The humoral response of mRNA COVID-19 vaccine in hematological diseases: The HEMVACO study.

OBJECTIVES: The HEMVACO study evaluated the humoral response after mRNA anti-SARS-CoV-2 vaccination in an hematological cohort. METHODS: HEMVACO was a prospective, multicentric study registered in ClinicalTrials.gov, number NCT04852796. Patients received two or three doses of BNT162b2 vaccine or mRNA-1273 vaccine. The SARS-CoV-2 TrimericS IgG titers were measured 1, 3, 6 and 12 months after the second dose. RESULTS: Only 16 patients (11.6%) were naive of hematological treatment and 77 patients (55.8%) were on active treatment for hemopathy. Among the 138 analyzed patients, positive antibody titer at 1 month was obtained in 68.1% of patients with mean serology at 850±883 BAU/ml. Risk factors for vaccine failure were anti-CD20 therapy (OR=111[14.3-873]; P<0.001), hypogammaglobulinemia under 8g/L (OR=2.49[1.05-5.92]; P=0.032) and lymphopenia under 1.5G/L (OR=2.47[1.18-5.17]; P=0.015). Anti-CD20 therapy induced no anti-SARS-CoV-2 seroconversion (96%). Seventy-eight patients (56.5%) received a third dose and could reach the SARS-CoV-2 TrimericS IgG titer of high-risk patients (P=0.54). The median titer at 379 BAU/ml distinguished two groups of vaccine response (99±121 BAU/ml versus 1,109±678 BAU/ml). CONCLUSION: Vaccination should be performed before anti-CD20 therapy if the hemopathy treatment can be delayed. Administration of the third vaccine dose was interesting for patients with suboptimal response, defined by a 379 BAU/ml titer in our study.

Elizabethkingia anophelis outbreak in France.

OBJECTIVE: We report an outbreak of Elizabethkingia anophelis infections in France. To the best of our knowledge, this is the first outbreak described in Europe. METHODS: Each E. anophelis-positive microbiological sample was considered a case. All patients were hospitalized in an infectious diseases unit. Clinical, environmental, and microbiological investigations (MALDI-TOF mass spectrometry, PCR, E-test) were performed for each case. RESULTS: Twenty cases were reported from September 2020 to September 2021, mainly community-acquired infections, responsible for nine deaths. The phylogenetic analysis showed a clonal origin and excluded nosocomial transmission. Despite the analysis of multiple environmental specimens, no source of contamination was identified. All strains were highly resistant to cefotaxime, ceftazidime, and imipenem. CONCLUSIONS: Clinicians and microbiologists should be aware of this multidrug-resistant bacterium, capable of causing severe infections. Most strains showed the lowest minimum inhibitory concentration values for cotrimoxazole and ciprofloxacin, making them the best choice for empirical antibiotic therapy.

Lactobacilli intra-tracheal administration protects from Pseudomonas aeruginosa pulmonary infection in mice - a proof of concept.

The spreading of antibiotic resistance is a major public health issue, which requires alternative treatments to antibiotics. Lactobacilli have shown abilities to prevent pneumonia in clinical studies when given by oral route, certainly through the gut-lung axis involvement. Rationally, respiratory administration of lactobacilli has been developed and studied in murine model, to prevent from respiratory pathogens. It allows a direct effect of probiotics into the respiratory system. To our knowledge, no study has ever focused on the effect of probiotic intra-respiratory administration to prevent from Pseudomonas aeruginosa (PA) pneumonia, a major respiratory pathogen associated with high morbidity rates. In this study, we evaluated the beneficial activity of three Lactobacillus strains (Lactobacillus fermentum K.C6.3.1E, Lactobacillus zeae Od.76, Lactobacillus paracasei ES.D.88) previously screened by ourselves and known to be particularly efficient in vitro in inhibiting PAO1 virulence factors. Cytotoxic assays in alveolar epithelial cell line A549 were performed, followed by the comparison of two lactobacilli prophylactic protocols (one or two administrations) by intra-tracheal administration in a C57BL/6 murine model of PA pneumonia. A549 cells viability was improved from 23 to 75% when lactobacilli were administered before PAO1 incubation, demonstrating a protective effect (P<0.001). A significant decrease of 2 log of PAO1 was observed 4 h after PAO1 instillation (3×106 cfu/mouse) in both groups receiving lactobacilli (9×106 cfu/mouse) compared to PAO1 group (P<0.05). One single prophylactic administration of lactobacilli significantly decreased the secretion by 50% in bronchoalveolar lavages of interleukin (IL)-6 and tumour necrosis factor-α compared to PAO1. No difference of secretion was observed for the IL-10 secretion, whatever the prophylactic study design. This is the first study highlighting that direct lung administration of Lactobacillus strains protect against PA pneumonia. Next step will be to decipher the mechanisms involved before developing this novel approach for human applications.

How to: identify non-tuberculous Mycobacterium species using MALDI-TOF mass spectrometry.

BACKGROUND: The implementation of MALDI-TOF MS for microorganism identification has changed the routine of the microbiology laboratories as we knew it. Most microorganisms can now be reliably identified within minutes using this inexpensive, user-friendly methodology. However, its application in the identification of mycobacteria isolates has been hampered by the structure of their cell wall. Improvements in the sample processing method and in the available database have proved key factors for the rapid and reliable identification of non-tuberculous mycobacteria isolates using MALDI-TOF MS. AIMS: The main objective is to provide information about the proceedings for the identification of non-tuberculous isolates using MALDI-TOF MS and to review different sample processing methods, available databases, and the interpretation of the results. SOURCES: Results from relevant studies on the use of the available MALDI-TOF MS instruments, the implementation of innovative sample processing methods, or the implementation of improved databases are discussed. CONTENT: Insight about the methodology required for reliable identification of non-tuberculous mycobacteria and its implementation in the microbiology laboratory routine is provided. IMPLICATIONS: Microbiology laboratories where MALDI-TOF MS is available can benefit from its capacity to identify most clinically interesting non-tuberculous mycobacteria in a rapid, reliable, and inexpensive manner.

[Pulmonary Mycobacterium abscessus sensu lato infection in patients without cystic fibrosis]. / Infection pulmonaire à Mycobacterium abscessus sensu lato chez des patients exempts de mucoviscidose.

INTRODUCTION: Infection with Mycobacterium abscessus sensu lato is uncommon in patients without cystic fibrosis. We are interested in these patients and have collected cases in Finistère between 2007 and 2011. CASE REPORTS: Four patients met the infection criteria recommended by the American Thoracic Society in 2007. Among them, all had Aspergillus spp. in sputum, 3 had gastroesophageal reflux and two had the criteria for allergic bronchopulmonary aspergillosis. We identified Mycobacterium massiliense in the single patient in our series whose therapeutic outcome was successful. CONCLUSION: By comparing these data with those in the literature, we believe that the search for allergic bronchopulmonary aspergillosis and gastroesophageal reflux is necessary in these patients and that species identification is essential for prognosis.