OBJECTIVE To study clinical distribution of Serratia and learn the antimicrobial susceptibility to S.marcescens in vitro in order to offer the reference to optimally selecting antibiotic.METHODS It was analyzed that the 222 Serratia strains were distributed in and the was deteted 164 S.marcescens strains were isolated from our hospital from 2001 to 2006.Their VITEK-2 of French Bio-M?rieux Company was adopted to proceed the identification of bacteria and antimicrobial susceptibility test.Data were analyzed by WHONET 5.4.RESULTS Serratia were mainly isolated from sputum,urine,blood,secretion,bile,cerebrospinal fluid,abdominal fluid,et al.Infection of both in-and out-patients could be caused by Serratia and most were in surgery ward.S.marcescens had higher drug resistance rates to piperacillin,cefazolin,cefuroxime,gentamicin and tobramycin which were all above 60%.They were all susceptible to imipenem(minimum inhibitory concentration only 1 ?g/ml) and their susceptible rates to piperacillin/tazobactam,ceftazidime,cefepime,and levofloxacin were all higher than 80%.CONCLUSIONS Serratia are less isolated from clinics,but have much higher antimicrobial resistance to the 1st and 2nd generation cephalosporin and show diversely drug resistance to 3rd cephalosporin,so physicians should pay attention to the infection caused by them.

OBJECTIVE With surveillance of the distribution and antibiotic resistance of Escherichia coli during the last six years in our hospital,the basis for the reasonable clinical use of antibiotic is provided to doctor.METHODS A total of 1 907 strains of E.coli isolated during the last six years were analyzed by Kirby-Bauer disk or VITEK-2 system.RESULTS Among 1 907 strains of E.coli,1 114 strains were isolated from urine,accounted for 58.4%;215 from pus or secret,accounted for 11.3%;165 from sputum,accounted for 8.7%;and 159 from blood,accounted for 8.3%.ESBLs production rate of E.coli increased steadily from 5.11%,10.34%,14.56%,15.14%,33.79% to 29.96%,separately during the six years.The resistance of E.coli with ESBLs to most antibiotics was much higher than those without ESBLs.And E.coli demonstrated much higher resistant rate to ciprofloxacin,penicillins,and first or second generation cephalosporins,and much lower to amikacin and cefoperazone/sulbactam.No strains were found to be resistant to imipenem.CONCLUSIONS E.coli is the major pathogen,causing nosocomial infection with multi-resistant mechanism, since ESBLs-producing strain is increasing as years gone,reasonable choice of antibiotic should be in term of result of antibiotic resistant test and patient symptom to cure the E.coli infection induced.

OBJECTIVE To compare the changing trends of antibiograms of Salmonella typhi and S.paratyphi A isolates.METHODS A total of 42 isolates of Salmonella obtained from blood cultures patients in the First Affiliated Hospital of Chinese Medical University between 2001-2004 were included in the study.K-B test was used for the antimicrobial susceptivity test and the results were read based on National Committee for Clinical Laboratory Standards(NCCLS) of USA.RESULTS Twenty two isolates were identified as S.typhi and 20 were identified as S.paratyphi A.Sensitivity of S.typhi isolates to cephalosporins and chloramphenicol was found to have increased from 2001 to 2004 while that of S.paratyphi A showed a decline,meanwhile there was obviously increasing in resistance to ciprofloxacin.CONCLUSIONS Perhaps the schedule of empirical treatment of typhoid fever needs to be adjusted.

Objective To investigate the alternations in gene/amino acid sequence of penicillin-binding protein (PBP)2x from clinical isolates of Streptococcus pneumoniae, and to find the reasons for the rapid surge of penicillin and cefotaxime nonsusceptibility among pneumococcal isolates from Shenyang. Methods Thirty-four strains of Streptococcus pneumoniae were collected from January 2006 to February 2007. The antibiotics susceptibility of these strains was detected. PCR amplification and direct sequencing of pbp2x genes were performed. The sequence variations of PBP genes of the penicillin nonsusceptible Streptococcus pneumoniae(PNSP) in this region were studied by BLAST analysis. Results Two prominent substitutions were common to 12 PNSP isolates for which the MIC of penicillin resistance and cefotaxime were at least 0.5 mg/L, which included the replacement of Thr338→Ala in the first conservative motif STMK and Leu546→Val adjacent to third conservative motif KSG. The importance of the exchange of His394→Leu was identified in one PNSP isolate 15. The remarkable finding in this study was Met342→Ile following the first conservative motif STMK. pbp2x sequences of eight PRSP isolates shared Lys501-Glu505-Thr507 substitutions which might be served as a unique marker for PRSP in this region. Novel gene and amino acid sequence variants in 17 isolate were identified in this study, and these sequences have been deposited in the GenBank database and assigned accession No. EU044831, EU089706-EU089709, EU106881-EU106884 and EU124672. Conclusion It is likely that the emergence of penicillin and cefotaxime nonsusceptible Streptococcus pneumoniae in Shenyang might be associated with novel gene sequence variants.

OBJECTIVE To learn the profile of Gram-negative bacilli in ICU ward during the eight years and analyze the drug resistant rates in order to provide the basis for empirical treatment of infection.METHODS The bacteria were identified by VITEK-2 and API system.Antibiotic sensitivity test adopted Kirby-Bauer method.Data were analyzed by WHONET5.4 software.RESULTS Totally 1492 strains of Gram-negative bacilli were isolated from ICU ward,which included 1146 strains of non-fermentaters,accounted for 76.8% and 346 strains of Enterobacteriaceae,accounted for 23.2%.The first five bacteria were Pseudomonas aeruginosa,Burkholderia cepacia,Acinetobacter baumannii,Stenotrophomonas maltophilia,and Escherichia coli by turns.The drug resistant rates were higher and had the tendency of increase by years.CONCLUSIONS Non-fermentaters are the main organisms in ICU ward.The species of bacteria are diversified and the drug resistant rates of them are serious,which should be monitored not only because helping clinical therapy but also discovering the prevalence of drug resistant strains.

Objective To investigate the alternations in gene/amino acid sequence of penicillin-binding protein (PBP) 2b from clinical isolates of penicillin-nonsusceptible Streptococcus pneumonia(PNSP) in this region.Methods 24 strains of Streptococcus pneumonia were collected from January to December 2006.The antibiotics susceptibility of these strains was detected.PCR amplification and direct sequencing of pbp2b genes were performed.The sequence variations of PBP genes of the PNSP in this region were studied with sequence BLAST analysis.Results Three prominent substitutions were common tO 13 PNSP isolates with minimal inhibitory concentration(MIC) at least 0.1 mg/L.These included the replacement of Thr445→Ala following the conservative motif SSN,Glu475→Gly and Thr488→Ala/Ser.The exchange of Glu332→Gly was identified in 12 PNSP isolates of which the MIC was at least 0.25 mg/L.Seven penicillin resistant Streptococcus pneumonia (PRSP) isolates (MIC≥3 mg/L)shared the amino acid substitution Ala618→Gly adiacent to third conserved (KTG) motif and the PBP2b sequences of seven PRSP isolates were classified within Back's group Ⅱ and were very similar to those of the Korean J77 isolate.Novel gene and amino acid sequence variants in isolate 14,15,8,11 and 24 was identified in this study and these gene sequences have been deposited in the GenBank database and assigned accession no.EU035970,EU056919,EU056920,EU056921 and EU106886.Conclusion Analysis of pbp2b genes revealed highly similar patterns of nucleotide and amino acid sequence variation among most resistant isolates.while penicillin intermediate Streptococcus pneumonia might be associated with novel gene sequence variants.

Objective To detect the encoding gene of efflux pump and two-component system, and investigate the effect of efflux inhibition on the multiresistance of Acinetobacter baumarmii. Methods PCR was used to detect the adeB, adeR and aries gene. Agar dilution was used to determine the minimum inhibitory concentrations(MIC) of ciprofloxacin, cefotaxime, amikacin and imipenem of 50 multiresistance Acinetobacter baumannii, with or without 25 μg/ml reserpine. Results 94%, 96% and 92% of 50 muhiresistance of Acinetobacter baumannii were detected for adeB, adeR and aries gene,respectively. At least four fold decrease of MIC was observed in 49, 50, 50 and 46 isolates for ciprofioxacin, cefotaxime, amikacin and imipenem, respectively. Conclusion The multiresistance of Acinetobacter baumannii is related to the effect of the efflux system.

OBJECTIVE To learn the epidemiology of respiratory infection in ICU and non-ICU wards,and analyze the difference of drug resistance of Gram-negative bacilli between those two wards in order to provide the basis of empirical therapy for the respiratory infection from the different wards.METHODS The bacteria were identified by VITEK-2 and API system.Antibiotic sensitivity test adopted by K-B method.Data were analyzed by WHONET 5.3 software.RESULTS Totally 2184 strains of Gram-negative bacilli were isolated all from the respiratory tract,among which 655 strains were isolated from ICU ward and 1529 strains were from non-ICU ward.In ICU ward,the first five bacteria were Pseudomonas aeruginosa,Burkholderia cepacia,Acinetobacter baumannii,Chryseobacterium meningosepticum,and Stenotrophomonas maltophilia.It showed that non-fermentatives were the main pathogenic bacteria in ICU.In non-ICU ward,the first five bacteria were P.aeruginosa,Klebsiella pneumoniae,A.baumannii,B.cepacia,and S.maltophilia.Drug resistant rate of strain from ICU ward was generally higher than that from non-ICU ward,while levofloxacin in ICU ward showed the better activity than in non-ICU ward.CONCLUSIONS The respiratory infection is one of the hazards in nosocomial infection,drug resistant rate of Gram-negative bacilli from respiratory specimen in ICU is generally higher than that in non-ICU,and the main strains are the mlti-resistant non-fermentatives,which should attract the clinician′s more attention.

OBJECTIVE To study the changing trends of drug-resistance of Acinetobacter baumannii isolates.METHODS All 668 isolates of A.baumannii were obtained from clinical patients in the First Affiliated Hospital of China University of Sciences Medical between 2001-2006.K-B test was used to determine the susceptibility and the results were read based on National Committee for Clinical Laboratory Standards(NCCLS)of the USA.RESULTS The number of A.baumannii isolates was increasing from 61 in the year of 2001 to 247 in the year of 2006.And during the six years,the resistant rate to ciprofloxacin,gentamicin and imipenem was increasing from 28.8%,25.4%,5.4% to 64.9%,72.7% and 48.5%,respectively.The resistant rate of the 50 multidrug-resistant A.baumannii isolates to polymyxin B was 18.6%.CONCLUSIONS During the six years,the isolating rate is increasing,the result showed that there is not a large scale outbreak.The resistant rate is so high that we must strengthen the monitoring and indentify the drug-resistance mechanisms.