Clinical and genomic features of a Listeria monocytogenes fatal case of meningitis in Madagascar.

Listeriosis constitutes a significant public health threat due to its high mortality rate. This study investigates the microbiological and genomic characteristics of Listeria monocytogenes isolates in Madagascar, where listeriosis is a notifiable disease. The analysis focuses on a fatal case of meningeal listeriosis in a 12-year-old child. Genomic analysis revealed a novel cgMLST type (L2-SL8-ST8-CT11697; CC8, serogroup Iia) with typical virulence and antibiotic resistance profiles. These isolates, unique to Madagascar, formed an independent clade in the phylogenetic tree. This study presents the first genomic characterization of Listeria isolates in Madagascar, highlighting the necessity of ongoing genomic surveillance to strengthen listeriosis prevention and control strategies in the region.

Liver involvement in dengue: A systematic review.

Liver involvement is an unusual yet frequently overlooked dengue complication. Pivotal for an efficient clinical management, the early diagnosis of dengue-associated liver involvement relies on an accurate description of its clinical and biological characteristics, its prognosis factors, its association with severe dengue and its clinical management. We conducted a systematic review by searching PubMed and Web of Science databases for original case reports, cohort and cross-sectional studies reporting the clinical and/or biological features of dengue-associated liver involvement. The study was registered in PROSPERO (CRD42021262657). Of the 2552 articles identified, 167 were included. Dengue-associated liver involvement was characterised by clinical features including abdominal pain, hepatomegaly, jaundice, nausea/vomiting, and an echogenic liver exhibiting hepatocellular necrosis and minimal inflammation. Elevated Aspartate Aminotransferase and Alanine Aminotransferase but also elevated bilirubin, Alkaline Phosphatase, gamma-glutamyl transferase, increased International Normalised Ratio, creatinine and creatine kinase, lower albumin and prolonged prothrombin and activated partial thromboplastin time were prevalent in dengue-associated liver involvement. Cardiovascular and haematological systems were frequently affected, translating in a strong association with severe dengue. Liver involvement was more common in males and older adults. It was associated with dengue virus serotype-2 and secondary infections. Early paracetamol intake increased the risk of liver involvement, which clinical management was mostly conservative. In conclusion, this systematic review demonstrates that early monitoring of transaminases, clinical assessment, and ultrasound examination allow an efficient diagnosis of dengue-associated liver involvement, enabling the early identification and management of severe dengue.

Listeria monocytogenes-associated spontaneous bacterial peritonitis in France: a nationwide observational study of 208 cases.

BACKGROUND: Listeriosis is a foodborne infection caused by Listeria monocytogenes. Three main forms of listeriosis are well characterised, but little is known about L monocytogenes-associated spontaneous bacterial peritonitis. We used data from the French national surveillance of listeriosis to perform a nationwide retrospective study. METHODS: All patients with L monocytogenes isolated by culture from a peritoneal fluid sample in France between April 1, 1993, and Dec 31, 2022, were included. Individuals for whom bacterial peritonitis was not confirmed and those who also had another type of invasive listeriosis were excluded. A standardised checklist was used to collect demographic, clinical, and biological data as well as antibiotic treatment and follow-up data. The primary outcome was to determine the characteristics of L monocytogenes-associated spontaneous bacterial peritonitis. We did descriptive analyses and assessed risk factors for 1-month mortality using an exploratory multivariable Cox model analysis. FINDINGS: Among the 8768 L monocytogenes cases reported, 208 (2%) were patients with L monocytogenes-associated spontaneous bacterial peritonitis. Mean age was 65 years (SD 13), 50 (24%) of 208 patients were female, and 158 (76%) were male (no data on race or ethnicity were available). 200 (98%) of 205 patients with L monocytogenes-associated spontaneous bacterial peritonitis with available data had immunosuppressive comorbidities, including cirrhosis (148 [74%] of 201 with available data), ongoing alcoholism (58 [62%] of 94), and ongoing neoplasia (60 [31%] of 195). Causes of ascites included cirrhosis (146 [70%] of 208), ongoing neoplasia (26 [13%]), end-stage heart failure (13 [6%]), and peritoneal dialysis (11 [5%]). Among those with available data, presentation was pauci-symptomatic and non-specific; only 67 (50%) of 135 patients presented with fever, 49 (37%) of 132 with abdominal pain, and 27 (21%) of 129 with diarrhoea. 61 (29%) of 208 patients were dead at 1 month, 92 (44%) were dead at 3 months, and 109 (52%) were dead at 6 months after diagnosis. Ongoing neoplasia (hazard ratio 2·42 [95% CI 1·05-5·56]; p=0·039), septic shock (8·03 [2·66-24·02]; p=0·0021), and high blood leukocyte count (1·05 [1·00-1·09]; p=0·045) were independently associated with 1-month mortality. INTERPRETATION: Despite the non-specific and mild presentation of L monocytogenes-associated spontaneous bacterial peritonitis, the outcome is poor and similar to that of neurolisteriosis, and so identification of L monocytogenes in ascitic fluid samples requires urgent parenteral amoxicillin-based treatment to avoid a fatal outcome. FUNDING: Institut Pasteur, Inserm, and French Public Health Agency. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

Phenotypic and genotypic antimicrobial resistance of Listeria monocytogenes: an observational study in France.

Background: Large-scale studies are needed to clarify antimicrobial resistance in the foodborne pathogen Listeria monocytogenes (Lm) and the effectiveness of listeriosis treatment options. Here we examined the antimicrobial resistance patterns in Lm over time and assessed genotype-phenotype concordances. Methods: We analyzed 5339 Lm isolates (2908 clinical and 2431 food isolates) collected in France and overseas territories, between 2012 and 2019. Whole genome sequencing was performed for all isolates and antimicrobial resistance profiles inferred from draft assemblies. Antimicrobial susceptibility towards 22 antimicrobials was determined for all clinical isolates, and in food isolates with acquired resistance genes. Findings: All tested isolates were resistant to at least 3 different classes of antimicrobials, consistent with Lm intrinsic traits. Acquired antimicrobial resistance in Lm was rare (2.23% isolates) and more prevalent in food (mainly lineage II) compared to clinical isolates (mainly lineage I) (3.74% vs 0.98%, p < 0.0001), and in isolates with disinfectants or stress resistance traits (e.g. bcrABC, 20.20% vs 7.20%, p < 0.0001), suggesting co-selection of resistance in food-production environments. Acquired antimicrobial resistance could be predicted from genomes with high accuracy (>99%), except for ciprofloxacin. Acquired antimicrobial phenotypes were towards tetracyclines (mostly due to tetM), trimethoprim (dfrD), lincosamides (lnuG), macrolides (ermB, mphB) and phenicols (fexA). Interpretation: The reference treatment for listeriosis (aminopenicillins/aminoglycosides) remains effective, with no acquired resistance observed. Continuous surveillance of antimicrobial resistance in clinical and food isolates is crucial to detect the emergence of novel resistance. Funding: Institut Pasteur, INSERM, Santé Publique France, Investissement d'Avenir program Laboratoire d'Excellence 'Integrative Biology of Emerging Infectious Diseases' (ANR-10-LABX-62-IBEID).

Protocol for live imaging of bacteria-cell interactions in genetically modified mouse small intestinal organoids.

Here, we present a protocol for microinjection of bacteria into mouse small intestinal organoids that recapitulates the natural route of infection of intestinal epithelial cells from the intestinal lumen. We describe steps for visualizing bacteria-cell interactions by live imaging of infected organoids using light sheet microscopy. We then detail procedures for generating doxycycline-inducible expression of mutant proteins in organoids to study essential gene functions. The different techniques described in this protocol can be used independently as required. For complete details on the use and execution of this protocol, please refer to Kim et al. (2021).1.