Antibiotic resistance remains a major threat to public health worldwide, especially in China, where multidrug-resistant bacteria are prevalent.National action plan on antimicrobial resistance 2016 to 2020 is a great and comprehensive plan for the control of antimicrobial resistance in China, and it is a perfect practice ofOne Healthconcept.To help readers to have a thorough understanding of this action plan, this paper gives a detailed introduction of the action plan, and points out the possible challenges in the implementation of the plan.

Antimicrobial resistance surveillance is the basis of drug resistance control. It is of great value to understand the development trend of drug resistance, newly emerging resistant bacteria, drug resistance control policy formulation, antimicrobial stewardship, new antibiotics research and development, and related basic researches. High quality surveillance lays a solid foundation to ensure the scientific value of the results; it is necessary to carry out active surveillance to obtain results under the same quality standard with uniform methods, which can make up for the lack of passive survey and guarantee the accurate application of data.

OBJECTIVE To determine the bacterial distribution and resistance of biliary tract infections in China.METHODS Disc diffusion test,MIC test or E-test were used to detect the antimicrobial sensitivity of bacterial isolates from bile specimens.WHONET software was applied for analysis of the bacterial sensitive data from 84 tertiary Mohnarin member hospitals at different area in China from June 1,2006 to May 31,2007.RESULTS A total of 1441 bacterial strains were collected in the survey period,which included 952 Gram-negative strains(66.1%),of which the top three were Escherichia coli(31.0%),Klebsiella pneumoniae(8.4%) and Pseudomonas aeruginosa(7.8%) and 489 Gram-positive strains(33.9%),the top three were Enterococcus faecalis(11.6%),E.faecium(9.5%) and Staphylococcus(7.4 %).Susceptibility results showed that the resistant rates of E.coli and K.pneumoniae to three generation cephalosporins and quinolones were 25.9-70.0%,17.9-44.8% and 66.9-70.9%,34.6-40.0%,respectively,which were comparable with the results of overall bacteria collection.The resistant rates of P.aeruginosa to imipenem and cefoperazone/sulbactam were 37.5%,13.8%,and the detection rate of meticillin-resistant Staphylococcus aureus(MRSA) from bile samples was higher than the results of overall bacteria collection.Vancomycin-resistant Enterococcus(VRE) were rare.CONCLUSIONS Gram-negative bacilli are still the predominant pathogens in biliary tract infections;the overall bacterial resistance is severe.MRSA is increasing.Prudent application of antibiotics in biliary tract infections needs to be emphasized.

OBJECTIVE To investigate the antibacterial resistance of clinical isolates from inpatients of non-ICU departments in China in 2006-2007.METHODS Clinical isolates were collected by member hospitals of Mohnarin according to unified protocol.Bacterial susceptibility testing was carried out using Kirby-Bauer(KB),MIC or E-test methods according to CLSI 2006.The data were analyzed by WHONET 5.4 software.RESULTS A total of 77253 clinical isolates from inpatients of non-ICU departments in Mohnarin member hospitals were collected from Jun 2006 to May 2007,of which Gram-negative bacteria accounted for 53549(69.3%),and Gram-positive cocci for 23704(30.7%).Meticillin-resistant Staphylococcus aureus(MRSA) and coagulase-negative Staphylococcus(MRCNS) strains accounted for 57.6% and 83.3%,respectively.There was no glycopeptide-resistant Staphylococcus to be found,but small part of coagulase-negative Staphylococcus was teicoplanin intermediate or resistant.50.9% Of Enterococcus faecalis and 69.9% of E.faecium strains were resistant to high concentration gentamicin.1.1% And 2.7% of E.faecalis and E.faecium isolates were resistant to vancomycin,0.8% and 2.7% resistant to teicoplanin.There were 9.9% isolates of Streptococcus pneumoniae were penicillin-nonsusceptible.About 34.5% Escherichia coli and 23.5% Klebsiella pneumoniae isolates were ESBLs-producing strains.Isolates of Enterobacteriaceae were still highly sensitive to imipenem and meropenem,the average resistant rate was less than 2%.There were about 70% E.coli isolates resistant to quinolones,and 20-60% of non-fermentative Gram-negative bacilli were resistant to antibacterials.CONCLUSIONS Bacterial resistance is severe in inpatients in our country,and the resistant rates are increasing.More effective measures should be taken

Objective To study the relationship between the gene mutations of DNA gyrase subunit A(gyrA)and quinolone resistance in Salmonella typhi. Methods The genes of gyrA DNA of Salmonella typhi S275(a clinically isolated quinolone susceptible strain)and its spontaneous quinolone-re-sistant mutant RGl were examined in this study with polymerase chain reaction(PCR),restrictive frag-ments length polymorphism(RFLP),single strand conformational polymorphism(SSCP)and nucleotide sequencing. Results Nudeotide sequencing of gyrA in Salmonella typhi S275 revealed that the bases of 128～426 kept highly conservative as compared with those of Escherichia coli KL-16,with only 7.49%difference in the gyrA nucleotides 128～426 between the two strains.Most of the mutations were silent mutations,which contributed to 3 amino acid substitutions in gyrase(including Thr-45→His,Arg-49→Leu and Val-56→Gly),and all these substitutions were located outside the quinolone resistance determining re-gion(amino acids 67-106 of subunit A of gyrase).In comparison with Salmonella typhi S275,a single mutation was found at base 247 of gyrA of Salmonella typhi RG1,with change transferred from T to G and led to a substitution of Ser-83→Ala.The mutation might be responsible for the increase of MICs of nalidixic acid,ofloxacin and ciprofloxacin against Salmonella typhi from 2,0.06 and<0.03 to 512,2,and 1 mg/L respectively.Ser-83→A1a was also a newly discovered substitution in gyrA of Salmonella spp.The results of PCR-RFLP and SSCP were in concordance with results of nucleotide sequencing. Conclu.sions The mutation of gyrase at the 83rd amino acid maybe play a principal role in the resistance of Salmonella typhi to quinolone.

Objective To evaluate the reliability of using imipenem,meropenem,cefoperazonesulbactam,piperacillin-tazobactam in the treatment of hospital-acquired Gram-negative bacterial infections with Monte Carlo simulation(MCS).Methods The MIC of the four agents collected from hospital-acquired infections were detected in accordance with broth dilution method of Clinical and Laboratory Standard Institute (CLSI).MCS were conducted with MICs and the pharmacokinetics parameters of the four agents based on conventional dose regimens.The cumulative fraction of response (CFR) of time over MIC target attainment in different dosing regimen were generated.Results A total of 2 541 strains,including 2 093 strains of Enterobacteriaceae and 448 strains of glucose non-fermentative bacilli were collected.The MIC90 of imipenem and meropenem against Enterobacteriaceae were less than 1 mg/L in general,whereas MICg0 of two agents with β-1actamase inhibitors was around 64 mg/L.As to glucose non-fermenting bacteria,MICs of all the four agents were very high,especially to Acinetobacter baumannii,which indicated MIC50 more than 32 mg/L.MCS revealed that carbapenems had significantly higher CFR than those with β-1actamase inhibitors.Imipenem and meropenem (1 g,q8 h) obtained CFRs of 74.69％ and 81.42％,respectively.The CFR of cefoperazone-sulbactam (2 g,q8 h) and piperacillin-tazobactam (4 g,q6 h) (both excluding β-1actamase inhibitors) were just 49.59％ and 27.66％ respectively,which increased after excluding A.baumannii in piperacillin-tazobactam.Conclusions The conventional dose regimens of imipenem and meropenem are reliable for the empiric therapy of Gram-negative hospital-acquired bacterial infections.Piperacillin-tazobactam is suggested to use with higher doses or prolonged infusion time to satisfy the time of drug concentration exceeded the MIC (T ＞ MIC) requirement.More clinical studies of cefoperazone-sulbactam should be conducted to optimize its regimen and guarantee its efficacy.

Objective To investigate Enterococci resistance to glycopeptides and their genotypes. Methods MICs of antimicrobial agents to Enterococci were determined with agar dilution test and van genes were amplified with PCR. Results 298 E. faecalis and 42 E. faecium clinical isolates were collected from 13 University teaching hospitals around China. The resistant rates of E. faecalis to penicillins were 14.1%～17.8%, which was much lower than those of E.feacium. No glycopeptides resistant Enterococci strain was detected. 8 E. faecalis and 1 E. faecium were intermediate sensitive to vancomycin but sensitive to teicoplanin with MICs of 8～16 and 0.25～2 mg/L, respectively. PCR amplification of van genes gave rise to only vanC2/3 gene positive in E. faecalis B144. Conclusions Glycopeptide resistant Enterococci is not common in China and no vanA or vanB type Enterococci was detected in this study. Penicillins, vancomycin and teicoplanin could be employed in the treatment of Enterococcus faecalis infections. High attention should be paid to future development of vancomycin resistant Enterococcus (VRE) in China.

Objective To determine the bacterial composition and resistance of wound infections in China. Methods Disc diffusion test,MIC test and E-test were used to detect the antimicrohial resistance of bacterial isolates from wound secretions.WHONET 5.4 was applied for analysis of the bacterial sensitive data from 86 domestic tertiary hospitals from June 1,2006 to May 31,2007. Results (1)2125 bacterial strains were coileeted in the survey period,which included 994 strains (46.8%) of Gram positive and 1131 strains (53.2%) of Gram negative bacteria,Staphylococcus(780 strains,36.7%),E.coli(338 strains,15.9%) and Pseudomonas aeruginosa (231 strains,10.9%)were the most common isolates.(2)38.2% and 84.1% of Staphylococcus aureus and Staphylococcus epidermidis were methicillin-resistant.respectively.No Staphylococcus strain was resistant to vancomycin or teicoplanin.(3)ESBLs positive rate of E.coli was about 60%,while the resistant rate to quinolones Was about 70%.(4)The resistant rates of Staphylococci and E.coli isolated from adults to aminoglyeoside and quinolones were higher than those from children.(5)The resistant rates of Staphylococei to cephalosporin,aminoglyeoside and quinolones from inpatients were higher than those from out-patients. Conclusion Staphylococci,E.coli and Pseudomonas aeriginoso were among the most common organisms isolated from wound infections.The ESBLs positive rate of E.coli from wound infections was higher than that from all specimen bacteria found in other surveys performed during the same period and the methicillin resistant Staphylococci were less than that.

Objective To analyze the influence factors of complications in CT-guided percutaneous pulmonary biopsy,and to explore the optimal methods of operation.Methods Totally 410 patients who underwent CT-guided percutaneous pulmonary biopsy were retrospectively analyzed,and the complications of biopsy were observed.Results Pulmo-related complications occurred in 54 patients (54/410,13.17%) ,including pneumothorax in 18 patients (18/410,4.39%) ,1 of them had pneumothorax and pulmonary bleeding around the needles in 35 patients (35/410,8.54%) ,15 of which with haemoptysis (15/410,3.66%) ,and 1 patient had acute pleura reaction.No severe complications such as infection.excessive bleeding,hemothorax,aeroembolism,needle track implantation metastasis occurred.Conclusion Accurate and skillful CT-guiding techniques and appropriate operation methods are important to improve the success rate and to reduce complications of CT-guided percutaneous pulmonary biopsy.

Objective To investigate the mechanism of cross resistant inducibility of ciprofloxacin and imipenem which led to cross resistance in Pseudomonas aeruginosa in vivo. Methods Cross resistant mutant strains were selected and induced with clinical isolates of P.aeruginosa PA5 susceptible to ciprofloxacin and imipenem by experiment of murine peritonitis. Mutation of DNA gyrase gene, drug uptake and membrance proteins of P.aeruginosa PA5 and its mutants resistant to ciprofloxacin and imipenem were examined. Results Both ciprofloxacin and imipenem could induce resistant strain of P.aeruginosa in experimental murine peritonitis, the cross resistance rates after ciprofloxacin and imipenem challenge were 3.8% and 0.98% respectively. The results of PCR SSCP showed that 3 of six cross resistant of P.aeruginosa strains had gyrA gene mutation. Electrophoresis of outer and inner membrane proteins did not exist any difference between cross resistant strains and their parent strain PA5. Fluorometric assay for ciprofloxacin uptake by bacterial cells indicated that the accumulation of ciprofloxacin in all cross resistant variants decreased to 1/2～1/3 compared with that of PA5. After chanllenge with CCCP, the drug uptake in cross resistance mutants increased to the same level as in PA5. Conclusions The results show that cross resistant strains of P. aeruginosa could be selected and induced in vivo. Active drug efflux is the major factor contributing to the cross resistance of P. aeruginosa to both quinolone and imipenem.