Outbreak of carbapenemase-producing Citrobacter farmeri in an intensive care haematology department linked to a persistent wastewater reservoir in one hospital room, France, 2019 to 2022.

In 2019-2022, a prolonged outbreak of oxacillinase (OXA)-48-producing Citrobacter farmeri due to a persistent environmental contamination, occurred in our haematology intensive care unit. In April 2019, we isolated OXA-48-producing C. farmeri from rectal samples of two patients in weekly screenings. The cases had stayed in the same hospital room but 4 months apart. We screened five patients who had stayed in this room between the two cases and identified a third case. Over the following 3 years, five other cases were detected, the last case in September 2022. In total, eight cases were detected: seven colonised with the bacterium and one infected with a lethal outcome. All cases stayed in the same hospital room. We detected OXA-48-producing C. farmeri from a shower, washbasin drains and wastewater drainage of the bathroom of the hospital room. Molecular typing confirmed that all C. farmeri isolates from the environment and the cases were indistinguishable. Despite bundle measures to control the outbreak, the bacterium persisted in the system, which resulted in transmission to new patients. A design defect in the placement of wastewater drains contributed to the persistence and proliferation of the bacterium. The room was closed after the last case and the bathroom rebuilt.

Scale-Up of Academic Mesenchymal Stromal Cell Production.

BACKGROUND: Many clinical trials have reported the use of mesenchymal stromal cells (MSCs) following the indication of severe SARS-CoV-2 infection. However, in the COVID19 pandemic context, academic laboratories had to adapt a production process to obtain MSCs in a very short time. Production processes, especially freezing/thawing cycles, or culture medium have impacts on MSC properties. We evaluated the impact of an intermediate cryopreservation state during MSC culture to increase production yields. METHODS: Seven Wharton's jelly (WJ)-MSC batches generated from seven different umbilical cords with only one cryopreservation step and 13 WJ-MSC batches produced with intermediate freezing were formed according to good manufacturing practices. The identity (phenotype and clonogenic capacities), safety (karyotype, telomerase activity, sterility, and donor qualification), and functionality (viability, mixed lymphocyte reaction) were analyzed. RESULTS: No significant differences between MSC production processes were observed, except for the clonogenic capacity, which was decreased, although it always remained above our specifications. CONCLUSIONS: Intermediate cryopreservation allows an increase in the production yield and has little impact on the basic characteristics of MSCs.

Usefulness of procalcitonin at admission as a risk-stratifying biomarker for 50-day in-hospital mortality among patients with community-acquired bloodstream infection: an observational cohort study.

PURPOSE: To assess the association between plasma procalcitonin concentration at hospital admission and the risk of 50-day in-hospital mortality among patients with community-acquired bloodstream infections. METHODS: We carried out a retrospective, observational cohort study with all consecutive patients with bacteriologically confirmed community-acquired bloodstream infections hospitalized between 2006 and 2012. We aimed to assess the association between plasma procalcitonin at admission and 50-day in-hospital mortality. Patients were included in the analysis if they had undergone a blood culture test within 48 hours of hospitalization with a concomitant procalcitonin assay (time < 12 hours between the two tests). Inclusion in the study began on the day of hospital admission, and each patient was followed until death, discharge from the hospital, or last known follow-up in the 50 days following hospital admission. The endpoint was the occurrence of all-cause in-hospital mortality during the 50 days following hospital admission. RESULTS: During the 7-year study period, 1593 patients were admitted to one of the healthcare facilities of the University Hospital of Nancy from home or through the emergency department and had positive blood cultures and concomitant procalcitonin assays. Among the patients, 452 met the selection criteria and were analyzed. In ROC analysis, procalcitonin at baseline was significantly associated with 50-day in-hospital mortality, with an optimal threshold > 4.24 ng/mL. A baseline procalcitonin > 4.24 ng/mL was independently associated with an increased risk of in-hospital mortality (multivariable logistic regression: odds ratio, 2.58; 95% CI, 1.57-4.25; P = 0.0002; Cox proportional hazard regression: hazard ratio, 2.01; 95% CI, 1.30-3.11; P = 0.002). In sensitivity analyses, baseline procalcitonin quartiles were independently associated with 50-day in-hospital mortality (multivariable logistic regression: odds ratio, 1.47; 95% CI, 1.17-1.85; P = 0.001; Cox proportional hazard regression: hazard ratio, 1.31; 95% CI, 1.07-1.60; P = 0.008). The independent associations between baseline procalcitonin and the risk of 50-day in-hospital mortality were maintained after adjusting for C-reactive protein and sepsis status at admission. CONCLUSION: Our data provide the first evidence of the usefulness of plasma procalcitonin at admission as a risk-stratifying biomarker for predicting 50-day in-hospital mortality among patients with community-acquired bloodstream infections.

An upgraded version of carbapenem inactivation method to detect Bacteroides fragilis carbapenemase.

An increase of carbapenemase-producing Bacteroides fragilis infections is observed. To detect such a resistance in B. fragilis, several tests exist that are expensive or show poor sensitivity and specificity. Therefore, we upgraded the Anaerobic Carbapenem Inactivation Method (Ana-CIM) to easily screen for carbapenemase-producing B. fragilis. The presence of carbapenemase cfiA gene was identified in 50 B. fragilis isolates by PCR. We modified the Ana-CIM by (1) increasing the bacterial inoculum, and (2) measuring the differences in diameter between the negative control and the testing disc. We correctly classified the cfiA-negative and positive isolates and could define a cut-off of positivity at 2 mm. Our modified Ana-CIM allowed to correctly discriminate the 31 cfiA-positive with meropenem MICs ranging from 1 to > 32 µg/mL. We anticipate that our modified Ana-CIM could be used in most clinical laboratories to easily screen for carbapenemase-producing B. fragilis, even at low levels.

Evaluating antibiotic stewardship and healthcare-associated infections surveillance assisted by computer: protocol for an interrupted time series study.

INTRODUCTION: Antibiotic resistance is one of the most pressing health threats that mankind faces now and in the coming decades. Antibiotic resistance leads to longer hospital stays, higher medical costs and increased mortality. In order to tackle antibiotic resistance, we will implement in our tertiary care university hospital a computerised-decision support system (CDSS) facilitating antibiotic stewardship and an electronic surveillance software (ESS) facilitating infection prevention and control activities. We describe the protocol to evaluate the impact of the CDSS/ESS combination in adult inpatients. METHODS AND ANALYSIS: We conduct a pragmatic, prospective, single-centre, before-after uncontrolled study with an interrupted time-series analysis 12 months before and 12 months after the introduction of the CDSS for antibiotic stewardship (APSS) and ESS for infection surveillance (ZINC). APSS and ZINC will assist, respectively, the antibiotic stewardship and the infection prevention and control teams of Nancy University Hospital (France). We will evaluate the impact of the CDSS/ESS on the antibiotic use in adult (≥18 years) inpatients (hospitalised ≥48 hours). The primary outcome is the prescription rate by all healthcare professionals from the hospital of all systemic antibiotics expressed in defined daily doses/1000 patients/month. Concurrently, we will assess the safety of the intervention, its impact on the appropriateness of antibiotic prescriptions and on additional precautions (isolation precautions) as recommended in guidelines, and on bacterial epidemiology (multidrug-resistant bacteria and Clostridioides difficile infections) in the hospital. Finally, we will evaluate the users' satisfaction and the cost of this intervention from the hospital perspective. ETHICS AND DISSEMINATION: The protocol has been approved by the Ethics Committee of Nancy University Hospital and registered on the ClinicalTrials platform. Results will be disseminated through conferences' presentations and publications in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT04976829.

Accuracy of procalcitonin for diagnosing peripheral blood culture contamination among patients with positive blood culture for potential contaminants.

PURPOSE: Blood culture contamination is still a frequently observed event and may lead to unnecessary antibiotic prescriptions and additional hazards and costs. However, in patients hospitalized in tertiary care, true bacteremias for pathogens that are classically considered as contaminants can be observed. We assessed the diagnostic accuracy of procalcitonin for differentiating blood culture contamination from bacteremia in patients with positive blood cultures for potential contaminants. METHODS: We carried out a retrospective, cross-sectional, observational study on consecutive patients hospitalized between January 2016 and May 2019 at the University Hospital of Nancy and who had a positive peripheral blood culture for a pathogen classically considered as a potential contaminant. RESULTS: During the study period, 156 patients were screened, and 154 were retained in the analysis. Among the variables that were significantly associated with a diagnosis of blood culture contamination in univariate analyses, four were maintained in multivariate logistic regression analysis: a number of positive blood culture bottles ≤ 2 (OR 23.76; 95% CI 1.94-291.12; P = 0.01), procalcitonin < 0.1 ng/mL (OR 14.88; 95% CI 1.62-136.47; P = 0.02), non-infection-related admission (OR 13.00; 95% CI 2.17-77.73; P = 0.005), and a percentage of positive blood culture bottles ≤ 25% (OR 12.15; 95% CI 2.02-73.15; P = 0.006). CONCLUSIONS: These data provide new evidence on the usefulness of plasma procalcitonin as a reliable diagnostic biomarker in the diagnostic algorithm of peripheral blood culture contamination among patients hospitalized in tertiary care. CLINICAL TRIAL: ClinicalTrials.gov #NCT04573894.

Clostridium haemolyticum Infection: A Cause of Hemolytic Anemia in a Patient with Bone Marrow Necrosis.

Clostridium haemolyticum is a sporulating Gram-positive anaerobic rod that is considered to be one of the most fastidious and oxygen-sensitive anaerobes. It is a well-known animal pathogen and the cause of bacillary hemoglobinuria primarily in cattle. To date, human infections caused by C. haemolyticum have been reported in three patients with malignant underlying diseases. We present herein the case of a 30-year-old obese woman with no significant past medical history who developed bacteremia caused by C. haemolyticum with massive intravascular hemolysis associated with bone marrow necrosis and acute renal failure. Because of subculture failure, the diagnosis was made on the basis of 16S rDNA sequencing and next-generation sequencing. The patient, who had been afebrile for 20 days after a 17-day-course of antibiotics, experienced a second bacteremic episode caused by C. haemolyticum. After having been successfully treated for 42 days with clindamycin and amoxicillin-clavulanic acid, the patient developed acute myeloid leukemia as a result of bone marrow regeneration. Although uncommon in humans, infections caused by C. haemolyticum are severe and should be considered in a febrile patient who has severe hemolytic anemia. This case also highlights the importance of using molecular techniques for the identification of this fastidious anaerobic organism.

Surface Properties of Parabacteroides distasonis and Impacts of Stress-Induced Molecules on Its Surface Adhesion and Biofilm Formation Capacities.

The gut microbiota is a complex and dynamic ecosystem whose balance and homeostasis are essential to the host's well-being and whose composition can be critically affected by various factors, including host stress. Parabacteroides distasonis causes well-known beneficial roles for its host, but is negatively impacted by stress. However, the mechanisms explaining its maintenance in the gut have not yet been explored, in particular its capacities to adhere onto (bio)surfaces, form biofilms and the way its physicochemical surface properties are affected by stressing conditions. In this paper, we reported adhesion and biofilm formation capacities of 14 unrelated strains of P. distasonis using a steam-based washing procedure, and the electrokinetic features of its surface. Results evidenced an important inter-strain variability for all experiments including the response to stress hormones. In fact, stress-induced molecules significantly impact P. distasonis adhesion and biofilm formation capacities in 35% and 23% of assays, respectively. This study not only provides basic data on the adhesion and biofilm formation capacities of P. distasonis to abiotic substrates but also paves the way for further research on how stress-molecules could be implicated in P. distasonis maintenance within the gut microbiota, which is a prerequisite for designing efficient solutions to optimize its survival within gut environment.

A New Look at the Genus Solobacterium: A Retrospective Analysis of Twenty-Seven Cases of Infection Involving S. moorei and a Review of Sequence Databases and the Literature.

Solobacterium moorei is an anaerobic Gram-positive bacillus present within the oral and the intestinal microbiota that has rarely been described in human infections. Besides its role in halitosis and oral infections, S. moorei is considered to be an opportunistic pathogen causing mainly bloodstream and surgical wound infections. We performed a retrospective study of 27 cases of infections involving S. moorei in two French university hospitals between 2006 and 2021 with the aim of increasing our knowledge of this unrecognized opportunistic pathogen. We also reviewed all the data available in the literature and in genetic and metagenomic sequence databases. In addition to previously reported infections, S. moorei had been isolated from various sites and involved in intra-abdominal, osteoarticular, and cerebral infections more rarely or not previously reported. Although mostly involved in polymicrobial infections, in seven cases, it was the only pathogen recovered. Not included in all mass spectrometry databases, its identification can require 16S rRNA gene sequencing. High susceptibility to antibiotics (apart from rifampicin, moxifloxacin, and clindamycin; 91.3%, 11.8%, and 4.3% of resistant strains, respectively) has been noted. Our global search strategy revealed S. moorei to be human-associated, widely distributed in the human microbiota, including the vaginal and skin microbiota, which may be other sources for infection in addition to the oral and gut microbiota.

Impact of a Model Used to Simulate Chronic Socio-Environmental Stressors Encountered during Spaceflight on Murine Intestinal Microbiota.

During deep-space travels, crewmembers face various physical and psychosocial stressors that could alter gut microbiota composition. Since it is well known that intestinal dysbiosis is involved in the onset or exacerbation of several disorders, the aim of this study was to evaluate changes in intestinal microbiota in a murine model used to mimic chronic psychosocial stressors encountered during a long-term space mission. We demonstrate that 3 weeks of exposure to this model (called CUMS for Chronic Unpredictable Mild Stress) induce significant change in intracaecal ß-diversity characterized by an important increase of the Firmicutes/Bacteroidetes ratio. These alterations are associated with a decrease of Porphyromonadaceae, particularly of the genus Barnesiella, a major member of gut microbiota in mice and humans where it is described as having protective properties. These results raise the question of the impact of stress-induced decrease of beneficial taxa, support recent data deduced from in-flight experimentations and other ground-based models, and emphasize the critical need for further studies exploring the impact of spaceflight on intestinal microbiota in order to propose strategies to countermeasure spaceflight-associated dysbiosis and its consequences on health.

Selective reporting of antibiotic susceptibility testing results: a promising antibiotic stewardship tool.

Introduction: Selective reporting of antibiotic susceptibility testing (AST) results is a potentially interesting tool for antibiotic stewardship. It consists of performing AST according to usual practices, but the results are reported to the prescriber only for a few antibiotics (i.e. first-line agents) or not reported at all when colonization is likely.Areas covered: We retrieved 20 studies exploring the impact of selective reporting. Overall, selective reporting is able to influence antibiotic use, both discouraging prescription in case of colonization, and promoting the selection of narrow-spectrum agents. Most studies concerned urine samples. Evidence on the impact on antibiotic resistance is insufficient. Unintended consequences were not observed, but evidence on this topic is scarce. Selective reporting is well implemented in a few countries, and a huge heterogeneity of practices exists.Expert opinion: Evidence shows that selective reporting can help reducing inappropriate and unnecessary antibiotic prescriptions. Uncomplicated urinary tract infections are probably the best initial target, both in hospital and community settings, but other non-severe infections can be a suitable option. The implementation of selective reporting should be promoted by the scientific community, with detailed practical guidelines, and its impact should be further assessed in large interventional studies.

Hypergravity disrupts murine intestinal microbiota.

During spaceflight, organisms are subjected to various physical stressors including modification of gravity (G) that, associated with lifestyle, could lead to impaired immunity, intestinal dysbiosis and thus potentially predispose astronauts to illness. Whether space travel affects microbiota homeostasis has not been thoroughly investigated. The aim of this study was to evaluate changes in intestinal microbiota and mucosa in a ground-based murine model consisting in a 21-days confinement of mice in a centrifuge running at 2 or 3G. Results revealed an increased α-diversity and a significant change in intracaecal ß-diversity observed only at 3G, with profiles characterized by a decrease of the Firmicutes/Bacteroidetes ratio. Compared to 1G microbiota, 12.1% of the taxa were significantly impacted in 3G microbiota, most of them (78%) being enriched. This study shows a G-level-dependent disruption of intracaecal microbiota, without alteration of mucosal integrity. These first data reinforce those recently obtained with in-flight experimentations or microgravity models, and emphasize the critical need for further studies exploring the impact of spaceflight on intestinal microbiota in order to optimize long-term space travel conditions.

A sequence database analysis of 5-nitroimidazole reductase and related proteins to expand knowledge on enzymes responsible for metronidazole inactivation.

nim genes are associated, in combination with other factors, with acquired resistance to metronidazole (MTZ) in anaerobes. These genes encode 5-nitroimidazole reductase enzymes (Nim proteins) that reduce MTZ into an inactive compound. Eleven variants (nimA to nimK) are currently described in anaerobes with either a chromosomal or a plasmidic location. Mostly found in members of the Bacteroides fragilis group, nim genes were demonstrated in anaerobic taxa outside the phylum Bacteroidetes. Nitroreductase enzymes, weakly related to those found in Bacteroidetes but associated with MTZ inactivation, were also characterized both in anaerobic and non-anaerobic taxa. Published data only poorly reflect the growing number of data from cultivation-independent studies and sequences deposited in databases. Considering this limitation, we performed herein an analysis of the sequence databases with the aim to increase the current knowledge on Nim protein distribution and diversity. The 250 sequences the most closely related to the 11 known Nim proteins were selected and analyzed for identity level and phylogenetic relationships with Nim A to K proteins. The analysis revealed a larger diversity of anaerobic species harboring known Nim proteins than that currently described in the literature. Putative new variants of known Nim proteins and novel Nim proteins were found. In addition, nitroreductase proteins and homologs related to the pyridoxamine 5'-phosphate oxidase family were found in highly diverse anaerobic and aerobic taxa of human but also animal and environmental origin. On the other hand, we found a very low number of sequences recovered from metagenomic studies. Considering the different databases currently available to identify antimicrobial resistance genes (ARG) among metagenomic sequences, we hypothesized that this may, at least in part, be related to the incompleteness of ARG databases because none of them includes the 11 described nim genes at the time of our study. Both the wide distribution of proteins with potential MTZ inactivation ability within the bacterial world and a wider diversity of Nim determinants than expected from published literature is underlined in this sequence database analysis.

Metronidazole resistance and nim genes in anaerobes: A review.

Acquired resistance to metronidazole, a 5-nitroimidazole drug largely used worldwide in the empirical treatment of infections caused by anaerobes, is worrisome, especially since such resistance has been described in multidrug-resistant anaerobic bacteria. In anaerobes, acquired resistance to metronidazole may be due to a combination of various and complex mechanisms. Among them, nim genes, possibly located on mobile genetic elements, encode nitro-imidazole-reductases responsible for drug inactivation. Since the first description of Nim proteins about 25 years ago, more nim genes have been identified; currently 11 nim genes are known (nimA to nimK). Mostly reported in Bacteroides fragilis group isolates, nim genes are now described in a variety of anaerobic genera encompassing the 4 main groups of Gram-negative and Gram-positive bacilli and cocci, with variable expression ranging from phenotypically silent to low-level or high-level resistance to metronidazole. This review describes the trends of metronidazole resistance rates among anaerobes over the past 20 years and summarizes current knowledge on mechanisms involved in this resistance. It also provides an update on the phylogenetic and geographical distribution of nim genes, the mechanisms involved in their expression and regulation, and their role in metronidazole resistance.

Evaluation of the Vitek MS and the MALDI Biotyper systems for the identification of less commonly isolated but clinically relevant anaerobes and facultative anaerobes.

The Vitek MS and MALDI Biotyper systems were evaluated for the identification of 221 strains belonging to less commonly isolated anaerobes and facultative anaerobes. Identifications were performed using direct deposit (DD), on-target extraction (FA) and full extraction (EXT). After DD, 29.9% and 34.3% of Gram-positive isolates (n = 137) as well as 36.9% and 58.3% of Gram-negative isolates (n = 84) were identified at the species-level with the Vitek-MS and the Biotyper system, respectively. The rates of correct species identification with the Biotyper system were significantly increased after extraction for Gram-positive isolates (FA: 75.2%, EXT: 78.1%) and Gram-negative isolates (FA: 72.6%, EXT: 78.6%). Extraction permitted to achieve higher correct species identification rates only for Gram-positive isolates (FA: 35.8%, EXT: 36.5%) with the Vitek MS. Thus, the accuracy of both systems needs to be further increased by expanding the databases. In the meantime, we recommend using a preliminary extraction step to obtain reliable results at least for the identification of Gram positive anaerobic bacteria with both systems.

Francisella tularensis endocarditis: two case reports and a literature review.

We report the first two cases of infective endocarditis caused by Francisella tularensis in Europe (two cases have previously been reported outside Europe). We suggest clinicians should consider tularemia as a possible diagnosis in endemic regions in cases of culture-negative endocarditis.

Rapid bench identification of methicillin-sensitive and methicillin-resistant Staphylococcus aureus: A multicenter comparative evaluation of Alere PBP2a Culture Colony Test (Alere) Versus Slidex MRSA detection (bioMérieux).

Using 30 clinical isolates of Staphylococcus aureus representative of the most prevalent clones circulating in France, the performance of the Alere™ PBP2a Culture Colony Test (CCT) and the Slidex(®) MRSA detection kit (SMD) were compared in 5 different labs. CCT demonstrated better performance and was easier to conduct in routine.