Objective： To establish an animal model of P.aeruginosa biofilm associated with chronic pulmonary infection and investigate the pathogenic effects of biofilm. Methods： Experiments in vitro, measuring the MICS, MBCS ...Objective： To establish an animal model of P.aeruginosa biofilm associated with chronic pulmonary infection and investigate the pathogenic effects of biofilm. Methods： Experiments in vitro, measuring the MICS, MBCS of levofloxacin（LFX）, ceftazidime（CAZ） in PAO579 in alginate beads and planktonic PAO579. Rats were challenged with 0.1 ml of PAO579（109CFU/ml） in alginate beads or 0.1 ml of planktonic PAO579（109CFU/ml）, 3,7,14 days after challenging, bacteriological, pathological features were observed. Results： The MICS, MBCS of LFX, CAZ in PAO579 in alginate beads were higher than those in planktonic PAO579 in vitro. CFU/lung in alginate beads group was significantly higher than that in planktonic bacteria group（P = 0.002, P = 0.004, P = 0.002, respectively）; macroscopic lung pathology and the inflammation in alginate beads group were significantly more severe compared to those in planktonic bacteria group in vivo. Conclusion： P.aeruginosa biofilm protected bacterium from killing of antibiotics and might mediate the host immune damage in the lung tissue and made bacterium evade the host immune defense.展开更多
Objective. To study the effects of two kinds of Chinese herbal medicine, Radix angelicae sinensis(RAS)(当归)and Shuanghuanglian(SHL)(双黄连) on chronic Pseudomonas aeruginosa(PA)lung infection in a rat model mimicking...Objective. To study the effects of two kinds of Chinese herbal medicine, Radix angelicae sinensis(RAS)(当归)and Shuanghuanglian(SHL)(双黄连) on chronic Pseudomonas aeruginosa(PA)lung infection in a rat model mimicking cystic fibrosis(CF). Methods.Rats were divided into RAS, SHL and control groups. All rats were challenged intratracheally with alginate embedded PA and the treatments with herbal medicine started on the same day of challenge. The drugs were administered subcutaneously once a day for ten days and the control group was treated with sterile saline.The rats were sacrificed two weeks after challenge. Results. Significantly improved lung bacterial clearance(P<005, P<001) and milder macroscopic lung pathology (P<0005) were found in the two treated groups compared to the control group. In the SHL treated group, the neutrophil percent in the peripheral blood leukocytes(P<005), the antiPA IgG level in serum (P<005), the incidence of lung abscesses(P<0005) and the incidence of acute lung inflammation(P<005) were significantly lower than in the control group. The RAS treatment reduced fever(P<005), decreased the incidence of lung abscesses(P<0005) and lung mast cell number (P<005), and lowered antiPA IgG1 level in serum(P<005) when compared to the control group. The antiPA bacterial activity test in SHL was weakly positive whereas in RAS it was negative. Conclusion.The treatment with both herbal medicines could increase the resistance of the rats against PA lung infection and they therefore might be potential promising drugs for stimulation of the immune system in CF patients with chronic PA lung infection.展开更多
Strain E1 with resistance to 18 mmol/L cadmium （Cd）, isolated from Cd-contaminated soil was identified by morphological observation, biochemical and physiological characterization and 16S rDNA sequence analysis. The...Strain E1 with resistance to 18 mmol/L cadmium （Cd）, isolated from Cd-contaminated soil was identified by morphological observation, biochemical and physiological characterization and 16S rDNA sequence analysis. The resistance to heavy metals Cd, Cu, Co, Mn, Pb, Zn and 12 antibiotics was examined. The ability of removing Cd from solution was studied. The characterizations show that strain El is affiliated to Pseudomonas aeruginosa （P aeruginosa）. Strain E1 has high resistance to heavy metals and the order is found to be Cd〉Mn〉Zn〉Cu〉Pb〉Co in solid media. Strain E1 also exhibits the resistance to 12 antibiotics. Both living and non-living cells of strain E1 can remove Cd from solution, and living cell has better biosorption than non-living cell.展开更多
A modified selective medium (modified Cetrimide Agar, mCA) consisting of 200 μg/mL benzalkonium chloride (BKC) was developed for the isolation of Pseudomonas aeruginosa from raw milk. Initially, a total of 55 isolate...A modified selective medium (modified Cetrimide Agar, mCA) consisting of 200 μg/mL benzalkonium chloride (BKC) was developed for the isolation of Pseudomonas aeruginosa from raw milk. Initially, a total of 55 isolates were obtained from 14 raw milk samples collected from several dairy plants in Ankara, Turkey. Among these isolates, 19 were identified as Pseudomonas aeruginosa, 28 as Pseudomonas fluorescens, 4 as Acinetobacter baumannii, 2 as Enterobacter intermedium, 1 asEnterobacter agglomerans, and 1 as Escherichia coli using Microbact biochemical test kit. BKC was chosen as a selective agent to suppress growth of competitive flora because it is very effective against a wide range of Gram-negative bacteria while P. aeruginosa is resistant. MICs (minimum inhibitory concentration) for BKC were determined by agar dilution method. The concentration of 200 μg/mL BKC inhibited competitive flora, while 90% of P. aeruginosa strains were resistant. When the results of enumeration of P. aeruginosa and other Gram (-) bacteria in Cetrimide Agar (CA) and mCA were compared, it was observed that mCA was more selective than the standard CA in preventing the growth of competitive flora especially of P. fluorescens.展开更多
Pseudomonas aeruginosa is one of the most common pathogenic bacteria, frequently found in different environmental samples. The prevalence of multidrug resistant isolates has become an alarming concern for both patient...Pseudomonas aeruginosa is one of the most common pathogenic bacteria, frequently found in different environmental samples. The prevalence of multidrug resistant isolates has become an alarming concern for both patients and their surroundings. The present study was carried out to record prevalence of P. aeruginosa in surface water of Dhaka city and to screen their antibiotic resistance pattern. The study was also extended to typing of resistant isolates according to extended spectrum beta lactamase production. Hereby, Kirby-Bauer method was applied to test antibiotic sensitivity according to Clinical and Laboratory Standards Institute. Then, the Ampicillin resistant isolates were screened for ESBL production by Double Disk Synergy Test (DDST). In these prospects, 52 water samples were tested, of which 32 were found positive for P. aeruginosa isolates. Hundred percent of the positive isolates were found to Ampicillin (AMP) resistant followed by 93.7% to both Tetracycline and Gentamycin and 71.8% to Co-triimoxazole. P. aeruginosa is completely susceptible to third generation antibiotics ciprofloxacin, Imipenem and Aztreonam followed by moderately susceptible to Polymyxin-B (78.2%) and Colistin (87.5%). According to DDST, all of the susceptible isolates were found positive for AMC type beta-lactamase production. It is evident from this study that the surface water is contaminated with antibiotic resistant P. aeruginosa and that through the water systems antibiotic resistance can be transferred to humans and animals. So, appropriate and rationale use of antibiotic should be applied to minimize the emergence of multidrug isolates to environment.展开更多
Objective To study MIC value of 7 boron derivatives namely [Boric acid （H3BO3）, Anhydrous Borax （Na2B407）, Sodium Borate （NaBO2）, Diammonium Tetraborate （NH4）2B4O7, Sodium Perborate （NaBO3）, Boron Trioxide ...Objective To study MIC value of 7 boron derivatives namely [Boric acid （H3BO3）, Anhydrous Borax （Na2B407）, Sodium Borate （NaBO2）, Diammonium Tetraborate （NH4）2B4O7, Sodium Perborate （NaBO3）, Boron Trioxide （B203）, Potassium Tetraborate （K2B407）] on E. coil and P. aeruginosa and their effects on survival of bacteria in lake water and resistance against kanamycin antibiotic. Methods MIC values of Boron derivatives and antibiotic were studied by broth microdilution method. The effect of boron derivatives on survival of bacteria in lake water were also determined with plate count. Results Sodium perborate was determined as the substances. Effectiveness increased as temperature most effective substance among the studied increased. E. coil was more affected from P. aeruginosa in 8 mg/mL sodium perborate concentration in lake water. Moreover, it was determined that MIC value of kanamycin antibiotic decreased 200 times by especially treating P. aeruginosa with sodium perborate in lake water. However, it can be stated that this change in resistance did not arise from microorganisms. Conclusion Sodium perborate solution can be used supportedly in kanamycin antibiotic applications for P. aeruginosa. Future studies are necessary to explore the relation between sodium perborate and kanamycin which is effective on P. aeruginosa in lake water.展开更多
The expression of IL-4 in a rat model of chronic pulmonary infection biofilm formation induced by Pseudomonas aeruginosa was investigated, in which SPF Wister rats were infected via trachea with 0.1 ml P. aeruginosa s...The expression of IL-4 in a rat model of chronic pulmonary infection biofilm formation induced by Pseudomonas aeruginosa was investigated, in which SPF Wister rats were infected via trachea with 0.1 ml P. aeruginosa strain PAO579 （ 10^9 CFU/ml） in alginate beads or the planktonic form of this bacterial strain （109 CFU/ml）, and on 3, 7 and 14 d after infection, the bacteriological and pathological changes were observed as well as the expression of the cytokine IL-4 was determined. It was demonstrated that the count of CFU per lung tissue in case of bacteria in alginate beads was significantly higher than that of bacteria in planktonic form, with more severe gross pathologic changes and inflammatory reactions in the alginate bead group in comparison with that of the planktonic forms （ P = 0. 002, P = 0. 004 and P = 0. 002, respectively）. In addition, the expression of IL-4 in the alginate bead group was also higher than that in the planktonic form （P = 0.02, P = 0.02 and P = 0.022, respectively）. A positive correlation between the level of IL-4 expression and the gross lung pathology in alginate bead group existed as demonstrated by simple regression analysis （r = 0.78, P 〈 0.02）. It is concluded that the chronic pulmonary infection with biofilm formation induced by P. aeruginosa tends to have the priority to the Th2 immune response.展开更多
Antimicrobial susceptibility test was performed on 57 clinical isolates of P. aeruginosa and 36 clinical isolates of Acinetobacter with 11 antimicrobial agents including getamicin, amikacin, ciprofloxacin, ofloxacin, ...Antimicrobial susceptibility test was performed on 57 clinical isolates of P. aeruginosa and 36 clinical isolates of Acinetobacter with 11 antimicrobial agents including getamicin, amikacin, ciprofloxacin, ofloxacin, fleroxacin, piperacillin, cefotaxime, cefoperazone/sulbactam, ceftazidime, cefoperazone and doxycycline. Transferable drug resistance plasmid carrying rates of these clinical isolates were also studied. On the basis of the in vitro activities, 52.63%(30/57) of the isolated strains of P. aeruginosa were susceptible to antimicrobial agents selected (except doxycycline), 41.67%(15/36) of the isolated strains of Acinetobacter were susceptible to 11 antimicrobial agents. The sensitivity rate of P.aeruginosa and Acinetobacter to antimicrobial agents selected was 70% or greater to all except doxycycline. Furthermore, the sensitivity rate of P.aeruginosa to amikacin ciprofloxacin, ceftazidime, cefoperazone, cefoperazone/sulbactam, and that of Acinetobacter to cefoperazone/sulbactam, amikacin was more than 90%,among them amikacin, cefoperazone/sulbactam being the most effective. Plasmid analysis showed that 15.79%(9/57) P.aeruginosa strains and 13.89%(5/36) Acinetobacter strains carried plasmid. Conjugative plasmid carrying rates of P. aeruginosa strains and Acinetobacter strains were 7.02%(4/57), 13.89%(5/36), respectively. Conjugative plasmid didn′t play an important role in the formation and dissemination of drug resistance of P. aeruginosa and Acinetobacter.展开更多
Objective: To develop a duplex real-time PCR assay for pharmaceutical rapid microbial detection of Staphylococcus aureus and Pseudomonas aeruginosa. Methods: The specific primers and probes were designed to amplify th...Objective: To develop a duplex real-time PCR assay for pharmaceutical rapid microbial detection of Staphylococcus aureus and Pseudomonas aeruginosa. Methods: The specific primers and probes were designed to amplify the femB gene of S. aureus and the DNA gyrase subunit B gene of P. aeruginosa. The sensitivity of the system was detected by a multiple proportional dilution method. In order to examine the specificity of the system, other twenty-one bacteria strains were assayed simultaneously. Results: A highly sensitive and specific duplex real-time PCR assay for the detection of S. aureus and P. aeruginosa was established. The sensitivity was 50 copies/μL. The specificity was 100%. The whole detection procedure can be finished within 2.5 h. Conclusion: The duplex real-time PCR method is efficient in detecting with good sensitivity and specificity. There is a good prospect of this method applying in disease prevention and pharmaceutical industry due to the simultaneous detection of two pathogens.展开更多
It is necessary to determine the susceptibility pattern of clinical isolates especially nosocomial one in the clinical settings for making strategy for effective empirical treatment & to reduce incidence of multid...It is necessary to determine the susceptibility pattern of clinical isolates especially nosocomial one in the clinical settings for making strategy for effective empirical treatment & to reduce incidence of multidrug resistant bugs. Aim of this study was to detect the antimicrobial susceptibility pattern of P. aeruginosa isolates from clinical samples between January 2014 to December 2015, received at department of Microbiology, GMC, Surat. Clinical isolates were confirmed as P. aeruginosa by phenotypic methods/Vitek2 compact system as per availability. Genetic sequencing could not be performed due to unavailability. Antimicrobial susceptibility tests were performed by Kirby-Bauer disc diffusion method/Vitek2 compact system & Interpretation was done according Clinical and Laboratory Standards Institute (CLSI) of that year [1] [2]. Seven hundred fifty seven P. aeruginosa strains were studied during the study period. Most of the isolates were from surgery ward (62%), followed by orthopaedic ward (15%). 65% of the total isolates were from swab samples followed by urine (7%), pus, fluid (5%) & devices (4%). 60% isolates were resistant to Ceftazidime & for other drugs resistance pattern was as follows: Cefepime (52%), Levofloxacin (49%), Ticarcillin/clavulanic acid (49%), Meropenem & Gentamycin (44%), Ciprofloxacin (43%), Amikacin (41%), Tobramycin (39%), Netlimycin (36%), Piperacillin (32%), Aztreonam (31%), Piperacillin/tazobactam (26%), Imipenem (23%) , Doripenem (12%) & Gatifloxacin (10%). As there is predominance of isolates from surgical ward in present study & resistance to carbapenem group of drugs was also found, indicating that most of the infection caused by Pseudomonas aeruginosa may be nosocomial.展开更多
Background: Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen that represents a major problem in many hospitals because of its increased resistance to antibiotics and the ability to cause nosocomial ...Background: Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen that represents a major problem in many hospitals because of its increased resistance to antibiotics and the ability to cause nosocomial infections. The present study aimed to phenotype and genotype isolates of P. aeruginosa from inpatients with UTIs at Urology and Nephrology center, Mansoura, Egypt to study their relatedness. Methods: Thirty nine isolates of P. aeruginosa were phenotypically typed by determination of O-serotypes by slide agglutination technique and antimicrobial resistance patterns by disk-diffusion method. The genetic diversity of isolates was illustrated by performing RAPD-PCR using M13 primer. Results: Serotypes O11, O6 and O10 were the most prevalent. Isolates showed high resistance rates to antipseudmonal antibiotics with high incidence (51.3%) of multidrug resistance (MDR). Amikacin was the most effective. A significant correlation was found between O6, O10 and MDR. A relatively high polymorphism was demonstrated among P. aeruginosa isolates by using RAPD-M13 fingerprinting. Cross transmission was suggested by phenotypically and clonally identical isolates. Conclusion: The study demonstrates the role of combining both classical and molecular typing as a valuable mean to study the origin and cross transmission of P. aeruginosa in UTIs for better assessment of treatment and infection control.展开更多
Silver nanoparticles (Ag-NPs), one of the most common types of nanomaterials in medical fields and consumer products, are known to have antimicrobial effects;these materials also undergo a series of chemical and biolo...Silver nanoparticles (Ag-NPs), one of the most common types of nanomaterials in medical fields and consumer products, are known to have antimicrobial effects;these materials also undergo a series of chemical and biological transformations in the environment. Although the pristine form of silver nanoparticles has been studied, less is known about the impacts of the transformed Ag-NPs on biological systems. This knowledge gap hinders the progress of effectively assessing the impacts of Ag-NPs on the environment and human health. In this study, we demonstrate that the most common form of transformed Ag-NPs, sulfidized silver nano-particles (Ag2S-NPs), show less damage on established Pseudomonas aeruginosa GFP (ATCC? 10145 GFP?) biofilm than the pristine form of the nanoparticle. At a dosage of 0.625 mg/L, the total biomass in the biofilm decreased 64% after being exposed to Ag-NPs and 44% after exposure to Ag2S-NPs. Live biofilms were also interrogated. We observed high reduction in live population for biofilm exposed to Ag-NPs and relatively low reduction by Ag2S-NPs at exposure concentrations higher than 0.625 mg/L. Compared with Ag-NPs, the lower solubility of Ag2S-NPs results in less Ag+ diffusion into established biofilms. Our results suggest that the sulfidation of Ag-NPs reduces their impacts on established biofilms, indicating that the transformed Ag-NPs may have less environmental or human health risks.展开更多
基金National Nature Science Associate Fundation(NSAF) of China (30760084)
文摘Objective： To establish an animal model of P.aeruginosa biofilm associated with chronic pulmonary infection and investigate the pathogenic effects of biofilm. Methods： Experiments in vitro, measuring the MICS, MBCS of levofloxacin（LFX）, ceftazidime（CAZ） in PAO579 in alginate beads and planktonic PAO579. Rats were challenged with 0.1 ml of PAO579（109CFU/ml） in alginate beads or 0.1 ml of planktonic PAO579（109CFU/ml）, 3,7,14 days after challenging, bacteriological, pathological features were observed. Results： The MICS, MBCS of LFX, CAZ in PAO579 in alginate beads were higher than those in planktonic PAO579 in vitro. CFU/lung in alginate beads group was significantly higher than that in planktonic bacteria group（P = 0.002, P = 0.004, P = 0.002, respectively）; macroscopic lung pathology and the inflammation in alginate beads group were significantly more severe compared to those in planktonic bacteria group in vivo. Conclusion： P.aeruginosa biofilm protected bacterium from killing of antibiotics and might mediate the host immune damage in the lung tissue and made bacterium evade the host immune defense.
文摘Objective. To study the effects of two kinds of Chinese herbal medicine, Radix angelicae sinensis(RAS)(当归)and Shuanghuanglian(SHL)(双黄连) on chronic Pseudomonas aeruginosa(PA)lung infection in a rat model mimicking cystic fibrosis(CF). Methods.Rats were divided into RAS, SHL and control groups. All rats were challenged intratracheally with alginate embedded PA and the treatments with herbal medicine started on the same day of challenge. The drugs were administered subcutaneously once a day for ten days and the control group was treated with sterile saline.The rats were sacrificed two weeks after challenge. Results. Significantly improved lung bacterial clearance(P<005, P<001) and milder macroscopic lung pathology (P<0005) were found in the two treated groups compared to the control group. In the SHL treated group, the neutrophil percent in the peripheral blood leukocytes(P<005), the antiPA IgG level in serum (P<005), the incidence of lung abscesses(P<0005) and the incidence of acute lung inflammation(P<005) were significantly lower than in the control group. The RAS treatment reduced fever(P<005), decreased the incidence of lung abscesses(P<0005) and lung mast cell number (P<005), and lowered antiPA IgG1 level in serum(P<005) when compared to the control group. The antiPA bacterial activity test in SHL was weakly positive whereas in RAS it was negative. Conclusion.The treatment with both herbal medicines could increase the resistance of the rats against PA lung infection and they therefore might be potential promising drugs for stimulation of the immune system in CF patients with chronic PA lung infection.
基金Project (50621063) supported by the National Natural Science Foundation of ChinaProject (2004CB619204) supported by the Major State Basic Research and Development Program of China
文摘Strain E1 with resistance to 18 mmol/L cadmium （Cd）, isolated from Cd-contaminated soil was identified by morphological observation, biochemical and physiological characterization and 16S rDNA sequence analysis. The resistance to heavy metals Cd, Cu, Co, Mn, Pb, Zn and 12 antibiotics was examined. The ability of removing Cd from solution was studied. The characterizations show that strain El is affiliated to Pseudomonas aeruginosa （P aeruginosa）. Strain E1 has high resistance to heavy metals and the order is found to be Cd〉Mn〉Zn〉Cu〉Pb〉Co in solid media. Strain E1 also exhibits the resistance to 12 antibiotics. Both living and non-living cells of strain E1 can remove Cd from solution, and living cell has better biosorption than non-living cell.
文摘A modified selective medium (modified Cetrimide Agar, mCA) consisting of 200 μg/mL benzalkonium chloride (BKC) was developed for the isolation of Pseudomonas aeruginosa from raw milk. Initially, a total of 55 isolates were obtained from 14 raw milk samples collected from several dairy plants in Ankara, Turkey. Among these isolates, 19 were identified as Pseudomonas aeruginosa, 28 as Pseudomonas fluorescens, 4 as Acinetobacter baumannii, 2 as Enterobacter intermedium, 1 asEnterobacter agglomerans, and 1 as Escherichia coli using Microbact biochemical test kit. BKC was chosen as a selective agent to suppress growth of competitive flora because it is very effective against a wide range of Gram-negative bacteria while P. aeruginosa is resistant. MICs (minimum inhibitory concentration) for BKC were determined by agar dilution method. The concentration of 200 μg/mL BKC inhibited competitive flora, while 90% of P. aeruginosa strains were resistant. When the results of enumeration of P. aeruginosa and other Gram (-) bacteria in Cetrimide Agar (CA) and mCA were compared, it was observed that mCA was more selective than the standard CA in preventing the growth of competitive flora especially of P. fluorescens.
文摘Pseudomonas aeruginosa is one of the most common pathogenic bacteria, frequently found in different environmental samples. The prevalence of multidrug resistant isolates has become an alarming concern for both patients and their surroundings. The present study was carried out to record prevalence of P. aeruginosa in surface water of Dhaka city and to screen their antibiotic resistance pattern. The study was also extended to typing of resistant isolates according to extended spectrum beta lactamase production. Hereby, Kirby-Bauer method was applied to test antibiotic sensitivity according to Clinical and Laboratory Standards Institute. Then, the Ampicillin resistant isolates were screened for ESBL production by Double Disk Synergy Test (DDST). In these prospects, 52 water samples were tested, of which 32 were found positive for P. aeruginosa isolates. Hundred percent of the positive isolates were found to Ampicillin (AMP) resistant followed by 93.7% to both Tetracycline and Gentamycin and 71.8% to Co-triimoxazole. P. aeruginosa is completely susceptible to third generation antibiotics ciprofloxacin, Imipenem and Aztreonam followed by moderately susceptible to Polymyxin-B (78.2%) and Colistin (87.5%). According to DDST, all of the susceptible isolates were found positive for AMC type beta-lactamase production. It is evident from this study that the surface water is contaminated with antibiotic resistant P. aeruginosa and that through the water systems antibiotic resistance can be transferred to humans and animals. So, appropriate and rationale use of antibiotic should be applied to minimize the emergence of multidrug isolates to environment.
基金supported by 2009--0214 numbered project of National Boron Research Institute(BOREN)-Turkey
文摘Objective To study MIC value of 7 boron derivatives namely [Boric acid （H3BO3）, Anhydrous Borax （Na2B407）, Sodium Borate （NaBO2）, Diammonium Tetraborate （NH4）2B4O7, Sodium Perborate （NaBO3）, Boron Trioxide （B203）, Potassium Tetraborate （K2B407）] on E. coil and P. aeruginosa and their effects on survival of bacteria in lake water and resistance against kanamycin antibiotic. Methods MIC values of Boron derivatives and antibiotic were studied by broth microdilution method. The effect of boron derivatives on survival of bacteria in lake water were also determined with plate count. Results Sodium perborate was determined as the substances. Effectiveness increased as temperature most effective substance among the studied increased. E. coil was more affected from P. aeruginosa in 8 mg/mL sodium perborate concentration in lake water. Moreover, it was determined that MIC value of kanamycin antibiotic decreased 200 times by especially treating P. aeruginosa with sodium perborate in lake water. However, it can be stated that this change in resistance did not arise from microorganisms. Conclusion Sodium perborate solution can be used supportedly in kanamycin antibiotic applications for P. aeruginosa. Future studies are necessary to explore the relation between sodium perborate and kanamycin which is effective on P. aeruginosa in lake water.
文摘The expression of IL-4 in a rat model of chronic pulmonary infection biofilm formation induced by Pseudomonas aeruginosa was investigated, in which SPF Wister rats were infected via trachea with 0.1 ml P. aeruginosa strain PAO579 （ 10^9 CFU/ml） in alginate beads or the planktonic form of this bacterial strain （109 CFU/ml）, and on 3, 7 and 14 d after infection, the bacteriological and pathological changes were observed as well as the expression of the cytokine IL-4 was determined. It was demonstrated that the count of CFU per lung tissue in case of bacteria in alginate beads was significantly higher than that of bacteria in planktonic form, with more severe gross pathologic changes and inflammatory reactions in the alginate bead group in comparison with that of the planktonic forms （ P = 0. 002, P = 0. 004 and P = 0. 002, respectively）. In addition, the expression of IL-4 in the alginate bead group was also higher than that in the planktonic form （P = 0.02, P = 0.02 and P = 0.022, respectively）. A positive correlation between the level of IL-4 expression and the gross lung pathology in alginate bead group existed as demonstrated by simple regression analysis （r = 0.78, P 〈 0.02）. It is concluded that the chronic pulmonary infection with biofilm formation induced by P. aeruginosa tends to have the priority to the Th2 immune response.
文摘Antimicrobial susceptibility test was performed on 57 clinical isolates of P. aeruginosa and 36 clinical isolates of Acinetobacter with 11 antimicrobial agents including getamicin, amikacin, ciprofloxacin, ofloxacin, fleroxacin, piperacillin, cefotaxime, cefoperazone/sulbactam, ceftazidime, cefoperazone and doxycycline. Transferable drug resistance plasmid carrying rates of these clinical isolates were also studied. On the basis of the in vitro activities, 52.63%(30/57) of the isolated strains of P. aeruginosa were susceptible to antimicrobial agents selected (except doxycycline), 41.67%(15/36) of the isolated strains of Acinetobacter were susceptible to 11 antimicrobial agents. The sensitivity rate of P.aeruginosa and Acinetobacter to antimicrobial agents selected was 70% or greater to all except doxycycline. Furthermore, the sensitivity rate of P.aeruginosa to amikacin ciprofloxacin, ceftazidime, cefoperazone, cefoperazone/sulbactam, and that of Acinetobacter to cefoperazone/sulbactam, amikacin was more than 90%,among them amikacin, cefoperazone/sulbactam being the most effective. Plasmid analysis showed that 15.79%(9/57) P.aeruginosa strains and 13.89%(5/36) Acinetobacter strains carried plasmid. Conjugative plasmid carrying rates of P. aeruginosa strains and Acinetobacter strains were 7.02%(4/57), 13.89%(5/36), respectively. Conjugative plasmid didn′t play an important role in the formation and dissemination of drug resistance of P. aeruginosa and Acinetobacter.
文摘Objective: To develop a duplex real-time PCR assay for pharmaceutical rapid microbial detection of Staphylococcus aureus and Pseudomonas aeruginosa. Methods: The specific primers and probes were designed to amplify the femB gene of S. aureus and the DNA gyrase subunit B gene of P. aeruginosa. The sensitivity of the system was detected by a multiple proportional dilution method. In order to examine the specificity of the system, other twenty-one bacteria strains were assayed simultaneously. Results: A highly sensitive and specific duplex real-time PCR assay for the detection of S. aureus and P. aeruginosa was established. The sensitivity was 50 copies/μL. The specificity was 100%. The whole detection procedure can be finished within 2.5 h. Conclusion: The duplex real-time PCR method is efficient in detecting with good sensitivity and specificity. There is a good prospect of this method applying in disease prevention and pharmaceutical industry due to the simultaneous detection of two pathogens.
文摘It is necessary to determine the susceptibility pattern of clinical isolates especially nosocomial one in the clinical settings for making strategy for effective empirical treatment & to reduce incidence of multidrug resistant bugs. Aim of this study was to detect the antimicrobial susceptibility pattern of P. aeruginosa isolates from clinical samples between January 2014 to December 2015, received at department of Microbiology, GMC, Surat. Clinical isolates were confirmed as P. aeruginosa by phenotypic methods/Vitek2 compact system as per availability. Genetic sequencing could not be performed due to unavailability. Antimicrobial susceptibility tests were performed by Kirby-Bauer disc diffusion method/Vitek2 compact system & Interpretation was done according Clinical and Laboratory Standards Institute (CLSI) of that year [1] [2]. Seven hundred fifty seven P. aeruginosa strains were studied during the study period. Most of the isolates were from surgery ward (62%), followed by orthopaedic ward (15%). 65% of the total isolates were from swab samples followed by urine (7%), pus, fluid (5%) & devices (4%). 60% isolates were resistant to Ceftazidime & for other drugs resistance pattern was as follows: Cefepime (52%), Levofloxacin (49%), Ticarcillin/clavulanic acid (49%), Meropenem & Gentamycin (44%), Ciprofloxacin (43%), Amikacin (41%), Tobramycin (39%), Netlimycin (36%), Piperacillin (32%), Aztreonam (31%), Piperacillin/tazobactam (26%), Imipenem (23%) , Doripenem (12%) & Gatifloxacin (10%). As there is predominance of isolates from surgical ward in present study & resistance to carbapenem group of drugs was also found, indicating that most of the infection caused by Pseudomonas aeruginosa may be nosocomial.
文摘Background: Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen that represents a major problem in many hospitals because of its increased resistance to antibiotics and the ability to cause nosocomial infections. The present study aimed to phenotype and genotype isolates of P. aeruginosa from inpatients with UTIs at Urology and Nephrology center, Mansoura, Egypt to study their relatedness. Methods: Thirty nine isolates of P. aeruginosa were phenotypically typed by determination of O-serotypes by slide agglutination technique and antimicrobial resistance patterns by disk-diffusion method. The genetic diversity of isolates was illustrated by performing RAPD-PCR using M13 primer. Results: Serotypes O11, O6 and O10 were the most prevalent. Isolates showed high resistance rates to antipseudmonal antibiotics with high incidence (51.3%) of multidrug resistance (MDR). Amikacin was the most effective. A significant correlation was found between O6, O10 and MDR. A relatively high polymorphism was demonstrated among P. aeruginosa isolates by using RAPD-M13 fingerprinting. Cross transmission was suggested by phenotypically and clonally identical isolates. Conclusion: The study demonstrates the role of combining both classical and molecular typing as a valuable mean to study the origin and cross transmission of P. aeruginosa in UTIs for better assessment of treatment and infection control.
文摘Silver nanoparticles (Ag-NPs), one of the most common types of nanomaterials in medical fields and consumer products, are known to have antimicrobial effects;these materials also undergo a series of chemical and biological transformations in the environment. Although the pristine form of silver nanoparticles has been studied, less is known about the impacts of the transformed Ag-NPs on biological systems. This knowledge gap hinders the progress of effectively assessing the impacts of Ag-NPs on the environment and human health. In this study, we demonstrate that the most common form of transformed Ag-NPs, sulfidized silver nano-particles (Ag2S-NPs), show less damage on established Pseudomonas aeruginosa GFP (ATCC? 10145 GFP?) biofilm than the pristine form of the nanoparticle. At a dosage of 0.625 mg/L, the total biomass in the biofilm decreased 64% after being exposed to Ag-NPs and 44% after exposure to Ag2S-NPs. Live biofilms were also interrogated. We observed high reduction in live population for biofilm exposed to Ag-NPs and relatively low reduction by Ag2S-NPs at exposure concentrations higher than 0.625 mg/L. Compared with Ag-NPs, the lower solubility of Ag2S-NPs results in less Ag+ diffusion into established biofilms. Our results suggest that the sulfidation of Ag-NPs reduces their impacts on established biofilms, indicating that the transformed Ag-NPs may have less environmental or human health risks.
