Quorum sensing, or auto induction, as a cell density dependent signaling mechanism in many microorganisms, is trig- gered via auto inducers which passively diffuse across the bacterial envelope and therefore intracell...Quorum sensing, or auto induction, as a cell density dependent signaling mechanism in many microorganisms, is trig- gered via auto inducers which passively diffuse across the bacterial envelope and therefore intracellulaly accumulate only at higher bacterial densities to regulate specialized processes such as genetic competence, bioluminescence, virulence and sporulation. N-acyl homoserine lactones are the most common type of signal molecules. Aquaculture is one of the fastest-growing food-producing indus- tries, but disease outbreaks caused by pathogenic bacteria are a significant constraint on the development of the sector worldwide. Many of these pathogens have been found to be controlled by their quorum sensing systems. As there is relevance between the pathogenic bacteria＇s virulence factor expression and their auto inducers, quorum quenching is a new effective anti-infective strategy to control infections caused by bacterial pathogens in aquaculture. The techniques used to do this mainly include the following： （1） the inhibition of signal molecule biosynthesis, （2） blocking signal transduction, and （3） chemical inactivation and biodegradation of signal molecules. To provide a basis for finding alternative means of controlling aquatic diseases by quorum quenching instead of treatment by antibiotics and disinfectants, we will discuss the examination, purification and identification of auto inducers in this paper.展开更多
Eighty four throat swabs were obtained from Basrah General Hospital inpatients （N = 34）： 17 were suffering from renal failure and the other 17 were diabetics; and from outpatients （N = 50）. Throat swabs were cult...Eighty four throat swabs were obtained from Basrah General Hospital inpatients （N = 34）： 17 were suffering from renal failure and the other 17 were diabetics; and from outpatients （N = 50）. Throat swabs were cultured first in the selective media Ashdown＇s broth then subcultured on Ashdown＇s agar to isolate Burkholderia pseudomallei which was recovered from seven cases （8.33%）. Four isolates were from renal failure patients （23.53%）, two from diabetic patients （11.76%） and the seventh isolate was from an outpatient with tonsillitis. All isolates were able to produce capsules, form filament chains, exhibit swarming motility and were arabinose non assimilators （Ara-） indicative of their virulence. Additionally, isolated B. pseudomallei were found to produce protease, lipase, hemolysin, and lecithinase and were able to produce biofilm, the root of many troublesome persistent infections that resist antibiotic treatment. Susceptibility of the seven isolates of B. pseudomallei toward 11 antibiotics was assessed, isolates were found multiply resistant to all antibiotics apart from ciproflaxin. This study confirms for the first time isolation of B. pseudomallei from immunocompromised patients in Basrah city of Iraq and describes their virulence potentials.展开更多
文摘Quorum sensing, or auto induction, as a cell density dependent signaling mechanism in many microorganisms, is trig- gered via auto inducers which passively diffuse across the bacterial envelope and therefore intracellulaly accumulate only at higher bacterial densities to regulate specialized processes such as genetic competence, bioluminescence, virulence and sporulation. N-acyl homoserine lactones are the most common type of signal molecules. Aquaculture is one of the fastest-growing food-producing indus- tries, but disease outbreaks caused by pathogenic bacteria are a significant constraint on the development of the sector worldwide. Many of these pathogens have been found to be controlled by their quorum sensing systems. As there is relevance between the pathogenic bacteria＇s virulence factor expression and their auto inducers, quorum quenching is a new effective anti-infective strategy to control infections caused by bacterial pathogens in aquaculture. The techniques used to do this mainly include the following： （1） the inhibition of signal molecule biosynthesis, （2） blocking signal transduction, and （3） chemical inactivation and biodegradation of signal molecules. To provide a basis for finding alternative means of controlling aquatic diseases by quorum quenching instead of treatment by antibiotics and disinfectants, we will discuss the examination, purification and identification of auto inducers in this paper.
文摘Eighty four throat swabs were obtained from Basrah General Hospital inpatients （N = 34）： 17 were suffering from renal failure and the other 17 were diabetics; and from outpatients （N = 50）. Throat swabs were cultured first in the selective media Ashdown＇s broth then subcultured on Ashdown＇s agar to isolate Burkholderia pseudomallei which was recovered from seven cases （8.33%）. Four isolates were from renal failure patients （23.53%）, two from diabetic patients （11.76%） and the seventh isolate was from an outpatient with tonsillitis. All isolates were able to produce capsules, form filament chains, exhibit swarming motility and were arabinose non assimilators （Ara-） indicative of their virulence. Additionally, isolated B. pseudomallei were found to produce protease, lipase, hemolysin, and lecithinase and were able to produce biofilm, the root of many troublesome persistent infections that resist antibiotic treatment. Susceptibility of the seven isolates of B. pseudomallei toward 11 antibiotics was assessed, isolates were found multiply resistant to all antibiotics apart from ciproflaxin. This study confirms for the first time isolation of B. pseudomallei from immunocompromised patients in Basrah city of Iraq and describes their virulence potentials.
