicrobial agent use rate after FAGIP results were available (79.1 % vs. 64.5 %, p = 0.000) and a higher rate of targeted therapy towards C. difficile infection in adults than in children (84.4 % vs. 69.0 %, p = 0.011). CONCLUSION: Paediatric diarrhoea patients showed higher positivity rates than adult patients. Application of FAGIP for acute diarrhoea might lower unnecessary antimicrobial use.

Prediction of methicillin-resistant Staphylococcus aureus and carbapenem-resistant Klebsiella pneumoniae from flagged blood cultures by combining rapid Sepsityper MALDI-TOF mass spectrometry with machine learning.

This study investigated combination of the Rapid Sepsityper Kit and a machine learning (ML)-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) approach for rapid prediction of methicillin-resistant Staphylococcus aureus (MRSA) and carbapenem-resistant Klebsiella pneumoniae (CRKP) from positive blood culture bottles. The study involved 461 patients with monomicrobial bloodstream infections. Species identification was performed using the conventional MALDI-TOF MS Biotyper system and the Rapid Sepsityper protocol. The data underwent preprocessing steps, and ML models were trained using preprocessed MALDI-TOF data and corresponding labels. The interpretability of the model was enhanced using SHapely Additive exPlanations values to identify significant features. In total, 44 S. aureus isolates comprising 406 MALDI-TOF MS files and 126 K. pneumoniae isolates comprising 1249 MALDI-TOF MS files were evaluated. This study demonstrated the feasibility of predicting MRSA among S. aureus and CRKP among K. pneumoniae isolates using MALDI-TOF MS and Sepsityper. Accuracy, area under the receiver operating characteristic curve, and F1 score for MRSA/methicillin-susceptible S. aureus were 0.875, 0.898 and 0.904, respectively; for CRKP/carbapenem-susceptible K. pneumoniae, these values were 0.766, 0.828 and 0.795, respectively. In conclusion, the novel ML-based MALDI-TOF MS approach enables rapid identification of MRSA and CRKP from flagged blood cultures within 1 h. This enables earlier initiation of targeted antimicrobial therapy, reducing deaths due to sepsis. The favourable performance and reduced turnaround time of this method suggest its potential as a rapid detection strategy in clinical microbiology laboratories, ultimately improving patient outcomes.

Previous nonhepatectomy abdominal surgery did not increase the difficulty in laparoscopic hepatectomy for hepatocellular carcinoma: A case-control study in 100 consecutive patients.

Objectives: Laparoscopic hepatectomy (LH) is still technically challenging for patients with previous nonhepatectomy abdominal surgery (AS). Therefore, this study aimed to assess the difficulty of performing LH for patients with hepatocellular carcinoma (HCC) and a history of nonhepatectomy AS during the initial developing period of LH. Materials and Methods: The retrospective study enrolled patients who were newly diagnosed with HCC receiving LH from January 2013 to June 2021. Demographic characteristics, perioperative variables, and surgical complications were prospectively collected. Results: One hundred patients were reviewed consecutively, comprising 23 in the AS group and 77 in the non-AS group. No significant differences were observed in median IWATE score (5 vs. 5, P = 0.194), operative time (219 vs. 200 min, P = 0.609), blood loss (100.0 vs. 200.0 mL, P = 0.734), transfusion rate (4.3% vs. 10.4%, P = 0.374), duration of parenchyma transection (90.0 vs. 72.4 min, P = 0.673), and mean nonparenchymal transection time (191.0 vs. 125.0 min, P = 0.228), without increasing the conversion rate (0.0% vs. 3.9%, P = 0.336), postoperative complications (30.3% vs. 33.8%, P = 0.488), and postoperative hospital stay (6 vs. 7 days, P = 0.060) in AS group and non-AS groups. Conclusion: History of previous nonhepatectomy AS can lead to longer nonparenchymal transection time instead of conversion and did not increase the difficulty. Prolonged nonparenchymal transection time did not increase the surgical complications, prolong the postoperative hospital stay, and compromise the survival outcomes.

Machine learning of cell population data, complete blood count, and differential count parameters for early prediction of bacteremia among adult patients with suspected bacterial infections and blood culture sampling in emergency departments.

BACKGROUND: Bacteremia is a life-threatening complication of infectious diseases. Bacteremia can be predicted using machine learning (ML) models, but these models have not utilized cell population data (CPD). METHODS: The derivation cohort from emergency department (ED) of China Medical University Hospital (CMUH) was used to develop the model and was prospectively validated in the same hospital. External validation was performed using cohorts from ED of Wei-Gong Memorial Hospital (WMH) and Tainan Municipal An-Nan Hospital (ANH). Adult patients who underwent complete blood count (CBC), differential count (DC), and blood culture tests were enrolled in the present study. The ML model was developed using CBC, DC, and CPD to predict bacteremia from positive blood cultures obtained within 4 h before or after the acquisition of CBC/DC blood samples. RESULTS: This study included 20,636 patients from CMUH, 664 from WMH, and 1622 patients from ANH. Another 3143 patients were included in the prospective validation cohort of CMUH. The CatBoost model achieved an area under the receiver operating characteristic curve of 0.844 in the derivation cross-validation, 0.812 in the prospective validation, 0.844 in the WMH external validation, and 0.847 in the ANH external validation. The most valuable predictors of bacteremia in the CatBoost model were the mean conductivity of lymphocytes, nucleated red blood cell count, mean conductivity of monocytes, and neutrophil-to-lymphocyte ratio. CONCLUSIONS: ML model that incorporated CBC, DC, and CPD showed excellent performance in predicting bacteremia among adult patients with suspected bacterial infections and blood culture sampling in emergency departments.

Direct prediction of carbapenem-resistant, carbapenemase-producing, and colistin-resistant Klebsiella pneumoniae isolates from routine MALDI-TOF mass spectra using machine learning and outcome evaluation.

The objective of this study was to develop a rapid prediction method for carbapenem-resistant Klebsiella pneumoniae (CRKP) and colistin-resistant K. pneumoniae (ColRKP) based on routine MALDI-TOF mass spectrometry (MS) results in order to formulate a suitable and rapid treatment strategy. A total of 830 CRKP and 1462 carbapenem-susceptible K. pneumoniae (CSKP) isolates were collected; 54 ColRKP isolates and 1592 colistin-intermediate K. pneumoniae (ColIKP) isolates were also included. Routine MALDI-TOF MS, antimicrobial susceptibility testing, NG-Test CARBA 5, and resistance gene detection were followed by machine learning (ML). Using the ML model, the accuracy and area under the curve for differentiating CRKP and CSKP were 0.8869 and 0.9551, respectively, and those for ColRKP and ColIKP were 0.8361 and 0.8447, respectively. The most important MS features of CRKP and ColRKP were m/z 4520-4529 and m/z 4170-4179, respectively. Of the CRKP isolates, MS m/z 4520-4529 was a potential biomarker for distinguishing KPC from OXA, NDM, IMP, and VIM. Of the 34 patients who received preliminary CRKP ML prediction results (by texting), 24 (70.6%) were confirmed to have CRKP infection. The mortality rate was lower in patients who received antibiotic regimen adjustment based on the preliminary ML prediction (4/14, 28.6%). In conclusion, the proposed model can provide rapid results for differentiating CRKP and CSKP, as well as ColRKP and ColIKP. The combination of ML-based CRKP with preliminary reporting of results can help physicians alter the regimen approximately 24 h earlier, resulting in improved survival of patients with timely antibiotic intervention.

Geographic patterns of antimicrobial susceptibilities for Bacteroides spp. worldwide: Results from the Antimicrobial Testing Leadership and Surveillance (ATLAS) programme, 2007-2020.

Antimicrobial susceptibilities of 4973 Bacteroides spp. isolates recovered from various sources of patients from 12 countries (99.6% from European countries) in the Antimicrobial Testing Leadership and Surveillance (ATLAS) programme, 2007-2020, were investigated. The minimum inhibitory concentrations (MICs) of the isolates with six commonly used agents were determined using the agar dilution method. Among the isolates, 10 Bacteroides spp. were included: B. fragilis (n=3180, 64.0%) was encountered most frequently, followed by B. thetaiotaomicron (n=675) and B. ovatus (n=409). During the 14 years, the proportion of B. fragilis declined, but the proportion of non-fragilis Bacteroides spp. increased. More than 90% of the isolates tested were susceptible to piperacillin-tazobactam, meropenem and tigecycline. Significantly lower susceptibility rates to cefoxitin (P<0.001), clindamycin (P<0.001), piperacillin/tazobactam (P<0.001) and tigecycline (P=0.006) were observed among non-fragilis Bacteroides spp. isolates than among B. fragilis isolates. Moreover, the susceptibility rates to clindamycin (P=0.003) and tigecycline (P=0.044) decreased significantly among non-fragilis Bacteroides spp. over time. Clindamycin susceptibility rates >80% were found in Greece (100%), Sweden (86.3%) and the UK (80.7%), and the lowest susceptibility rates were found in the USA (42.9%) and Japan (53.9%). In conclusion, the susceptibility of Bacteroides spp. to commonly used antibiotics varied geographically. Empirical antibiotic therapy for suspected anaerobic infections with clindamycin and cefoxitin should be avoided due to high resistance rates. Piperacillin-tazobactam, meropenem, metronidazole and tigecycline could be considered favourable options for the treatment of infections caused by Bacteroides spp.

Evaluation of the Rapid Sepsityper protocol and specific MBT-Sepsityper module for the identification of bacteremia and fungemia using Bruker Biotyper MALDI-TOF MS.

The rapid identification method, the Rapid Sepsityper protocol with a specific MBT-Sepsityper module (Bruker Daltonics), based on the MALDI Biotyper platform, accurately identified 93.5% (116/124) of microorganisms at the species level in the 124 flagged blood culture samples from patients with monomicrobial bloodstream infections. Gram-negative bacilli (95.6%, 43/45) had a higher identification rate than Gram-positive cocci (93.3%, 70/75) and yeasts (75%, 3/4). The Rapid Sepsityper protocol displayed poor identification performance for polymicrobial samples.

Sub-second periodicity in a fast radio burst.

Fast radio bursts (FRBs) are millisecond-duration flashes of radio waves that are visible at distances of billions of light years1. The nature of their progenitors and their emission mechanism remain open astrophysical questions2. Here we report the detection of the multicomponent FRB 20191221A and the identification of a periodic separation of 216.8(1) ms between its components, with a significance of 6.5σ. The long (roughly 3 s) duration and nine or more components forming the pulse profile make this source an outlier in the FRB population. Such short periodicity provides strong evidence for a neutron-star origin of the event. Moreover, our detection favours emission arising from the neutron-star magnetosphere3,4, as opposed to emission regions located further away from the star, as predicted by some models5.

Serum myostatin level is a positive predictor of endothelial function measured by digital thermal monitoring of vascular reactivity in kidney transplantation patients.

OBJECTIVES: Myostatin is a myokine predominantly expressed and secreted in skeletal muscle in response to stimulations, including oxidative stress or inflammation. We investigated a potential association between myostatin levels and endothelial function among kidney transplantation (KT) patients. MATERIALS AND METHODS: Fasting blood samples were collected from 64 KT patients. The endothelial function that indicated by vascular reactivity index (VRI) was measured by digital thermal monitoring test. Serum myostatin levels were measured using a commercial enzyme-linked immunosorbent assay kit. All patients were categorized into three groups according to their VRI values: poor vascular reactivity was considered if VRI <1.0; 1.0 ≤VRI <2.0 indicated intermediate vascular reactivity, and VRI ≥2.0 was grouped as good vascular reactivity. RESULTS: Seven KT patients (10.9%) were categorized as poor vascular reactivity, 24 KT patients (37.5%) were grouped as intermediate vascular reactivity, and 33 KT patients had good vascular reactivity. Advanced age (r = -0.372, P = 0.002) and serum alkaline phosphate (ALP) level (r = -0.341, P = 0.006) were negatively correlated with VRI. However, serum myostatin level (r = 0.430, P < 0.001) was positively correlated with VRI. In multivariable forward stepwise linear regression analysis, high serum level of myostatin (ß = 0.441, adjusted R 2 change = 0.171; P < 0.001), advanced age (ß = -0.317, adjusted R 2 change = 0.138; P = 0.003), and serum ALP level (ß = -0.270, adjusted R 2 change = 0.060; P = 0.011) were significantly associated with VRI in KT patients. CONCLUSION: Our study showed that fasting myostatin level was positively associated with VRI and endothelial function among KT patients.

Detection of respiratory pathogens by application of multiplex PCR panel during early period of COVID-19 pandemic in a tertiary hospital in Central Taiwan.

BACKGROUND: Respiratory tract infections (RTIs) represent a major cause of clinical visits worldwide. Viral epidemiology of RTIs in adults has been less studied compared to children. FilmArray respiratory panel (FA-RP), a multiplex, real time polymerase chain reaction method can simultaneously detect the nucleic acids of multiple pathogens. The purpose of this study is to analyze the epidemiology and clinical presentations of an RTI cohort. METHODS: This retrospective cohort study was conducted at China Medical University Hospital (CMUH) and China Medical University Children's Hospital (CMUCH), from January 2020 to June 2020. The FA-RP results were collected and analyzed according to upper versus lower RTIs. RESULTS: Among 253 respiratory samples tested, 135 (53.4%) were from adults and 118 (46.6%) from children. A total positive rate of 33.9% (86/253) was found, with 21.48% (29/135) in adults and 48.31% (57/118) in children. Human rhinovirus/Enterovirus (HRV/EV) was detected in most of the age groups and was more common in URIs. HRV/EV was found as a frequent co-detection virus. Among children, HRV/EV was the most detected pathogen of URIs, while the most predominant pathogen in LRIs was Mycoplasma pneumoniae. CONCLUSIONS: FA-RP has the potential to improve the detection rate of respiratory pathogens. The positive rate of FA-RP was higher in children compared to adults, which likely corresponds to the higher incidence of viral RTIs in children. Different pathogens may lead to different types of respiratory infections.

Dense magnetized plasma associated with a fast radio burst.

Fast radio bursts are bright, unresolved, non-repeating, broadband, millisecond flashes, found primarily at high Galactic latitudes, with dispersion measures much larger than expected for a Galactic source. The inferred all-sky burst rate is comparable to the core-collapse supernova rate out to redshift 0.5. If the observed dispersion measures are assumed to be dominated by the intergalactic medium, the sources are at cosmological distances with redshifts of 0.2 to 1 (refs 10 and 11). These parameters are consistent with a wide range of source models. One fast burst revealed circular polarization of the radio emission, but no linear polarization was detected, and hence no Faraday rotation measure could be determined. Here we report the examination of archival data revealing Faraday rotation in the fast radio burst FRB 110523. Its radio flux and dispersion measure are consistent with values from previously reported bursts and, accounting for a Galactic contribution to the dispersion and using a model of intergalactic electron density, we place the source at a maximum redshift of 0.5. The burst has a much higher rotation measure than expected for this line of sight through the Milky Way and the intergalactic medium, indicating magnetization in the vicinity of the source itself or within a host galaxy. The pulse was scattered by two distinct plasma screens during propagation, which requires either a dense nebula associated with the source or a location within the central region of its host galaxy. The detection in this instance of magnetization and scattering that are both local to the source favours models involving young stellar populations such as magnetars over models involving the mergers of older neutron stars, which are more likely to be located in low-density regions of the host galaxy.

Repeated colonization by multi-drug-resistant Acinetobacter calcoaceticus-A. baumannii complex and changes in antimicrobial susceptibilities in surgical intensive care units.

BACKGROUND: A nosocomial outbreak of multi-drug-resistant Acinetobacter calcoaceticus-A. baumannii (MDR-ACB) complex infection occurred in a newly constructed building at a 2,500-bed tertiary medical center in Taiwan. METHODS: An investigation was carried out by molecular approaches to trace the bacteria. Antimicrobial susceptibilities, risk factors, and the occurrence of nosocomial MDR-ACB infections were investigated. From January to December 2009, 53 patients were infected with MDR-ACB, and 23 environmental surveys were performed in two surgical intensive care units (ICUs) within the new building. Forty-two clinical isolates were obtained from patients and 22 samples from nine environmental surveys. RESULTS: Forty clinical isolates (95.2%) and 18 environmental samples (81.8%) were positive for MDR-ACB of type A, the predominant outbreak strain. This strain was identical to that isolated in an outbreak in the old hospital in 2006, as proved by repetitive extragenic palindromic-based polymerase chain reaction and pulsed-field gel electrophoresis. Although the outbreak isolates contained blaOXA-23-like and blaOXA-51-like genes, analysis of the antimicrobial susceptibilities demonstrated increases in resistance to cefepime and imipenem-cilastatin in MDR-ACB isolated in the later outbreak. CONCLUSIONS: Not only patients or healthcare workers, but also medical equipment, might have carried the predominant outbreak strain from the old district to the new building. Therefore, even in a new environment, infection control programs must be enforced continually, and healthcare providers must be educated repeatedly to prevent recurrent outbreaks of MDR-ACB infection in the hospital setting.

Evaluation of the blood volume effect on the diagnosis of bacteremia in automated blood culture systems.

BACKGROUND: Blood culture volume is the most important variable in detecting bacteremia and fungemia. However, the majority of hospitals in Taiwan do not meet the criteria for an ideal blood culture volume (8-10 mL per bottle, two bottles per set) during collection. METHODS: The object of this study is to initiate an educational program for healthcare workers to increase blood volume collection and to evaluate the relationship between blood volumes and bacteremia recovery rate for detecting bacteremia and fungemia effectively by using the BD BACTEC 9240 blood culture system. RESULTS: After education, the blood sample volume ≥5 mL group increased from 2.93% to 71.24%. For a total of 4,844 bottles, the relative improvement in recovery rate for detection has increased by 17.81% between the <5 mL group and the ≥5 mL group. The recovery rates for the low-volume (<3 mL), mid-volume (3-7 mL), high-volume (8-10 mL) and extreme high-volume (>10 mL) groups are 13.31%, 15.02%, 17.68%, and 14.96%, respectively. CONCLUSION: With good blood collection practice, our study found that blood volume obtained was in direct proportion to recovery rate for the detection of bacteremia and fungemia.