Analysis Of Mohnarin Bacterial Surveillance And Clinical Analysis Of HAP Combine With Bloodstream Infection Caused By Acinetobacter Baumannii In Intensive Care Unit And The Molecular Epidemiological Study

In recent years, antimicrobial resistance has become a major global health concern,the high mortality rates of infection disease need us to pay high attention. WorldHealth Organization recommend that each member-state establish a nationalsurveillance program of antimicrobial resistance is the effective way to solve thisproblem. Since2006, there are more than one thousand hospitals join in the ministryof health national antimicrobial resistance investigation net and more than1.5millionstains information has been collected. It would be highly significant for the rationalantibiotic use in clinical practice by this surveillance. Because of the increaseresistance rate, multi-drug resistance Acinetobacter baumannii has became one of themost dangerous pathogens in21st century. Combining the antimicrobial test resultand clinical characteristics about infective patient could help us to explore the riskfactors for bloodstream infection. In order to definitude the clonal typing ofAcinetobacter baumannii, methods of multilocus sequence typing(MLST) andpulsed-field gel electrophoresis(PFGE) were used for the bacteria from differenthospitals in Guangdong province, and it is crucial for preventing the spread ofMDRAB within different areas.Part1: Analysis of Mohnarin bacterial surveillance2012-2013Objective: To investigate antimicrobial resistance of clinical isolates fromtertiary-level facilities submitted to Surveillance of Antimicrobial Resistance in2013. To learn the feature of bacterial resistance in China compared with the early data.Methods: Disc diffusion test (K-B methods) and automated instrument was employedto study the antimicrobial resistance. WHONET5.6was applied for analysisaccording to2013CLSI standard.Results: In the year of2013,of2014006clinical isolates, Gram positive cocciaccounted for23.0%, Gram negative bacilli accounted for77.0%. The detection ratesof methicillin-resistant strains was34.0%in S.aureus and68.0%in conagulasenegative Staphylococcus. No VISA or VRSA isolate was found.6.2%S. pneumoniaisolates were penicillin-resistant (PRSP) according to2013CLSI criterion. Theprevalence of ESBLs-producing strains was57.6%in E. coli and33.9%in Klebsiellaspp. isolate on average. For the whole country,the lowest resistance rates forA.baumannii are minocycline (23.5%),Cefoperazone/Sulbactam(30.8%),Levofloxacin(32.5%). Compare with data in2012, the resistant rates ofA.baumannii to imipenem was increased from46.9%to57.5%, respectively.Conclusions: The bacterial resistance situation is ameliorate but still quiteserious,expecially for the A.baumannii. The increase detection rate ofcarbapenem-resistant acinetobacter baumannii pose a serious threat to clinicalpractice.It is urgent to enhance the surveillance of bacterial resistance to guide theappropriate use of antibiotics in clinical.Part2: The bacterial resistance surveillance of Guangdong in2012-2013Objective: To investigate the susceptibility and resistance of clinical isolates from themajor hospitals in Guangdong.Methods:64hospitals were involved in this program. Bacterial susceptibility testingwas carried out using MIC and Kirby-Bauer method. Results were analyzed accordingto CLSI2013.Results: A total of94412clinical isolates were collected from January to December2013, of which gram negative organisms and gram positive organisms accounted for69.9%and30.1%，respectively. Methicillin resistant strains in S.aureus (MRSA)accounted for36.2%. The resistance rates of MR strains to β-lactams and other antimicrobial agents were much higher than those of MS strains. No staphylococcalstrain was resistant to vancomycin or linezolid. The resistance rate of E.faecalisstrains to most of the drugs tested was much lower than those of E. faecium. A fewstrains of E. faecium and E.faecalis were found resistant to vancomycin and linezolid.Regarding non-meningitis S.pneumoniae strains, the rate of PRSP were high. Strainsof Enterobacteriaceae were highly susceptible to imipenem. The resistance rates ofP.aeruginosa to imipenem were19.4%. The resistance rates of A. baumanii were55.3%, respectively. Compared with the data of year2012, the prevalence ofmulti-drug resistant A.baumanii increased markedly.Conclusions: Bacterial resistance is on the rise, especially the incidence of multi-drugresistant A.baumanii, which has become a major challenge to medical clinics. It isurgent to choose antibiotics rationally and strengthen infection contro1．Part3: Clinical analysis of HAP combine with bloodstream infection caused byAcinetobacter baumannii in intensive care unitObjective: To explore the clinical characteristic,risk factors and antimicrobialresistance of bloodstream infections caused by Acinetobacter baumannii in intensivecare unit.Methods: Clinical data from90patients with positive Acinetobacter baumanniisputum culture hospitalized in First Affiliated Hospital of Guangzhou MedicalUniversity from January2012to January2013were analyzedretrospectively.According to the result of blood culture,the patients were divided intobloodstream infection and non-bloodstream infection.Data ondemographic,underlying diseases,auxiliary examinations,invasive medicalprocedures,APACHEⅡscore and bacterial resistance to antibiotics were collected.The influence factors of bloodstream infection were analyzed by T-test andChi-square test.Results: Compare to non-bloodstream infection,the ICU stay(16±25.5，-4.175),mechanical ventilation(9±19.5，-3.081), CRRT(45.9%，4.498),central venous catheter(100%，5.222), APACHEⅡscore (25±9.5，-4.808) and PCT(1.84±9.47，-3.801) are obvious different from bloodstream infection（P＜0.05).The isolates frombloodstream infection have a serious antimicrobial resistance phenomenon.Conclusions: The invasive medical procedures such as mechanical ventilation andcentral venous catheter could highly increase the risk of Acinetobacter baumanniibloodstream infection;PCT and APACHEⅡscore have great significance on the earlydiagnosis of bloodstream infection; Acinetobacter baumannii isolates frombloodstream in ICU are muti-drug resistance and associate with high mortality rate.Part4: Molecular epidemiological study of Acinetobacter baumannii frombloodstream infectionObjective: To explore the molecular characteristics and gene homology ofbloodstream infection caused by Acinetobacter baumannii,and to provide evidence forthe nosocomial infective control.Methods: Combine with pulsed field gel electrophoresis and multilocus sequencetyping for investigate homology of46Acinetobacter baumannii from differenthospital in Guangdong province. BioNumerrics and Eburst were used for analyze theresult of PFGE and MLST.Results: MLST results showed that46bloodstream infection A.baumannii werebelong to nine sequence type,and the main type were ST195and ST457.PFGE resultsshowed that germs were divide into3main clonal type,both A type and B type wereinclude6subtypes.Conclusions: The result of PFGE in accordance with MLST, A.baumanni isolate fromblood in different hospitals of Guangdong province had the level disseminationfeature, the main clonal types were ST195and ST457,both of them were belongCC92.