The life-saving benefit of dexamethasone in severe COVID-19 is linked to a reversal of monocyte dysregulation.

Dexamethasone is a life-saving treatment for severe COVID-19, yet its mechanism of action is unknown, and many patients deteriorate or die despite timely treatment initiation. Here, we identify dexamethasone treatment-induced cellular and molecular changes associated with improved survival in COVID-19 patients. We observed a reversal of transcriptional hallmark signatures in monocytes associated with severe COVID-19 and the induction of a monocyte substate characterized by the expression of glucocorticoid-response genes. These molecular responses to dexamethasone were detected in circulating and pulmonary monocytes, and they were directly linked to survival. Monocyte single-cell RNA sequencing (scRNA-seq)-derived signatures were enriched in whole blood transcriptomes of patients with fatal outcome in two independent cohorts, highlighting the potential for identifying non-responders refractory to dexamethasone. Our findings link the effects of dexamethasone to specific immunomodulation and reversal of monocyte dysregulation, and they highlight the potential of single-cell omics for monitoring in vivo target engagement of immunomodulatory drugs and for patient stratification for precision medicine approaches.

Clinically used broad-spectrum antibiotics compromise inflammatory monocyte-dependent antibacterial defense in the lung.

Hospital-acquired pneumonia (HAP) is associated with high mortality and costs, and frequently caused by multidrug-resistant (MDR) bacteria. Although prior antimicrobial therapy is a major risk factor for HAP, the underlying mechanism remains incompletely understood. Here, we demonstrate that antibiotic therapy in hospitalized patients is associated with decreased diversity of the gut microbiome and depletion of short-chain fatty acid (SCFA) producers. Infection experiments with mice transplanted with patient fecal material reveal that these antibiotic-induced microbiota perturbations impair pulmonary defense against MDR Klebsiella pneumoniae. This is dependent on inflammatory monocytes (IMs), whose fatty acid receptor (FFAR)2/3-controlled and phagolysosome-dependent antibacterial activity is compromized in mice transplanted with antibiotic-associated patient microbiota. Collectively, we characterize how clinically relevant antibiotics affect antimicrobial defense in the context of human microbiota, and reveal a critical impairment of IM´s antimicrobial activity. Our study provides additional arguments for the rational use of antibiotics and offers mechanistic insights for the development of novel prophylactic strategies to protect high-risk patients from HAP.

Percutaneous drainage and combined praziquantel-albendazole therapy: a novel approach for the treatment of simple echinococcal liver cysts.

Cystic echinococcosis (CE) is a worldwide helminthic zoonosis causing serious disease in humans. The WHO Informal Working Group on Echinococcosis recommends a stage-specific treatment approach of hepatic CE that facilitates the decision on what therapy option is most appropriate. Percutaneous aspiration, instillation of a scolicide, e.g., ethanol or hypertonic saline, and subsequent re-aspiration (PAIR) have been advocated for treating medium-size unilocular WHO-stage CE1 cysts. PAIR can pose a risk of toxic cholangitis because of spillage of ethanol in the case of a cysto-biliary fistula or of life-threatening hypernatriaemia when hypertonic saline is used. The purpose of our study is to develop an alternative, safe, minimally invasive method to treat CE1 cysts, avoiding the use of toxic topic scolicides.We opt for percutaneous drainage (PD) in four patients: the intrahepatic drainage catheter is placed under CT-fluoroscopy, intracystic fluid is aspirated, and the viability of intracystic echinococcal protoscolices is assessed microscopically. Oral praziquantel (PZQ) is added to albendazole (ABZ) instead of using topical scolicidals.Protoscolices degenerate within 5 to 10 days after PZQ co-medication at a cumulative dosage of 250 to 335 mg/kg, and the cysts collapse. The cysts degenerate, and no sign of spillage nor relapse is observed in the follow-up time of up to 24 months post-intervention.In conclusion, PD combined with oral PZQ under ABZ coverage is preferable to PAIR in patients with unilocular echinococcal cysts.