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The efficacy of mesenchymal stem cell therapy in experimental sepsis induced by carbapenem-resistant K. pneumoniae in neutropenic mice model

Especially in recent years, the intensive use of antibiotics has caused multiple drug resistance in Klebsiella pneumoniae. In the absence of a new antibiotic, alternative treatment options have emerged. The aim of this study was to investigate the efficacy of mesenchymal stem cell (MSC) treatment of carbapenem-resistant K. pneumoniae sepsis in neutropenic murine model. BALB-c mice were divided into two groups as control (positive and negative) and treatment groups (colistin, colistin + MSC, MSC) after the development of neutropenia with cyclophosphamide. Sepsis was developed in mice by intraperitoneal injection of carbapenem-resistant K. pneumoniae. Three hours after inoculation of the bacteria, colistin and MSC were given in the treatment groups intraperitoneally. Colistin injection was repeated every 12 h, while MSC was administered as 2nd dose after 48 h. Mice were sacrificed at 48 and 96 h. The right lung and half of the liver were quantitatively cultured, and the bacterial load was calculated as cfu/g. The left lung, the other half of the liver tissue, and both kidneys were evaluated histopathologically. IL-6 and TNF-α cytokine levels in mouse sera were determined by ELISA. Bacterial loads in lung and liver tissues of neutropenic mice were lower in the MSC + colistin-treated group at 48 and 96 h compared to colistin and MSC monotherapy groups. Also, bacterial eradication was started the earliest in MSC + colistin group. It was concluded that combining colistin with MSC provided improved therapeutic effects compared to colistin or MSC monotherapy.

An evaluation of risk factors to predict target concentration non-attainment in critically ill patients prior to empiric β-lactam therapy

To determine whether target concentration non-attainment can be anticipated in critically ill patients prior to initiating empiric β-lactam antibiotic therapy based on readily available clinical factors. Retrospective review of consecutive patients treated with piperacillin or meropenem and who underwent therapeutic drug monitoring (TDM) at St Vincent's Hospital (Sydney, Australia) between January 2013 and December 2015 was performed. Predefined subgroups were patients who received continuous renal replacement therapy (CRRT) and those who did not (non-CRRT). Potential risk factors were evaluated by correlation with β-lactam antibiotic trough concentrations (C_min) lower than or equal to targeted minimum inhibitory concentration (MIC). Only the first drug concentration after initiation of the antibiotic treatment was included to reflect empirical dose selection. A total of n = 249 patients (piperacillin, n = 169; meropenem, n = 80) were investigated. For non-CRRT patients (n = 210), multivariate analysis demonstrated the following: male gender (p = 0.006); younger age (p = 0.015); prescribed daily antibiotic dose less than 1.5 times the product information recommendations (p = 0.004); lack of positive microbiology (p = 0.006); lower overall illness severity (p = 0.005); and estimated glomerular filtration rate (eGFR) ≥ 90 mL/min/1.73 m² (p < 0.001), to be associated with C_min ≤ MIC. No predictor variable was found to be significantly associated with C_min ≤ MIC for the CRRT cohort. Evaluating the risk of target concentration non-attainment using simple clinical factors is possible at the bedside for non-CRRT patients prior to empiric antibiotic initiation. Clinicians should be wary of selecting doses based on the product information especially when treating younger male patients with apparently 'normal' renal function.