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 determine the possible genetic background and the source of our hospital's 43 clinical isolates of multidrug-resistant Acinetobacter baumannii, and the category of gene cassettes in type 1 integrons of all strains.Methods Restriction enzyme Apa I was chosed for all strains in pulsed-field gel electrophoresis (PFGE) methods.Multilocus sequence typing ( MLST) was used to compare the allelic profiles of all the strains. PCR method was used for amplify the integrons of all strains. Results PFGE results showed that 43 strains were divided into four types. A-type and B-type were divided into 4 and 2 subtypes, respectively. The MLST results showed the existing of three allelic profiles; 1-3-3-2-2-7-3, 1-3-3-2-2-11-3, and 1-3-3-2-2-14-3.B-type and D-type of PFGE have the same allelic profile(1-3-3-2-2-11-3).A-type strains were detected mainly in ICU, and in burn unit only found B- and D-type.The same integron was detected in 62.8% of the strains.The constituent ratio of A1,A2,A3,A4,B1,B2,C and D-type was 40.7% , 18.5% , 7.4% , 3.7% , 14.8% , 3.7% , 3.7% and 7.4% , respectively.Conclusions The coexistence of multiple cloning system in this region was proved by the PFGE and MLST, and the same clone can evolve to different subtypes when stimulated by different environmental conditions; and the different carrying-situationt of the same integron in strains prove the possibility of the change during the evolution of resistance mechanisms.

s were 0.573±0.016, 0.707±0.008 and 0.711±0.013). Conclusions CXCL10 can express stablely in MCF-7 cell lines, which resulted in down-regulation of expression of VEGF and STAT3 gene. CXCL10 played an important role in anti-tumor effect.

Objective To investigate drug resistance and carbapenemase genotypes of carbapenemresistant Acinetobacter baumannii.Methods A total of 75 clinical isolated strains of carbapenem-resistant Acinetobacter baumannii were collected from Taizhou Hospital in Zhejiang province during January 2011 and June 2012.Vitek 2 Compact microbial identification system was used for bacterial identification and drug susceptibility test,and modified Hodge test was used to screen strains producing carbapenemases.Genotypes of carbapenamases were determined by polymerase chain reaction.Results All 75 carbapenem-resistant Acinetobacter baumannii strains were resistant to most antibacterial agents except amikacin.The resistant rate to amikacin was 13.3％ (10/75).OXA-23 gene was positive in 69 strains (92.0％),and OXA-51 gene was positive in 67 strains (89.3％).No IMP,VIM and SIM gene was observed.Conclusion OXA enzyme is the main cause of drug resistance in this group of carbapenem-resistant Acinetobacter baumannii,and OXA-23 and OXA-51 genes are the most popular carbapenemnases coding genes.

Objective: To evaluate diagnostic performance of Todd-Hewitt (T-H) broth culture method, direct culture method, liquid chromogenic culture method, and loop-mediated isothermal amplification (LAMP) method for screening group B streptococcus (GBS) during late pregnancy. Methods: In the retrospective study, the rectal vaginal secretions samples were collected from pregnant women at 35 to 37 weeks at the obstetrics clinic of Guangzhou Women and Children′s Medical Center affiliated to Guangzhou Medical University during October 2016 to April 2018. For the purposes of clinical evaluation, T-H broth culture was used as the standard reference method, and double-blind trials were used to evaluate diagnostic performance of direct culture method, liquid chromogenic culture method, and LAMP method for screening group B streptococcus during late pregnancy in three research stages. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), coincidence rate and Yoden index for each method were calculated. Also, the level of agreement between each method and T-H broth was assessed using the kappa (k) coefficient. Results: A total of 969 specimens were detected by the T-H enrichment culture method, and 90 were positive (9.3%). The sensitivities from high to low were LAMP method [100% (25/25)], direct culture method [81.5% (22/27), 95%CI:65.8%-97.1%], and liquid color culture method [71.1% (27/38), 95%CI:55.9%-86.2%]. Specificities were direct culture method [100% (282/282)], liquid color culture method [98.1% (455/464), 95%CI:96.8%-99.3%], and LAMP method [94.0% (125/133), 95%CI: 89.9%-98.1%]. The coincidence rates were direct culture method [98.4% (22+282)/309], liquid color culture method [96.0% (27+455)/502], and LAMP method [94.9% (25+125)/158]. The Kappa values of the direct culture method (0.889), LAMP method (0.832) and the enrichment culture method were all ≥0.75, and that of the liquid color culture method was 0.708. The false negative rate of direct culture method was 18.5% (5/27), and no false negative case by LAMP method, but its false positive rate was 6.0% (8/133). The false negative rate and false positive rate of liquid color culture method were 28.9% (11/38) and 1.9% (9/464), respectively. Conclusions Of the three screening methods compared in this study, only the LAMP method has the advantages in sensitivity, specificity, and coincidence rate compared with T-H enriched culture method, while the others have a certain degree of false negatives rate. The clinical laboratory can introduce these methods based on laboratory facilities and staffing, or refer to the European and American guidelines and combine the recommended antenatal GBS screening method with intrapartum nucleic acid amplification tests to best meet the clinical demands.

Objective To raise awareness of the late-onset meningitis caused by group B streptococcus (GBS) which was homogenous to the maternal colonization.Methods The clinical data of late-onset GBS meningitis in neonates twins whose pathogens were homogenous to their maternal colonization were collected from Department of Neonatology,Guangzhou Women and Children's Medical Center.The general conditions,clinical symptoms,laboratory tests and drug treatment of the twins and their mother were retrospectively analyzed,and the GBS homology during inpatient care was tested.And the progress of the twins' condition was investigated by telephone follow-up.Results The mother had two pregnancies without prenatal GBS screening or intrapartum antimicrobial intervention for GBS,everything was normal during pregnancy and delivery.Twins were born through cesarean section.The elder sister was discharged with Linezolid taken orally after 167 days in hospital without convulsions,shaking or other discomfort.The elder sister was followed up for every 2 weeks,and in the last time of follow-up,cerebrospinal fluid white blood cell counts were 45 × 106/L,protein level was 1.52 g/L and Linezolid was withdrawn.The younger brother was discharged after 58 days in hospital with follow-up for every 2 weeks,and in the last time of follow-up,cerebrospinal fluid white blood cell counts were 30 × 106/L,protein level was 0.66 g/L.During the hospitalization and follow-up without convulsions and irritation,and the cranial magnetic resonance imaging of the twin brother was normal.Test results showed that the GBS bacteria strain for twins and their mother were all serotype Ⅲ.The possibility of the GBS homology was more than 90％.Conclusions The toxicity of serotype Ⅲ GBS strain was strong.More proactive precautions should be considered to apply for the mother whose first birth already had GBS infection.Early identification and intervention of infection risk factors would help optimize the anti-infection treatment program and reduce nerve system damage and other adverse outcomes caused by invasive GBS infection.

Objective To investigate the susceptibility and resistance of clinical isolates from hospitals in several regions of China .Methods Fifteen general hospitals and two children′s hospitals were involved in this program . Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby‐Bauer method or automated systems .Results were analyzed according to CLSI 2014 breakpoints .Results A total of 78 955 clinical isolates were collected from January to December 2014 ,of which gram negative organisms and gram positive cocci accounted for 72 .6% and 27 .4% ,respectively . Methicillin‐resistant strains in S .aureus(MRSA)and coagulase negative Staphylococcus(MRCNS)accounted for an average of 44 .6% and 83 .0 % ,respectively .The resistance rates of methicillin‐resistant strains to β‐lactams and other antimicrobial agents were much higher than those of methicillin‐susceptible strains .However ,92 .0% of MRSA strains were still susceptible to trimethoprim‐sulfamethoxazole ,while 85 .6% of MRCNS strains were susceptible to rifampin .No staphylococcal strains were found resistant to vancomycin ,teicoplanin or linezolid .In Enterococcus spp .,the resistance rates of E .f aecalis strains to most tested drugs (except chloramphenicol) were much lower than those of E . f aecium .Some strains of both species were resistant to vancomycin .Vancomycin resistant strains of E . f aecalis and E . f aecium were mainly V anA ,V anB or V anM type based on their phenotype or genotype .Regarding non‐meningitis S .pneumoniae strains ,the prevalence of penicillin‐susceptible S .pneumoniae strains isolated from both adults and children were higher than those isolated in 2013 ,but the prevalence of penicillin‐intermediate S . pneumoniae or penicillin‐resistant S . pneumoniae strains decreased . The prevalence of ESBLs producingstrainswas55.8% in E.coliand29.9% in Klebsiellaspp.(K.pneumoniaeand K.oxytoca)and24.0% in Proteus mirabilis isolates on average . ESBLs‐producing Enterobacteriaceae strains were more resistant than non‐ESBLs‐producing strains in terms of antibiotic resistance rates . The strains of Enterobacteriaceae were still highly susceptible to carbapenems .Overall less than 10 % of these strains were resistant to carbapenems . About 62 .4% and 66 .7% of Acinetobacter spp .(A .baumannii accounts for 93 .0 % ) strains were resistant to imipenem and meropenem ,respectively . Compared with the data of year 2013 ,extensively‐drug resistant strains in K . pneumoniae and A .baumannii increased . Conclusions The antibiotic resistance of clinical bacterial isolates is growing .The disseminated multi‐drug or pan‐drug resistant strains in a special region poses a serious threat to clinical practice and implies the importance of strengthening infection control .

Objective To investigate the clinical characteristics,antibiotic susceptibilities and serotypes of Group B Streptococcus(GBS)isolated from neonatal meningitis to provide references for the prevention and treatment of neonatal GBS meningitis. Methods From June 2013 to June 2016,we surveyed the GBS strains iso-lated from purulent meningitis of < 90 days infants from Guangzhou Women and Children′s Medical Center. The GBS isolates were identified and the minimum inhibitory concentration of the antibiotics was determined by Vitek 2 Compact automatic bacterial identification system.GBS serotyping was performed using Strep-B-Latex?rapid latex agglutination test kit. Results A total of 46 cases of neonatal GBS meningitis,15 cases of early-onset infection and 31 cases of late-onset infection were diagnosed. 78.3% of GBS meningitis with varying degrees of complica-tions.Among 41 survivors with 3~24 months follow-up,50% of the early-onset and 44.8% of the late-onset GBS meningitis with varying degrees of neurological sequelae.Four capsular types were identified among the 46 isolates, serotype-Ⅲwas the most prevalent(73.9%),followed by Ib(19.6%),V(4.3%)and Ia(2.2%).All the isolates were susceptible to penicillins,cephalosporins,linezolid and vancomycin. Conclusion The highly pathogenic serotype-Ⅲ was the predominant serotype among neonatal GBS meningitis in Guangzhou,Therefore,it is neces-sary to strengthen the epidemiological surveillance of GBS invasive infection and the effective implementation of pre-ventive measures.

Objective To understand the changing resistance proifle ofProteus,Serratia,Citrobacter,Morganella andProvidencia in hospitals across China according to the data from CHINET Antimicrobial Resistance Surveillance Program 2005-2014.Methods Antimicrobial susceptibility was tested by using Kirby-Bauer method or automatic minimum inhibitory concentration determination according to a uniifed protocol.Results A total of 21 663 clinical isolates were collected from January 2005 to December 2014. The proportion ofProteus andSerratia isolates increased with time from 1.41% in 2005 to 2.09% in 2014, and from 0.99% in 2005 to 1.28% in 2014 among all the isolates. No change was found for the proportion ofCitrobacter,Morganella, orProvidencia. Less than 10% of theProteus isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, ceftazidime, cefoxitin, amikacin and tigecycline. Less than 10% of theSerratia isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, amikacin and tigecycline. Less than 20% of theCitrobacter isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, cefepime, amikacin and tigecycline. Less than 10% of theMorganella isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, cefepime, amikacin and tigecycline. Less than 20% of theProvidencia isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, cefepime, cefoxitin and tigecycline.Conclusions The antibiotic resistance ofProteus,Serratia, Citrobacter,Morganella andProvidencia isolates in hospitals across China is growing during the period from 2005 to 2014. Strengthening infection control and rational antibiotic use are effective to slow the growth of drug resistance.

Objective To investigate the distribution and antibiotic resistance proifle of clinicalEnterobacter isolates using the data from CHINET during the period from 2005 through 2014.Methods A total of 20 558 clinical strains ofEnterobacter spp. were collected from 2005 to 2014 in CHINET Antimicrobial Resistance Surveillance Program. Antimicrobial susceptibility testing was performed with Kirby-Bauer or minimum inhibitory concentration method. The results were analyzed according to CLSI 2014 breakpoints.ResultsEnterobacter cloacae andEnterobacter aerogenes accounted for 71.1% (14 617/20558) and 20.1% (4 129/20 558) of all theEnterobacterisolates, respectively. The proportion ofEnterobacter spp. increased with time from 3.5% in 2005 to 4.3% in 2014. The main source of the isolates was respiratory tract, accounting for 55.2% (11 358/20 558). More than 90% of theEnterobacterisolates were resistant to cefazolin and cefoxitin, but less than 30% of the strains were resistant to cefepime, piperacillin-tazobactam, cefoperazone-sulbactam, amikacin, gentamicin, ciprolfoxacin, meropenem, imipenem and ertapenem. TheEnterobacterisolates showed a trend of declining resistance to most antibiotics except ertapenem and meropenem. The resistance proifle ofEnterobacterisolates varied with departments where they were isolated. The strains from ICU and Department of Surgery were relatively more resistant to antibiotics. The prevalence of multi-drug resistant (MDR) strains was decreasing, but the prevalence of carbapenem-resistantEnterobacter (CRE, resistant to any of imipenem, meropenem or ertapenem) was increasing. The MDR and CRE strains were primarily isolated from ICU and Department of Surgery. At least 30% of the MDREnterobacter strains were resistant to any of the antimicrobial agents tested except meropenem, imipenem and ertapenem and at least 35% of the CRE strains were resistant to any of the antimicrobial agents tested except amikacin and ciprolfoxacin.Conclusions TheEnterobacter isolates in CHINET Antimicrobial Resistance Surveillance Program showed decreasing resistance to most of the antimicrobial agents tested since 2011, but the prevalence of CRE strains increased progressively. Effective measures should be carried out to prevent the spread of CRE strains in hospitals.