Microbial Community Dynamics and Response to Plant Growth-Promoting Microorganisms in the Rhizosphere of Four Common Food Crops Cultivated in Hydroponics.

Plant growth promoting microorganisms (PGPMs) of the plant root zone microbiome have received limited attention in hydroponic cultivation systems. In the framework of a project aimed at the development of a biological life support system for manned missions in space, we investigated the effects of PGPMs on four common food crops (durum and bread wheat, potato and soybean) cultivated in recirculating hydroponic systems for a whole life cycle. Each crop was inoculated with a commercial PGPM mixture and the composition of the microbial communities associated with their root rhizosphere, rhizoplane/endosphere and with the recirculating nutrient solution was characterised through 16S- and ITS-targeted Illumina MiSeq sequencing. PGPM addition was shown to induce changes in the composition of these communities, though these changes varied both between crops and over time. Microbial communities of PGPM-treated plants were shown to be more stable over time. Though additional development is required, this study highlights the potential benefits that PGPMs may confer to plants grown in hydroponic systems, particularly when cultivated in extreme environments such as space.

Long-term outcome and health-related quality of life in difficult-to-wean patients with and without ventilator dependency at ICU discharge: a retrospective cohort study.

BACKGROUND: Long-term outcome and quality of life (QOL) in patients requiring prolonged mechanical ventilation after failure to wean in the ICU is scarcely documented. We aimed to evaluate long-term survival and QOL in patients discharged from the ICU with a tracheostomy for difficult weaning, and with or without ventilator dependency at ICU discharge. METHODS: We retrospectively investigated post-ICU trajectories and survival in patients requiring tracheostomy for difficult weaning admitted to the medical ICU of a tertiary center between 1999 and 2013, discriminating between patients who were ventilator dependent or were weaned at ICU discharge. In 2014, a QOL assessment was done in survivors with the use of the Short Form Health Survey (SF-36) and the Severe Respiratory Insufficiency questionnaire. RESULTS: A total of 114 patients was included, of whom 59 were ventilator dependent and 55 were weaned at ICU discharge. One-year survival rates were 73 % and 69 %, respectively. Overall QOL scores for physical functioning were low, and not significantly different between patients ventilated and those weaned at ICU discharge; scores for social functioning and mental health were less below norm and similar between both groups. CONCLUSIONS: Long-term survival in patients discharged from the ICU with tracheostomy and ventilator dependency after failure to wean was not significantly different from that of patients with tracheostomy and weaned at ICU discharge. Despite the physical QOL scores being low in both groups, mental QOL was acceptable. Given the intrinsic limitations of this retrospective study, prospective and preferentially multicenter studies are required to confirm these preliminary results.

A survey of beta-lactam antibiotics and vancomycin dosing strategies in intensive care units and general wards in Belgian hospitals.

Extended and continuous infusions with beta-lactam antibiotics have been suggested as a means of pharmacokinetic and pharmacodynamic optimisation of antimicrobial therapy. Vancomycin is also frequently administered in continuous infusion, although more for practical reasons. A survey was undertaken to investigate the recommendations by the local antibiotic management teams (AMTs) in Belgian acute hospitals concerning the administration (intermittent, extended or continuous infusion) and therapeutic drug monitoring of four beta-lactam antibiotics (ceftazidime, cefepime, piperacillin-tazobactam, meropenem) and vancomycin for adult patients with a normal kidney function. A structured questionnaire survey comprising three domains was developed and approved by the members of the Belgian Antibiotic Policy Coordination Committee (BAPCOC). The questionnaire was sent by e-mail to the official AMT correspondents of 105 Belgian hospitals, followed by two reminders. The response rate was 32 %, with 94 %, 59 %, 100 %, 100 % and 100 % of the participating Belgian hospitals using ceftazidime, cefepime, piperacillin-tazobactam, meropenem and vancomycin, respectively. Comparing intensive care unit (ICU) with non-ICU wards showed a higher implementation of extended or continuous infusions for ceftazidime (81 % vs. 41 %), cefepime (35 % vs. 10 %), piperacillin-tazobactam (38 % vs. 12 %), meropenem (68 % vs. 35 %) and vancomycin (79 % vs. 44 %) on the ICU wards. A majority of the hospitals recommended a loading dose prior to the first dose. For vancomycin, the loading dose and the trough target concentration were too low based on the current literature. This survey shows that extended and continuous infusions with beta-lactams and vancomycin are widely implemented in Belgian hospitals.

An unusual case of rectal perforation after liver transplantation.

We present the case of a 50-year-old patient in whom an anastomotic biliary stricture after liver transplantation was treated endoscopically by sphincterotomy, dilatation and stenting using a plastic biliary stent. A distal migration of the stent caused a perforation of the rectum which was treated following stent extraction per anum -- conservatively with antibiotics and temporary bowel rest.

Antimicrobial prescription in severe COVID-19 and CAP: a matched case-control study.

BACKGROUND: In severe coronavirus diseases 2019 (COVID-19), a high and potentially excessive use of antimicrobials for suspected bacterial co-infection and intensive care unit (ICU)-acquired infections has been repeatedly reported. OBJECTIVES: To compare an ICU cohort of community-acquired pneumonia (CAP) with a cohort of severe COVID-19 pertaining to co-infections, ICU-acquired infections and associated antimicrobial consumption. METHODS: We retrospectively compared a cohort of CAP patients with a cohort of COVID-19 patients matched according to organ failure, ICU length of stay (LOS) and ventilation days. Patient data such as demographics, infection focus, probability and severity, ICU severity scores and ICU and in-hospital mortality, days of antimicrobial therapy (DOT) and number of antimicrobial prescriptions, using an incremental scale, were registered and analysed. The total number of cultures (sputum, urinary, blood cultures) was collected and corrected for ICU LOS. FINDINGS: CAP patients (n = 148) were matched to COVID-19 patients (n = 74). Significantly less sputum cultures (68.2% versus 18.9%, P < 0.05) and bronchoalveolar lavages (BAL) (73.7% versus 36.5%, P < 0.05) were performed in COVID-19 patients. Six (8.1%) COVID-19 patients were diagnosed with a co-infection. Respectively, 58 of 148 (39.2%) CAP and 38 of 74 (51.4%) COVID-19 patients (P = 0.09) developed ICU-acquired infections. Antimicrobial distribution, both in the number of prescriptions and DOT, was similar in both cohorts. CONCLUSIONS: We found a low rate of microbiologically confirmed bacterial co-infection and a high rate of ICU-acquired infections in COVID-19 patients. Infection probabilities, antimicrobial prescriptions and DOT were comparable with a matched CAP cohort.

Saturable elimination of piperacillin in critically ill patients: implications for continuous infusion.

The study aimed to evaluate saturation of piperacillin elimination in critically ill adult patients. Seventeen critically ill adult patients received continuous and intermittent infusion of piperacillin/tazobactam. Piperacillin plasma concentrations (n = 217) were analysed using population pharmacokinetic (PopPK) modelling. Post-hoc simulations were performed to evaluate the type I error rate associated with the study. Unseen data were used to validate the final model. The mean error (ME) and root mean square error (RMSE) were calculated as a measure of bias and imprecision, respectively. A PopPK model with parallel linear and non-linear elimination best fitted the data. The median and 95% confidence interval (CI) for the model parameters drug clearance (CL), volume of central compartment (V), volume of peripheral compartment (Vp) and intercompartmental clearance (Q) were 9 (7.69-11) L/h, 6.18 (4.93-11.2) L, 11.17 (7.26-12) L and 15.61 (12.66-23.8) L/h, respectively. The Michaelis-Menten constant (Km) and the maximum elimination rate for Michaelis-Menten elimination (Vmax) were estimated without population variability in the model to avoid overfitting and inflation of the type I error rate. The population estimates for Km and Vmax were 37.09 mg/L and 353.57 mg/h, respectively. The bias (ME) was -20.8 (95% CI -26.2 to -15.4) mg/L, whilst imprecision (RMSE) was 49.2 (95% CI 41.2-56) mg/L. In conclusion, piperacillin elimination is (partially) saturable. Moreover, the population estimate for Km lies within the therapeutic window and therefore saturation of elimination should be accounted for when defining optimum dosing regimens for piperacillin in critically ill patients.

Systematic surveillance cultures as a tool to predict involvement of multidrug antibiotic resistant bacteria in ventilator-associated pneumonia.

OBJECTIVE: To assess prediction of multidrug resistant (MDR) pathogens in ventilator-associated pneumonia (VAP) by systematic surveillance cultures (SC) and to assess the contribution of SC to initial antibiotic therapy. DESIGN: Prospective cohort study of patients with microbiologically confirmed VAP. Comparison of actual early antibiotic coverage with three hypothetical empirical schemes. SETTING: A 50-bed university hospital ICU. SC consisted of oral, nasal, urinary and rectal samples upon admission, 3-weekly urinary and 1-weekly oral, nasal, and rectal samples in all patients, 3-weekly tracheal aspirates in intubated patients. RESULTS: MDR pathogens were found in 86 of 199 VAP episodes. Sensitivity of SC to predict MDR pathogens was 69% (tracheal SC) and 82% (all SC); specificity was 96% (tracheal) and 91% (all), respectively. Appropriate antibiotic coverage within 24 h and 48 h following MDR VAP was 77% and 89%, respectively. A carbapenem-based empirical scheme would have been equally appropriate (83% vs. 77% at 24 h; 83% vs. 89% at 48 h), but a beta-lactam-fluoroquinolone empirical therapy would have been less (59% vs. 77% at 24 h; 59% vs. 89% at 48 h) as would have been beta-lactam-aminoglycoside therapy (68% vs. 77% at 24 h; 68% vs. 89% at 48 h). Empirical comparators would have resulted in significantly more prescription of broad-spectrum antibiotics within the first 48 h. CONCLUSIONS: With MDR pathogens highly prevalent, systematic SC predicted MDR pathogens causing VAP in 69% to 82% and may have contributed to high rates of early appropriate antibiotic therapy with limited use of broad-spectrum antimicrobials.

Support vector machine versus logistic regression modeling for prediction of hospital mortality in critically ill patients with haematological malignancies.

BACKGROUND: Several models for mortality prediction have been constructed for critically ill patients with haematological malignancies in recent years. These models have proven to be equally or more accurate in predicting hospital mortality in patients with haematological malignancies than ICU severity of illness scores such as the APACHE II or SAPS II 1. The objective of this study is to compare the accuracy of predicting hospital mortality in patients with haematological malignancies admitted to the ICU between models based on multiple logistic regression (MLR) and support vector machine (SVM) based models. METHODS: 352 patients with haematological malignancies admitted to the ICU between 1997 and 2006 for a life-threatening complication were included. 252 patient records were used for training of the models and 100 were used for validation. In a first model 12 input variables were included for comparison between MLR and SVM. In a second more complex model 17 input variables were used. MLR and SVM analysis were performed independently from each other. Discrimination was evaluated using the area under the receiver operating characteristic (ROC) curves (+/- SE). RESULTS: The area under ROC curve for the MLR and SVM in the validation data set were 0.768 (+/- 0.04) vs. 0.802 (+/- 0.04) in the first model (p = 0.19) and 0.781 (+/- 0.05) vs. 0.808 (+/- 0.04) in the second more complex model (p = 0.44). SVM needed only 4 variables to make its prediction in both models, whereas MLR needed 7 and 8 variables in the first and second model respectively. CONCLUSION: The discriminative power of both the MLR and SVM models was good. No statistically significant differences were found in discriminative power between MLR and SVM for prediction of hospital mortality in critically ill patients with haematological malignancies.

Injury of the axillary artery after a proximal humeral fracture: a case report and overview of the literature.

A traumatic lesion of the axillary artery after a proximal humeral fracture is very uncommon. The clinical presentation can be very misleading and therefore it is mandatory to have a high index of suspicion and, as presented in this case report, to check the pulsations in different positions. Open repair remains the golden standard for most surgeons, but, in selected cases, an endovascular approach is feasible. The functional outcome is mostly determined by the associated trauma, especially the injury to the nervous structures.

Staphylococcus aureus colonization at ICU admission as a risk factor for developing S. aureus ICU pneumonia.

OBJECTIVE: To quantify the incidence of intensive care unit (ICU)-acquired pneumonia caused by Staphylococcus aureus (S. aureus) and its association with S. aureus colonization at ICU admission. METHODS: This was a post-hoc analysis of two cohort studies in critically ill patients. The primary outcome was the incidence of microbiologically confirmed S. aureus ICU-acquired pneumonia. Incidences of S. aureus ICU pneumonia and associations with S. aureus colonization at ICU admission were determined using competing risks analyses. In all ICUs, patients were screened for respiratory tract S. aureus carriage on admission as part of infection control policies. Pooling of data was not deemed possible because of heterogeneity in baseline differences in patient population. RESULTS: The two cohort studies contained data of 9156 ICU patients. The average carriage rate of S. aureus among screened patients was 12.7%. In total, 1185 (12.9%) patients developed ICU pneumonia. Incidences of S. aureus ICU pneumonia were 1.33% and 1.08% in cohorts 1 and 2, respectively. After accounting for competing events, the adjusted subdistribution hazard ratio (SHR) of S. aureus colonization at admission for developing S. aureus ICU pneumonia was 9.55 (95% CI 5.31-17.18) in cohort 1 and 14.54 (95% CI 7.24-29.21) in cohort 2. CONCLUSION: The overall cumulative incidence of S. aureus ICU pneumonia in these ICUs was low. Patients colonized with S. aureus at ICU admission had an up to 15 times increased risk for developing this outcome compared with non-colonized patients.

Total correction of tetralogy of Fallot following palliation.

Fifty three patients with Tetralogy of Fallot were totally corrected following palliation. Intracardiac repair was not adversely influenced by a Blalock Taussig shunt or a Waterston shunt which did not produce kinking of the RPA. The results were less satisfactory after correction following a Potts shunt or a Waterston shunt with kinking at the site of the anastomosis.

Implantable Holter may reveal cause of unexplained syncope.

A definitive diagnosis in patients with syncope is often problematic if the cause is not evident after initial clinical assessment. The cause of syncope may be not established due to the infrequent, episodic occurrence. A symptom-rhythm correlation is frequently an unattainable gold standard in many patients. The implantable Holter has added a powerful tool to the diagnostic armamentarium in the field of arrhythmia detection and may assume a prominent role in the investigation of syncope.

Validity analysis of a unique infection surveillance system in the intensive care unit by analysis of a data warehouse built through a workflow-integrated software application.

BACKGROUND: An electronic decision support programme was developed within the intensive care unit (ICU) that provides an overview of all infection-related patient data, and allows ICU physicians to add clinical information during patient rounds, resulting in prospective compilation of a database. AIM: To assess the validity of computer-assisted surveillance (CAS) of ICU-acquired infection performed by analysis of this database. METHODS: CAS was compared with prospective paper-based surveillance (PBS) for ICU-acquired respiratory tract infection (RTI), bloodstream infection (BSI) and urinary tract infection (UTI) over four months at a 36-bed medical and surgical ICU. An independent panel reviewed the data in the case of discrepancy between CAS and PBS. FINDINGS: PBS identified 89 ICU-acquired infections (13 BSI, 18 UTI, 58 RTI) and CAS identified 90 ICU-acquired infections (14 BSI, 17 UTI, 59 RTI) in 876 ICU admissions. There was agreement between CAS and PBS on 13 BSI (100 %), 14 UTI (77.8 %) and 42 RTI (72.4 %). Overall, there was agreement on 69 infections (77.5%), resulting in a kappa score of 0.74. Discrepancy between PBS and CAS was the result of capture error in 11 and 14 infections, respectively. Interobserver disagreement on probability (13 RTI) and focus (two RTI, one UTI) occurred for 16 episodes. The time required to collect information using CAS is less than 30% of the time required when using PBS. CONCLUSION: CAS for ICU-acquired infection by analysis of a database built through daily workflow is a feasible surveillance method and has good agreement with PBS. Discrepancy between CAS and PBS is largely due to interobserver variability.

Extended versus bolus infusion of meropenem and piperacillin: a pharmacokinetic analysis.

BACKGROUND: Extended infusion of beta-lactam antibiotics has been advocated as a method for optimizing antibiotic exposure in critically ill patients. The objective of this study was to compare the pharmacokinetics/pharmacodynamics of extended infusion versus bolus infusion of piperacillin and meropenem in critically ill patients with normal renal function. METHODS: A prospective study of 3 hours extended infusion of meropenem and piperacillin in critically ill patients without renal dysfunction. Results from the extended infusion cohort were compared to previously published bolus infusion data in critically ill patients. RESULTS: Twenty extended infusion patients (15 piperacillin, 5 meropenem) were compared with 13 bolus infusion patients (8 piperacillin, 5 meropenem). The demographic and clinical characteristics between both groups were not statistically different. Significant pharmacokinetic differences were observed in median (interquartile range) Cmax for both meropenem (extended infusion 17 [12.6-21.9] vs. bolus 85.2 [66.7-140.3]; P=0.01) and piperacillin (extended infusion 76.2 [57.7-92.6] vs. bolus 240.2 [168.5-275.4]; P=0.001). Considerable pharmacokinetic variability existed in each group for both drugs. Compared to bolus infusion, fT>MIC using extended infusion was higher for both drugs: 96% (IQR 71-100%) compared to 77% (IQR 41-93%) for piperacillin (P=0.05) and 82% (IQR 63-89%) compared to 51% (IQR 48-63%) for meropenem (P=0.095); assuming a MIC of 16 mg/L and 2 mg/L respectively. CONCLUSION: This study confirms that extended infusion in critically ill patients result in advantageous pharmacokinetic profiles by increasing the fT>MIC for piperacillin and meropenem. In a significant subpopulation of critically ill patients with normal renal function, a 100% fT>MIC target is not reached, even with 3-hour extended infusions.

Therapeutic drug monitoring-based dose optimisation of piperacillin and meropenem: a randomised controlled trial.

PURPOSE: There is variability in the pharmacokinetics (PK) of antibiotics (AB) in critically ill patients. Therapeutic drug monitoring (TDM) could overcome this variability and increase PK target attainment. The objective of this study was to analyse the effect of a dose-adaption strategy based on daily TDM on target attainment. METHODS: This was a prospective, partially blinded, and randomised controlled trial in patients with normal kidney function treated with meropenem (MEM) or piperacillin/tazobactam (PTZ). The intervention group underwent daily TDM, with dose adjustment when necessary. The predefined PK/pharmacodynamic (PK/PD) target was 100% fT>4MIC [percentage of time during a dosing interval that the free (f) drug concentration exceeded 4 times the MIC]. The control group received conventional treatment. The primary endpoint was the proportion of patients that reached 100% fT>4MIC and 100 % fT>MIC at 72 h. RESULTS: Forty-one patients (median age 56 years) were included in the study. Pneumonia was the primary infectious diagnosis. At baseline, 100% fT>4MIC was achieved in 21% of the PTZ patients and in none of the MEM patients; 100% fT>MIC was achieved in 71% of the PTZ patients and 46 % of the MEM patients. Of the patients in the intervention group, 76 % needed dose adaptation, and five required an additional increase. At 72 h, target attainment rates for 100% fT>4MIC and 100% fT>MIC were higher in the intervention group: 58 vs. 16%, p = 0.007 and 95 vs. 68%, p = 0.045, respectively. CONCLUSIONS: Among critically ill patients with normal kidney function, a strategy of dose adaptation based on daily TDM led to an increase in PK/PD target attainment compared to conventional dosing.

Factors associated with inadequate early vancomycin levels in critically ill patients treated with continuous infusion.

Vancomycin administration using a loading dose and continuous infusion (CI) results in more rapid attainment of adequate concentrations. The aim of this retrospective study of ICU patients receiving vancomycin was to determine the efficacy of a vancomycin dosing protocol using a weight-based loading dose and to identify factors associated with inadequate concentrations. Patients received a loading dose (<65 kg, 1000 mg; ≥65 kg, 1500 mg), and 2000 mg/24 h CI with subsequent dose adaptation. Adequate levels were defined as concentrations ≥15 mg/L. In total, 227 patients (154 males) were included in the study (mean age 56.5 ± 16.1 years; mean APACHE II score 19.30 ± 7.7). The mean loading dose was 1129 ± 369 mg (15.07 ± 4.99 mg/kg). The dosing protocol was applied in 126 patients (55.5%). Mean vancomycin levels were 19.32 mg/L and 21.08 mg/L on Days 2 and 3, respectively. Vancomycin levels on Day 2 were adequate in 70.5% of patients, increasing to 84.1% on Day 3. Patients who received an appropriate loading dose more often had adequate vancomycin levels on Day 2. Older age, female sex, higher creatinine concentration, lower body temperature and use of a loading dose according to the vancomycin dosing protocol were independently associated with adequate vancomycin levels. A weight-based loading dose plus CI of vancomycin resulted in adequate concentrations in most patients and was superior compared with a non-standardised loading dose. Some patients may require higher doses, and factors other than weight, such as kidney function, age and sex, play a role.

Long-term outcomes and quality of life in critically ill patients with hematological or solid malignancies: a single center study.

PURPOSE: Data concerning long-term outcomes and quality of life (QOL) in critically ill cancer patients are scarce. The aims of this study were to assess long-term outcomes and QOL in critically ill patients with hematological (HM) or solid malignancies (SM) 3 months and 1 year after intensive care unit (ICU) discharge, to compare these with QOL before ICU admission, and to identify prognostic indicators of long-term QOL. METHODS: During a 1 year prospective observational cohort analysis, consecutive patients with HM or SM admitted to the medical or surgical ICU of a university hospital were screened for inclusion. Cancer data, demographics, co-morbidity, severity of illness, organ failures, and outcomes were collected. The QOL before ICU admission, 3 months, and 1 year after ICU discharge was assessed using standardized questionnaires (EuroQoL-5D, Medical Outcomes Study 36-item Short Form Health Survey). Statistical significance was attained at P < 0.05. RESULTS: There were 483 patients (85 HM, 398 SM) (64% men) with a median age of 62 years included. Mortality rates of HM compared to SM were, respectively: hospital (34 vs. 13%), 3 months (42 vs. 17%), and 1 year (66 vs. 36%) (P < 0.001). QOL declined at 3 months, but improved at 1 year although it remained under baseline QOL, particularly in HM. Older age (P = 0.007), severe comorbidity (P = 0.035), and HM (P = 0.041) were independently associated with poorer QOL at 1 year. CONCLUSIONS: Long-term outcomes and QOL were poor, particularly in HM. Long-term expectations should play a larger role during multidisciplinary triage decisions upon referral to the ICU.