Objective Fungal keratitis（FK） is a vision-threatening infection,whose treatment requires more effective and safer anti-fungal agent exploitation urgently.With this aim,we focused on the effect of an extracellular p...Objective Fungal keratitis（FK） is a vision-threatening infection,whose treatment requires more effective and safer anti-fungal agent exploitation urgently.With this aim,we focused on the effect of an extracellular polysaccharide on fungal adhesion to human corneal epithelial cells.Methods We performed the cytotoxicity assays of the extracellular polysaccharide EPS-II from an antarctic bacterium Pseudoaltermonas and evaluated its inhibitory effect on Candida albicans cells＇ adherence to human corneal epithelial cells（HCECs）.Results EPS-II,which displayed minor cytotoxicity but also promoted proliferation of HCECs,could inhibit the adherence of yeast cells to HCECs in a dose-dependent manner.EPS-II could also suppress the subsequent PI3K/AKT signaling pathway,and thereby decrease the expression of early inflammatory cytokines.Conclusions ExtracellularpolysaccharideEPS-IIwassuggestedasanewnaturalagentforattenuatingFK.展开更多
BACKGROUND The oral cavity harbors more than 700 species of bacteria,which play crucial roles in the development of various oral diseases including caries,endodontic infection,periodontal infection,and diverse oral di...BACKGROUND The oral cavity harbors more than 700 species of bacteria,which play crucial roles in the development of various oral diseases including caries,endodontic infection,periodontal infection,and diverse oral diseases.AIM To investigate the antimicrobial action of Cymbopogon Schoenanthus and Pelargonium graveolens essential oils against Streptococcus mutans,Staphylococcus aureus,Candida albicans,Ca.dubliniensis,and Ca.krusei.METHODS Minimum microbicidal concentration was determined following Clinical and Laboratory Standards Institute documents.The synergistic antimicrobial activity was evaluated using the Broth microdilution checkerboard method,and the antibiofilm activity was evaluated with the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay.Data were analyzed by one-way analysis of variance followed by the Tukey post-hoc test(P≤0.05).RESULTS C.schoenanthus and P.graveolens essential oils were as effective as 0.12%chlorhexidine against S.mutans and St.aureus monotypic biofilms after 24 h.After 24 h P.graveolens essential oil at 0.25%was more effective than the nystatin group,and C.schoenanthus essential oil at 0.25%was as effective as the nystatin group.CONCLUSION C.schoenanthus and P.graveolens essential oils are effective against S.mutans,St.aureus,Ca.albicans,Ca.dubliniensis,and Ca.krusei at different concentrations after 5 min and 24 h.展开更多
OBJECTIVE: To study antimicrobial effect of Sodium houttuyfonate(SH) on Staphylococcus epidermidis(SE) and Candida albicans(CA). METHODS: The prepared strain broths(OD600 =0.05) containing SE and CA were firstly used ...OBJECTIVE: To study antimicrobial effect of Sodium houttuyfonate(SH) on Staphylococcus epidermidis(SE) and Candida albicans(CA). METHODS: The prepared strain broths(OD600 =0.05) containing SE and CA were firstly used to test the minimal inhibitory concentrations(MICs) of SH, azithromycin(AZM) and fluconazole(FLU) by micro-dilution method. Then the biofilms of SE and CA were matured in 96-well plates, and co-cultured with SH, AZM and FLU for 1, 2 and 3 days to assess the antibiofilm efficacies of the agents with different concentrations by crystal violet staining method. At last, the treated biofilms of SE and CA by 2× MIC agents were observed by scanning electronic microscope. RESULTS: The MICs of SE and CA were 256 and 1024 μg/mL, respectively. After the 1st, 2nd and 3rd day of medications, the suppressions of biofilm were about 60%(P<0.01), 76%(P=0.000) and 75%(P=0.000) by 2×MIC SH, the suppressions of biofilm were about 90%(P=0.000), 88%(P=0.000) and 90%(P=0.000) by 2×MIC SH, which could be testified by scanning electron microscope results. However, the inhibitions of biofilm attachment had no significant difference for SE by SH and azithromycin and CA by SH and fluconazole. CONCLUSION: SH had widely anti-pathogenic effect on pathogenic biofilm formation of either bacteria or fungus, had more influence on enclosed cells of SE and CA than the traditional antibiotics, revealing its target might be the extracellular polymeric substances, and was more active to inhibit the growth of CA than SE.展开更多
The Ca. LSU intron flanking a 129 bp cxon upstream and a fOO bp exondownstream was inserted into the lacZ gene on pRS426 to transform E. coli. Northern blot analysisand RT-PCR showed that splicing of Ca. LSU in E. col...The Ca. LSU intron flanking a 129 bp cxon upstream and a fOO bp exondownstream was inserted into the lacZ gene on pRS426 to transform E. coli. Northern blot analysisand RT-PCR showed that splicing of Ca. LSU in E. coli is efficient upon inducible expression of theprecursor RNA, In contrast, co-lranscriptional self-splicing of the intron in vitro is much lessactive. Therefore, this E. coli splicing system can be used as a better model to investigate theeffect of the ribozyme inhibitors on Ca. LSUsplicing in living cell. We examined (he effects ofneomycin sulfatc and pentamidine on Ca. LSU splicing in E. coli, and found that these drugsdoes-dependently inhibit the intron splicing. However, heomycin is more potent than pentamidine inthis action.展开更多
Objective： Invasive pulmonary candidiasis is a disease with high incidence, difficult treatment, poor prognosis, and high mortality. The present study analyzed the influence of cinnamaldehyde on 1,3-β-D-glucans in t...Objective： Invasive pulmonary candidiasis is a disease with high incidence, difficult treatment, poor prognosis, and high mortality. The present study analyzed the influence of cinnamaldehyde on 1,3-β-D-glucans in the cell wall of Candida albicans in order to provide a theoretical basis for the research of antifungal drugs.Methods： An immunosuppressed BALB/c mouse model with invasive pulmonary candidiasis was established by nasal perfusion of 50 μL of C. albicans suspension（107 cfu/mL）. 1,3-β-D-glucans examination and electron microscopy were carried out. Fluconazole was used as the control.Results： Cinnamaldehyde was administered at a dose of 240 mg/kg/d for 14 consecutive days, and the measured value of 1,3-β-D-glucans was（1160.62 ± 89.65） pg/mL, whereas that of fluconazole was（4285.87 ± 215.62） pg/m L. The difference between the two groups was statistically significant（P 〈 0.05）.Electron microscopy observation indicated that the 2-3 layers outside the cell wall of C. albicans（1,3-β-D-glucans layer） were rough, deformed, and incomplete, although the cell membrane was clear and intact.Conclusion： Cinnamaldehyde demonstrated special efficacy on 1,3-β-D-glucans in the cell wall of C. albicans.展开更多
Mostly candida resides as an opportunistic organism on epithelial surfaces of human being. However, under auspicious conditions can cause infections including serious life threatening invasive candidiasis with subsequ...Mostly candida resides as an opportunistic organism on epithelial surfaces of human being. However, under auspicious conditions can cause infections including serious life threatening invasive candidiasis with subsequent mortality particularly in immune deficit and hospitalized patients having co-morbids. Limited data are published on the prevalence of candidiasis, based on the researches conducted at few tertiary care settings which are not representing the overall disease burden in our country, Pakistan. Therefore, this study was conducted to evaluate the frequency and sensitivity patterns of candidiasis in our community. Methods: Out of total 1020 specimens, 130 clinical samples were identified as candidal positive, obtained from March to May 2018. These samples were isolated from vagina, oropharynx, urine, tracheal aspirates, pus, blood, tips of the intubations, wounds and fluids of the body cavities. Identification of candida, its species and antifungal sensitivity screening was done by Kirby Bauer’s disk diffusion method according to CLSI guide lines’ (M - 44 A2 series, 2009). Results: A significant majority, 80 (61.5%) of candidal strains were isolated from females with female to male ratio 8:5 and most of these isolates were obtained from high vaginal swabs (43.75%). Four candidal species (Candida albicans 80%, Candida tropicalis 10%, Candida glabrata 9.2% and Candida ciferrii 0.8%) were isolated from all positive specimens. Maximum number of the positive samples 52 (40%) were obtained from ICU patients. Sensitivity test of candidal positive samples revealed that commonly used azole antifungal drugs, fluconazole and voriconazole were highly resistant, with respective 57.7% and 70.8% resistance. Conclusion: Candidiasis is highly prevalent in our clinical set up and more frequently infecting females in comparison to males as most of the positive isolates were retrieved from HVS (high vaginal swabs). Still, C. albicans was found to be the most prevalent specie isolated among all candida samples. Our study also demonstrated that the resistance of most commonly prescribed antifungals, azoles have shown a rapid rise. Therefore, it is recommended that before prescription of antifungal drugs the clinicians should routinely recommend culture and sensitivity testing of samples taken from candida infected individuals.展开更多
Background The cytochrome P450 lanosterol 14a-demethylase （Ergllp） encoded by ERG11 gene is the primary target for azole antifungals. Changes in azole affinity of this enzyme caused by amino acid substitutions have ...Background The cytochrome P450 lanosterol 14a-demethylase （Ergllp） encoded by ERG11 gene is the primary target for azole antifungals. Changes in azole affinity of this enzyme caused by amino acid substitutions have been reported as a mechanism of azole antifungal resistance. This study aimed to investigate the relationship between amino acid substitutions in Erg11 p from fluconazole resistant Candida a/bicans （C. albicans） isolates and their cross-resistance to azoles. Methods Mutations in ERG11 gene were screened in 10 clinical isolates of fluconazole resistant C. albicans strains. DNA sequence of ERG11 was determined by PCR based DNA sequencing. Results In the 10 isolates, 19 types of amino acid substitutions were found, of which 10 substitutions （F72S, F103L, F1451, F198L, G206D, G227D, N349S, F416S, F422L and T482A） have not been reported previously. Mutations in ERG11 gene were detected in 9 isolates of fluconazole resistant C. albicans, but were not detected in 1 isolate. Conclusions Although no definite correlation was found between the type of amino acid substitutions in Ergllp and the phenotype of cross-resistance to azoles, the substitutions F72S, F1451 and G227D in our study may be highly associated with resistance to azoles because of their special location in Erg11p.展开更多
基金partially supported by the National Natural Scientific Foundation (81000369)the Doctor Foundation of Shandong Province (BS2009SW018)
文摘Objective Fungal keratitis（FK） is a vision-threatening infection,whose treatment requires more effective and safer anti-fungal agent exploitation urgently.With this aim,we focused on the effect of an extracellular polysaccharide on fungal adhesion to human corneal epithelial cells.Methods We performed the cytotoxicity assays of the extracellular polysaccharide EPS-II from an antarctic bacterium Pseudoaltermonas and evaluated its inhibitory effect on Candida albicans cells＇ adherence to human corneal epithelial cells（HCECs）.Results EPS-II,which displayed minor cytotoxicity but also promoted proliferation of HCECs,could inhibit the adherence of yeast cells to HCECs in a dose-dependent manner.EPS-II could also suppress the subsequent PI3K/AKT signaling pathway,and thereby decrease the expression of early inflammatory cytokines.Conclusions ExtracellularpolysaccharideEPS-IIwassuggestedasanewnaturalagentforattenuatingFK.
文摘BACKGROUND The oral cavity harbors more than 700 species of bacteria,which play crucial roles in the development of various oral diseases including caries,endodontic infection,periodontal infection,and diverse oral diseases.AIM To investigate the antimicrobial action of Cymbopogon Schoenanthus and Pelargonium graveolens essential oils against Streptococcus mutans,Staphylococcus aureus,Candida albicans,Ca.dubliniensis,and Ca.krusei.METHODS Minimum microbicidal concentration was determined following Clinical and Laboratory Standards Institute documents.The synergistic antimicrobial activity was evaluated using the Broth microdilution checkerboard method,and the antibiofilm activity was evaluated with the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay.Data were analyzed by one-way analysis of variance followed by the Tukey post-hoc test(P≤0.05).RESULTS C.schoenanthus and P.graveolens essential oils were as effective as 0.12%chlorhexidine against S.mutans and St.aureus monotypic biofilms after 24 h.After 24 h P.graveolens essential oil at 0.25%was more effective than the nystatin group,and C.schoenanthus essential oil at 0.25%was as effective as the nystatin group.CONCLUSION C.schoenanthus and P.graveolens essential oils are effective against S.mutans,St.aureus,Ca.albicans,Ca.dubliniensis,and Ca.krusei at different concentrations after 5 min and 24 h.
基金Supported by the National Natural Science Foundation of China(No.81173629)
文摘OBJECTIVE: To study antimicrobial effect of Sodium houttuyfonate(SH) on Staphylococcus epidermidis(SE) and Candida albicans(CA). METHODS: The prepared strain broths(OD600 =0.05) containing SE and CA were firstly used to test the minimal inhibitory concentrations(MICs) of SH, azithromycin(AZM) and fluconazole(FLU) by micro-dilution method. Then the biofilms of SE and CA were matured in 96-well plates, and co-cultured with SH, AZM and FLU for 1, 2 and 3 days to assess the antibiofilm efficacies of the agents with different concentrations by crystal violet staining method. At last, the treated biofilms of SE and CA by 2× MIC agents were observed by scanning electronic microscope. RESULTS: The MICs of SE and CA were 256 and 1024 μg/mL, respectively. After the 1st, 2nd and 3rd day of medications, the suppressions of biofilm were about 60%(P<0.01), 76%(P=0.000) and 75%(P=0.000) by 2×MIC SH, the suppressions of biofilm were about 90%(P=0.000), 88%(P=0.000) and 90%(P=0.000) by 2×MIC SH, which could be testified by scanning electron microscope results. However, the inhibitions of biofilm attachment had no significant difference for SE by SH and azithromycin and CA by SH and fluconazole. CONCLUSION: SH had widely anti-pathogenic effect on pathogenic biofilm formation of either bacteria or fungus, had more influence on enclosed cells of SE and CA than the traditional antibiotics, revealing its target might be the extracellular polymeric substances, and was more active to inhibit the growth of CA than SE.
基金Supported by the National Natural Science Foundation of China (30170213) and the Foundation of Wuhan University(0000028)
文摘The Ca. LSU intron flanking a 129 bp cxon upstream and a fOO bp exondownstream was inserted into the lacZ gene on pRS426 to transform E. coli. Northern blot analysisand RT-PCR showed that splicing of Ca. LSU in E. coli is efficient upon inducible expression of theprecursor RNA, In contrast, co-lranscriptional self-splicing of the intron in vitro is much lessactive. Therefore, this E. coli splicing system can be used as a better model to investigate theeffect of the ribozyme inhibitors on Ca. LSUsplicing in living cell. We examined (he effects ofneomycin sulfatc and pentamidine on Ca. LSU splicing in E. coli, and found that these drugsdoes-dependently inhibit the intron splicing. However, heomycin is more potent than pentamidine inthis action.
基金supported by Hebei Natural Science Foundation (H2013206316)
文摘Objective： Invasive pulmonary candidiasis is a disease with high incidence, difficult treatment, poor prognosis, and high mortality. The present study analyzed the influence of cinnamaldehyde on 1,3-β-D-glucans in the cell wall of Candida albicans in order to provide a theoretical basis for the research of antifungal drugs.Methods： An immunosuppressed BALB/c mouse model with invasive pulmonary candidiasis was established by nasal perfusion of 50 μL of C. albicans suspension（107 cfu/mL）. 1,3-β-D-glucans examination and electron microscopy were carried out. Fluconazole was used as the control.Results： Cinnamaldehyde was administered at a dose of 240 mg/kg/d for 14 consecutive days, and the measured value of 1,3-β-D-glucans was（1160.62 ± 89.65） pg/mL, whereas that of fluconazole was（4285.87 ± 215.62） pg/m L. The difference between the two groups was statistically significant（P 〈 0.05）.Electron microscopy observation indicated that the 2-3 layers outside the cell wall of C. albicans（1,3-β-D-glucans layer） were rough, deformed, and incomplete, although the cell membrane was clear and intact.Conclusion： Cinnamaldehyde demonstrated special efficacy on 1,3-β-D-glucans in the cell wall of C. albicans.
文摘Mostly candida resides as an opportunistic organism on epithelial surfaces of human being. However, under auspicious conditions can cause infections including serious life threatening invasive candidiasis with subsequent mortality particularly in immune deficit and hospitalized patients having co-morbids. Limited data are published on the prevalence of candidiasis, based on the researches conducted at few tertiary care settings which are not representing the overall disease burden in our country, Pakistan. Therefore, this study was conducted to evaluate the frequency and sensitivity patterns of candidiasis in our community. Methods: Out of total 1020 specimens, 130 clinical samples were identified as candidal positive, obtained from March to May 2018. These samples were isolated from vagina, oropharynx, urine, tracheal aspirates, pus, blood, tips of the intubations, wounds and fluids of the body cavities. Identification of candida, its species and antifungal sensitivity screening was done by Kirby Bauer’s disk diffusion method according to CLSI guide lines’ (M - 44 A2 series, 2009). Results: A significant majority, 80 (61.5%) of candidal strains were isolated from females with female to male ratio 8:5 and most of these isolates were obtained from high vaginal swabs (43.75%). Four candidal species (Candida albicans 80%, Candida tropicalis 10%, Candida glabrata 9.2% and Candida ciferrii 0.8%) were isolated from all positive specimens. Maximum number of the positive samples 52 (40%) were obtained from ICU patients. Sensitivity test of candidal positive samples revealed that commonly used azole antifungal drugs, fluconazole and voriconazole were highly resistant, with respective 57.7% and 70.8% resistance. Conclusion: Candidiasis is highly prevalent in our clinical set up and more frequently infecting females in comparison to males as most of the positive isolates were retrieved from HVS (high vaginal swabs). Still, C. albicans was found to be the most prevalent specie isolated among all candida samples. Our study also demonstrated that the resistance of most commonly prescribed antifungals, azoles have shown a rapid rise. Therefore, it is recommended that before prescription of antifungal drugs the clinicians should routinely recommend culture and sensitivity testing of samples taken from candida infected individuals.
文摘Background The cytochrome P450 lanosterol 14a-demethylase （Ergllp） encoded by ERG11 gene is the primary target for azole antifungals. Changes in azole affinity of this enzyme caused by amino acid substitutions have been reported as a mechanism of azole antifungal resistance. This study aimed to investigate the relationship between amino acid substitutions in Erg11 p from fluconazole resistant Candida a/bicans （C. albicans） isolates and their cross-resistance to azoles. Methods Mutations in ERG11 gene were screened in 10 clinical isolates of fluconazole resistant C. albicans strains. DNA sequence of ERG11 was determined by PCR based DNA sequencing. Results In the 10 isolates, 19 types of amino acid substitutions were found, of which 10 substitutions （F72S, F103L, F1451, F198L, G206D, G227D, N349S, F416S, F422L and T482A） have not been reported previously. Mutations in ERG11 gene were detected in 9 isolates of fluconazole resistant C. albicans, but were not detected in 1 isolate. Conclusions Although no definite correlation was found between the type of amino acid substitutions in Ergllp and the phenotype of cross-resistance to azoles, the substitutions F72S, F1451 and G227D in our study may be highly associated with resistance to azoles because of their special location in Erg11p.
