Potential impact of real-time processing and rapid susceptibility testing of blood samples in Gram-negative bloodstream infections in intensive care patients.

INTRODUCTION: Timely and appropriate therapy is critical in patients with Gram-negative bloodstream infections (GNBSI). Most bacteriology laboratories process blood specimen in the daytime, during laboratory operating hours, and use conventional culture for antimicrobial susceptibility testing (AST). We simulated the potential impact of real-time processing and rapid AST (7 hours) on early adaptation of the antibiotic regimen in intensive care unit (ICU) patients with GNBSI. METHODS: All GNBSI episodes occurring in the ICUs of 2 hospitals in Paris were included. Data were collected. For each episode of bacteremia, we simulated the impact of three strategies: (1) Real-time processing coupled with conventional techniques (Gram stain and standard AST); (2) Standard processing coupled with rapid AST; and (3) Real-time processing coupled with rapid AST. RESULTS: We included 109 episodes in 98 patients. Forty-two patients (48%) died during ICU stay. AST results led to a change of the antibiotic regimen in 66 (61%) episodes, mainly de-escalation (54/109, 55%). In standard care, median time from sample collection to definitive AST result was 65.9 hours (±26.7). The three strategies would have reduced time-to-result by 9.2 hours (±7.1), 30.8 hours (±19.7) and 40.0 hours (±20.6) respectively. Compared to standard care, strategies 1, 2 and 3 would have avoided 20, 69 and 90 patient-days of broad-spectrum antibiotics respectively. CONCLUSION: In addition to real-time processing of blood samples, rapid AST would be the most effective strategy to shorten time-to-result in critical patients with GNBSI.

One-day prevalence of asymptomatic carriage of toxigenic and non-toxigenic Clostridioides difficile in 10 French hospitals.

BACKGROUND: Asymptomatic faecal carriage of Clostridioides difficile has been widely evaluated, but its prevalence across a wide range of clinical departments and related risk factors are not well described. The objectives of the PORTADIFF study were to evaluate the prevalence and identifying risk factors leading to asymptomatic carriage of both toxigenic and non-toxigenic C. difficile. METHODS: The PORTADIFF study was a 1-day prevalence study carried out in 10 different French hospitals. Adult patients, who agreed to participate, were included in this study and provided a fresh stool sample. C. difficile strains isolated from carriage were characterized by polymerase chain reaction (PCR) detection of tcdA, tcdB, cdtA and cdtB, and PCR ribotyping. RESULTS: In total, 721 patients were included in this study. The median age was 73 years (range 18-101 years) and the male/female ratio was 1.06. C. difficile (either toxigenic or non-toxigenic strains) was isolated from 79 (11%) patients; 42 (5.8%) strains were toxigenic. The prevalence rates of asymptomatic carriage ranged from 5% on surgical wards to 19% on long-term care wards. The main risk factors associated with asymptomatic carriage were antibiotic treatment within the preceding 3 months (81.8% vs 53.7%; P<0.01), hospitalization within the preceding 2 months (55.8% vs 33%; P<0.01), cumulative duration of hospital stay before study inclusion (mean 50.1 vs 34.5 days; P<0.047), and hospitalization on a ward with high global incidence of C. difficile infection. CONCLUSION: Eleven percent of hospitalized patients were asymptomatic carriers of toxigenic or non-toxigenic C. difficile, and may constitute a potential reservoir of C. difficile strains.

Inoculum effect of Enterobacterales co-expressing OXA-48 and CTX-M on the susceptibility to ceftazidime/avibactam and meropenem.

BACKGROUND: The treatment of infections caused by OXA-48/CTX-M-coproducing Enterobacterales may be based on new beta-lactam/beta-lactamase inhibitors, such as ceftazidime/avibactam (CZA), or on high dose of meropenem (MER). However, bacterial density at the infection site may vary widely, and the inoculum effect of such antimicrobial strategies has never been specifically investigated. To determine if CZA or MER susceptibilities are impacted by high inocula of Enterobacterales co-expressing both enzymes: OXA-48 like and CTX-M. METHODS: Determination of an inoculum effect was performed with a standard inoculum of 108 CFU/mL (0.5 McFarland) as recommended by EUCAST guidelines and compared to a twofold increase as well as a tenfold increase (1 McFarland and 5 McFarland respectively). RESULTS: Thirty-nine isolates of ceftazidime-resistant Enterobacterales were included of which 27 (70%) co-expressed OXA-48 + CTX-M-15, 6 (15%) OXA-48 + CTX-M-14, and 6 (15%) OXA-181 + CTX-M-15. The susceptibility to the CZA combination was preserved whatever the inoculum used. Regarding MER, 24 (61.5%) of the isolates were susceptible to MER with the standard inoculum, 19 (48.7%) with a twofold increase, and only 15 (38.5%) with a tenfold increase. CONCLUSION: We showed that in vitro inoculum effect was observed with meropenem but not with CZA for OXA-48- combined with CTX-M-producing Enterobacterales.

Suction drainage fluid culture during septic orthopaedic surgery, a retrospective study.

We evaluated the usefulness of suction drainage fluid culture after septic orthopaedic surgery to predict early surgical reintervention. We conducted a retrospective observational study, at the Groupe Hospitalier Paris Saint-Joseph between 2014 and 2019. All the patients undergoing septic orthopaedic surgery, with perioperative samples and a postoperative suction drainage device, were enrolled. We compared the group with positive or negative postoperative drainage fluid cultures, respectively, on surgical outcome. We included 246 patients. The drainage fluid culture was positive in 42.3% of the cases. Early surgical reintervention concerned 14.6% of the cases (n = 36), including 61.1% of patients with positive drainage fluid culture (n = 22/36). The risk factors associated with positive drainage fluid cultures were the debridement of the infected site (without orthopaedic device removal), an infection located at the spine, perioperative positive cultures to Staphylococcus aureus. The complete change of the orthopaedic device, and coagulase-negative staphylococci on the preoperative samples, was associated with negative drainage fluid cultures. Positive drainage fluid culture was predictive of early surgical reintervention, and coagulase-negative staphylococci in the preoperative samples and knee infection were predictive of surgical success. Postoperative drainage fluid cultures were predictive of early surgical reintervention. Randomized multicentric studies should be further conducted.

Epidemiology and clinical characteristics of Klebsiella spp. meningitis in France.

OBJECTIVES: To describe the epidemiology of Klebsiella spp. meningitis in France with respect to clinical and bacteriological data. METHODS: We performed a four-year multicenter, retrospective, observational study. The primary objective was to provide a clinical description of patients with Klebsiella spp. meningitis. Secondary objectives were to compare community-acquired meningitis and healthcare-associated meningitis and to analyze factors associated with mortality. RESULTS: We enrolled 131 patients with Klebsiella spp. meningitis. Eighty-two (62.6%) infections were reported following neurosurgery. Twenty-eight strains (21.4%) were resistant to third-generation cephalosporins (3GC). The median [IQR] cellularity was 980/mm3 [116-5550], the median protein level was 5.67 [1.62-9] g/L and the median CSF glucose level was 2.5 [0-3.4] mmol/L. The in-hospital mortality rate was 23.6%. Community-acquired meningitis isolates were more frequently susceptible to 3GC than isolates from healthcare-associated meningitis (89.2% versus 72%; P=0.04). Comorbidities reported for patients with community-acquired meningitis were mainly diabetes mellitus and liver cirrhosis. In multivariate analysis, focal neurological disorder at the time of diagnosis was the only factor associated with in-hospital mortality (P=0.01). CONCLUSIONS: Purulent meningitis caused by Klebsiella spp. needs to be considered in patients with community-acquired meningitis and preexisting conditions, as well as in case of meningitis following neurosurgical procedures.

Sparse Coding in Temporal Association Cortex Improves Complex Sound Discriminability.

The mouse auditory cortex is comprised of several auditory fields spanning the dorsoventral axis of the temporal lobe. The ventral most auditory field is the temporal association cortex (TeA), which remains largely unstudied. Using Neuropixels probes, we simultaneously recorded from primary auditory cortex (AUDp), secondary auditory cortex (AUDv), and TeA, characterizing neuronal responses to pure tones and frequency modulated (FM) sweeps in awake head-restrained female mice. As compared with AUDp and AUDv, single-unit (SU) responses to pure tones in TeA were sparser, delayed, and prolonged. Responses to FMs were also sparser. Population analysis showed that the sparser responses in TeA render it less sensitive to pure tones, yet more sensitive to FMs. When characterizing responses to pure tones under anesthesia, the distinct signature of TeA was changed considerably as compared with that in awake mice, implying that responses in TeA are strongly modulated by non-feedforward connections. Together, these findings provide a basic electrophysiological description of TeA as an integral part of sound processing along the cortical hierarchy.SIGNIFICANCE STATEMENT This is the first comprehensive characterization of the auditory responses in the awake mouse auditory temporal association cortex (TeA). The study provides the foundations for further investigation of TeA and its involvement in auditory learning, plasticity, auditory driven behaviors etc. The study was conducted using state of the art data collection tools, allowing for simultaneous recording from multiple cortical regions and numerous neurons.

Relative faecal abundance of extended-spectrum ß-lactamase-producing Enterobacterales and its impact on infections among intensive care unit patients: a pilot study.

This pilot prospective study assessed the association between the faecal relative abundance of extended-spectrum ß-lactamase-producing Enterobacterales (ESBL-PE) and the occurrence of ESBL-PE related infections. Twenty-four patients were included. The median ESBL relative abundance was 32.4%. The mean ESBL-PE relative abundance (ESBL-PE-RA) was more than five-fold higher in patients exposed during the last three months to antibiotics (P = 0.002). Furthermore, the mean ESBL relative abundance was more than two-fold higher in patients colonized with non-E. coli strains (P = 0.044). The mean ESBL-PE-RA was more than 10-fold higher for the concordant patients than for the discordant patients (59.1% vs 4.9%; P < 0.001).

Young adult-born neurons improve odor coding by mitral cells.

New neurons are continuously generated in the adult brain through a process called adult neurogenesis. This form of plasticity has been correlated with numerous behavioral and cognitive phenomena, but it remains unclear if and how adult-born neurons (abNs) contribute to mature neural circuits. We established a highly specific and efficient experimental system to target abNs for causal manipulations. Using this system with chemogenetics and imaging, we found that abNs effectively sharpen mitral cells (MCs) tuning and improve their power to discriminate among odors. The effects on MCs responses peaked when abNs were young and decreased as they matured. To explain the mechanism of our observations, we simulated the olfactory bulb circuit by modelling the incorporation of abNs into the circuit. We show that higher excitability and broad input connectivity, two well-characterized features of young neurons, underlie their unique ability to boost circuit computation.

Clinical evaluation of subcutaneous administration of cefepime.

OBJECTIVES: Cefepime is a fourth-generation cephalosporin active against Pseudomonas aeruginosa and most Enterobacteriaceae. Intravenous (IV) administration is the standard route of prescription. However, subcutaneous administration (SC) may represent an interesting alternative. We aimed to evaluate SC administration of cefepime versus the IV route in geriatric patients. PATIENTS AND METHODS: Multicenter retrospective analysis in patients treated with cefepime by SC route who underwent plasma concentration monitoring. RESULTS: Twelve patients were included in the SC group and matched to 12 patients in the IV group. The median and mean Cmin levels were 29.05mg/L [14.2-48.2]; 33.4mg/L (±21.8) in the SC group and 31.9mg/L [26.5-51.7]; 39.6mg/L (±27) (P=NS) in the IV group. No local SC administration-related complications were reported. No relapse was observed over six months of follow up. CONCLUSION: Subcutaneous use of cefepime seems to have the same clinical and microbiological effectiveness as parenteral administration.

Emergence of Ceftriaxone Resistance during a Case of Pneumococcal Meningitis with Fatal Evolution.

We report a case of a 62-year-old man treated for Streptococcus pneumoniae meningitis by ceftriaxone and dexamethasone. After neurological improvement, neurological degradation by vasculitis occurred, despite effective concentrations of ceftriaxone in the serum and cerebrospinal fluid (CSF). S. pneumoniae with increased MICs to third-generation-cephalosporins (3GC) was isolated from the ventricular fluid 10 days after the isolation of the first strain. Isolate analysis showed that a mutation in the penicillin-binding protein 2X (PBP2X) has occurred under treatment.

Infections caused by naturally AmpC-producing Enterobacteriaceae: Can we use third-generation cephalosporins? A narrative review.

The burden of antibiotic-resistant infections among Gram-negative bacteria is increasing. Resistance to third-generation cephalosporins (3GCs) in Enterobacteriaceae is mainly conferred by the acquisition of ß-lactamases or by deregulation of natural genetically-encoded ß-lactamase enzymes. Enterobacteriaceae such as Enterobacter spp., Serratia marcescens, Citrobacter freundii, Providencia spp. and Morganella morganii (ESCPM group) possess chromosomally-encoded inducible AmpC ß-lactamases. AmpC can be overproduced as a response to ß-lactam antibiotic exposure or by constitutive dysfunction of the AmpC regulation system. This overproduction can lead to the inactivation of 3GCs. Based on small clinical studies, international guidelines and expert recommendations suggest that 3GCs should be avoided as definitive therapy for infections caused by ESCPM group organisms. In this narrative review, we discuss the published literature and evaluate the risk related to 3GC use in the case of documented ESCPM infection.

Clinical impact of rapid bacterial identification by MALDI-TOF MS combined with the bêta-LACTA™ test on early antibiotic adaptation by an antimicrobial stewardship team in bloodstream infections.

BACKGROUND: Bloodstream infections (BSI) can potentially be life-threatening infections and are associated with a high crude mortality, moreover with an inappropriate first-line antibiotic therapy. Bacterial resistance is more and more frequently observed. New strategies of BSI management are urgently needed. MATERIALS AND METHODS: During an 18-months period, we prospectively evaluated the clinical impact of rapid bacterial identification by MALDI-TOF MS technology combined with an antimicrobial stewardship team (AST) intervention. Furthermore, during an 8-months period, we combined this strategy with the rapid detection of third-generation cephalosporin (3GC) resistance by the Bêta-LACTA™ test (BLT) directly on blood cultures. We then evaluated the theoretical impact of BLT on antibiotic therapy adaptation and establishment of infection control measures. RESULTS: A total of 335 blood cultures were enrolled during the study. MALDI-TOF MS gave accurate identification for 301 blood cultures (89,8%) and led to early antibiotic therapy adaptation for 73 episodes (21.8%). BLT was performed on 141 blood cultures, revealing 28 3GC-resistant bacteria (19.9%). Twenty-one patients (75%) received a non-adapted first-line treatment. The antibiotic therapy adaptation was delayed by 28.1 hours and the establishment of infection control measures by 35 hours with antimicrobial susceptibility testing, compared to the theoretical adaptation with BLT result. CONCLUSIONS: These tools can be included in a strategy of bloodstream infections management for a better patient care, optimizing and saving the use of antibiotics, notably carbapenems as well as diminishing the spread of multi-drug resistant bacteria by applying rapidly infection control measures.

Clinical diagnostic and therapeutic aspects of 221 consecutive anorectal Chlamydia trachomatis and Neisseria gonorrhoeae sexually transmitted infections among men who have sex with men.

OBJECTIVES: Proctitis caused by Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are known as sexually transmitted infections (STI). This study describes their clinical, diagnostic and therapeutic aspects. METHODS: Between 01/2013-03/2015, all MSM consulting for proctitis at proctology Institute-Saint-Joseph's Hospital, Paris, were included. Demographic, past-medical history, STI status and medical treatment were collected. Detection of CT/NG was performed by Transcription-Mediated Amplification (TMA) and antimicrobial susceptibilities for Ng by agar diffusion method. RESULTS: On 441 rectal samples collected, 221 (50.1%) were positive: 109 Ct (49.3%), 70 Ng (31.7%), 42 positive for both etiologies (19%). Among Ng infections, no resistance was detected to azithromycin and ceftriaxone. However, 84 strains (43.2%) were resistant to fluoroquinolones. More than one episode was diagnosed for 10 (5.1%) and 12 (6.2%) patients with CT and NG infections respectively. Anal abscesses were found for 27 (13.9%) patients, and 14 (7.2%) of them underwent surgery for anal fistula. CONCLUSIONS: The prevalence of CT/NG anorectal infections described is high on symptomatic patients, and a significant level of abscess was reported. These results confirm the interest of the association of recommended antibiotics excluding quinolones. Prospective studies would be relevant on complicated forms of anorectal infections.

Carriage of ESBL-producing Enterobacteriaceae in French hospitals: the PORTABLSE study.

BACKGROUND: Currently, contact precautions are recommended for patients colonized or infected with extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE). Recent studies have challenged this strategy. This study aimed to assess the rate of ESBL-PE faecal carriage among hospitalized patients according to type of hospital ward, and to identify risk factors associated with carriage. METHODS: A point prevalence study was conducted in five different types of hospital ward [medical, surgical, intensive care unit (ICU), after care and rehabilitation, and geriatric] in eight French hospitals. All patients included in the study provided a fresh stool sample. RESULTS: In total, 554 patients were included in the study, with a median age of 73 years (range 60-82 years). The overall faecal carriage rate of ESBL-PE was 17.7%. The most frequently encountered species among ESBL-PE was Escherichia coli (71.4%), followed by Klebsiella pneumoniae (14.3%). Risk factors associated with ESBL-PE faecal carriage on univariate analysis were: living in the Paris region (P<0.01) and hospitalization on a geriatric ward (P<0.01). Interestingly, the cumulative duration of hospital stay before screening was not associated with a significantly higher prevalence of ESBL-PE carriage, regardless of ward type. The ESBL-PE colonization rate was much higher for patients hospitalized on geriatric wards (28.1%) and ICUs (21.7%) compared with those for patients hospitalized on surgical wards (14.8%), medical wards (12.8%) or aftercare and rehabilitation (11.2%). CONCLUSION: The overall prevalence of ESBL-PE faecal carriage was 17.7%, with only 21% of patients identified previously as carriers. The delay between admission and screening was not associated with an increase in ESBL-PE faecal carriage.

Implementation of Alere i Influenza A & B point of care test for the diagnosis of influenza in an ED.

STUDY OBJECTIVE: This study aimed to evaluate the impact of implementing rapid point-of-care testing (POCT) with the Alere i Influenza A & B in an emergency department (ED) during an influenza epidemic. METHODS: Direct nasal swabs were prospectively collected following the physical examination of patients aged >18years who presented to the ED of a tertiary hospital in France with influenza-like illness (ILI) symptoms (N=301) between February 1st and March 31st, 2016, which coincided with an influenza epidemic. Laboratory-based testing (standard of care) was used to obtain a diagnosis in February 2016 (pre-POCT cohort) and positive results were confirmed using polymerase chain reaction. The primary endpoint was patient time in the ED. RESULTS: A total of 169 and 132 patients participated in the pre-POCT phase and POCT phase respectively. A significantly higher proportion of patients received a positive diagnosis in the POCT cohort compared with the pre-POCT cohort (31% versus 5.3%, P<0.01). Mean time spent in the ED and hospitalization rate were significantly lower in the POCT cohort (6.06h versus 4.15h, P=0.03, and 44.4% versus 9.7%, P=0.02, respectively). Despite similar rates in the prescription of antibiotics and antiviral therapies, the proportion of patients who were referred for additional tests was significantly lower in the POCT cohort (78.1% versus 62.1%, P=0.003, and 80.5% versus 63.6%, P=0.01, respectively). CONCLUSIONS: The Alere i Influenza A & B POCT reduced the length of stay in ED, the hospitalization rates, and the number of additional diagnostic tests compared with standard of care testing.

Alterations of microRNAs throughout the malignant evolution of cutaneous squamous cell carcinoma: the role of miR-497 in epithelial to mesenchymal transition of keratinocytes.

Skin carcinogenesis is known to be a multi-step process with several stages along its malignant evolution. We hypothesized that transformation of normal epidermis to cutaneous squamous cell carcinoma (cSCC) is causally linked to alterations in microRNAs (miRNA) expression. For this end we decided to evaluate their alterations in the pathologic states ending in cSCC. Total RNA was extracted from formalin fixed paraffin embedded biopsies of five stages along the malignant evolution of keratinocytes towards cSCC: Normal epidermis, solar elastosis, actinic keratosis KIN1-2, advanced actinic keratosis KIN3 and well-differentiated cSCC. Next-generation small RNA sequencing was performed. We found that 18 miRNAs are overexpressed and 28 miRNAs are underexpressed in cSCC compared to normal epidermis. miR-424, miR-320, miR-222 and miR-15a showed the highest fold change among the overexpressed miRNAs. And miR-100, miR-101 and miR-497 showed the highest fold change among the underexpressed miRNAs. Heat map of hierarchical clustering analysis of significantly changed miRNAs and principle component analysis disclosed that the most prominent change in miRNAs expression occurred in the switch from 'early' stages; normal epidermis, solar elastosis and early actinic keratosis to the 'late' stages of epidermal carcinogenesis; late actinic keratosis and cSCC. We found several miRNAs with 'stage specific' alterations while others display a clear 'gradual', either progressive increase or decrease in expression along the malignant evolution of keratinocytes. The observed alterations focused in miRNAs involved in the regulation of AKT/mTOR or in those involved in epithelial to mesenchymal transition. We chose to concentrate on the evaluation of the molecular role of miR-497. We found that it induces reversion of epithelial to mesenchymal transition. We proved that SERPINE-1 is its biochemical target. The present study allows us to further study the pathways that are regulated by miRNAs along the malignant evolution of keratinocytes towards cSCC.

Infections caused by Tissierella praeacuta: A report of two cases and literature review.

Herein we report two cases of infections caused by Tissierella praeacuta and a review of the literature. The first case was a septic pseudarthrosis of the left femur after multiple fractures. Two per-operative samples were positive with T. praeacuta. The patient was successfully treated by piperacillin - tazobactam and metronidazole. The second case was a bacteremia in a patient suffering from pyonephrosis and a hepatic abscess. The treatment was meropenem. No relapses were observed in both cases. Identification of the strains using MALDI-TOF coupled to mass spectrometry (MS) (Beckman coulter, France) was inconclusive in the two cases. Identification by 16S rRNA sequencing was then performed. This bacterium was susceptible to beta-lactams, chloramphenicol, rifampicine and metronidazole.

Prospective evaluation of the Alere i Influenza A&B nucleic acid amplification versus Xpert Flu/RSV.

The rapid and accurate detection of influenza virus in respiratory specimens is required for optimal management of patients with acute respiratory infections. Because of the variability of the symptoms and the numerous other causes of influenza-like illness, the diagnosis of influenza cannot be made on the basis of clinical criteria alone. Thus, rapid influenza diagnostic tests have been developed such as the Alere i Influenza A&B isothermal nucleic acid assay. We prospectively evaluated the performance of the Alere i Influenza A&B assay in comparison with our routine Xpert Flu/RSV assay. Positive samples were subtyped according to the protocol from the National Influenza Center (Paris, France). A total of 96 respiratory nasal swab samples were analyzed: with both methods, 38 were positive and 56 were negative. Samples were prospectively collected from January 20 to April 8, 2015, from patient (86 adult and 10 pediatric patients) presenting with an influenza-like illness through the French influenza season. In comparison with the Xpert Flu/RSV assay, the overall sensitivity and specificity of the Alere i Influenza A&B assay were 95% and 100%, respectively. Our results indicate that the Alere i Influenza A&B assay has a good overall analytical performance and a high degree of concordance with the PCR-based Xpert Flu/RSV assay. The Alere i Influenza A&B isothermal nucleic acid amplification test is a powerful tool for influenza detection due to its high sensitivity and specificity as well as its ability to generate results within 15min.