BACKGROUND The upsurge of antibiotic resistance is a significant challenge to public health,and the dry pipeline of new antibiotics has prompted the discovery of alternative treatment approaches.Enterococcus faecalis(...BACKGROUND The upsurge of antibiotic resistance is a significant challenge to public health,and the dry pipeline of new antibiotics has prompted the discovery of alternative treatment approaches.Enterococcus faecalis(E.faecalis)isolates are often multidrugresistant,posing challenges to antibiotic therapy.Bacteriophage therapy is being explored as an alternative method to treat the growing population of antibioticresistant infections.Nevertheless,many inherent limitations of phages diminish their therapeutic utility,notably the restricted host range and quick development of mutants.The specific types and quantities of bacteriophages and antibiotics may be crucial in generating the optimal phage-antibiotic synergy.AIM To optimize the doses,order,and timing to optimize the synergy of phages and vancomycin on different bacteria states.METHODS A volume of 180μL of E.faecalis bacteria in the logarithmic growth phase,with a concentration of approximately 1×10^(8)colony forming units(CFUs)/mL,was introduced onto a microtitre plate.Subsequently,20μL of phage suspension(1×10^(6)PFUs/mL),vancomycin(16μg/mL),or a combination of both was introduced into the designated wells in the specified sequence and incubated at 37°C for 48 hours.The number of live bacteria was counted at different time points using standardized CFU counting protocols.RESULTS The biofilm model demonstrated that combining phages with vancomycin can eradicate the biofilm.Sequential therapy,involving phage application 8 hours before the antibiotic at a concentration of 108 PFUs/mL,proved the most efficient in eliminating the biofilms and killing the planktonic form of E.faecalis.CONCLUSION The combination of phageɸEFP01 at a higher concentration with a subinhibitory concentration of vancomycin yields a synergistic antibacterial outcome on E.faecalis strain resistant to vancomycin.展开更多
Since the discovery of Helicobacter pylori (H. pylori) in 1983, numerous detection methods for the presence of the bacterium have been developed. Each one of them has been associated with advantages and disadvantages....Since the discovery of Helicobacter pylori (H. pylori) in 1983, numerous detection methods for the presence of the bacterium have been developed. Each one of them has been associated with advantages and disadvantages. Noninvasive tests such as serology, <sup>13</sup>C urea breath test (UBT) and stool antigen tests are usually preferred by the clinicians. Serology has its own limitation especially in endemic areas while <sup>13</sup>C UBT is technically very demanding. The stool antigen detection method, although specific, is usually associated with poor sensitivity. The <sup>13</sup>C UBT is believed to be specific, but with present revelation of the fact that stomach is colonized by many other urease producing bacteria makes it questionable. Histology, culture, rapid urease test and polymerase chain reaction (PCR) are the tests which are carried out on antral biopsies collected by invasive means. Histology has been proposed to be very sensitive and specific but the question is how by simply looking the morphology of the bacteria in the microscope, one can claim that the curved bacterium is exclusively H. pylori. Rapid urease test (RUT), the doctor’s test, is also challenged because the presence of other urease producing bacteria in the stomach cannot be denied. Moreover, RUT has been reported with poor sensitivity specially, when density of the bacterium is low. Isolation of H. pylori is essential to investigate its growth requirements, antibiotic susceptibility testing, studying virulence factor to develop vaccine and many more explorations. It has also got several disadvantages i.e., special condition for transporting, media, incubation and few days waiting for the colonies to appear, apart from the speed essentially needed to process the specimens. Till date, majority of the microbiological laboratories in the world are not equipped and trained to isolate such fastidious bacterium. The option left is PCR methods to detect H. pylori’s DNA in gastric mucosa, gastric juice, saliva, dental plaques and environmental specimens. There are speculations for false positivity due to detection of non-pylori Helicobacters due to genetic sharing; and false negativity due to low bacterial counts and presence of PCR inhibitors. However, specimen collection, transportation and processing do not require speed and special conditions. PCR based diagnosis may be considered as gold standard by designing primers extremely specific to H. pylori and targeting at least more than one conserved genes. Similarly specificity of PCR may be improved by use of internal Primers. Further, nested PCR will take care of false negatives by countering the effect of PCR inhibitors and low bacterial counts. Therefore, nested PCR based methods if performed properly, may be proposed as gold standard test.展开更多
Carcinoma of the gallbladder (CaGB) is the fifth commonest gastrointestinal tract cancer and is endemic in several countries. The interplay of genetic susceptibility, infections, and life style factors has been propos...Carcinoma of the gallbladder (CaGB) is the fifth commonest gastrointestinal tract cancer and is endemic in several countries. The interplay of genetic susceptibility, infections, and life style factors has been proposed to be responsible for carcinogenesis of gallbladder. Persistence of infection leading to chronic inflammation, and production of certain toxins and metabolites with carcinogenic potentials, by certain bacteria has been speculated to be involved in the transformation of the gallbladder epithelium. Therefore, any bacteria that have evolved to acquire both of the above carcinogenic mechanisms can cause cancer. Salmonella typhi has been found to be prominently associated with CaGB. Chronic typhoid carriage (persistence) and production of mediators of chronic infl ammation and a genotoxic toxin (cytotoxic distending toxin, CdtB) are also known for this bacterium. Furthermore, the natural concentrating function of the gallbladder might amplify the carcinogenic effect of the mediators of carcinogenesis. In addition to S. typhi, certain species of Helicobacter (H. bilis and H. hepaticus) and Escherichia coli have also been implicated in carcinogenesis. As the isolation rate is verypoor with the presently available culture techniques, the existence of bacteria in a viable but non-cultivable state is quite likely; therefore, sensitive and specif ic molecular techniques might reveal the etiological role of bacterial infection in gallbladder carcinogenesis. If bacteria are found to be causing cancers, then eradication of such infections might help in reducing the incidence of some cancers.展开更多
AIM:To characterize oxidase-and urease-producing bacterial isolates,grown aerobically,that originated from antral biopsies of patients suffering from acid peptic diseases.METHODS:A total of 258 antral biopsy specimens...AIM:To characterize oxidase-and urease-producing bacterial isolates,grown aerobically,that originated from antral biopsies of patients suffering from acid peptic diseases.METHODS:A total of 258 antral biopsy specimens were subjected to isolation of bacteria followed by tests for oxidase and urease production,acid tolerance and aerobic growth.The selected isolates were further characterized by molecular techniques viz.amplifications for 16S rRNA using universal eubacterial and HSP60 gene specific primers.The amplicons were subjected to restriction analysis and partial sequencing.A phylogenetic tree was generated using unweighted pair group method with arithmetic mean(UPGMA) from evolutionary distance computed with bootstrap test of phylogeny.Assessment of acidity tolerance of bacteria isolated from antrum was performed using hydrochloric acid from 10-7 mol/L to 10-1 mol/L.RESULTS:Of the 258 antral biopsy specimens collected from patients,179(69.4%) were positive for urease production by rapid urease test and 31%(80/258) yielded typical Helicobacter pylori(H.pylori) after 5-7 d of incubation under a microaerophilic environment.A total of 240(93%) antral biopsies yielded homogeneous semi-translucent and small colonies after overnight incubation.The partial 16S rRNA sequences revealed that the isolates had 99% similarity with Pseudomonas species.A phylogenetic tree on the basis of 16S rRNA sequences denoted that JQ927226 and JQ927227 were likely to be related to Pseudomonas fluorescens(P.fluorescens).On the basis ofHSP60 sequences applied to the UPGMA phylogenetic tree,it was observed that isolated strains in an aerobic environment were likely to be P.fluorescens,and HSP60 sequences had more discriminatory potential rather than 16S rRNA sequences.Interestingly,this bacterium was acid tolerant for hours at low pH.Further,a total of 250(96.9%) genomic DNA samples of 258 biopsy specimens and DNA from 240 bacterial isolates were positive for the 613 bp amplicons by targeting P.fluorescens-specific conserved putative outer membrane protein gene sequences.CONCLUSION:This study indicates that bacterial isolates from antral biopsies grown aerobically were P.fluorescens,and thus acid-tolerant bacteria other than H.pylori can also colonize the stomach and may be implicated in pathogenesis/protection.展开更多
Objective: To investigate new scolicidal agent from natural resources to cope with the side effects associated with synthetic drugs in Echinococcosis. Methods: The scolicidal potential of methanolic fruit powder extra...Objective: To investigate new scolicidal agent from natural resources to cope with the side effects associated with synthetic drugs in Echinococcosis. Methods: The scolicidal potential of methanolic fruit powder extract (10 and 20 mg/mL) of Mallotus philippinensis ( M. philippinensis ) was investigated. Viability of protoscoleces was confirmed by trypan blue exclusion method, where mortality was observed at concentration of 10 and 20 mg/mL in 60 min treatment against Echinococcus granulosus ( E. granulosus ), under in-vitro conditions with reference to the known standard drug Praziquantel . Results: At concentration 10 and 20 mg/mL, the mortality rate was observed 97% and 99% respectively for 60 min treatment; while up to 93% mortality was observed with 20 mg/mL for only 10 min treatment. The concentration above 20 mg/mL for above 2 h showed 100% mortality, irrespective of further incubation. Conclusions: As compared with the standard anti-parasitic drug Praziquantel our extract has significant scolicidal activity with almost no associated side effects.展开更多
Objective:To investigate antimicrobial and bronchodialator effect of hydroalcholic extract of polyherbal drug Shirishadi containing Shirisha(Albezzia lebbeck),Nagarmotha(Cyprus ratandus) & Kantakari(Solanum xantho...Objective:To investigate antimicrobial and bronchodialator effect of hydroalcholic extract of polyherbal drug Shirishadi containing Shirisha(Albezzia lebbeck),Nagarmotha(Cyprus ratandus) & Kantakari(Solanum xanthocarpum).Methods:Antimicrobial activity was evaluated by discdiffusion method and MIC,MBC,MFC were calculated by micro dilution method.Hydroalcholic extract of this preparation was investigated for its phytochemical analysis,phenol and Oavonoid were determined by speclrophotometric method and in vivo bronchodilator effect was analysed by convulsion time.Results:The phytochemical tests revealed presence of alkaloids, anthraquinones,carbohydrates,flavonoids,saponins and tannins.The antimicrobial result showed the MIC of 6.25 mg/ml.against Staphylococcus aureus and 12.5 mg/mL.for Escherichia coli and 12.5 mg/mL against remaining bacteria tested,with strong antifungal activity.The maximum inhibition zone is found against Pseudomonas aeruginosa with MIC 16 mg/mL Drug showed significant bronchodilator effect with 27.86%& 36.13%increase in preconvulsion time of guinea pigs prebeated with 100 & 200 mg/kg body weight of extract.Conclusions:The study reveals that the extracts possess antibacterial activity and antifungal activity in a dose dependent manner. This antimicrobial property may be due to presence of several saponins,further studies are highly needed for the drug development.展开更多
文摘BACKGROUND The upsurge of antibiotic resistance is a significant challenge to public health,and the dry pipeline of new antibiotics has prompted the discovery of alternative treatment approaches.Enterococcus faecalis(E.faecalis)isolates are often multidrugresistant,posing challenges to antibiotic therapy.Bacteriophage therapy is being explored as an alternative method to treat the growing population of antibioticresistant infections.Nevertheless,many inherent limitations of phages diminish their therapeutic utility,notably the restricted host range and quick development of mutants.The specific types and quantities of bacteriophages and antibiotics may be crucial in generating the optimal phage-antibiotic synergy.AIM To optimize the doses,order,and timing to optimize the synergy of phages and vancomycin on different bacteria states.METHODS A volume of 180μL of E.faecalis bacteria in the logarithmic growth phase,with a concentration of approximately 1×10^(8)colony forming units(CFUs)/mL,was introduced onto a microtitre plate.Subsequently,20μL of phage suspension(1×10^(6)PFUs/mL),vancomycin(16μg/mL),or a combination of both was introduced into the designated wells in the specified sequence and incubated at 37°C for 48 hours.The number of live bacteria was counted at different time points using standardized CFU counting protocols.RESULTS The biofilm model demonstrated that combining phages with vancomycin can eradicate the biofilm.Sequential therapy,involving phage application 8 hours before the antibiotic at a concentration of 108 PFUs/mL,proved the most efficient in eliminating the biofilms and killing the planktonic form of E.faecalis.CONCLUSION The combination of phageɸEFP01 at a higher concentration with a subinhibitory concentration of vancomycin yields a synergistic antibacterial outcome on E.faecalis strain resistant to vancomycin.
基金Supported by Council of Scientific and Industrial Research,New Delhi,India in the form of Senior Research Fellowship awarded to Patel SK
文摘Since the discovery of Helicobacter pylori (H. pylori) in 1983, numerous detection methods for the presence of the bacterium have been developed. Each one of them has been associated with advantages and disadvantages. Noninvasive tests such as serology, <sup>13</sup>C urea breath test (UBT) and stool antigen tests are usually preferred by the clinicians. Serology has its own limitation especially in endemic areas while <sup>13</sup>C UBT is technically very demanding. The stool antigen detection method, although specific, is usually associated with poor sensitivity. The <sup>13</sup>C UBT is believed to be specific, but with present revelation of the fact that stomach is colonized by many other urease producing bacteria makes it questionable. Histology, culture, rapid urease test and polymerase chain reaction (PCR) are the tests which are carried out on antral biopsies collected by invasive means. Histology has been proposed to be very sensitive and specific but the question is how by simply looking the morphology of the bacteria in the microscope, one can claim that the curved bacterium is exclusively H. pylori. Rapid urease test (RUT), the doctor’s test, is also challenged because the presence of other urease producing bacteria in the stomach cannot be denied. Moreover, RUT has been reported with poor sensitivity specially, when density of the bacterium is low. Isolation of H. pylori is essential to investigate its growth requirements, antibiotic susceptibility testing, studying virulence factor to develop vaccine and many more explorations. It has also got several disadvantages i.e., special condition for transporting, media, incubation and few days waiting for the colonies to appear, apart from the speed essentially needed to process the specimens. Till date, majority of the microbiological laboratories in the world are not equipped and trained to isolate such fastidious bacterium. The option left is PCR methods to detect H. pylori’s DNA in gastric mucosa, gastric juice, saliva, dental plaques and environmental specimens. There are speculations for false positivity due to detection of non-pylori Helicobacters due to genetic sharing; and false negativity due to low bacterial counts and presence of PCR inhibitors. However, specimen collection, transportation and processing do not require speed and special conditions. PCR based diagnosis may be considered as gold standard by designing primers extremely specific to H. pylori and targeting at least more than one conserved genes. Similarly specificity of PCR may be improved by use of internal Primers. Further, nested PCR will take care of false negatives by countering the effect of PCR inhibitors and low bacterial counts. Therefore, nested PCR based methods if performed properly, may be proposed as gold standard test.
文摘Carcinoma of the gallbladder (CaGB) is the fifth commonest gastrointestinal tract cancer and is endemic in several countries. The interplay of genetic susceptibility, infections, and life style factors has been proposed to be responsible for carcinogenesis of gallbladder. Persistence of infection leading to chronic inflammation, and production of certain toxins and metabolites with carcinogenic potentials, by certain bacteria has been speculated to be involved in the transformation of the gallbladder epithelium. Therefore, any bacteria that have evolved to acquire both of the above carcinogenic mechanisms can cause cancer. Salmonella typhi has been found to be prominently associated with CaGB. Chronic typhoid carriage (persistence) and production of mediators of chronic infl ammation and a genotoxic toxin (cytotoxic distending toxin, CdtB) are also known for this bacterium. Furthermore, the natural concentrating function of the gallbladder might amplify the carcinogenic effect of the mediators of carcinogenesis. In addition to S. typhi, certain species of Helicobacter (H. bilis and H. hepaticus) and Escherichia coli have also been implicated in carcinogenesis. As the isolation rate is verypoor with the presently available culture techniques, the existence of bacteria in a viable but non-cultivable state is quite likely; therefore, sensitive and specif ic molecular techniques might reveal the etiological role of bacterial infection in gallbladder carcinogenesis. If bacteria are found to be causing cancers, then eradication of such infections might help in reducing the incidence of some cancers.
基金Supported by Department of Biotechnology,Government of India,No. 102/IFD/SAN/PR1310/2006-07Council of Scientific and Industrial Research,New Delhi,India,in the form of Senior Research Fellowship (to Patel SK)
文摘AIM:To characterize oxidase-and urease-producing bacterial isolates,grown aerobically,that originated from antral biopsies of patients suffering from acid peptic diseases.METHODS:A total of 258 antral biopsy specimens were subjected to isolation of bacteria followed by tests for oxidase and urease production,acid tolerance and aerobic growth.The selected isolates were further characterized by molecular techniques viz.amplifications for 16S rRNA using universal eubacterial and HSP60 gene specific primers.The amplicons were subjected to restriction analysis and partial sequencing.A phylogenetic tree was generated using unweighted pair group method with arithmetic mean(UPGMA) from evolutionary distance computed with bootstrap test of phylogeny.Assessment of acidity tolerance of bacteria isolated from antrum was performed using hydrochloric acid from 10-7 mol/L to 10-1 mol/L.RESULTS:Of the 258 antral biopsy specimens collected from patients,179(69.4%) were positive for urease production by rapid urease test and 31%(80/258) yielded typical Helicobacter pylori(H.pylori) after 5-7 d of incubation under a microaerophilic environment.A total of 240(93%) antral biopsies yielded homogeneous semi-translucent and small colonies after overnight incubation.The partial 16S rRNA sequences revealed that the isolates had 99% similarity with Pseudomonas species.A phylogenetic tree on the basis of 16S rRNA sequences denoted that JQ927226 and JQ927227 were likely to be related to Pseudomonas fluorescens(P.fluorescens).On the basis ofHSP60 sequences applied to the UPGMA phylogenetic tree,it was observed that isolated strains in an aerobic environment were likely to be P.fluorescens,and HSP60 sequences had more discriminatory potential rather than 16S rRNA sequences.Interestingly,this bacterium was acid tolerant for hours at low pH.Further,a total of 250(96.9%) genomic DNA samples of 258 biopsy specimens and DNA from 240 bacterial isolates were positive for the 613 bp amplicons by targeting P.fluorescens-specific conserved putative outer membrane protein gene sequences.CONCLUSION:This study indicates that bacterial isolates from antral biopsies grown aerobically were P.fluorescens,and thus acid-tolerant bacteria other than H.pylori can also colonize the stomach and may be implicated in pathogenesis/protection.
基金support provided by Department of Science and Technology,Government of India, New Delhi, in the form of project grant(vide file no.SR/SO/HS-0062/2009)
文摘Objective: To investigate new scolicidal agent from natural resources to cope with the side effects associated with synthetic drugs in Echinococcosis. Methods: The scolicidal potential of methanolic fruit powder extract (10 and 20 mg/mL) of Mallotus philippinensis ( M. philippinensis ) was investigated. Viability of protoscoleces was confirmed by trypan blue exclusion method, where mortality was observed at concentration of 10 and 20 mg/mL in 60 min treatment against Echinococcus granulosus ( E. granulosus ), under in-vitro conditions with reference to the known standard drug Praziquantel . Results: At concentration 10 and 20 mg/mL, the mortality rate was observed 97% and 99% respectively for 60 min treatment; while up to 93% mortality was observed with 20 mg/mL for only 10 min treatment. The concentration above 20 mg/mL for above 2 h showed 100% mortality, irrespective of further incubation. Conclusions: As compared with the standard anti-parasitic drug Praziquantel our extract has significant scolicidal activity with almost no associated side effects.
文摘Objective:To investigate antimicrobial and bronchodialator effect of hydroalcholic extract of polyherbal drug Shirishadi containing Shirisha(Albezzia lebbeck),Nagarmotha(Cyprus ratandus) & Kantakari(Solanum xanthocarpum).Methods:Antimicrobial activity was evaluated by discdiffusion method and MIC,MBC,MFC were calculated by micro dilution method.Hydroalcholic extract of this preparation was investigated for its phytochemical analysis,phenol and Oavonoid were determined by speclrophotometric method and in vivo bronchodilator effect was analysed by convulsion time.Results:The phytochemical tests revealed presence of alkaloids, anthraquinones,carbohydrates,flavonoids,saponins and tannins.The antimicrobial result showed the MIC of 6.25 mg/ml.against Staphylococcus aureus and 12.5 mg/mL.for Escherichia coli and 12.5 mg/mL against remaining bacteria tested,with strong antifungal activity.The maximum inhibition zone is found against Pseudomonas aeruginosa with MIC 16 mg/mL Drug showed significant bronchodilator effect with 27.86%& 36.13%increase in preconvulsion time of guinea pigs prebeated with 100 & 200 mg/kg body weight of extract.Conclusions:The study reveals that the extracts possess antibacterial activity and antifungal activity in a dose dependent manner. This antimicrobial property may be due to presence of several saponins,further studies are highly needed for the drug development.
