Beneficial effects of citrulline enteral administration on sepsis-induced T cell mitochondrial dysfunction.

Severe sepsis induces a sustained immune dysfunction associated with poor clinical behavior. In particular, lymphopenia along with increased lymphocyte apoptosis and decreased lymphocyte proliferation, enhanced circulating regulatory T cells (Treg), and the emergence of myeloid-derived suppressor cells (MDSCs) have all been associated with persistent organ dysfunction, secondary infections, and late mortality. The mechanisms involved in MDSC-mediated T cell dysfunction during sepsis share some features with those described in malignancies such as arginine deprivation. We hypothesized that increasing arginine availability would restore T cell function and decrease sepsis-induced immunosuppression. Using a mouse model of sepsis based on cecal ligation and puncture and secondary pneumonia triggered by methicillin-resistant Staphylococcus aureus inoculation, we demonstrated that citrulline administration was more efficient than arginine in increasing arginine plasma levels and restoring T cell mitochondrial function and proliferation while reducing sepsis-induced Treg and MDSC expansion. Because there is no specific therapeutic strategy to restore immune function after sepsis, we believe that our study provides evidence for developing citrulline-based clinical studies in sepsis.

Impact of Intraoperative Allogeneic Platelet Transfusion on Healthcare-Associated Infections in Cardiac Surgery: Insights From a Large Single-Center Cohort Study.

OBJECTIVES: Despite significant improvement in patient blood management, cardiac surgery remains a high hemorrhagic risk procedure. Platelet transfusion is used commonly to treat thrombocytopenia-associated perioperative bleeding. Allogeneic platelet transfusion may induce transfusion-related immunomodulation. However, its association with postoperative healthcare-associated infections is still a matter of debate. The objective was to evaluate the impact of allogeneic platelet transfusion during cardiac surgery on postoperative healthcare-associated infection incidence. DESIGN: Retrospective cohort study. SETTING: Tertiary referral academic center. PARTICIPANTS: Patients undergoing cardiac surgery from 2012 to 2018. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Intraoperative platelet transfusion was defined as exposure in a causal model. The primary outcome was the incidence of healthcare-associated infections comprised of bloodstream infection, hospital-acquired pneumonia, and surgical-site infection. Among 7,662 included patients, 528 patients (6.8%) were exposed to intraoperative platelet transfusion, and 329 patients (4.3%) developed 454 postoperative infections. Bloodstream infection affected 106 patients (1.4%), hospital-acquired pneumonia affected 174 patients (2.3%), and surgical-site infection affected 148 patients (1.9%). Intraoperative platelet transfusion was associated with an increased risk of bloodstream infection after adjustment by multivariable logistic regression (odds ratio [OR] 2.85; 95% CI 1.40-5.8; p = 0.004; n = 7,662), propensity score matching (OR 3.95; 95% CI 1.57-12.0), p = 0.007; n = 766), and propensity score overlap weighting (OR 3.04; 95% CI 1.51-6.1, p = 0.002; n = 7,762). Surgical-site infection and hospital-acquired pneumonia were not significantly associated with platelet transfusion. CONCLUSIONS: These results suggested that intraoperative allogeneic platelet transfusion is a risk factor for bloodstream infection after cardiac surgery. These results supported the development of patient blood management strategies aimed at minimizing perioperative platelet transfusion in cardiac surgery.

Effectiveness of a multimodal intervention to improve blood culture collection in an adult emergency department.

We investigated the impact of a multimodal intervention to improve the compliance of BC collections as a composite outcome, taking into account both blood volume collected and absence of solitary BC. We performed a quasi-experimental study using a before-after design (5 months for pre- and post-intervention evaluation) in an adult emergency department at a tertiary care hospital that showed that a multimodal intervention was associated with a dramatic increase in the proportion of blood cultures that were collected as recommended per national guidelines, from 17.3% (328/1896) to 68.9% (744/1080), P < 0.0001. The implementation of such intervention in other settings could improve the diagnosis of bloodstream infections and reduce irrelevant costs.

Early discontinuation of combination antibiotic therapy in severe community-acquired pneumonia: a retrospective cohort study.

BACKGROUND: Severe community-acquired pneumonia (SCAP) is commonly treated with an empiric combination therapy, including a macrolide, or a quinolone and a ß-lactam. However, the risk of Legionella pneumonia may lead to a prolonged combination therapy even after negative urinary antigen tests (UAT). METHODS: We conducted a retrospective cohort study in a French intensive care unit (ICU) over 6 years and included all the patients admitted with documented SCAP. All patients received an empirical combination therapy with a ß-lactam plus a macrolide or quinolone, and a Legionella UAT was performed. Macrolide or quinolone were discontinued when the UAT was confirmed negative. We examined the clinical and epidemiological features of SCAP and analysed the independent factors associated with ICU mortality. RESULTS: Among the 856 patients with documented SCAP, 26 patients had atypical pneumonia: 18 Legionella pneumophila (LP) serogroup 1, 3 Mycoplasma pneumonia (MP), and 5 Chlamydia psittaci (CP). UAT diagnosed 16 (89%) Legionella pneumonia and PCR confirmed the diagnosis for the other atypical pneumonia. No atypical pneumonia was found by culture only. Type of pathogen was not associated with a higher ICU mortality in the multivariate analysis. CONCLUSION: Legionella pneumophila UAT proved to be highly effective in detecting the majority of cases, with only a negligible percentage of patients being missed, but is not sufficient to diagnose atypical pneumonia, and culture did not provide any supplementary information. These results suggest that the discontinuation of macrolides or quinolones may be a safe option when Legionella UAT is negative in countries with a low incidence of Legionella pneumonia.

Distribution of Achromobacter Species in 12 French Cystic Fibrosis Centers in 2020 by a Retrospective MALDI-TOF MS Spectrum Analysis.

Achromobacter spp. are nonfermenting Gram-negative bacilli mainly studied among cystic fibrosis (CF) patients. The identification of the 19 species within the genus is time-consuming (nrdA-sequencing), thus data concerning the distribution of the species are limited to specific studies. Recently, we built a database using MALDI-TOF mass spectrometry (MS) (Bruker) that allows rapid and accurate species identification and detection of the multiresistant epidemic clones: A. xylosoxidans ST137 spreading among CF patients in various French and Belgium centers, and A. ruhlandii DES in Denmark. Here, we first assessed whether species identification could be achieved with our database solely by analysis of MS spectra without availability of isolates. Then, we conducted a multicentric study describing the distribution of Achromobacter species and of the clone ST137 among French CF centers. We collected and analyzed with our local database the spectra of Achromobacter isolates from 193 patients (528 samples) from 12 centers during 2020. In total, our approach enabled to conclude for 502/528 samples (95.1%), corresponding to 181 patients. Eleven species were detected, only five being involved in chronic colonization, A. xylosoxidans (86.4%), A. insuavis (9.1%), A. mucicolens (2.3%), A. marplatensis (1.1%) and A. genogroup 3 (1.1%). This study confirmed the high prevalence of A. xylosoxidans in chronic colonizations and the circulation of the clone A. xylosoxidans ST137 in France: four patients in two centers. The present study is the first to report the distribution of Achromobacter species from CF patients samples using retrospective MALDI-TOF/MS data. This easy approach could enable future large-scale epidemiological studies.

Capnocytophaga zoonotic infections: a 10-year retrospective study (the French CANCAN study).

Zoonotic species of Capnocytophaga genus belong to the oral microbiota of dogs and cats. They may be responsible for serious human infections, mainly after animal bites, with a high mortality rate. In France, only few cases have been reported and no multicenter study has been conducted. Our aim was to describe the French epidemiology of Capnocytophaga zoonosis. We conducted a multicenter (21 centers) retrospective non-interventional, observational study in France describing the epidemiology of Capnocytophaga zoonosis (C. canimorsus, C. cynodegmi, C. canis) over 10 years with regard to clinical and bacteriological data. From 2009 to 2018, 44 cases of Capnocytophaga zoonotic infections were described (C. canimorsus, n = 41; C. cynodegmi, n = 3). We observed an increase (2.5 times) in the number of cases over the study period (from the first to the last 5 years of the study). The most frequent clinical presentations were sepsis (n = 37), skin and soft tissue infections (n = 12), meningitis (n = 8), osteoarticular infections (n = 6), and endocarditis (n = 2). About one-third of patients with sepsis went into septic shock. Mortality rate was 11%. Mortality and meningitis rates were significantly higher for alcoholic patients (p = 0.044 and p = 0.006, respectively). Other comorbidities included smoking, splenectomy, diabetes mellitus, and immunosuppressive therapy are associated to zoonotic Capnocytophaga infection. Eighty-two percent of cases involved contact with dogs, mostly included bites (63%). Despite all isolates were susceptible to the amoxicillin-clavulanic acid combination, three of them were resistant to amoxicillin.

Use of rifampicin and graft removal are associated with better outcomes in prosthetic vascular graft infection.

OBJECTIVES: Prosthetic vascular graft infection (PVGI) is a very severe disease. We aimed to determine the factors associated with treatment failure. METHODS: Patients admitted to two University Hospitals with PVGI were included in this retrospective study. PVGI was classified as possible, probable or proven according to an original set of diagnostic criteria. We defined treatment failure if one of the following events occurred within the first year after PVGI diagnosis: death and infection recurrence due to the same or another pathogen. RESULTS: One hundred and twelve patients were diagnosed with possible (n = 26), probable (n = 22) and proven (n = 64) PVGI. Bacterial documentation was obtained for 81% of patients. The most frequently identified pathogen was Staphylococcus aureus (n = 39). Surgery was performed in 96 patients (86%). Antibiotics were administered for more than 6 weeks in 41% of patients. Treatment failure occurred in 30 patients (27.5%). The factors associated with a lower probability of treatment failure were total removal of the infected graft (OR = 0.2, 95% CI [0.1-0.6]), rifampicin administration (OR = 0.3 [0.1-0.9]) and possible PVGI according to the GRIP criteria (OR = 0.3 [0.1-0.9]). CONCLUSIONS: Treatment failure occurred in 27.5% of patients with PVGI. Total removal of the infected graft and rifampicin administration were associated with better outcomes.

Determination of amoxicillin and cotrimoxazole concentrations in sputum of patients with cystic fibrosis.

In the management of cystic fibrosis, treatments against Staphylococcus aureus and Haemophilus influenzae such as amoxicillin or cotrimoxazole have to be prescribed and the antibiotherapy's efficacy may be linked to the concentration that reaches the infected site. As cystic fibrosis patients present disturbed pharmacokinetics parameters, drug monitoring would be relevant to assess the lung distribution of antibiotics and to optimize dosing regimens. In this context, the aim of the study was to develop and validate HPLC-based methods for the determination of both antibiotics in bronchial sputum from cystic fibrosis patients, in order to assess the distribution of the drugs into the lungs. Plasma proteins were precipitated by acetonitrile and amoxicillin concentrations in sputum were determined by HPLC coupled with tandem-mass spectrometry. Following liquid extraction with ethyl acetate, cotrimoxazole was quantified by HPLC using ultraviolet detection. Both methods were rapid, specific, accurate and reproducible. The method was applied to patient samples. In three treated patients, concentrations of amoxicillin in sputum were similar and below the lower limit of quantification (0.1 µg/g) and in six patients, sputum concentrations up to 11.1 and 6.4 µg/g were measured for sulfamethoxazole and trimethoprim, respectively.

Chronic meningococcemia: a report of 26 cases and literature review.

Chronic meningococcemia is defined by blood culture(s) positive for Neisseria meningitidis, symptoms duration > 7 days, and neither meningitis nor shock on admission. This series of 26 consecutive cases illustrates that this is a rare disease (< 5% of meningococcemia, < 0.05 cases per 100,000 inhabitants per year), mostly affecting young adults, males, with no predisposing condition. Major symptoms include fever, rash, and arthralgia. Median time between symptoms onset, and diagnosis is 28 days. Most patients fully recover with a 1-week course of parenteral betalactams.

Opportunistic Pulmonary Bordetella hinzii Infection after Avian Exposure.

We report 2 cases of pulmonary Bordetella hinzii infection in immunodeficient patients. One of these rare cases demonstrated the potential transmission of the bacteria from an avian reservoir through occupational exposure and its persistence in humans. We establish bacteriologic management of these infections and suggest therapeutic options if needed.

First case of disseminated infection with Nocardia cerradoensis in a human.

Here we report in a human, a renal transplant patient, the first disseminated infection with Nocardia cerradoensis, isolated after a brain biopsy. Species identification was based on 16S rRNA, gyrB, and hsp65 gene analyses. Antibiotic treatment was successful by combining carbapenems and aminoglycosides and then switching to oral trimethoprim-sulfamethoxazole.

High-dose continuous oxacillin infusion results in achievement of pharmacokinetics targets in critically ill patients with deep sternal wound infections following cardiac surgery.

Knowledge regarding antimicrobial therapy strategies in deep sternal wound infections (DSWI) following cardiac surgery is limited. Therefore, we aimed to determine the steady-state plasma and mediastinal concentrations of oxacillin administered by continuous infusion in critically ill patients with DSWI and to compare these concentrations with the susceptibility of staphylococci recovered. A continuous infusion of oxacillin (150 to 200 mg/kg of body weight/24 h) was administered after a loading dose (50 mg/kg). Plasma and mediastinal concentrations of total and unbound oxacillin were determined 4 h after the loading dose (H4) and then at day 1 (H24) and day 2 (H48). Twelve patients were included. Nine patients exhibited bacteremia, 5 were in septic shock, 8 were positive for Staphylococcus aureus, and 4 were positive for coagulase-negative staphylococci. The median MIC (first to third interquartile range) was 0.25 (0.24 to 0.41) mg/liter. Median plasma concentrations of total and unbound oxacillin at H4, H24, and H48 were, respectively, 64.4 (41.4 to 78.5) and 20.4 (12.4 to 30.4) mg/liter, 56.9 (31.4 to 80.6) and 21.7 (6.5 to 27.3) mg/liter, and 57.5 (32.2 to 85.1) and 20 (14.3 to 35.7) mg/liter. The median mediastinal concentrations of total and unbound oxacillin at H4, H24, and H48 were, respectively, 2.3 (0.7 to 25.9) and 0.9 (<0.5 to 15) mg/liter, 29.1 (19.7 to 38.2) and 12.6 (5.9 to 19.8) mg/liter, and 31.6 (14.9 to 42.9) and 17.1 (6.7 to 26.7) mg/liter. High-dose oxacillin delivered by continuous infusion is a valuable strategy to achieve our pharmacokinetic target (4× MIC) at the site of action at H24. But concerns remain in cases of higher MICs, emphasizing the need for clinicians to obtain the MICs for the bacteria and to monitor oxacillin concentrations, especially the unbound forms, at the target site.

Clinical features and treatment outcomes of bone and joint nontuberculous mycobacterial infections according to immune status: a 9-year retrospective observational cohort.

OBJECTIVES: Nontuberculous mycobacteria (NTM) bone and joint infections (BJIs) are uncommon. We evaluated the characteristics of BJIs and identified differences according to immune status. METHODS: We performed a multicenter retrospective study in France involving patients with documented NTM BJI over a 9-year period. We collected the clinical and microbiological characteristics, management, and clinical outcomes of the patients. RESULTS: Overall, 95 patients were included, of whom 50.5% (48/95) were immunosuppressed. Tenosynovitis was more frequent in the immunocompetent group, and native arthritis more common in the immunosuppressed group. Mycobacerium marinum and M. abscessus complex were significantly more frequent in the immunocompetent group, and M. avium and M. xenopi were significantly more frequent in the immunosuppressed group. The combination of antibiotherapy with surgery tended to be more frequent in the immunocompetent than the immunosuppressed group (63.8% (30/47) vs 47.8% (22/46), respectively); of the latter, 45.7% (21/46) received antimicrobial therapy alone, a higher frequency than in the immunocompetent group (23.4%, 11/47). The median duration of antimicrobial treatment was similar in the two groups (11 months). Mortality was significantly higher in the immunosuppressed group. CONCLUSIONS: Although the clinical presentations and the NTM species involved in BJI differed according to immune status, most recovered completely after treatment.

The Role of Next-Generation Sequencing (NGS) in the Management of Tuberculosis: Practical Review for Implementation in Routine.

Next-generation sequencing (NGS) has modernized the field of tuberculosis (TB) research by enabling high-throughput sequencing of the entire genome of Mycobacterium tuberculosis (MTB), which is the causative agent of TB. NGS has provided insights into the genetic diversity of MTB, which are crucial for understanding the evolution and transmission of the disease, and it has facilitated the identification of drug-resistant strains, enabling rapid and accurate tailoring of treatment. However, the high cost and the technical complexities of NGS currently limit its widespread use in clinical settings. International recommendations are thus necessary to facilitate the interpretation of polymorphisms, and an experimental approach is still necessary to correlate them to phenotypic data. This review aims to present a comparative, step-by-step, and up-to-date review of the techniques available for the implementation of this approach in routine laboratory workflow. Ongoing research on NGS for TB holds promise for improving our understanding of the disease and for developing more efficacious treatments.

Early detection of plasma d-lactate: Toward a new highly-specific biomarker of bacteraemia?

Background: Bloodstream infections are a leading cause of mortality. Their detection relies on blood cultures (BCs) but time to positivity is often between tens of hours and days. d-lactate is a metabolite widely produced by bacteria but very few in human. We aimed to evaluate d-lactate, d-lactate/l-lactate ratio and d-lactate/total lactate ratio in plasma as potential early biomarkers of bacteraemia on a strictly biological standpoint. Methods: A total of 228 plasma specimens were collected from patients who had confirmed bacteraemia (n = 131) and healthy outpatients (n = 97). Specific l-lactate and d-lactate analyses were performed using enzymatic assays and analytical performances of d-lactate, d-lactate/total lactate and d-lactate/l-lactate ratios for the diagnosis of bacteraemia were assessed. Results: A preliminary in vitro study confirmed that all strains of Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus were able to produce d-lactate at significant levels. In patients, plasma d-lactate level was the most specific biomarker predicting a bacteraemia profile with a specificity and predictive positive value of 100% using a cut-off of 131 µmol.L-1. However, sensitivity and negative predictive value were rather low, estimated at 31% and 52%, respectively. d-lactate displayed an Area Under Receiver Operating Characteristic (AUROC) curve of 0.696 with a P value < 0.0001. There was no difference of d-lactate levels between BCs bottles positive for Gram-positive or Gram-negative bacteria (p = 0.55). Conclusion: d-lactate shows promise as a specific early biomarker of bacterial metabolism. The development of rapid automated assays could raise clinical applications for infectious diseases diagnosis including early bacteraemia prediction.

Non-HACEK gram-negative bacilli endocarditis: a multicentre retrospective case-control study.

BACKGROUND: Infective endocarditis (IE) caused by non-HACEK gram-negative bacilli (GNB) is poorly characterised and may be emerging as a consequence of medical progress. METHODS: We performed an observational retrospective case-control study. Cases were non-HACEK GNB IE, definite or possible (modified Duke criteria), diagnosed in adults between 2007 and 2020 in six French referral hospitals. Two controls were included for each case (IE due to other bacteria, matched by sites and diagnosis date). RESULTS: Non-HACEK GNB were identified in 2.4% (77/3230) of all IE during the study period, with a mean age of 69.2 ± 14.6 years, and a large male predominance (53/77, 69%). Primary pathogens were Escherichia coli (n = 33), Klebsiella sp. (n = 12) and Serratia marcescens (n = 9), including eight (10%) multidrug-resistant GNB. Compared to controls (n = 154: 43% Streptococcus sp., 41% Staphylococcus sp. and 12% Enterococcus sp.), non-HACEK GNB IE were independently associated with intravenous drug use (IVDU, 8% vs. 2%, p = .003), active neoplasia (15% vs. 6%, p = .009), haemodialysis (9% vs. 3%, p = .007) and healthcare-associated IE (36% vs. 18%, p = .002). Urinary tract was the main source of infection (n = 25, 33%) and recent invasive procedures were reported in 29% of cases. Non-HACEK GNB IE were at lower risk of embolism (31% vs. 47%, p = .002). One-year mortality was high (n = 28, 36%). Comorbidities, particularly malignant hemopathy and cirrhosis, were associated with increased risk of death. CONCLUSIONS: Non-HACEK GNB are rarely responsible for IE, mostly as healthcare-associated IE in patients with complex comorbidities (end-stage renal disease, neoplasia), or in IVDUs.

Mortality due to hospital-acquired infection after cardiac surgery.

PURPOSE: Hospital-acquired infections have been associated with significant morbidity and mortality in critically ill surgical patients. However, little is known about mortality due to hospital-acquired infections in cardiac surgery. METHODS: We conducted a retrospective analysis of prospectively collected data from the cardiac surgery unit of a university hospital. All patients who underwent cardiac surgery over a 7-year period were included. Patients with hospital-acquired infections were matched 1:1 with patients with nonhospital-acquired infections based on risk factors for hospital-acquired infections and death after cardiac surgery using propensity score matching. We performed a competitive risk analysis to study the mortality fraction due to hospital-acquired infections. RESULTS: Of 8853 patients who underwent cardiac surgery, 370 (4.2%) developed 500 postoperative infections (incidence density rate 4.2 hospital-acquired infections per 1000 patient-days). Crude hospital mortality was significantly higher in patients with hospital-acquired infections than in matched patients who did not develop hospital-acquired infections, 15.4% and 5.7%, respectively (P < .001). The in-hospital mortality fraction due to hospital-acquired infections in our cohort was 17.1% (12.3%-22.8%). Pseudomonas aeruginosa infection (hazard ratio, 2.09; 95% confidence interval, 1.23-3.49; P = .005), bloodstream infection (hazard ratio, 2.08; 95% confidence interval, 1.19-3.63; P = .010), and pneumonia (hazard ratio, 1.68; 95% confidence interval, 1.02-2.77; P = .04) were each independently associated with increased hospital mortality. CONCLUSIONS: Although hospital-acquired infections are relatively uncommon after cardiac surgery (4.2%), these infections have a major impact on postoperative mortality (attributable mortality fraction, 17.1%).

Neutrophil function and bactericidal activity against Staphylococcus aureus after cardiac surgery with cardiopulmonary bypass.

Staphylococcus aureus is the main bacterial pathogen encountered in mediastinitis after cardiac surgical procedures; it remains a devastating complication with a high mortality rate. As neutrophils have a primordial role in the defense against staphylococcus infection and cardiopulmonary bypass (CPB) is known to induce immunosuppression, the aim of this study was to investigate CPB impact on neutrophil functions. Patients without known immunosuppression scheduled for cardiac surgery with CPB were included. Bone marrow and blood samples were harvested before, during, and after surgery. Neutrophil phenotypic maturation and functions (migration, adhesion, neutrophil extracellular trap [NET] release, reactive oxygen species (ROS) production, phagocytosis, and bacteria killing) were investigated. Two types of Staphylococcus aureus strains (one from asymptomatic nasal carriage and another from mediastinitis infected tissues) were used to assess in vitro bacterial direct impact on neutrophils. We found that CPB induced a systemic inflammation with an increase in circulating mature neutrophils after surgery. Bone marrow sample analysis did not reveal any modification of neutrophil maturation during CPB. Neutrophil lifespan was significantly increased and functions such as NET release and ROS production were enhanced after CPB whereas bacteria killing and phagocytosis were not impacted. Results were similar with the two different isolates of Staphylococcus aureus. These data suggest that CPB induces a recruitment of mature neutrophils via a demargination process rather than impacting their maturation in the bone marrow. In addition, neutrophils are fully efficient after CPB and do not contribute to postoperative immunosuppression.