Objective To research the clinical department distribution and drug resistance of Enterobacteriaceae bacteria to pro‐vide a theoretical basis for clinical rational use of antimicrobial drugs .Methods The Whonet 5 .6 software was adopted to conduct the retrospective analysis on Enterobacteriaceae bacteria isolated in the General Hospital of Ningxia Medical University and the Af‐filiated Cardiovascular Disease Hospital from 2011 to 2013 .Results A total of 7 315 strains of Enterobacteriaceae bacteria were i‐solated ;the top three of bacteria were 2 971 strains (40 .6% ) of Escherichia coli ,2 339 strains (32 .0% ) of K lebsiella pneumoniae and 1 117 strains (15 .3% ) of Enterobacter cloacae ;in the source of specimen ,the respiratory tract specimens had the highest isola‐tion rate (46 .6% ,3 410 strains) ,followed by the pus and secretion specimens (13 .9% ,1 015 strains) ,and the urine specimens (13 .0% ,953 strains) ;the isolated bacterial strains were mainly derived from the pediatric department (17 .5% ,1 282 isolates) ,res‐piration department (7 .1% ,518 strains) and ICU (6 .4% ,468 strains) ;the highest sensitivity of antibacterial drugs were carbapen‐ems ,amikacin and piperacillin/tazobactam also maintained a good antibacterial activity ,the resistance rate was 1 .3% - 7 .6% .Con‐clusion Enterobacteriaceae has a higher isolation rate in the clinical specimens and its resistance rates to antibacterial drugs are generally higher .The surveillance on bacterial drug resistance should be strengthened so as to provide a theoretical basis for the ra‐tional use of antimicrobial drugs and effective control of nosocomial infections .

Objective To explore the presence of myeloid-derived suppressor cells (MDSC) in patients with non-Hodgkin lymphoma (NHL) and its clinical value. Methods Peripheral blood samples were collected from 69 NHL patients and 21 healthy controls admitted in Jilin Cancer Hospital from January 2014 to February 2015. Flow cytometry was conducted to identify unique cell surface markers of MDSC using antibodies against CD11b, CD33, CD14 or HLA-DR. MDSC were enriched by immunomagnetic beads, then arginase 1 (Arg-1), inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) in which were detected by real time-PCR. In vitro, cell proliferation assay was used to test T cell function. Statistical analysis was used to explore the correlation between MDSC and clinical features. Results There were a high level of CD11b+CD14+CD33+cells in peripheral blood of NHL patients. The morphology of the cells belonged to mononuclear cells. The ratio of monocytic CD11b+CD14+CD33+cells in NHL patients was higher than those in healthy controls [(42±10) ％ vs. (34±11) ％, t= 0.300, P= 0.005]. The expressions of Arg-1, COX-2 and iNOS in CD11b+CD14+CD33+and CD11b+CD14+CD33-cells were 0.12±0.04 vs. 1.00±0.25 (t= 6.095, P=0.024), 3.03±0.45 vs. 1.00±0.78 (t= 7.766, P= 0.016) and 0.29±0.11 vs. 1.00±0.04 (t= 1.987, P= 0.209), respectively. In addition, the CD11b+CD14+CD33+cells inhibited T cell proliferation. The levels of MDSC in patients with different international prognostic index (IPI) score were significantly different (F= 2.536, P=0.049), but the levels of MDSC in patients with different sex, age, pathological type, stage, serum lactate dehydrogenase, physical status staging criteria and β2-microglobulin had no differences (all P < 0.05). Conclusions CD11b+ CD14+ CD33+ cells are characterized as MDSC in terms of higher level in NHL patients, expressing myeloid-specific proteins, and inhibiting T cell proliferation. The expression of MDSC is associated with IPI score, implying it might be a novel biomarker in clinical practice for NHL patients.

Objective: To investigate the application of metagenomic next-generation sequencing (mNGS) in detection of the rare or difficult-to-cultivate pathogens. Methods: One patient with acute lymphoblastic leukemia who went through allogeneic hematopoietic stem cell transplantation (allo-HSCT) developed symptoms of infection after transplantation. Conventional microbial culture, polymerase chain reaction (PCR), and mNGS combined with biological information analysis were performed with plasma and cerebrospinal fluid samples, the anti-infective treatment was adjusted according to the test results, and the efficacy was assessed. Results: No suspected pathogens were detected by microbial culture and PCR in the cerebrospinal fluid and plasma samples since the patient developed infection symptoms. However, Legionella pneumophila was analyzed by mNGS in the cerebrospinal fluid specimen on day 23 after allo-HSCT (reads count: 19 655), and it was considered as the principal pathogen after comprehensively evaluating the patient's clinical manifestations and the test results. Then the antimicrobial treatments were adjusted according to the patient's clinical manifestations and laboratory test results, and the number of gene sequences of Legionella pneumophila was monitored by mNGS method. Azithromycin, tigecycline, and other antibiotics effective for Legionella pneumophila were used after detecting this pathogen. A total of 15 mNGS analysis were performed during the 5-month period, and the highest number of Legionella pneumophila sequences monitored in the cerebrospinal fluid was 2 226, the lowest was 253 and eventually turned negative. The clinical symptoms and treatment outcomes were consistent with the mNGS monitoring results. Conclusions The mNGS technology has significant value in detection of the rare and difficult-to-cultivate pathogens. The mNGS technology provides a valuable supplement to microbial culture and PCR methods.