Background: Colistin is increasingly used as the last therapeutic option for the treatment of multidrug-resistant, Gram-negative bacterial infections. To ensure safe and efficacious use of colistin, therapeutic drug monitoring (TDM) is needed due to its narrow therapeutic window. This study aimed to evaluate the pharmacokinetic (PK) characteristics of colistin and to guide TDM in colistin-treated patients in Korea. Methods: In a prospective study, we analyzed PK characteristics in 15 patients who intravenously received colistin methanesulfonate twice per day. Colistin methanesulfonate doses were adjusted based on renal function of the subjects. The appropriate blood sampling points for TDM were evaluated by analyzing the correlations between the PK parameters and the plasma concentrations at each time point. Results: The mean values for the minimum, maximum, and average concentrations (Cmin, Cmax, and Caverage) of colistin at steady state were 2.29, 5.5, and 3.38 mg/L, respectively. The dose-normalized Cmin, Cmax, Caverage, and area under the plasma concentration–time curve from 0 to the last measurable concentration (AUClast) showed negative correlations with the creatinine clearance. The combination of the 0- and 2-hour post-dose plasma concentrations was evaluated as the appropriate sampling point for TDM. Two patients reported nephrotoxic adverse events during colistin administration. Conclusions: Our study clarifies the PK characteristics of successful colistin treatment using TDM. Further evaluations in a larger patient population are needed to confirm the clinical usefulness of colistin TDM.

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This study was conducted to assess emergence of daptomycin-nonsusceptible (DAP-NS) phenotype in DAP-naive patients with invasive Staphylococcus aureus (ISA) infections in Korea. A total of 208 S. aureus clinical isolates were selected from a previous prospective study on ISA infections and evaluated for DAP-NS. Although DAP has never been introduced in Korea, five DAP-NS S. aureus strains (2.4%) were identified among 208 S. aureus strains collected from ISA infections. The DAP-NS phenotype was observed only in methicillin-resistant S. aureus (MRSA) strains, but not in methicillin-susceptible S. aureus strains. One DAP-NS MRSA strain belonged to sequence type 72 (ST72) and four were ST5 MRSA strains, three of which were heteroresistant vancomycin (VAN)-intermediate S. aureus. All these five DAP-NS MRSA strains were from healthcare-associated infections without prior exposure to VAN within 30 days. While the ST72 MRSA strain exhibited DAP-NS phenotype via charge repulsion mechanism, four ST5 DAP-NS S. aureus strains had charge-independent DAP-NS mechanism. None of the five DAP-NS strains displayed significant increase in cell wall thickness, indicating that altered cell wall thickness was not associated with the observed DAP-NS phenotype.

Non-Hodgkin's lymphoma of B-cell type is the second most common neoplasm after Kaposi's sarcoma among patients with human immunodeficiency virus infection. Most non-Hodgkin's lymphoma cases that are associated with acquired immunodeficiency syndrome (AIDS) involve extranodal sites, especially the digestive tract and the central nervous system. We report a case of multiple jejunal intussusception caused by Burkitt lymphoma in a 42-year-old AIDS patient. Upper gastrointestinal endoscopy and surgical biopsy were performed and a complete diagnostic study including histological and immunohistochemical analyses showed Burkitt lymphoma.

Systemic arterial supply from the descending thoracic aorta to the basal segment of the left lower lobe without a pulmonary arterial supply is a rare congenital anomaly within the spectrum of sequestration lung disease. The most common pattern of anomalous systemic artery to the lung arises from the descending thoracic aorta and feeds the basal segments of the left lower lobe. We report an extremely rare case of a 29-year-old woman who underwent a successful left upper lobectomy for the treatment of recurrent massive hemoptysis from anomalous bronchial arterial supply to the lingular segment of left upper lobe.