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.

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.

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 related clinical factors and homology of strains in Stenotrophomonas maltophilia (S. Maltophilia) infections in 15 patients with liver transplantation. Methods Fifteen patients with S. Maltophilia infection from September to December 2006 were enrolled and their clinical data were collected. Minimal inhibitory concentrations (MICs) of 10 antimierobial agents against S. Maltophilia were determined by Etest strips. Antibiogram was carried out by resistance analysis assembly with WHONET 5 software. The genomic DNA of all the isolates was digested with Xbal and subjected to pulse-field gel electrophoresis (PFGE). Results All patients received mechanical ventilation during the treatment and had a history of long-term use of extended-spectrum β-lactamases and quinolones. MICs of 10 antimicrobial agents indicated that S. Maltophilia were susceptible to several antimicrobial agents including compound sulfamethoxazole and ciprofloxacin, but the best active agent against these resistant isolates was minocycline in vitro. The results of all 15 S. Maltophilia antibiograms were accordance with PFGE patterns. All 15 S. Maltophilia isolates were classified as 2 PFGE patterns: 9 for pattern A and 6 for pattern B. Conclusion Mechanical ventilation might be associated with the S. Maltophilia septicemia in patients with liver transplantation.

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.

Objective To investigate the prevalence of the genotypes of extended spectrum ? lactamses (ESBLs) in klebsiella pneumoniae and eschrichia coli, which were isolated in Hangzhou City from 2000 to 2001. Methods Total of 198 isolates of E. coil and K. pneumoniae were isolated from five hospitals in Hangzhou. ESBLs-producing isolates were detected by inhibitor-potentiated disc diffusion test, Agar dilution method was used to determine the minimum inhibitory concentrations (MIC) of cefotaxime and ceftazidime.ESBLs genes were analysed by isoelectric focusing (IEF) assay and PCR initially,genotypes were determined by sequencing. Results 51 isolates (25.76%) from 198 E. coil and K. pneumoniae strains were obtained. In ESBLs producers, the ESBLs types of SHV, TEM, CTX-M were 17.65%,84.31% and 80.39% respectively. genotypes were: SHV 11,12;TEM 1;CTX M 3and CTX M 3 like, CTX M 13,14. respectively. Conclusions CTX M type were the major genotypes of ESBLs in klebsiella pneumoniae and eschrichia coli isolated in Hangzhou city.

Objective To observe the effects of Qutantongluo decoction on the expression of TGF-β1 in renal tissue of diabetic nephropathy(DN) rats,which can help to understand the mechanism of action.Methods The rats models of diabetic nephropathy were established by injecting with streptozotocin intraperi-toneally.All Wistar rats were randomly divided into 6 groups:the normal control group,the model control group,Benazepril Hydrochloridec group ( 1 mg/kg ·d-1 ),Qutantongluo decoction low dose group (3 g/kg ·d-1 ),Qutantongluo decoction median dose group (4.5 g/kg · d-1 ),and Qutantongluo decoction high dose group (6 g/kg · d-1 ).Rats in the normal control group and the model control group were given celiac perfusion of distilled water once at the same time and dose.All the rats were gavaged once daily for 8 weeks.The expression of TGF-β1 at the level of gene and protein in renal tissue were tested by immunohistochemistry and RT-PCR methods.Results Compared with the model control group(2.79±0.22),the expression of TGF-β1 at the level of protein in renal tissue of Benazepril Hydrochloridec group (1.55 ±0.12)and the Qutantongluo decoction low dose group ( 1.54± 0.16),Qutantongluo decoction median dose group (1.49 ± 0.17),Qutantongluo decoction high dose group(l.39±0.25) decreased significantly (P＜0.05).Compared with the model control group (0.35±0.07),the expression of TGF-β1 mRNA in renal tissue of Benazepril Hydrochloridec group(0.35± 0.07)and the Qutantongluo decoction low dose group(0.39±0.03),Qutantongluo decoction median dose group (0.35± 0.06),Qutantongluo decoction high dose group (0.32± 0.07) decreased significantly (P＜0.05).Conclusion Qutantongluo decoction can down regulate the expression of TGF-β1 in kidney,which may be one of the mechanisms of Qutantongluo decoction effectiveness in clinical treatment of diabetic nephropathies.