In vitro Activity of Cefepime/Avibactam Against Carbapenem Resistant Klebsiella pneumoniae and Integrative Metabolomics-Proteomics Approach for Resistance Mechanism: A Single-Center Study.

Purpose: We aimed to evaluate the in vitro antibacterial effects of combination of cefepime/avibactam against carbapenem-resistant Klebsiella pneumonia (CRKP) and explore the resistance mechanism of FEP/AVI. Patients and Methods: This study explored the in vitro antibacterial activities of ceftazidime/avibactam (CAZ/AVI) and cefepime/avibactam (FEP/AVI) against 40 and 76 CRKP clinical isolates. Proteomics and metabolomics were employed to investigate the resistance mechanisms of CRKP to FEP/AVI. Results: FEP/AVI (MIC50/MIC90 0.5/4-64/4 µg/mL, resistance rate 17.1%) showed better antibacterial activity against CRKP than CAZ/AVI (MIC50/MIC90 4/4-128/4 µg/mL, resistance rate 20%) in vitro. Bioinformatics analysis showed that the differentially expressed proteins (DEPs) were enriched in alanine, aspartate and glutamate metabolism, and ribosome. Remarkably, transcriptional and translational activity-related pathways were inhibited in FEP/AVI resistant CRKP. Overlap analysis suggested that H-NS might play an important role in resistance to FEP/AVI in CRKP. The mRNA levels of DEPs-related genes (adhE, gltB, purA, ftsI and hns) showed the same trends as DEPs in FEP/AVI susceptible and resistant strains. FEP/AVI resistant isolates demonstrated stronger biofilm formation capacity than susceptible isolates. Metabolomics results showed that disturbed metabolites were mainly lipids, and adenine was decreased in FEP/AVI resistant CRKP. Conclusion: These results indicated that H-NS, GltB and SpoT may directly or indirectly promote biofilm formation of CRKP and led to FEP/AVI resistance, but inhibited ribosomal function. Our study provides a mechanistic insight into the acquisition of resistance to FEP/AVI in Klebsiella pneumoniae.

Antibody seroconversion in asymptomatic and symptomatic patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

OBJECTIVES: Asymptomatic and symptomatic patients may transmit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but their clinical features and immune responses remain largely unclear. We aimed to characterise the clinical features and immune responses of asymptomatic and symptomatic patients infected with SARS-CoV-2. METHODS: We collected clinical, laboratory and epidemiological records of patients hospitalised in a coronavirus field hospital in Wuhan. We performed qualitative detection of anti-SARS-CoV-2 immunoglobulin M (IgM) and immunoglobulin G (IgG) using archived blood samples. RESULTS: Of 214 patients with SARS-CoV-2, 26 (12%) were asymptomatic at hospital admission and during hospitalisation. Most asymptomatic patients were ≤ 60 years (96%) and females (65%) and had few comorbidities (< 16%). Serum levels of white and red blood cells were higher in asymptomatic than in symptomatic patients (P-values < 0.05). During hospitalisation, IgG seroconversion was commonly observed in both asymptomatic and symptomatic patients (85% versus 94%, P-value = 0.07); in contrast, IgM seroconversion was less common in asymptomatic than in symptomatic patients (31% versus 74%, P-value < 0.001). The median time from the first virus-positive screening to IgG or IgM seroconversion was significantly shorter in asymptomatic than in symptomatic patients (median: 7 versus 14 days, P-value < 0.01). Furthermore, IgG/IgM seroconversion rates increased concomitantly with the clearance of SARS-CoV-2 in both asymptomatic and symptomatic patients. At the time of virus clearance, IgG/IgM titres and plasma neutralisation capacity were significantly lower in recovered asymptomatic than in recovered symptomatic patients (P-values < 0.01). CONCLUSION: Asymptomatic and symptomatic patients exhibited different kinetics of IgG/IgM responses to SARS-CoV-2. Asymptomatic patients may transmit SARS-CoV-2, highlighting the importance of early diagnosis and treatment.

[Tissue distribution of PEGylated puerarin in acute myocardial ischemia mode rats].

The aim of this study is to explore the tissue distribution of PEGylated puerarin in acute myocardial ischemia model rats. Healthy male SD rats were randomly divided into two groups (30 each). Both were given PEGylated puerarin at a dose of 488 mg x kg(-1). After 5 min of medication, one group was normal rats, another group with acute myocardial ischemia was established by peritoneal injection of 50 mg x kg(-1) isoprenaline. After administration, the animals were executed at 30, 60, 90, 120, 150 and 180 min, then heart, liver, spleen, lung, kidney were extracted. The content of puerarin in organ tissue was determined by HPLC. The results showed that the AUC of tissue distribution of PEGylated puerarin in normal rats was liver > kidney > heart ≈ spleen > lung > brain. While the AUC of tissue distribution of PEGylated puerarin in acute myocardial ischemia model rats was liver ≈ heart > kidney > lung ≈ spleen > brain. AUC(heart) of PEGylated puerarin in acute myocardial ischemia model rats was 1.7 times than that of the normal rats, and there was significant difference (P < 0.05). Thus, PEGylated puerarin had a good heart-targeting property in early myocardial infarction area, drugs could accumulate in the ischemic myocardium. It provided important information for further study and clinic use of PEGylated puerarin.