Demirin Vibrio vulnificus’un klinik ve çevresel suşların büyümesi ve hemolizin/sitolizin ekspresyonu üzerine etkisi

Yıl 2020, , 121 - 126, 31.12.2020

Sedat Çam

https://doi.org/10.35864/evmd.788440

Öz

Yüksek demir seviyeleri, oldukça ölümcül olan insan patojeni Vibrio vulnificus’un büyümesi ve virülansı ile güçlü bir şekilde ilişkilidir. Bu çalışma, farklı demir konsantrasyonları altında (7, 10, 15, 30 ve 50 μM) dört klinik ve dört çevresel V. vulnificus suşlarının, büyüme oranlarını ve hemolizin/sitolizin kodlayan genin (vvhA) ekspresyon seviyelerini incelemiştir. Ekspresyon seviyeleri 2-ΔΔCT yöntemine göre belirlenmiştir. Demir konsantrasyonu arttıkça vvhA transkripsiyon aşağı regülasyonu gözlenmiştir. Test edilen tüm suşlarda, 30 ve 50 uM ferrik klorür konsantrasyonları seviyesinde düşük konsantrasyonlara kıyasla anlamlı bir fark gözlenmiştir (p <0.001). Artan demir konsantrasyonu, tüm izolatların daha hızlı büyüme oranları ile anlamlı derecede ilişkiliydi (p <0.05). Demir seviyesinin artması, suşların büyüme oranını artırmıştır. Klinik suşların demir ile korelasyonu çevresel izolatlardan daha yüksek olarak gözlenlenmiştir. Bu çalışma, yüksek demir konsantrasyonları altında V. vulnificus’un klinik suşların nispeten artmış büyüme oranlarının, altta yatan bir hastalıktan dolayı aşırı demir yükü olan hastalarda bu patojenin daha yüksek virülansını açıklayabileceğini düşündürmektedir.

Anahtar Kelimeler

büyüme, demir, patojen, virülans, vvhA

The effect of iron on the expression of hemolysin/cytolysin and growth of clinical and environmental strains of Vibrio vulnificus

Öz

Elevated levels of iron are strongly correlated with the growth and virulence of highly lethal human-pathogen Vibrio vulnificus. The present study examined the expression level of hemolysin/cytolysin-encoding gene (vvhA) and the growth rate of four clinical and four environmental strains of V. vulnificus under different iron concentrations (7, 10, 15, 30, and 50 μM). The expression levels of vvhA were determined according to the 2-ΔΔCT method. vvhA transcription was down-regulated as iron concentration increased. A significant difference was observed at the level of 30 and 50 μM ferric chloride concentrations compared to the lower concentrations in all the strains tested (p <0.001). Conversely, elevated iron concentration was significantly correlated with the higher growth rates of all the isolates (p <0.05). Increasing iron levels elevated the growth rate of the strains. Clinical strains appeared to be more correlated with high iron levels than environmental isolates. This study suggested that relatively increased growth rates of clinical strains of V. vulnificus under elevated iron concentrations might explain higher virulence of this pathogen in patients with iron overload from an underlying disease.

Anahtar Kelimeler

growth, iron, pathogen, virulence, vvhA

Kaynakça

• 1. Baker-Austin C, Oliver, JD. (2018) Vibrio vulnificus: New insights into a deadly opportunistic pathogen. Environ Microbiol. 20, 423-430.
• 2. Bisharat N, Cohen DI, Harding RM, Falush D, Crook DW, Peto T, Maiden MC. (2005). Hybrid Vibrio vulnificus. Emerg Infect Dis. 11, 30-35.
• 3. Campbell MS, Wright AC. (2003). Real-time PCR analysis of Vibrio vulnificus from oysters. Appl Environ Microbiol. 69, 7137-7144.
• 4. Cassat JE, Skaar EP. (2013). Iron in infection and immunity. Cell Host Microbe. 13, 509-519.
• 5. Çam S, Brinkmeyer R. (2019). Development of selective enrichment medium for clinical isolates of Vibrio vulnificus based upon virulence correlating genes. Harran Üniv Vet Fak Derg. 8, 173-179.
• 6. Çam S, Brinkmeyer R. (2020). The effects of temperature, ph, and iron on biofilm formation by clinical versus environmental strains of Vibrio vulnificus. Folia Microbiol. 65, 557-566.
• 7. Çam S, Brinkmeyer R, Schwarz JR. (2019). Quantitative PCR enumeration of vcgC and 16S rRNA type A and B genes as virulence indicators for environmental and clinical strains of Vibrio vulnificus in Galveston Bay oysters. Can J Microbiol. 65, 613-621.
• 8. Gray LD, Kreger AS. (1987). Mouse skin damage caused by cytolysin from Vibrio vulnificus and by V. Vulnificus infection. J Infect Dis. 155, 236-241.
• 9. Hor L, Chang Y, Chang C, Lei H, Ou JT. (2000). Mechanism of high susceptibility of iron-overloaded mouse to Vibrio vulnificus infection. Microbiol Immunol. 44, 871-878.
• 10. Horseman MA, Surani S. (2011). A comprehensive review of Vibrio vulnificus: An important cause of severe sepsis and skin and soft-tissue infection. Int J Infect Dis. 15, e157-e166.
• 11. Jeong HG, Satchell KJF. (2012). Additive function of Vibrio vulnificus martx(vv) and vvhA cytolysins promotes rapid growth and epithelial tissue necrosis during intestinal infection. PLoS pathog. 8, e1002581.
• 12. Jones MK, Oliver JD. (2009). Vibrio vulnificus: Disease and pathogenesis. Infect Immun. 77, 1723-1733.
• 13. Kawase T, Miyoshi S, Sultan Z, Shinoda S. (2004). Regulation system for protease production in Vibrio vulnificus. FEMS Microbiol Lett. 240, 55-59.
• 14. Kim CM, Chung YY, Shin SH. (2009). Iron differentially regulates gene expression and extracellular secretion of Vibrio vulnificus cytolysin-hemolysin. J Infect Dis. 200, 582-589.
• 15. Kim CM, Park RY, Choi MH, Sun HY, Shin SH. (2007). Ferrophilic characteristics of Vibrio vulnificus and potential usefulness of iron chelation therapy. J Infect Dis. 195, 90-98.
• 16. Kim SY, Lee SE, Kim YR, Kim CM, Ryu PY, Choy HE, Chung SS, Rhee JH. (2003). Regulation of Vibrio vulnificus virulence by the luxs quorum-sensing system. Mol Microbiol. 48, 1647-1664.
• 17. Lee BC, Kim SH, Choi SH, Kim TS. (2005). Induction of interleukin-8 production via nuclear factor-κb activation in human intestinal epithelial cells infected with Vibrio vulnificus. Immunol. 115, 506-515.
• 18. Leng F, Liz S, Wu W, Zhang J, Song J, Zhong M. (2019). Epidemiology, pathogenetic mechanism, clinical characteristics, and treatment of Vibrio vulnificus infection: A case report and literature review. Eur J Clin Microbiol Infect Dis. 38, 1999-2004.
• 19. Livak KJ, Schmittgen TD. (2001). Analysis of relative gene expression data using real-time quantitative pcr and the 2-ΔΔCT method. Methods. 25, 402-408.
• 20. Oliver JD. (2005). Wound infections caused by Vibrio vulnificus and other marine bacteria. Epidemiol Infect. 133, 383-391.
• 21. Park JW, Ma SN, Song ES, Song CH, Chae MR, Park BH, Rho RW, Park SD, Kim HR. (1996). Pulmonary damage by Vibrio vulnificus cytolysin. Infect Immun. 64, 2873-2876.
• 22. Senoh M, Miyoshi SI, Okamoto K, Fouz B, Amaro C, Shinoda S. (2005). The cytotoxin-hemolysin genes of human and eel pathogenic Vibrio vulnificus strains: Comparison of nucleotide sequences and application to the genetic grouping. Microbiol Immunol. 49, 513-519.
• 23. Starks AM, Bourdage KL, Thiaville PC, Gulig PA. (2006). Use of a marker plasmid to examine differential rates of growth and death between clinical and environmental strains of Vibrio vulnificus in experimentally infected mice. Mol Microbiol. 61, 310-323.
• 24. Wright AC, Morris JG. (1991). The extracellular cytolysin of Vibrio vulnificus: Inactivation and relationship to virulence in mice. Infect Immun. 59, 192-197.