Differences in Colistin-resistant Acinetobacter baumannii Clinical Isolates Between Patients With and Without Prior Colistin Treatment

BACKGROUND: The increasing morbidity and mortality rates associated with Acinetobacter baumannii are due to the emergence of drug resistance and the limited treatment options. We compared characteristics of colistin-resistant Acinetobacter baumannii (CR-AB) clinical isolates recovered from patients with and without prior colistin treatment. We assessed whether prior colistin treatment affects the resistance mechanism of CR-AB isolates, mortality rates, and clinical characteristics. Additionally, a proper method for identifying CR-AB was determined. METHODS: We collected 36 non-duplicate CR-AB clinical isolates resistant to colistin. Antimicrobial susceptibility testing, Sanger sequencing analysis, molecular typing, lipid A structure analysis, and in vitro synergy testing were performed. Eleven colistin-susceptible AB isolates were used as controls. RESULTS: Despite no differences in clinical characteristics between patients with and without prior colistin treatment, resistance-causing genetic mutations were more frequent in isolates from colistin-treated patients. Distinct mutations were overlooked via the Sanger sequencing method, perhaps because of a masking effect by the colistin-susceptible AB subpopulation of CR-AB isolates lacking genetic mutations. However, modified lipid A analysis revealed colistin resistance peaks, despite the population heterogeneity, and peak levels were significantly different between the groups. CONCLUSIONS: Although prior colistin use did not induce clinical or susceptibility differences, we demonstrated that identification of CR-AB by sequencing is insufficient. We propose that population heterogeneity has a masking effect, especially in colistin non-treated patients; therefore, accurate testing methods reflecting physiological alterations of the bacteria, such as phosphoethanolamine-modified lipid A identification by matrix-assisted laser desorption ionization-time of flight, should be employed.

First Case Report of Human Infection With Ochrobactrum tritici Causing Bacteremia and Cholecystitis

No abstract available.

Epidemiology and Characteristics of Metallo-beta-Lactamase-Producing Pseudomonas aeruginosa

Metallo-beta-lactamase-producing Pseudomonas aeruginosa (MPPA) is an important nosocomial pathogen that shows resistance to all beta-lactam antibiotics except monobactams. There are various types of metallo-beta-lactamases (MBLs) in carbapenem-resistant P. aeruginosa including Imipenemase (IMP), Verona integron-encoded metallo-beta-lactamase (VIM), Sao Paulo metallo-beta-lactamase (SPM), Germany imipenemase (GIM), New Delhi metallo-beta-lactamase (NDM), Florence imipenemase (FIM). Each MBL gene is located on specific genetic elements including integrons, transposons, plasmids, or on the chromosome, in which they carry genes encoding determinants of resistance to carbapenems and other antibiotics, conferring multidrug resistance to P. aeruginosa. In addition, these genetic elements are transferable to other Gram-negative species, increasing the antimicrobial resistance rate and complicating the treatment of infected patients. Therefore, it is essential to understand the epidemiology, resistance mechanism, and molecular characteristics of MPPA for infection control and prevention of a possible global health crisis. Here, we highlight the characteristics of MPPA.

Vitamin D Status in South Korean Military Personnel with Acute Eosinophilic Pneumonia: A Pilot Study / 결핵및호흡기질환

BACKGROUND: A relationship between low vitamin D levels and the development or outcomes of respiratory diseases has been identified. However, there is no data on the vitamin D status in patients with acute eosinophilic pneumonia (AEP). We evaluated the vitamin D status in patients with AEP among South Korean military personnel. METHODS: We prospectively compared the serum levels of total 25-hydroxyvitamin D [25(OH)D], 25(OH)D3, and 25(OH)D2 among patients with AEP, pulmonary tuberculosis (PTB), and community-acquired pneumonia (CAP). RESULTS: In total, 65 patients with respiratory diseases, including AEP (n=24), PTB (n=19), and CAP (n=22), were identified. Of the 24 patients with AEP, 2 (8%) had deficient total 25(OH)D levels ( or =10 to or =30 to <100 ng/mL). The difference in the total 25(OH)D levels among patients with AEP, PTB, and CAP was not statistically significant (p=0.230). The median levels of total 25(OH)D, 25(OH)D3, and 25(OH)D2 were 22.84, 22.84, and 0.00 ng/mL, respectively, and no differences in the 25(OH)D level were present among patients with AEP, PTB, and CAP with the exception of the total 25(OH)D level between patients with AEP and PTB (p=0.042). CONCLUSION: We have shown that low vitamin D levels are frequently found in patients with AEP and are comparable with those in patients with PTB and CAP.

Usefulness of Thyroglobulin Measurement in Fine-needle Aspirates of Lymph Nodes for the Diagnosis of Lymph Node Metastasis of Papillary Thyroid Cancer

BACKGROUND: Previous studies have shown that thyroglobulin (Tg) measurement in fine-needle aspirates (FNA) of lymph nodes can assist in evaluating cervical lymph node metastasis. In this study, we evaluated the diagnostic performances of FNA-Tg, serum-Tg, and FNA-Tg/serum-Tg in detecting lymph node metastasis. METHODS: We retrospectively analyzed the diagnostic performances of FNA-Tg and serum-Tg in 641 cases (518 patients) with papillary thyroid cancer that underwent ultrasonography-guided fine-needle aspiration of cervical lymph nodes between March 2009 and February 2010. RESULTS: The number of lymph nodes and median FNA-Tg level of the positive lymph node cytology group were 99 and 1,300 ng/mL (range, 0.2-5,000), respectively, whereas corresponding values in the negative cytology group were 359 and 4.7 ng/mL (range, 0.1-1,173). The AUCs of FNA-Tg, serum-Tg, and FNA-Tg/serum-Tg ratio were 0.93 (95% CI, 0.90-0.97), 0.64 (95% CI, 0.57-0.70), and 0.83 (95% CI, 0.78-0.88), respectively. The sensitivity and specificity of FNA-Tg were 90.9% and 98.3%, respectively, and the percentage agreement with the cytology results was 96.7%. CONCLUSIONS: The agreement of FNA-Tg with the cytology results was good at the cutoff value of 35.9 ng/mL. The measurement of FNA-Tg in cases with uninterpretable cytology results can be useful in evaluating lymph node metastasis of papillary thyroid cancer.

Quality Assessment of Red Blood Cells, Pooled Platelets and Frozen Plasma Processed by the Buffy Coat Method / 대한수혈학회지

BACKGROUND: Buffy coat method is one of the blood components processing methods widely used in many countries including Europe and Canada. For the first time in Korea, we evaluated the qualities of blood components manufactured by buffy coat method. METHODS: We collected 400 mL whole bloods using the quadruple top and bottom blood bag from thirty-five donors. Whole bloods were processed into leukoreduced RBC, leukoreduced pooled platelet, and 24 hr frozen plasma by the buffy coat method with blood bags and instruments of Fenwal and Fresenius. The qualities of each blood component were analyzed at each scheduled day, and compared with the standard guidelines of quality control in Korean Red Cross. RESULTS: The volume and hemoglobin of RBCs were lower than the standard guidelines. Comparing with the standard of apheresis platelets, leukoreduced pooled platelets showed higher total platelet yield with the median 3.70x10(11)/unit. Frozen plasma showed increased volume recovery than the standard guideline, but the activity of factor VIII at Day 35 was decreased to 0.66+/-0.14 IU/mL. CONCLUSION: We have found that the yields of pooled platelet and the frozen plasma processed by buffy coat method were higher than the standard guidelines. To introduce the buffy coat method to routine blood component separation process in Korea, further evaluations about the cost-effectiveness of buffy coat method are required.

Automated Collection of Leukoreduced Double Red Blood Cell Units using an Alyx Apheresis Device / 대한수혈학회지

BACKGROUND: Automated collection of leukoreduced double red blood cell (RBC) units has been used to improve blood collection efficiency in many countries. The aim of this study was to evaluate leukoreduced double RBC unit collection using apheresis and to determine its clinical uses. METHODS: Automated leukoreduced double RBC units were collected from 17 healthy male volunteers using an Alyx apheresis device (Baxter, DeerWeld, IL). Our institutional criteria for male donors were as follows: height > or =170 cm, weight > or =70 kg, and hemoglobin > or =14.5 g/dL. Each donor's complete blood count (CBC) was determined before and after the apheresis procedure. In order to validate the final leukoreduced double RBC units, white blood cell (WBC) counts were measured manually using a Nageotte chamber. RESULTS: Leukoreduced double RBC units were collected in an average of 27+/-7 min, without specific donor reactions. The average volume of one unit of leukoreduced RBCs was 281+/-6 mL. Each donor's hemoglobin (P<0.001) and hematocrit (P<0.001) were significantly lower after donation, though WBC and platelet counts were no different. No residual WBCs were found in the leukoreduced, filtered product upon Nageotte chamber counting. Twenty-eight units of leukoreduced RBCs from 14 donors were transfused to patients who required leukoreduced RBCs, without specific transfusion reactions. CONCLUSION: The Alyx apheresis device allowed for safe and effective collection of leukoreduced double RBC units from a single donor. Automatically collected leukoreduced double RBC units were transfused to patients for the first time in Korea.

Automated Collection of Leukoreduced Double Red Blood Cell Units using an Alyx Apheresis Device / 대한수혈학회지

BACKGROUND: Automated collection of leukoreduced double red blood cell (RBC) units has been used to improve blood collection efficiency in many countries. The aim of this study was to evaluate leukoreduced double RBC unit collection using apheresis and to determine its clinical uses. METHODS: Automated leukoreduced double RBC units were collected from 17 healthy male volunteers using an Alyx apheresis device (Baxter, DeerWeld, IL). Our institutional criteria for male donors were as follows: height > or =170 cm, weight > or =70 kg, and hemoglobin > or =14.5 g/dL. Each donor's complete blood count (CBC) was determined before and after the apheresis procedure. In order to validate the final leukoreduced double RBC units, white blood cell (WBC) counts were measured manually using a Nageotte chamber. RESULTS: Leukoreduced double RBC units were collected in an average of 27+/-7 min, without specific donor reactions. The average volume of one unit of leukoreduced RBCs was 281+/-6 mL. Each donor's hemoglobin (P<0.001) and hematocrit (P<0.001) were significantly lower after donation, though WBC and platelet counts were no different. No residual WBCs were found in the leukoreduced, filtered product upon Nageotte chamber counting. Twenty-eight units of leukoreduced RBCs from 14 donors were transfused to patients who required leukoreduced RBCs, without specific transfusion reactions. CONCLUSION: The Alyx apheresis device allowed for safe and effective collection of leukoreduced double RBC units from a single donor. Automatically collected leukoreduced double RBC units were transfused to patients for the first time in Korea.