Mycoplasma pneumoniae(MP) is a common pathogen found in respiratory tract infections of children and is susceptible to macrolides, tetracycline, aminogly-cosides, and quinoloines . Of all these antibiotics, macrolides is the frist choice for children. However,in recent years, strains which are resistant to common drugs have been selected in vitro and isolated from patients Point mutation at antibitics target site of these 8trains is one of the molecular mechanisms.The study of MP resistance can provide theoretical guidance for rational choice of antibiotics and application.

Objective To determine pathogens and epidemiological characteristics of adults with acute respiratory infection (ARI) in Beijing area.Methods During 2015,a total of 2 700 cases of ARI were sampled and detected for 9 respiratory pathogens including Legionella pneumophila type1 (LP1),mycoplasma pneumoniae (MP),qrickettsia (COX),chlamydia pneumoniae (CP),adenovirus (ADV),respiratory syncytial virus (RSV),influenza virus type A and B (INFA,IFVB) and parainfluenza viruses type1,2 and 3 (PIVs) using indirect fluorescence immunoassay.Results A total of 620 cases of ARI were tested positive with positive rate of 22.97％ (620/2 700).MP had the highest prevalence followed by LP1,INFB,COX,CP,PIVs,INFA,ADV and RSV in turn.There were 109 cases found mixed infection with the proportion of 17.58％ (109/620).Mixed infection of LP1 along with MP was the most common pattern.The highest detection rate of pathogens was observed in November,whereas the lowest in April in terms of months (x2 =31.288,P＜ 0.01).Different pathogens had distinct prevalent features.The prevalence of male was significant higher than that of female (x2 =6.402,P =0.011).As for stratificated by age,the middle-aged people had the highest infection rate (x2 =9.094,P=0.059).There was no significant difference between the out-and in-patient in terms of infection rate (x2 =0.114,P=0.736).Conclusion MP,LP1 and INFB accounted for ARI of adults in Beijing area during 2015.

Objective To investigate the protective effect of lipsomal clodronate against hepatic injury in rats with acute necrotizing pancreatitis (ANP). Methods 48 SD rats were randomly divided into control group, ANP group and lipsomal clodronate group, respectively. The models of ANP were established by injection of sodium taurocholate into the pancreatic capsule. Lipsomal clodronate was prepared by means of thin film. Blank liposomes and clodronate-containing liposomes was injected via caudal vein in ANP group and lipsomal clodronate group, respectively. The rats were sacrificed at 2, 6 h after ANP induction, the serum levels of ALT, AST and AMS, IL-6,IL-12 were measured, and pathologic changes of liver and pancreas were observed. Results At 6 h, serum level of ALT was (73 ± 11) U/L, (257 ± 33) U/L and (184 ± 29) U/L in control group, ANP group and lipsomal clodronate group, respectively;serum levels of AST were (190 ± 32)U/L, (590 ± 70)U/L and (430±52)U/L, respectively;serum levels of AMS were (814±80)U/L, (5031 ± 471) U/L and (2843 ± 236) U/L, respectively, serum levels of IL-6 were (26.7 ± 5.7) pmol/L, (218.0 ±4.7)pmol/L and (112.3 ± 8. O) pmol/L, respectively;serum levels of IL-12 were (4. 2 ± 1.0) pmol/L,(309.5 ± 8.5) pmol/L and (153.7 ± 6.3) pmol/L. The values in ANP group and lipsomal clodronate group were significantly higher than those in control group, while the values in lipsomal clodronate group were significantly lower than those in ANP group (P < 0. 01). Pathologic changes of liver and pancreas were significantly attenuated in lipsomal clodronate group. Conclusions Intravenous liposomal clodronate could exert protective effects on the hepatic injury in rats with ANP.

Objective To investigate the protective effect of clodronate SPIO liposomes on liver injury of rats with severe acute pancreatitis(SAP)and the role of MRI in evaluating the extent of liver injury.Methods Superparamagnetic Fe3O4 nanoparticles were prepared by chemical coprecipitation.Clodronate-SPIO-containing liposomes was prepared by the thin-film method.SAP models were prepared by a uniform injection of sodium taurocholate(2 ml/kg body weight)into the subcapsular space of the pancreas.SD rats were randomly divided into control group,SAP plus SPIO group, and clodronate-SPIO-containing liposome group.Six hours after SAP models were available,T2-weighted MRI scanning(in the same plane)of the liver of rats in each group were performed.At the end of the scanning,blood samples were taken from the supcrior mesenteric vein to measure the contents of serum ALT and AST.Meanwhile, The pathological changes in the liver and pancreas were observed.Results Transmission electron microscopic examination showed that liposomes had a uniform size.No changes in the pancreas of rats in control group were noted.The pathological changes in the pancreas and liver of rats in SAP plus clodronate-SPIO-containing liposome group were significantly milder than those in SAP plus SPIO liposome group.The contents of serum ALT and AST in rats in SAP plus SPIO liposome group were significantly higher than those in control group(P＜0.01), while the contents of serum ALT and AST in rats in SAP plus clodronate-SPIO-containing group were significantly lower than those in SAP plus SPIO liposome group(P＜0.01).The MRI signal intensity of the liver in SAP plus SPIO liposome group and SAP plus clodronate-SPIO-containing liposome group was significantly lower than that in control group.The significant changes in the MRI signal intensity of the liver in SAP plus SPIO liposome group and SAP plus Clodronate-SPIO liposome group were noted(P＜0.01).Conclusion Clodronate-containing liposomes have protective effects against liver injury in SAP rats and SPIO can be used as a tracer for MRI examination.

Objective To study the distribution of antinuclear antibodies ( ANAs) in a healthy population and the significance of using ANAs screening test in medical examination .Methods The ANAs were measured by indirect immunofluorescence assay ( IIF) .The Western blot assay was used to detect fif-teen specific antibodies against auto-antigens .Results 3519 out of all 25 110 subjects showed ANAs titers>1∶100 , and among them male and female subjects were respectively accounted for 1143 and 2376 .1489 out of all subjects had ANAs titers >1∶320 , and among them male and female subjects were respectively accounted for 406 and 1083 .The positive rates of ANAs at different titers showed significant differences be -tween male and female subjects .Among subjects with ANAs titers >1∶320 , the number of male subjects showed a steady increase with the age , while the percentage of female subjects reached to two peaks during the periods of puberty and menopause .The fifteen specific antibodies were detected in 659 out of 1489 sub-jects with ANAs titers>1∶320 and anti-Ro-52 (14.2%) accounted for the majority , followed by anti-M2 (12.7%) and anti-SSA (9.6%).Conclusion ANAs can be detected among healthy population of all ages, but their distribution varied with gender and age .ANAs screening test is necessary for medical exami-nation of healthy population , especially for female during period of puberty or menopause .The population with positive ANAs should be followed-up closely and educated for the prevention of autoimmune diseases .

Objective To investigate the protective effects of lipsomal clodronate on renal injury in rats with severe acute pancreatifis and the assessment of renal injury. Method Totally 48 rats were randomly divided into three group:normal control group (C);SAP group, in which rats were treated with pure liposomal (P);treatment group, in which SAP rats were treated with liposomal clodronate disodium(T). The SAP model of rat was induced by injection of 5 % sodium taurochohte beneath the pancreatic membrane. Rats of normal control group received isovolumetric injections of 0.9% physiological saline solution instead of sodium taurocholate. Blood samples were collected to measure AMS,BUN,Cr,IL-6 and IL-12 at 2 hors, 6 hours after SAP. At the same time, the samples of pancreatic and renal tissues were taken for observing the pathological changes. Results Compared with controlgroup, serious renal and pancreatic damages were found in group P, and the AMS, BUN, Cr levels elevated signifi-candy (P < 0.01). Compared with group P,the renal and pancreatic damages were attenuated in group T, and the levels of Cr and AMS decreased significantly (P < 0.01), and the IL-6, IL-12 were decreased at 2 hours and 6 hours (P < 0.01). The BUN decreased significantly at6 hours (P < 0.05). Conciusions Excessive release of inflammatory mediator play an important role in renal injury in SAP. Lipsomal clodronate disodium can alleviate the damage of pancreas and kidney.

Objective To develope a new Real-time quantitative PCR assay using SYBR green as fluorescence reporter, which is rapid, specific, sensitive, cheap and accurate for the detection of mycoplasma pneumoniae(MP), and evaluated its clinical application value.Methods The sequence of the 23S rRNA gene in MP type strain FH was selected as amplified regions, and specific primers were designed.Then the related plasmids were extracted as standards,and the absolute quantitative standard curve was established.The sensitivity ,specificity of the fluorescence quantitative PCR assay was compared with the nest-PCR and kit;To calculate correlation coefficient, coincidence rate and kappa coefficient, clinical samples were detected using above-mentioned methods and cultivation,respectively.Results The detection sensitivity of the new real-time PCR and nest-PCR was 10 copies of FH DNA,while the kit 100 copies.In the specificity tests,the MP sample was positive,while mycoplasma hominis and other four bacteria were all negative.We applied this real-time PCR assay ,nest-PCR, kit and cultivation to 182 clinical specimens, and the detection rates were 55.49％, 52.75％, 47.25％ and 39.01％ ,respectively.The total consistency rate and Kappa coefficient of the new real-time PCR method and nest-PCR were 89.6％ ,0.790, respectively;while those of the new method and cultivation were 83.5 ％ ,0.678, respectively.The total consistency rate and Kappa coefficient of the new real-time PCR method and the kit were 89.6％ ,0.792,respectively;and the correlation coefficient of these two methods was 0.923,P ＜ 0.001.Conclusion Compared with other methods, the new real-time PCR assay could be used to detect mycoplasma pneumoniae quickly and economically, with high sensitivity and specificity ,revealing great utility value on varied instrumentation platforms.

Objective To investigate the clinical characteristics of adult patients with community acquired pneumonia (CAP) caused by acute Mycoplasma pneumoniae (MP) infection, and provide evidence for early identification of MP infection. Methods A prospective, multicenter and cross-sectional study was conducted. 452 adult patients with CAP admitted to Beijing Friendship Hospital, Beijing Guangwai Hospital and Air Force General Hospital from August 2011 to October 2015 were enrolled. The diagnosis of adult MP infection was confirmed by the combined application of double serum antibody titer and MP-DNA nested polymerase chain reaction (PCR) through testing serum and throat swab samples from patients to identify acute infections, past infections, pathogen carrying, and non-MP infection. The clinical characteristics of patients with acute MP infection were summarized by analyzing the baseline data, clinical parameters and chest imaging findings in patients with non-MP infection and acute MP infection. Results Of 452 enrolling patients with CAP, 288 patients (63.7%) suffered from MP infection, and 164 patients (36.3%) with non-MP infection. There were 56 patients (12.4%) with acute infection, 10 patients (2.2%) with past infections, 222 patients (49.1%) with pathogen carriers in MP infective patients indicating susceptible to MP in adult patients. There were no significant differences in gender, age, fever extent, duration of fever, sputum production, shortness of breath, rales, underlying diseases, etc. between non-MP infection and acute MP infection patients, which suggested that the baseline data of the two groups were equilibrium. The acute infection rates of MP in summer and autumn (43.9% and 43.5% respectively) were more than those in spring and winter (13.3% and 12.3% respectively). It was shown by laboratory examination results that serum cardiac troponin T (cTnT) increased significantly in acute MP infectious patients more than that in non-MP infection patients (30.4% vs. 9.8%, P < 0.01), which indicated that patients with acute MP infection were more likely to have myocardial injury. While there were no significant differences in blood routine, blood electrolytes, blood glucose, as well as heart, liver and kidney function between the two groups. It was shown by chest imaging that the diffuse lesions (57.1% vs. 37.2%), mediastinal lymphadenopathy (60.7% vs. 37.8%) were less founded in the middle lobe of the right lung (12.5% vs. 32.9%), which were the main manifestations in patients with acute MP infection as compared with non-MP infection patients with statistical difference (all P < 0.01). There were no significant differences in the chest imaging performances of pulmonary ground glass shadow, lobar and segmental consolidation, patch shadow, a shadow, acinar nodules, grinding glass density nodules, the photic zone, hilar lymphadenopathy and pleural effusion occurrence between the two groups. Conclusion Adult CAP patients are easy to carry MP, myocardial damage is a common complication in acute MP infectious patients which are characteristic of image findings of diffuse lung disease, mediastinal lymphadenopathy and less founded in the middle lobe of the right lung.

Objective To investigate status of macrolide resistance and determine molecular mechanisms in Mycoplasma pneumoniae.Nethods All of 370 throat swab specimens were cultured to isolate Mycoplasma pneumoniae.Mycoplasma pneumoniae isolates were identified by nested PCR for specific 16SrRNA gene.Antibiotic susceptibility test was done to identify acrolide resistant strains.23SrRNA gene wag amplified by nested PCR followed by direct automatic sequencing method.The DNA sequences were compared to the sequence of Mycoplasma pneumoniae M129(accession no.X68422)to find molecular mechanisms of drug resistance.Results Fifty clinical strains were isolated from 370 specimens.Of 50 strains.4 strains were susceptible to macrulide,46 strains were macrolide resistant with the percentage of 92%.MICs of resistant strains to erythromycin.Azithromycin and josamycin were elevated.The sequence of 23SrRNA gene in 4 Susceptible strains and the reference strain FH was identical to Mycoplagma pneumoniae gene in GenBank.46 resistant strains arbored a point mutation respectively,among them,40 strains had all A to G transition at position 2063.1 strain had an A to C transition at position 2063,the other five strains showed an A to G transition at position 2064.Conclusions Macrolide resistance in Mycoplasma pneumoniae iS very serious health conceru.The point mutation in 23SrRNA.Xpecailly predominant position 2063 mutation contributed to the macrolide resistance in Mycoplagma pneumoniae.The MICs of resistant strains to erythromycin,azithromycin and iosamycin are much higher than Mycoplasma pneumoniae reference strain FH.

Objective: To investigate the diagnosis and treatment of adult small bowel torsion in order to improve early diagnosis and improve prognosis. Methods: Clinical data of 43 cases of small bowel torsion from January 2012 to December 2017 were collected. All of them were confirmed by surgery as small bowel torsion. After admission, white blood cell count > 18 × 10⁹/L was found in 5 patients; and hemoglobin<100 g/L was found in 5 patients; abdomen CT examination in 39 patients showed 33 cases had intestinal torsion; 14 cases suggested possible mesenteric and root torsion. Results: All patients underwent surgical treatment. During the operation, there were 11 cases with intestinal torsion ≥ 720°; 13 cases underwent simple bowel torsion in surgical operation; 4 cases underwent decompression combined with reduction of the bowel; 1 case was treated with reduction and jejunostomy; and small intestine resection was performed for intestinal necrosis. Twenty-two patients had small bowel resection and jejunostomy was performed in 3 cases. The small intestine was resected 7-240 cm, with an average of about 66 cm. Conclusions Small bowel torsion should be diagnosed and operated as soon as possible. The suspected necrotic bowel should be removed and more healthy intestine should be reserved. The patient′s vital signs should be observed dynamically after operation to prevent the occurrence of intestinal necrosis and septic shock, to avoid excessive intestinal necrosis that would lead to postoperative short bowel syndrome, and to improve the patient's cure rate and reduce hospital stay.