Objective To investigate the resistance of clinical isolates of P.aeruginosa in China during 2005.Methods Clinical isolates of P.aeruginosa from 7 teaching hospitals in China were collected and antimicrobial susceptibility were tested by Kirby-Bauer method.Results A total of 2 323 clinical isolates of P.aeruginosa were collected.The resistance rates of P.aeruginosa to antimicrobial agents from low to high were amikacin(22.5%),cefoperazone-sulbactam(22.8%),cefepime(27.6%),ceftazidime(28.9%),imipenem(31.3%),ciprofloxacin(31.7%),meropenem(33.7%),piperacillin-tazobactam(34.4%),aztreonam(36.8%),piperacillin(44.2%),ticarcillin-clavulanic acid(50.9%).Multi-drug resistant(MDR)and pan-drug resistant(PDR)strains accounted for 8.4% and 4.2%,respectively.Some(36.7%-53.4%)of the strains resistant to other antimicrobial agents were still susceptible to amikacin.Therefore,combination therapy of ?-lactams plus an aminoglycoside is usually indicated for serious infections caused by P.aeruginosa.By 'interpretative reading' of the susceptibility pattern of 'predictive drugs',we can predict the underlying resistance mechanisms.Conclusions The surveillance data indicate that the resistance of P.aeruginosa in China is relatively serious and its resistance mechanisms are very complicated.Close attention should be paid to this problem by physicians and clinical laboratory.

To understand the situation of drug-resistant of China based on the bacterial resistance monitoring data in 2010.Using the international guidelines for reference to propose the prevention and infection control strategy.The monitoring data shows that bacterial resistance is still growing in China which brings enormous difficulties on clinical treatment and poses a serious threat to the safety of patients.By strengthening the surveillance of bacterial resistance,reducing the use of antibiotics,strengthening the etiological examination,improving the use of antibiotics,strictly carrying out hand hygiene,disinfection and isolation system will be the key points of the prevention and infection control for drug-resistant bacteria.

Objective To verify if the multidrug resistant stains of P.aeruginosa isolated from different patients in burn ward have the same origin. Methods The susceptibility testing was performed with Etest,and the strains were typed by rep PCR with the primer ERIC2 and M13 following electrophoresis in agarose gel. Results There were multidrug resistant P.aeruginosa strains in burn ward,and analysis of the PCR productions indicated that all these multidrug resistant strains have an identical band pattern different from the sensitive strains. Conclusions The multidrug resistant strains of P. aeruginosa derive from a common origin.

OBJECTIVE To investigate the epidemic characteristics and drug resistance profile of clinical bacteria in hematology ward of our hospital. METHODS The susceptibility testing of clinical isolates from hematology ward was performed and the ESBLs producing strains were detected using K-B method.The results were analyzed by WHONET5. RESULTS Out of the 397 clinical isolates, 65.2% were Gram-negative bacilli and 34.8% were Gram-positive cocci.In Gram-negative bacilli,55% were Enterobacteriaceae and 44% were nonfermenting Gram-negative bacilli.In Gram-positive cocci,60.8% were Staphylococcus spp and 38.4% were Enterococcus spp.The ESBLs producing strains in Escherichia coli and Klebsiella spp were 55.8% and 19.2%,respectively.The MRSA in S.aureus and MRCNS in coagulase negative Staphylococcus were 40.9% and 95.2%,respectively.No resistance to carbapenem was detected in Enterobacteriaceae and no resistance to vancomycin was detected in Gram-positive cocci.The resistance rate of nonfermenting Gram-negative bacilli to cefoperazone/sulbactam was less than 2.1%. CONCLUSIONS The data will be useful for the early empiric administration of antimicrobial agent in hematology ward.

OBJECTIVE To evaluate the effect of delayed entry(0-24 h) into BacT/Alert 3D and BACTEC 9120 and the effect of 2 incubation temperatures(22 ℃ vs 35 ℃) on culture positivity.METHODS We utilized the BacT/Alert system with FA bottles and the BACTEC 9120 system with Plus(Aerobic) bottles.Four clinical bacterial species,Staphylococcus aureus,Escherichia coli,Streptococus pneumoniae,Candida albicans,were used as the test strains.and 5 ml of blood were added to each bottle.Each species was inoculated into the bottles 3 times at an inoculum size of 10 CFU/ml,102 CFU/ml and 108 CFU/ml,respectively.The inoculated bottles were cultured using the respective instruments after they were allowed to stand at room temperature(22 ℃)and 35 ℃ for 0,8,16 and 24 h.Time-to-detection and culture positivity were evaluated.RESULTS The delay in transportation of blood culture bottles stored at room temperature(22 ℃) or 35 ℃ had no effect on the recovery rate for BACTEC 3D at less than 24 h preincubation time and for BacT/Alert 9120 at less than 16h preincubation time.The positivity rate decreased significantly for BacT/Alert 9120 for 24 h of delay.Culture positivity of BacT/Alert 3D was higher than BACTEC 9120 for 24 h of delay.CONCLUSIONS The delayed entry for BacT/Alert 3D should be within 24 h,but the delayed entry for BACTEC 9120 should be within 16 h.

Objective To analyze the distribution and antimicrobial resistance of pathogenic bacteria in urinary tract infection (UTI)so as to provide evidence for appropriate selection of antimicrobial agents in clinical practice. Methods From January 2001 to December 2008 in Shanghai Ruijin Hospital,4683 strains of pathogenic bacteria isolated from urine samples were detected by ATB system;drug susceptibility test was performed with disk diffusion method and pathogenic bacteria distribution and drug resistance was analyzed with WHO NET 5.3 software. Results Among 4683 strains of pathogenic bacteria,most was gramnegative bacilli,accounting for about 77.8%,of which predominant strain was Escherichia coli (68.7%,3217/4683).The predominant strain of gram-positive bacteria was Enterococcus faecalis,accounting for 10.0%(468/4683).Escherichia coli showed hish resistance rotes to ampicillin,piperacillin and compound snlfamethoxazole(SMZ-TMP),which were 76.6%,61.7%and 57.4%respectively,while a low resistance to imipenem,cefoperazone-sulbactam,piperacillin-tazobactam,Enterococcus faecalis showed high resistance rates to erythromycin,gentamicin and levofloxacin,which were 65.8%,43.2%and 31.1%respectively,and were most susceptive to vancomycin and teicoplanin, both with resistance rates of 0. The susceptibility rate of Enterobacteriaceae to imipenem was 100%. From 2006 to 2008, the detection rate of extend-spectrum β-lactamases ESBLs -producing Escherichia coil in outpatient increased year by year, from 28.7% to 43.3% (P＜0.05), whereas no significant change was found in inpatients. The detection rate of (ESBLs)-producing Escherichia coil in inpatients was significantly higher than that in outpatients (P＜0.05).The detection rate of ESBLs-producing Escherichia coil was 23.6%. The antimicrobial resistance rate in elderly patients was significantly higher than that in overall antimicrobial resistance rote (P＜0.05). Conclusions The predominant bacteria of UTI are still gram-negative bacteria, main of which is Escherichia col. Bacteria are resistant to a variety of antibiotics. Approximate selection of antibiotics in clinical practice should be made on the basis of susceptibility test results.

Objective To investigate the species and drug resistance of pathogens causing bloodstream infections in hospitalized patients,and provide scientific evidence for antimicrobial use and control of healthcare-associated blood-stream infection.Methods From January 1 to December 31,2012,16 428 blood specimens were performed blood culture,pathogens were isolated and performed antimicrobial susceptibility testing.Results Of 16 428 blood speci-mens from 5 546 patients,384 (6.92%)were positive for blood culture,398 pathogenic isolates were detected,of which gram-positive bacteria,gram-negative bacteria,and fungi accounted for 23.62% (n=94),68.34% (n=272),and 8.04% (n=32)respectively,positive rate of blood culture were highest in 61-80 age group(8.26%), the top five departments of positive rate of blood culture were departments of burn,traditional Chinese medicine, cardiac intensive care unit,transplantation and traumatology;gram-positive cocci were highly susceptible to vanco-mycin,teicoplanin and linezolid,one Enterococcus faecium strain was found to be resistant to vancomycin;Among gram-negative bacilli,Enterobacteriaceae were highly susceptible to amikacin and carbapenems;drug resistance rates of Acinetobacterbaumannii and Pseudomonasaeruginosa to carbapenems was 70.97% and 35.90% respective-ly.Conclusion Gram-negative bacteria are the major pathogens causing bloodstream infection,positive rate of blood culture of elderly people is high.It is necessary to conduct regular surveillance on distribution and drug resistance of pathogens.

OBJECTIVE To type Staphylococcus epidermidis and analyze its polymorphism by randomly amplified polymorphic DNA(RAPD),and provide the method for analysis of homogeneity of S.epidermidis.METHODS Twenty one collected strains from ophthalmology ward were analyzed using random primer RAPD1 with RAPD.RESULTS On the basis of bands,difference of clinical strains was analyzed.Twenty one strians of S.epidermidis were divided into 5 patterns.Among them type Ⅰ taken 71 percent(15/21).CONCLUSIONS Typing of S.epidermidis by RAPD at molecular level is very rapid,easy and reliable.It can apply to track pathogens of the hospital and study epidemiology of the bacteria.

OBJECTIVE To investigate the ESBLs produced by clinical strains of Enterobacter cloacae.METHODS Production of ESBLs was identified with modification of the double-disk test(MDDT).Eight kinds of primers(CTXM,CTXM-1,CTX-M-2,CTX-M-9,SHV,TEM,VEB,and PER)were used for the PCR amplification.Gene clone and DNA sequencing were performed then.RESULTS The result of MDDT was positive,amplicons were gained by PCR amplification with CTXM-1.DNA sequencing of amplicons of this strain revealed ESBLs of CTX-M-3.CONCLUSIONS ESBLs are the important reason for E.cloacae resisting to the third-generation cephalosporins.

OBJECTIVE To investigate the distribution and antibiotic susceptibility of pathogens causing urinary infection,for the guide of rational use of antimicrobial agents in clinic. METHODS The bacteria isolated from the middle segment urine sample were identified by ATB system,and K-B method was used to study the antimicrobial resistance.The data were analyzed by WHONET 5.3. RESULTS Escherichia coli was one of the most common bacteria in the urinary tract infection(57.6%),and then were Enterococcus(14.4%).The results of antibiotic susceptibility test in vitro showed the susceptibility rate of Enterobacteriaceae and Acinetobacter baumannii to imipenem,was 100.0%,but the resistance rate of Pseudomonas aeruginosa was 13.6%.Gram-positive cocci were sensitive to glycopeptide antibiotics and linezolid. CONCLUSIONS Clinician should pay attention to the kinds of pathogenic bacteria causing urinary tract infection and their susceptibility to clinically common used antibiotics for reasonable use of drugs.