ABSTRACT
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.
ABSTRACT
Objective To observe the formation of Staphylococcus aureus biofilm and the inhibitory and dispersive effects of betaine on the biofilm.Methods The inhibitory and dispersive effects of 0.1％ betaine on the biofilm from 20 strains of Staphylococcus aureus were examined by crystal violet assay.Results All the 20 strains of Staphylococcus aureus formed biofilm.The biofilm of methicillinsensitive Staphylococcus aureus (MSSA) was formed in 24 hours with peak value of absorbance (A590 nm) (1.99 ± 0.53).The biofilm of methicillin-resistant Staphylococcus atureus(MRSA) was formed in 48 hours with peak value of absorbance(A590 nm) (1.13 ±0.47).After adding betaine,the absorbance(A590 nm) of MSSA biofilm fell down to(1.74 ± 0.61) in 24 hours,while the absorbance(A590 nm) of MRSA biofilm fell down to(0.40 ± 0.12) in 48 hours,which was significantly reduced compared with the controls (t =2.43,5.84,P ＜ 0.05 respectively).When adding betaine after the biofilm formed,the absorbancies (A590 nm) of both MSSA and MRSA showed no significant difference compared with the controls (P ＞ 0.05).Conclusion Betaine could inhibit biofilm formation of Staphylococcus aureus at concentration of 0.1％,but it could not disperse the mature biofilm of Staphylococcus aureus.
ABSTRACT
Objective To investigate the distribution and antimicrobial resistance profile of clinical gram-negative bacterial isolates in the First Afifliated Hospital of Nanjing Medical University during 2014.Methods Bacteria identiifcation was performed by API system or the VITEK-2 Compact automatic identiifcation system. Disk diffusion susceptibility testing or VITEK-2 Compact automatic identification system was used to determine the susceptibility to antimicrobial agents. All data were analyzed using WHONET 5.6 software.Results Among the total 7 931 clinical isolates in 2014, gram-negative bacteria accounted for 64.2% (5 088/7 931). The top three pathogens wereE. coli,A. baumannii andK. pneumoniae. Notably, during the year 2014, 195 strains of carbapenem-resistantEnterobacteriaceaewere isolated, about 6.9% of all theEnterobacteriaceae isolates. Meanwhile, 613 (66.5%) strains of multiple drug resistantA. baumannii and 197 (28.7%) strains of multiple drug resistantP. aeruginosa were isolated.Conclusion During the year 2014, the resistance of the gram-negative bacteria in this hospital is mainly characterized by carbapenem-resistantEnterobacteriaceae, multiple drug resistant A. baumanniiand multiple drug resistantP. aeruginosa. Surveillance of antimicrobial resistance is beneifcial for rational use of antibiotics.
ABSTRACT
Objective To investigate the diagnostic value of detection of protein SP70 in differentiating benign and malignant pleural effusion.Methods A case-control study was conducted from July 2011 to February 2012.108 cases of pleural effusion from patients with clinically proven lung cancers and 122 cases of benign pleural effusion were collected.SP70 was detected by Sandwich ELISA,while CEA,CYFRA21-1,NSE were measured by electrochemiluminescence immunoassay for comparison.Meanwhile,protein SP70 on exfoliated cells in pleural effusion was detected by direct immunofluorescence,and was compared with the results of HE staining.The differences between the groups were evaluated by the chisquare test Fisher' s exact test.Results Positive rates of SP70,CEA,CYFRA21-1,NSE were 72.2％,58.3％,52.8％ and 30.6％ in malignant pleural effusion,obviously higher than benign pleural effusio (9.8％,13.1％,23.0％ and 19.7％).The specificity of SP70,CEA,CYFRA21-1,NSE were 90.2％,86.9％,77.0％ and 80.3％,NSCLC had significantly higher positive rate than SCLC(74.3％ ＞0.0％,P =0.02 ＜ 0.05),detection of protein SP70 in malignant pleural effusion had significantly higher coincidence rate than HE staining(72.2％ vs 47.2％,x2 =14.03,P ＜ 0.05).Conclusion Determination of the protein SP70 in pleural effusion and in exfoliated cells,can improve the sensitivity and specificity of the diagnosis of malignant pleural effusion.