A calmodulin-like protein regulates plasmodesmal closure during bacterial immune responses

Plants sense microbial signatures via activation of pattern recognition receptors (PPRs), which trigger a range of cellular defences. One response is the closure of plasmodesmata, which reduces symplastic connectivity and the capacity for direct molecular exchange between host cells. Plasmodesmal flux is regulated by a variety of environmental cues but the downstream signalling pathways are poorly defined, especially the way in which calcium regulates plasmodesmal closure. Here, we identify that closure of plasmodesmata in response to bacterial flagellin, but not fungal chitin, is mediated by a plasmodesmal-localized Ca2+ -binding protein Calmodulin-like 41 (CML41). CML41 is transcriptionally upregulated by flg22 and facilitates rapid callose deposition at plasmodesmata following flg22 treatment. CML41 acts independently of other defence responses triggered by flg22 perception and reduces bacterial infection. We propose that CML41 enables Ca2+ -signalling specificity during bacterial pathogen attack and is required for a complete defence response against Pseudomonas syringae.Bo Xu, Cecilia Cheval, Anuphon Laohavisit, Bradleigh Hocking, David Chiasson, Tjelvar S. G. Olsson, Ken Shirasu, Christine Faulkner and Matthew Gilliha

Achromobacter spp. and MALDI-TOF mass spectrometry, development of a database and application to epidemiological studies.

Achromobacter spp. (19 espèces) est un pathogène émergent chez les patients atteints de mucoviscidose. Les données sur les espèces ou les types manquent pour comprendre l'épidémiologie et l'impact clinique chez ces patients. En effet, Les méthodes de référence pour l’identification des espèces et le typage sont des techniques de biologie moléculaires non applicables en routine au laboratoire. Nous avons construit la première base de données par spectrométrie de masse MALDI-TOF (Bruker) comprenant 18 espèces d’Achromobacter en incluant 205 souches identifiées par la méthode de référence (séquençage du gène nrdA). Deux stratégies de typage (MALDI Biotyper ; ClinProTools) ont été comparées à la MultiLocus Sequence Typing et l’Electrophorèse en Champ Pulsé, incluant 202 souches cliniques ou environnementales d’A. xylosoxidans et d’A. ruhlandii (Etats-Unis, Danemark, France et Belgique). Cette étude est la première comparant la technique de spectrométrie de masse MALDI-TOF par rapport au séquençage du gène nrdA pour l’identification au rang d’espèce des bactéries du genre Achromobacter. L’utilisation de notre nouvelle base est une alternative fiable pour l’identification au rang d’espèce de ces bactéries et pour le typage, notamment la détection des souches clonales épidémiques multi-résistantes A. xylosoxidans ST 137 et A. ruhlandii DES. De plus, notre base de données étant fiable, elle nous a permis de conduire une étude épidémiologique rétrospective dans 12 centres français permettant de decrire la distribution des espèces et de détecter le clone A. xylosoxidans ST 137 chez les patients atteints de mucoviscidose en France en 2020. Au total, 11 espèces ont été identifiées, A. xylosoxidans étant l'espèce la plus répandue dans chaque centre et le clone épidémique A. xylosoxidans ST 137 a été détecté chez 4 patients de deux centres. L’utilisation de cette méthode rapide permettra ainsi de mieux comprendre l'épidémiologie d’Achromobacter chez ces patients et de guider les études cliniques à venir.Achromobacter spp. (19 species) is an emerging pathogen in cystic fibrosis patients. Data on species or types are lacking to understand the epidemiology and clinical impact in these patients. Indeed, the reference methods for species identification and typing are molecular biology techniques not applicable in the diagnostic laboratory. We have built the first MALDI-TOF mass spectrometry database (Bruker) comprising 18 Achromobacter species including 205 strains identified by the reference method (nrdA gene sequencing). Two typing strategies (MALDI Biotyper; ClinProTools) were compared to MultiLocus Sequence Typing and Pulse Field Electrophoresis, including 202 clinical or environmental strains of A. xylosoxidans and A. ruhlandii (USA, Denmark, France and Belgium). This study is the first to compare the MALDI-TOF mass spectrometry technique with nrdA gene sequencing for species-level identification of bacteria of the genus Achromobacter. The use of our new database is a reliable alternative for the species identification of these bacteria and for typing, including the detection of the epidemic multiresistant clonal strains A. xylosoxidans ST 137 and A. ruhlandii DES. Moreover, as our database is reliable, it allowed us to conduct a retrospective epidemiological study in 12 French centers to describe the distribution of species and to detect the A. xylosoxidans ST 137 clone in cystic fibrosis patients in France in 2020. In total, 11 species were identified, with A. xylosoxidans being the most common species in each centre and the epidemic clone A. xylosoxidans ST 137 was detected in 4 patients from two centers. The use of this rapid method will thus allow a better understanding of the epidemiology of Achromobacter in these patients and guide future clinical studies

Interview with Thomas Eubanks

Supporting oral interview conducted for the The Houts Farm: a porción of Edinburg publication.https://scholarworks.utrgv.edu/chapsoralhistories/1080/thumbnail.jp

Case series of 12 Bartonella quintana endocarditis from the Southwest Indian Ocean

International audienceBackground Bartonella spp. are fastidious bacteria frequently identified as the cause of blood culture-negative (BCN) endocarditis. However, Bartonella infections are difficult to diagnose in routine laboratory testing and their incidence is probably underestimated. We investigated the epidemiological and clinical features of Bartonella endocarditis cases diagnosed between 2009 and 2021 on Reunion Island (Southwest Indian Ocean). Method We retrospectively included all patients diagnosed with Bartonella endocarditis at Reunion Island University Hospital during this period. Endocarditis was diagnosed on the basis of microbiological findings, including serological tests (IFA) and PCR on cardiac valves, and the modified Duke criteria. We used then the multispacer typing (MST) method to genotype the available Bartonella strains. Findings We report 12 cases of B . quintana endocarditis on Reunion Island (83.3% in men, median patient age: 32 years). All the patients originated from the Comoros archipelago. The traditional risk factors for B . quintana infection (homelessness, alcoholism, exposure to body lice) were absent in all but two of the patients, who reported head louse infestations in childhood. Previous heart disease leading to valve dysfunction was recorded in 50% of patients. All patients underwent cardiac valve surgery and antimicrobial therapy with a regimen including doxycycline. All patients presented high C-reactive protein concentrations, anemia and negative blood cultures. The titer of IgG antibodies against Bartonella sp. exceeded 1:800 in 42% of patients. Specific PCR on cardiac valves confirmed the diagnosis of B . quintana endocarditis in all patients. Genotyping by the MST method was performed on four strains detected in preserved excised valves and was contributive for three, which displayed the MST6 genotype. Conclusions Bartonella quintana is an important cause of infective endocarditis in the Comoros archipelago and should be suspected in patients with mitral valve dysfunction and BCN from this area

Multifocal cutaneous phaeohyphomycosis caused by Paraconiothyrium cyclothyrioides in an immunocompromised patient: A case report

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Nosocomial cluster of carbapenemase-producing Enterobacter cloacae in an intensive care unit dedicated COVID-19

International audienceConcomitant prevention of SARS-CoV-2 and extensively drug-resistant bacteria transmission is a difficult challenge in intensive care units dedicated to COVID-19 patients. We report a nosocomial cluster of four patients carrying NDM-1 plasmid-encoded carbapenemase-producing Enterobacter cloacae. Two main factors may have contributed to crosstransmission: misuse of gloves and absence of change of personal protective equipment, in the context of COVID-19-associated shortage. This work highlights the importance of maintaining infection control measures to prevent CPE cross-transmission despite the difficult context and that this type of outbreak can potentially involve several species of Enterobacterales

Emerging Corynebacterium diphtheriae Species Complex Infections, Réunion Island, France, 2015–2020

Clinical, epidemiologic, and microbiologic analyses revealed emergence of 26 cases of Corynebacterium diphtheriae species complex infections on Réunion Island, France, during 2015–2020. Isolates were genetically diverse, indicating circulation and local transmission of several diphtheria sublineages. Clinicians should remain aware of the risk for diphtheria and improve diagnostic methods and patient management

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Rapid Detection of Isolates Belonging to the Epidemic Clones Achromobacter xylosoxidans ST137 and Achromobacter ruhlandii DES from Cystic Fibrosis Patients.

spp. are increasingly reported among cystic fibrosis patients. Genotyping requires time-consuming methods such as multilocus sequence typing or pulsed-field gel electrophoresis. Therefore, data on the prevalence of multiresistant epidemic clones, especially A. xylosoxidans ST137 (AxST137) and the Danish epidemic strain (DES), are lacking. We recently developed and published a database for species identification by matrix-assisted laser desorption-ionization-time of flight mass spectrometry (MALDI-TOF MS; Bruker Daltonics). The aim of this study was to evaluate the ability of the MALDI-TOF MS to distinguish these multiresistant epidemic clones within species. All the spectra of A. xylosoxidans ( = 1,571) and ( = 174) used to build the local database were analyzed by ClinProTools, MALDI Biotyper PCA, MALDI Biotyper dendrogram, and flexAnalysis software for biomarker peak detection. Two hundred two isolates (including 48 isolates of AxST137 and 7 of DES) were tested. Specific biomarker peaks were identified: absent peak at 6,651 for AxST137 isolates and present peak at 9,438 for DES isolates. All tested isolates were well typed by our local database and clustered within distinct groups (ST137 or non-ST137 and DES or non-DES) no matter the MALDI-TOF software or only by simple visual inspection of the spectra by any user. The use of MALDI-TOF MS allowed us to identify isolates of A. xylosoxidans belonging to the AxST137 clone that spread in France and Belgium (the Belgian epidemic clone) and of belonging to the DES clone. This tool will help the implementation of segregation measures to avoid interpatient transmission of these resistant clones