Effects of betaine on formation and dispersion of Pseudomonas aeruginosa biofilm and its drug-resistance / 临床检验杂志

Objective To investigate the effects of betaine on the formation and dispersion of biofilm of Pseudomonas aeruginosa and its drug-resistance.Methods A total of 20 strains of Pseudomonas aeruginosa were obtained from clinical inpatients.The biofilm formation abilities of the Pseudomonas aeruginosa were evaluated by violet staining,and the effects of betaine on the formation and dispersion of biofilm were studied.The minimum inhibitory concentration (MIC) values of Pseudomonas aeruginosa on ciprofloxacin were compared with the controls when biofilm was formed and inhibited.Results Biofilm was formed in all the 20 strains of Pseudomonas aeruginosa in 24 hours with absorbance (A590 nm) (1.90 ± 0.66).Betaine significantly inhibited biofilm formation of Pseudomonasaeruginosa in 24 hours compared with control group(t =4.36,P ＜ 0.01) and the maximum inhibition reached in 48 hours with absorbance(A590 nm) (1.12 ±0.60).The maximum dispersion of betaine on mature biofilm of Pseudomonas aeruginosa reached in 24 hours.The MIC range of ciprofloxacin to the 20 strains of Pseudomonas aeruginosa was 0.03 to 4 μg/mL with 0.25 μg/mL of MIC50 and 2 μg/mL of MIC90.After the biofilm was inhibited by belaine,the MIC of ciprofloxacin to Pseudomonas aeruginosa did not changed.The MIC of ciprofloxacin to biofilm-formed Pseudomonas aeruginosa was more than 16 μg/mL.Conclusion Betaine could effectively inhibit the formation of biofilm and disperse the mature biofilm of Pseudomonas aeruginosa,which may provide more choices for the treatment of clinical infection.The germicidal efficacy of ciprofloxacin has no changed on the biofilm-formed bacteria when inhibition of betaine was involved.

Pathogen distribution and susceptibility profile of fungal isolates from bloodstream infections during the period from 2013 through 2015 / 中国感染与化疗杂志

Objective To investigate the pathogen distribution and susceptibility profile of fungal isolates from bloodstream infections,and valuate the clinical utility of G test in diagnosis of fungal infections for the purpose to improve antifungal therapy.Methods A retrospective analysis was carried out to analyze the fungal pathogens isolated from bloodstream infections in the First Affiliated Hospital of Nanjing Medical University during the period from January 2013 through December 2015 and their antimicrobial susceptibility.Results A total of 114 fungal strains were isolated from bloodstream infections during the 3-year period,most of which were Candida (99/114,86.8％),especially Candida albicans (30.7％).About 41.2％ (47/114) of the fungal strains were isolated from Department of Thoracic Surgery (10,5 and 4 strains in 2013,2014 and 2015),Hematology (11 strains in 2014),and ICU (7 strains in 2014).Antimicrobial susceptibility testing showed that all the fungal strains (100％) were susceptible to amphotericin B,but 83.5％ susceptible to itraconazole (the lowest).G test was positive before the result of blood culture in 13 of the 54 patients who received G test.Conclusions Candida was the most common fungus in fungal bloodstream infection.Amphotericin B is the most active antifungal agent in vitro.Blood culture combined with serological test can provide clinicians an earlier and reliable diagnosis.

Antimicrobial susceptibility surveillance in China: a MOHNARIN program report (2009-2010) / 中华检验医学杂志

Objective To investigate the bacterial resistance in nationwide and understand the distribution of bacterial and resistance trend.MethodsThe 6507 clinical isolates were collected from 19 hospitals in 17 cities.The susceptibility tests were performed using agar dilution method recommended by Clinical and Laboratory Standards Institute (CLSI) in central laboratory.The values of MIC50,MIC90 and MICrange were calculated by SPSS 17.0 and the susceptibilities of isolates to antimicrobial agents were determined by using CLSI (2010) guideline.Of all 6507 isolates,4691 strains were collected from target wards and 1816 were isolated from others wards.ResultsAmong 4691 strains,1156 were Gram-positive (24.6％ ) and 3535 were Gram-negative (75.4％).Based on the minimum inhibitory concentration results,the prevalence of methicillin resistant Stapylococcus aureus and methicillin resistant Stapylococcus epidermidis are 51.6％ ( 325/630 ) and 87.0％ ( 228/262 ) respectively.Staphylococci showing intermediate or full resistance to vancomycin were not observed. Coagulase negative Staphylococci showed 2.5％ (16/642)intermediate rate and 1.6％ ( 10/642 ) full resistance rate to teicoplanin,and showed 0.5％ ( 3/642 )resistance rate to linezolid.Antibiotic resistance rate of Enterococcus faecalis to ampicillin was 17.1％(19/111),while the resistance rate of Enterococcus faecium to ampicillin reached up to 85.0％(164/193).Three Enterococcus faecium were resistant to glycopeptides.The prevalence of penicillin resistance Streptococcus pneumoniae and penicillin intermediate Streptococcus pneumoniae were 41.2％ ( 145/352) and 37.2％ (131/352) respectively based on oral penicillin criterion,while the prevalence were 0.0％ (0/352) and 6.0％(21/352) based on vein to non-meningitis criterion.A vast majority of Enterobacteriaceae maintained high susceptibility to carbapenems,with resistance rate less than 2.0％.In addition,tigecycline,moxalactam,fosfomycin and amikacin displayed desirable antibacterial activity against Enterbacteriaceae,and resistance rates to these drugs were all less than 10.0％.For non-fermenting Gramnegative isolates,resistance rate of Pseudomonas aeruginosa and Acinetobacter baumannii to imipenem were 23.1％ ( 139/601 ) and 53.5％ (419/784) respectively.Resistance rate of Acinetobacter baumannii was much higher than that during the period 2007 - 2008.Colistin,tigecycline,minocycline and fosfomycin demonstrated good antibacterial activity against Acinetobacter baumannii in vitro.Conclusions Compared with MOHNARIN 2007 -2008year surveillance results, significant increase in resistance rate of Acinetobacter baumannii was demonstrated.Resistant strains to linezolid and tigecycline were found.Bacterial resistance has been a widespread problem in our country,which requires much more attention.

Antimicrobial resistance surveillance study among Streptococcus pneumoniae clinically isolated from 14 teaching hospitals in 2005-2008 in China / 中华检验医学杂志

Objective To investigate antimicrobial resistance among Streptococcus pneumoniae clinically isolated from 14 teaching hospitals located at different areas in China in 2005-2008 and to give logical guidance for clinical empirical therapy.Methods A total of 1 317 non-repetitive S.pneumoniae isolates in 14 teaching hospitals from 2005-2008 were collected and sent to the central lab for reidentification and susceptibility testing, including 271 isolates collected in 2005, 391 isolates collected in 2006, 363 isolates collected in 2007 and 292 isolates collected in 2008. Most of the isolates were from community-acquired respiratory tract infections, which were isolated from outpatient or emergency department patients with respiratory tract infections or those patients with respiratory tract infections within ≤48 hours hospitalization.The districts where the organisms were isolated include North China, Northeast China, South China, Central and Northwest China and East China.The patients included adults, teenagers and children.The minimum inhibitory concentrations (MICs) or inhibitory zone diameter of 17 antimicrobial agents were determined by Etest method, agar dilution method or disk diffusion method.WHONET5.5 software was used to analyze susceptibility rate, intermediate rate, resistance rate, MIC50 and MIC90.Results Linezolid (100%) and fluoroquinolones (95.2%-99.7%) showed excellent activities against S.pneumoniae.Among β-lactams, amoxicillin-clavulanic acid remained high activities (73.8%-92.1%),followed by penicillin, ceftriaxone and cefepime with year-over-year decrease in activities.The activities of three second-generation cephalosporins were low (36.3%-38.4% in 2008).The activities of erythromycin, azithromycin, clindamycin, trimethoprim/sulfamethoxazole and tetracycline against S.pneumoniae were poor and decreased year over year.The incidence of penicillin non-susceptible S.pneumoniae (PNSP) was increasing especially for PISP (from 4.4% in 2005 to 20.2% in 2008).The incidence of PNSP in North China was low (6.0%), while this value were high in central China and East China (30.1% and 38.7%, separately).The incidence of PNSP in adults (15.7%) was obviously lower than that in children(≤5 years:33.0%) and teenagers (6-17 years:38.2%).Conclusions linezolid and fluoroquinolones showed excellent in vitro activity against S.pneumoniae, followed by penicillin and cephalosporins with year-over-year decrease of activity. Clinicians should pay more attention when using those antimicrobial agents with poor activity against S.pneumoniae, which include macrolides, clindamycin, trimethoprim/sulfamethoxazole and tetracycline.

Evaluation of the susceptibility interpretation on Escherichia coli, Klebsiella pneumonia, Proteus mirabilis in China by agar dilution method according to the changes of cephalosporin breakpoints in CLSI 2010 / 中华检验医学杂志

Objective To evaluate the influences of susceptibility interpretation of Escherichia coli,Klebsiella pneumonia and Proteus mirabilis in China mainland according to the old and new ceftazidime,cefotaxime and ceftriaxone breakpoints in CLSI M100-S20 and CLSI M100-S19. Methods First, We analyzed the antibacterial susceptibility results of the three bacteria by agar dilution method in the SEANIR surveillance item, which were collected from 15 national hospitals between the year of 2005 and 2007 and excluded the AmpC enzyme positive isolates according to the PGR-DNA sequencing method and/or the antibacterial susceptibility phenotype. ESBL phenotype was confirmed by the CLSI phenotypic confirmatory test. Antibacterial susceptibility of the total 2733 Escherichia coli, Klebsiella pneumonia, Proteus mirabilis isolates was retrospectively analyzed by WHONET 5. 4 software according to the breakpoints of the CLSI M100-S19 (S19) and CLSI M100-S20 (S20). Second, 207 isolates of Peking Union Medical College Hospital with the results of both agar dilution method and disk diffusion method were performed by recurrent analysis. Then we observed the inter-method agreement through the scatter diagram according to the breakpoints of S19 and S20. Results First, as to the ESBL positive Escherichia coli, Klebsiella pneumonia and Proteus mirabili.s, the resistant rate of cefotaxime increased from 65.2% , 55.5%, 14. 6% under S19 (64 μg/ml) to 99. 7%, 96. 2% , 93. 8% under S20 (4 μg/ml). The susceptibility rates decreased from 6. 0%, 11.5%, 33.3% under S19 (8 μg/ml) to 0%, 0. 2%, 0% under S20 ( 1 μg/ml). Ceftriaxone had the same trend as cefotaxime. Though ceftazidime was more active than cefotaxime and ceftriaxone, as to the ESBL positive Escherichia coli and Klebsiella pneumonia, the resistant rates slightly increased from 30. 3%,43. 2% under S19 (32 μg/ml) to42.0%, 56. 0% under S20 (16 μg/ml). The susceptibility rates slightly decreased from 58. 1%, 44. 1% under S19 (8 μg/ml) to 44. 7%, 28.0% under S20 (4 μg/ml). Second,as to the ESBL negative Escherichia coli, Klebsiella pneumonia and Proteus mirabilis, all the susceptibility rates of ceftazidime, cefotaxime and ceftriaxone were between 99. 2%-100. 0%, the resistant rate were between 0%-0. 4%. Third, the S20 MIC breakpoints had a good correspondence with the ESBL phenotype.Fourth, according to the recurrent analysis of MIC testing and disk dilution method, r value was 0. 67,0. 79, 0. 77 for ceftazidime, cefotaxime and ceftriaxone, respectively, and all P value were under 0. 01. The intermethod rates of S19 and S20 were both acceptable. Conclusions If the cefotaxime and ceftriaxone S20 new breakpoints were used, the concordance of antibacterial susceptibility results and ESBL phenotype would increase greatly. The clinician could select proper antibiotics according to the antibacterial susceptibility results and clinical symptoms. It is no longer necessary to edit results for cephalosporins, aztreonam, or penicillins from susceptible to resistant. However, until laboratories implement the new interpretive criteria,ESBL testing should be performed as described in Supplemental Table 2A-S1. The relationship between the new breakpoints of ceftazidime and clinical outcomes need to be further evaluated.

Characterization and culture of isolated primary dairy goat mammary gland epithelial cells / 生物工程学报

Based on the in vitro culturing system developed for epithelial cells in mammary gland of Xinong Saanen dairy goats using tissue explant culture, high density cultivation, and continuous passaging, the cultured epithelial cells were evaluated by growth curve fitting, karyotype analysis, immunofluorescence staining (keratin, epithelial membrane antigen (EMA), vimentin, beta-casein), oil red staining and RT-PCR of beta-casein gene. The results showed that the growth of epithelial cells with the model number of chromosome of 60 demonstrated a typical 'S' shape curve, the positive gene expression of keratin, EMA, vimentin and beta-casein was detected, the cytoplasmic lipid droplets were observed following the oil red staining, the cultured cells expressed the mRNA of beta-casein. In conclusion, the current in vitro culturing system can obtain the normal mammary gland epithelial cells with the function of secretion.

Disinfectant and Antibiotic Resistance Genotypes in Escherichia coli Isolated from Urine / 中华医院感染学杂志

OBJECTIVE To investigate the disinfectant and antibiotic resistance genotypes in 60 strains of Escherichia coli isolated from urine.METHODS Sixty strains of E.coli isolated from inpatients′ urine were collected from Jan 2006 to Oct 2008.Antibiotic susceptibility tests for fifteen antibiotics were performed by Kirby-Bauer method.And three kinds of disinfectant and antibiotic resistance genes(qacE△1,tehA,merA)were analyzed by polymerase chain reaction(PCR) and DNA sequencing.RESULTS More than 70.0% of the sixty strains of E.coli were susceptible to imipenem,piperacillin/tazobactam,cefoxitin,amikacin and gentamicin,and less than 50.0% were susceptible to the other ten antibiotics.There were 42 strains with qacE△1 gene(70.0%),10 strains with merA gene(16.7%) and all strains with tehA gene.The sequence of the first strain was different from those reported in GenBank,so it was a new subtype.CONCLUSIONS There are 70% of E.coli strains isolated from urine samples with qacE△1 gene.And disinfectant resistance may be one of the main factors for hospital infection in the future.

Antimlcrobial resistance analysis among nosocomial gram-negative bacilli from 10 teaching hospitals in China in 2006 / 中华检验医学杂志

Objective To investigate antimicrobial resistance among nosocomial gram-negative bacilli in 2006.Methods About 987 consecutive and non-repetitive gram-negative bacilli were isolated from 10 teaching hospitals from Sep.to Dec.in 2006 in China.All of these isolates were sent to the central laboratory for reidentification and susceptibility testing.The minimal inhibitory concentration(MICs)of meropenem and other antibacterial agents were determined by agar dilution method.Results The activity of antibacterial agents against Enterobacteriaceae was as fol lows in descending order of susceptible rate: meropenem(susceptible rate 99.8%),imipenem(99.5%),piperacillin/tazobactam(91.3%),amikacin (89.3%),cefepime(83.8%),cefoperazone/sulbactam(79.7%),ceftazidime(74.7%),cefotaxime (57.7%),ceftriaxone(56.6%),ciprofloxacin(53.6%).The prevalence of extended-spectrum β-Iactamases(ESBL)was 59.0% in Escherichia coli,33.0%in Klebsiella pneumoniae and 8.0%in Proteus mirabilis.The most active agents against E.coli and K.pneumoniae were meropenem,imipenem(99.2%. 100%),piperacillin/tazobactam(90.8%-97.0%),and amikacin(83.8%-92.4%).Cefepime Was more active against K.pneumoniae than E.coli(85.4% vs.65.2%).Against E.cloacae,E.aerogenes and Citrobacter freundii,the most active agents were as follows in desecnding order:meropenem,imipenem (99.2%-100%),amikacin(85.2%-92.6%),cefepime(81.5%-85.9%),piperacillin/tazobactam (73.4%-87.2%),cefoperazone/sutbactam(65.6%-77.7%),and ciprofloxacin(53.1%-72.3%).The most active agents against Pseudomonas aeruginosa were amikacin(83.5%),followed by meropenem (79.1%),piperacillin/tazobactam(74.1%),and imipenem(70.9%).The most susceptible agents against Acinetobacter baumannii were imipenem(79.1%),meropenem(73.4%) and cefoperazone/ sulbaetam(54.7%).Mutiresistant A.baumannii increased up to 53.0%.The most active agents against Burkholderia cepacia were meropenem(73.3%),eeflazidime(73.3%),and piperacillin/tazobactam (62.2%).Conclusions Carbapenems remained very high activity against Enterobacteriaceae.Increasing resistance to 10 antimicrobials agents tested from A.baumanni and P.aeruginosa brought great concern.

Antimicrobial Resistance Surveillance on Hospital-and Community-acquired Pathogens in 10 Teaching Hospitals in China / 中华医院感染学杂志

OBJECTIVE To investigate the antimicrobial resistance of hospital-and community-acquired pathogens collected from 10 teaching hospitals located at different areas in China in 2006.METHODS According to the study protocol,the strains of Streptococcus pneumoniae,meticillin-susceptible Staphylococcus aureus(MSSA),Escherichia coli and Klebsiella pneumoniae were collected and sent to the central lab for reidentification and susceptibility testing.The minimal inhibitory concentrations(MICs) of antimicrobial agents against Str.pneumoniae were determined by Etest method and MICs of antimicrobial agents against S.aureus,E.coli and K.pneumoniae strains were determined by agar dilution method.WHONET5.4 software was used to analyze the data.RESULTS Among 353 Str.pneumoniae strains,74.2% were penicillin-susceptible(PSSP),9.6% were penicillin-intermediate(PISP) and 16.2% were penicillin-resistant(PRSP).Strains from different hospitals showed different sensitivity to penicillin.Among ?-lactam antibiotics,cefuroxime showed the lowest susceptibility rate of 0%(for PRSP) to 76.7%(for PSSP).The susceptibility rate to ceftriaxone and amoxicillin-clavulanic acid was 98.1% and 98.9% in PSSP group,61.8% and 64.7% in PISP group,and 15.8% and 10.5% in PRSP group.The ESBLs rate was 56.2% among 267 Escherichia strains and 42.7% among 206 K.pneumoniae strains.For ESBLs-producing strains,the susceptibility rates to cefotaxime and ceftriaxone were low and the rate to ceftazidime was relatively high among ?-lactam antibiotics.73.4% MSSA strains produced ?-lactamase.?-Lactam antibiotics tested showed high susceptibility against MSSA strains.The susceptibility rate was 98.9-100%.The susceptibility rate to ciprofloxacin and levofloxacin was 80.8% and 88.1%,separately.CONCLUSIONS Fluoroquinolones show high susceptibility against Str.pneumoniae.Ceftriaxone and amoxicillin-clavulanic acid have relatively high susceptibility among ?-lactams.For MSSA and non-ESBLs-producing E.coli and K.pneumoniae strains,?-lactams show high susceptibility.For ESBLs-producing E.coli and K.pneumoniae strains,the susceptibility rates to cefotaxime and ceftriaxone are low and that to ceftazidime,cefepime and cefoperazone-sulbactam are relatively high.

Antimicrobial resistance analysis among nosocomial gram-negative bacilli from 10 teaching hospitals in China / 中华检验医学杂志

80% activity rate against E.coli included piperacillin/tazobactam(93.4%)、ceftazidime(86%),and amikacin(83.3%);The susceptible rate to piperacillin/tazobactam in K.pneumoniae was 84.6%. The susceptible rate to ceftazidime decreased from 82.3% to 69.9%, which was lower than to cefepime (77.2%). Over 50% of Enterobacter cloacae were resistant to ceftazidime, cefotaxime and ceftriaxone. Susceptible rates to piperacillin/tazobactam in E. cloacae,E. aerogenes,Citrobacter freundii and Serratia marcescens (67.7%-96.4%) were higher than those to cefepime (68.8%-77.5%), cefoperazone/sulbactam (59.7%-87.5%). Susceptibility to amikacin among these 4 species (70%-83.7%) was higher than to ciprofloxacin (48.1%-79.5%). All of Morganella morganii and Proteus vulgaris isolates were susceptible to meropenem and imipenem; Over 90% of the isolates were susceptible to cefepime, cefoperazone/sulbactam and piperacillin/tazobactam.The most active agent against Pseudomonas aeruginosa was meropenem (84%), followed by amikacin, piperacillin/tazobactam, ceftazidime and imipenem (72.5%-76.6%). Mutiple-drug-resistant Acinetobacter baumannii increased from 33% in 2003 to 48% in 2004. Resistance to carbapenems increased to 18% in this species in 2004. The most active agents against Burkholderia cepacia were meropenme (64.9%), cefoperazon/sulbactam (63.2%), ceftazidime (59.6%), piperacillin/tazobactam (56.1%) and cefepime (52.6%).Conclusions Carbapenems remained very high activity against Enterobacteriaceae. Increasing resistance to 10 antimicrobials agents tested among A. baumanni brought great concern. Meropenem was 4-to 16-fold more active against common gram-negative bacilli than imipenem.

Comparison of in Vitro Antimicrobial Activity of Econazole with other Six Antibacterial Drugs / 中华皮肤科杂志

Objective To assess the antimicrobial actitivity of econazole nitrate in comparison with other six antibacterial drugs. Methods The minimal inhibitory concentrations (MICs) of econazole nitrate (Eco), neomycin (Neo), erythromycin (E), penicillin (P), cefotaxime sodium (Cef), ciprofloxacin (Cip) and amikacin (An) to 222 strains of Staphylococcus spp isolated from the lesions of patients with eczema and atopic dermatitis were determined by using the broth dilution method. Results MIC50 values of Eco were similar to Neo, Cip, An and Cef, and lower than those of P and E on methicillin-sensitive Staphylococcus aureus (MSSA); significantly lower than those of the other six antibacterial drugs on methicillin-resistant Staphylococcus aureus (MRSA); similar to An, Cip and P, and lower than those of Neo, Cef and E on methicillin-sensitive and coagulase-negative Staphylococcus (MSCNS); and similar to An, Cip P or Neo, and lower than Cef and E on methicillin-resistant and coagulase negative Staphylococus (MRCNS). Based on the NCCLS standards, the resistance rates of Cip, P and E were very high to either Staphylococcus areus or coagulase-negative Staphylococcus (CNS). The resistance rates of An and Cef of were lower to MSSA, but higher than 50% to MRSA. MIC90 value of Eco was similar to its MIC50, and lower than the MIC value reported in the literature. The MIC90 value of neomycin was muich higher than the MIC50 value of econazole. Conclusion Econazole nitrate has antibacterial activity to both Staphylococcus areus and CNS. MIC90 value of Eco is similar to its MIC50, and no resistance to Eco was found.