Pseudomonas aeruginosa Inhibits the Growth of Cryptococcus Species
Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA. Mycopathologia
(Impact Factor: 1.53).
11/2011; 173(5-6):451-61. DOI: 10.1007/s11046-011-9494-7
Pseudomonas aeruginosa is a ubiquitous and opportunistic bacterium that inhibits the growth of different microorganisms, including Gram-positive bacteria and fungi such as Candida spp. and Aspergillus fumigatus. In this study, we investigated the interaction between P. aeruginosa and Cryptococcus spp. We found that P. aeruginosa PA14 and, to a lesser extent, PAO1 significantly inhibited the growth of Cryptococcus spp. The inhibition of growth was observed on solid medium by the visualization of a zone of inhibition of yeast growth and in liquid culture by viable cell counting. Interestingly, such inhibition was only observed when P. aeruginosa and Cryptococcus were co-cultured. Minimal inhibition was observed when cell-cell contact was prevented using a separation membrane, suggesting that cell contact is required for inhibition. Using mutant strains of Pseudomonas quinoline signaling, we showed that P. aeruginosa inhibited the growth of Cryptococcus spp. by producing antifungal molecules pyocyanin, a redox-active phenazine, and 2-heptyl-3,4-dihydroxyquinoline (PQS), an extracellular quorum-sensing signal. Because both P. aeruginosa and Cryptococcus neoformans are commonly found in lung infections of immunocompromised patients, this study may have important implication for the interaction of these microbes in both an ecological and a clinical point of view.
Available from: Hongyan Hou
- "Hughes and Kim (7) demonstrated that in CF patients infected with PA, only 10% of patients produced positive CA skin tests compared with 30% positivity in those free of PA, indicating that the antifungal substance produced by PA prevents Candida infections. There are also studies investigating the growth inhibition effect of PA in Cryptococcus species (12,13). However, to the best of our knowledge, there have been no studies regarding the isolation of Cryptococcus species from patients with CF. "
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ABSTRACT: The aim of the present study was to investigate the inhibitory effect of Pseudomonas aeruginosa (PA) on pathogenic fungi, including Candida albicans (CA), Candida tropicalis (CT), Candida glabrata (CG), Candida parapsilosis (CP) and Candida krusei (CK), in vitro and in vivo. In total, 24 PA strains were collected from clinical specimens and identified by Gram staining, oxidase production and the API 20NE system. Cross-streak, disk diffusion and co-culture methods were used to observe the inhibitory effect of PA. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was used to analyze differences in the bacterial proteins of PA. A blood infection model in mice was used to evaluate the effect of PA on fungi in vivo. The in vitro and in vivo results demonstrated that a number of PA isolates exhibited a marked inhibitory effect on pathogenic fungi, including CA, CT, CP, CG and CK, while other PA strains exhibited no effect. Therefore, PA exhibits an inhibitory effect on pathogenic fungi and this activity may be important in the treatment of patients. It was hypothesized that PA secretes various types of proteins to suppress the growth of fungal filaments, which subsequently inhibits pathogenic fungi.
Experimental and therapeutic medicine 06/2014; 7(6):1516-1520. DOI:10.3892/etm.2014.1631 · 1.27 Impact Factor
Available from: link.springer.com
Mycopathologia 04/2012; 173(5-6):283-5. DOI:10.1007/s11046-012-9544-9 · 1.53 Impact Factor
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ABSTRACT: In this review we have summarized the known virulent factors of P. aeruginosa in the development of ventilator associated pneumonia (VAP). This gram negative rod bacterium colonizes through several pathogenic mechanisms that can be summarized as follows: 1) cell surface virulence factors; 2) secreted virulence factors; 3) type secretion system; 4) quorum sensing. Another additional aspect that is covered is the capacity of P. aeruginosa of organized growth as a biofilm, which is a particular growth pattern in which bacteria gain high levels of antimicrobial resistance. The development of new antimicrobial strategies may use this understanding of the bacterium behavior for possible prevention, or eradication of the infective agent, in case of severe infections.
Current Respiratory Medicine Reviews 04/2013; 9(1):26-33. DOI:10.2174/1573398X11309010004
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