The key to improve the clinic antimicrobial therapy results is correct diagnosis of infection,pathogens and antibiotic resistance.To deal with increasingly complex pathogens and drug resistance,the clinic and lab should cooperate and communicate as often as possible,improve the level of pathogen diagnosis,interpretate of the microbiological examination report correctly and explore the mechanisms and treatment of antimicrobial resistant pathogens.Besides,they should make full use of the inflammatory markers to further enhance anti-infective levels.

The term "superbugs" refers to microbes with resistance to almost all antibiotics specifically recommended for the treatment. The superbugs disseminating worldwide included methicillinresistant Staphylococcus aureus ; vancomycin-resistant Staphylococcus aureus ; vancomycin-resistant Enterococcus ;carbapenem-resistant Gram-negative bacillus. Due to abuse of antibiotics, novel "superbug"emerged gradually, which demands optimizing antibiotic use, reinforcing surveillance of "superbugs" as well as nosocomial infection control.

Community-acquired methicillin-resistant Staphylococcus aureus ( CA-MRSA ) has been increasingly frequently isolated from patients worldwide, and is an emerging threat to public health.CA-MRSA strains differ from hospital-acquired MRSA strains in their epidemiologies, clinical features and genetic backgrounds, and the predominant CA-MRSA strains vary between geographic settings.This paper reviews literatures on the definition, epidemiology, clinical manifestations, treatment and virulent factors of CA-MRSA or CA-MRSA infection, and points out that we should further promote studies on epidemiology, molecular genetic properties of CA-MRSA and clinical management of CA-MRSA infection.

Objective To analyse the encoding gene sequence of extended spectrum ? lactamase produced by Klebsiella pneumoniae E95 strain in Zhejiang Province and identify its ESBLs subtype. Methods The gene of ESBLs produced by E95 strain was amplified by PCR. The purified PCR product was cloned into pGEM Teasy vector and then sequenced by Sanger's dideoxy chain termination composition method. Results The encoded gene of ESBLs was identified as SHV by PCR. Its PCR product had 812 nucleotides. It had the same gene sequence as the gene encoding SHV 12 discovered in Swiss. Conclusions The ESBLs produced by Klebsiella pneumoniae E95 strain isolated from a patient in Zhejiang Province is SHV 12.

Objective To construct the mice pneumonia model with imipenem-resistant Acinetobacter baumannii and provide experimental model in anti-pan-resistant Acinetobacter baumannii therapy study. Methods A total number of 120 4-week-old BALB/C male mice were randomly selected and divided into three groups including micro-intratracheal injection, ultrasonic atomizing and nasal dripping. The mice were treated with methotrexate to induce hypo-immunity in every group. These BALB/C mice of normal immunity and hypo-immunity were infected through Imipenem-resistant Acinetobacter baumannii by microintratracheal injection, ultrasonic atomizing and nasal dripping, respectively. The morbidity, mortality,bacterial clearance rate and histopathology in lung were determined. Results The morbidities of BALB/C mice with hypo-immunity infected by micro-intratracheal injection and ultrasonic atomizing achieved 100%(30/30), while the mortalities were 100% (10/10) and 33.3% (3/10), respectively. Mice in two groups above displayed the influx of neutrophils, lymphocytes and macrophages in the peri-bronchial and alveolar interstitial space 12-24 h after pulmonary infection. In addtion, the mice in micro-intratracheal injection group displayed coUapse of partial alveolar walls, formation of abscesses and bacterial colonies in alveoli. While the lung pathology in mice of ultrasonic atomizing group was characterized by cell degeneration in some regions in the lungs, slight relaxation, congestion in alveolar wall vessels and normal of bronchial and alveolar tissue 24 h after inoculation. Degeneration in peri-tracheal and peri-bronchial areas was observed 24-48 h after inoculation, along with highly expanded pulmonary blood vessels and edems. The inflammation was reduced at 48 hours. There was no obvious pulmonary infection in BALB/C mice with hypo-immunity by nasal dripping with mortality of 0% (0/10) and no significant histopathologic change in lungs. Conclusions BALB/C mice with hypo-immunity pneumonia model with Imipenem-resistant Acinetobacter baumannii can be conducted by micro-intratracheal injection or ultrasonic atomizing, but the latter has the advantages of high-productivity, easy-operation, low-cost, time-saving and usefulness. Mice with normal immunity are not susceptible to imipenem-resistant Acinetobacter baumannii.

Objectives To investigate the properties and distributions of ampC gene among different drug-resistant strains of Serratia marcescens,and the relationship of control gene ampR with AmpC enzymes′ expressions.Methods According to the results of inducting experiment with 1/2 MIC of beta-lactam antibiotics (CTX),three-dimensional testing and isoelectric focusing electrophoresis testing,143 strains of S.marcescens were classified into three groups:including induction group, continuous low-production group and hyperproduction group. In each group, the sequences of ampC and ampR genes were amplified using the method of PCR. The products of PCR were analyzed. The plasmid-mediated beta-lactamases were detected using the method of conjugation experiment.Results Among 143 strains of S.marcescens, the continuous low -production strains, induction strains and hyperproduction strains were 14,103,and 18, respectively.125 and 99 strains were ampC and ampR gene positive, respectively.The detection rate of ampR in hyperproduction group was lower than other groups.5 sites of ampC genes and 4 sites in the Open Reading Frame (ORF) of ampR gene were easily mutated in 5 induction strains and 2 hyperproduction strains.Conclusions The production of inducing drug-resistance of some S.marcescens might be related to mutation of ampC gene encoding AmpC beta-lactamases and the ORF mutation in ampR. The continuous hyperproduction drug-resistance had something to do with deletion mutation in ampR in segmental hyperproduction strains.The plasmid-mediated AmpC enzymes hadn′t been found in S.marcescens.

Objective To investigate the resistance-related genes of Shigella sonnei with decreased susceptibility to fluoroquinolones.MethodsA total of 131 strains of Shigella sonnei were analyzed for their antimicrobial susceptibility.Mutations within the quinolone resistance determining regions (QRDR) of gyrA and parC were detected by polymerase chain reaction (PCR) and PCR products were then sequenced. Meanwhile, the plasmid-mediated quinolone resistance (PMQR) genes,qnr and aac(6')-Ib-cr were screened by PCR.ResultsResistance rates of 131 Shigella sonnei isolates to nalidixic acid,tetracycline,ampicillin and trimethoprim-sulfamethoxazole were 100.0％,93.9％,93.2％ and 92.8％,respectively.All strains were susceptible to norfloxacin,ciprofloxacin,levofloxacin,while 94％ nalidixic acid-resistant Shigella sonnei strains showed reduced susceptibilities to fluoroquinolones.All of nalidixic acid-resistant Shigella sonnei strains presented a single mutation at codon 83 (Ser→Leu) of gyrA genes,but no mutations were detected in parC gene.And PMQR genes qnr and aac (6’)-Ib-cr were not detected.Conclusions The nalidixic acid-resistant Shigella sonnei strains with reduced susceptibility to fluoroquinolones are common in the clinical practice,which may mainly due to a single mutation at codon 83 (Ser→Leu) of gyrA genes.

Objective To evaluate the synergy effect of Meropenem and Sulbactam combination against Meropenem-resistant and Meropenem-susceptible A.baumannii in vitro and optimize combination ratio of Meropenem and Sulbactam to achieve best synergy effect.Methods Evaluating the synergy effect of Meropenem and Sulbaetam combination through microdilution checkerboard method against Meropenemresistant and Meropenem-susceptible A.baumannii,isolated from inpatients of Chinese hospitals.Assessing the synergy effect of combination in different ratios of Meropenem to Sulbactam.Results The checkerboard method with the combination of Meropenem and Sulbactam demonstrated 25.0％ ( 10/40 ) synergism,67.5％ (28/40) partial synergism,7.5％ (3/40) additive,no indifference and antagonism in Meropenemsusceptible isolates,and 27.5％ (11/40) synergism,40.0％ (16/40) partial synergism,25.0％(10/40) additive,no indifference and antagonism in Meropenem-resistant isolates.Eleven Meropenemresistant isolates which showed synergism in synergy test were tested for MICs of combination of Meropenem and Sulbactam,using ratios of 4∶ 1,2∶ 1,1∶1 and 1∶2,and the MIC90 were 64∶ 16,64∶ 32,32∶32,32∶64 μg/ml,respectively.Conclusions Meropenem and Sulbactam combination show synergism or partial synergism against most A.baumannii isolates.The optimal ration of combination for clinical use may be 1∶ 1.

Purpose　To investigate the role of urokinase plasminogen activator (uPA),uPA receptor (uPAR),tissue type plasminogen activator (tPA) and plasminogen activator inhibitor 1 (PAI-1) in the invasiveness of human breast cancer cells.　Methods　Three human breast cancer cell lines with different invasive ability were taken as research targets.RT-PCR and milk plates methods were used to detect the expression of uPA system members and the PA activities,respectively.Modified Boyden's chamber model was employed to detect the invasive ability of cancer cell.　Results　MDA-MB-231 could express high level of uPA,uPAR,PAI-1 and low level of tPA.MDA-MB-435 could express lower level of uPA and hight level of tPA,but no PAI-1 and uPAR were detected.MCF-7 could express lower level of uPAR and high level of PAI-1,but no uPA and tPA were detected.MDA-MB-231 cells showed the highest total PA and uPA activity.MDA-MB-435 cells also showed high total PA activity,but almost all the activity owed to tPA.MCF-7 showed almost no PA activity.Correlated with their PA activities,MDA-MB-231 was found the most invasive in vitro,followed by MDA-MB-435,and MCF-7 almost had no invasive ability.The antibodies against uPA and uPAR were significantly effective in reducing the matrigel invasiveness of MDA-MB-231 by approximately 83.1% and 43.9% respectively (P<0.05).　Conclusions　Co-expression of uPA,uPAR and PAI-1 in human breast cancer highly correlates with the invasiveness in vitro.

Objective To evaluate different tigecycline susceptibility testing methods for A.baumannii.Methods Thirty carbapenem resistant A.baumannii (CRAB) and 30 carbapenem sensitive A.baumannii (CSAB) isolates were randomly collected from 30 hospitals during January to December in 2010 in China retrospectively.MIC and inhibitory zone diameters for tigecyclinc were determined by the susceptibility testing methods such as broth microdilution (BMD),agar dilution,E test,MIC Test Strip (MTS),Vitek2.Data were analyzed by comparing the results from each method to those produced by the reference BMD method.The effects of two different susceptibility test media (M-H and ISO-Sensitest Agar) on the MIC of tigecycline were also analyzed.Results For CSAB isolates,the MIC50/MIC90 of BMD,agar dilution,E test,MTS and Vitek2 were as follows:0.125/0.25 mg/L,0.125/0.25 mg/L,0.5/1 mg/L,0.125/0.25 mg/L and 0.5/0.5 mg/L.Compared with BMD method,the categorical agreement rates (CA) of each method were ≥90％,and produced no very major errors (VME) by Food and Drug Administration (FDA)/ European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints.For CRAB isolates,the MIC50/MIC90 of BMD,agar dilution,E test,MTS and Vitek2 were as follows:2/4 mg/L,4/4 mg/L,4/4 mg/L,1/2 mg/L and 2/4 mg/L.Compared with BMD method,MTS produced 3.3％ (1/30)/6.7％ (2/30) VME(FDA/EUCAST breakpoints),and no method CA was ≥90％.The CA between disk diffusion and BMD results were higher by using the criteria of Jones than FDA breakpoints,but only 66.7％ (20/30) were observed in CRAB isolates,and produced no VME.The MIC of tigecycline determined using M-H agar were usually higher than those using ISO-sensitest Agar.Conclusions Agar dilution,E test,Vitek 2 and disk diffusion appear not to be a suitable method for routine susceptibility testing of tigecycline for CRAB strains.Tigecycline intermediate or resistant results determined by these methods require confirmation by BMD,and MTS results also need to be interpreted with caution.