Original Article

Role of biofilms in the survival of Legionella pneumophila to sodium chloride treatment

Abstract

Background and Objectives: Legionnaires’ disease continues to be a public health concern. Colonized water distribution systems are often implicated in Legionella transmission, despite the use of various disinfection strategies, the bacterium is capable to persist and survive in water systems. The aim of this study was to investigate the persistence of Legionella pneumophila to sodium chloride over time at different temperatures and analysing the role of biofilms in the survival of this bacteria.
Materials and Methods: L. pneumophila serogroup 1 and L. pneumophila serogroup 2-15 were used to study the effect of sodium chloride on planktonic and sessile cells. The tested concentrations were: 0.5%, 1%, 2%, 3%, 4%, 6% and 8% (W/V) NaCl. Biofilms were grown on 24-well microplates.
Results: At 20°C, L. pneumophila planktonic cells were able to survive in sodium chloride concentrations up to 2%. However, at 37°C, a sodium chloride concentration over 1.5%, reduced systematically the numbers of bacterial cells. Biofilms were grown for 20 days in the absence and presence of sodium chloride. The results show that bacterial strains were able to survive and regrow after the sodium chloride shock (2-3%). Moreover, it seems that this effect is less expressed with the age of the biofilm; old biofilms were more persistent than the young ones.
Conclusion: Results from this study demonstrate that the sodium chloride disinfection strategy was effective on Legionella pneumophila planktonic cells but not on biofilms, which demonstrate the role of biofilms in the persistence and recolonization of L. pneumophila in water distribution systems.

1. Palusińska-Szysz M, Cendrowska-Pinkosz M. Pathogenicity of the family Legionellaceae. Arch Immunol Ther Exp (Warsz) 2009;57:279-290.
2. Mondino S, Schmidt S, Rolando M, Escoll P, Gomez-Valero L, Buchrieser C. Legionnaires’ disease: state of the art knowledge of pathogenesis mechanisms of Legionella. Annu Rev Pathol 2020;15:439-466.
3. Fields BS, Benson RF, Besser RE. Legionella and Legionnaires' disease: 25 years of investigation. Clin Microbiol Rev 2002;15:506-526.
4. Yu VL, Plouffe JF, Pastoris MC, Stout JE, Schousboe M, Widmer A, et al. Distribution of Legionella species and serogroups isolated by culture in patients with sporadic community-acquired legionellosis: an international collaborative survey. J Infect Dis 2002;186:127-128.
5. Eboigbodin KE, Seth A, Biggs CA. A review of biofilms in domestic plumbing. J Am Water Works Assoc 2008;100:131-138.
6. Keevil CW (2002). Pathogens in environmental biofilms. In: Encyclopedia of environmental microbiology. Ed, G Bitton. Wiley, 4th ed. New York, pp. 2339-2356.
7. Cianciotto NP. Pathogenicity of Legionella pneumophila. Int J Med Microbiol 2001;291:331-343.
8. Liguori G, Di Onofrio V, Gallè F, Liguori R, Nastro RA, Guida M. Occurrence of Legionella spp. in thermal environments: virulence factors and biofilm formation in isolates from a spa. Microchem J 2014;112:109-112.
9. Flemming HC, Percival SL, Walker JT. Contamination potential of biofilms in water distribution systems. Water Sci Technol 2002;2:227-280.
10. Szewzyk U, Szewzyk R, Manz W, Schleifer KH. Microbiological safety of drinking water. Annu Rec Microbiol 2000;54:81-127.
11. Cooper IR, Hanlon GW. Resistance of Legionella pneumophila serotype 1 biofilms to chlorine-based disinfection. J Hosp Infect 2010;74:152-159.
12. Assaidi A, Ellouali M, Latrache H, Mabrouki M, Timinouni M, Zahir H, et al. Adhesion of Legionella pneumophila on glass and plumbing materials commonly used in domestic water systems. Int J Environ Health Res 2018;28:125-133.
13. Shirtliff ME, Mader JT, Camper AK. Molecular interactions in biofilms. Chem Biol 2002;9:859-871.
14. Assaidi A, Ellouali M, Latrache H, Mabrouki M, Hamadi F, Timinouni M, et al. Effect of temperature and plumbing materials on biofilm formation by Legionella pneumophila serogroup 1 and 2-15. J Adhes Sci Technol 2018;32:1471-1484.
15. Assaidi A, Ellouali M, Latrache H, Zahir H, Karoumi A, Mliji EM. Chlorine disinfection against Legionella pneumophila biofilms. J Water Sanit Hyg Dev 2020;10:885-893.
16. Marchesi I, Marchegiano P, Bargellini A, Cencetti S, Frezza G, Miselli M, et al. Effectiveness of different methods to control Legionella in the water supply: ten-year experience in an Italian university hospital. J Hosp Infect 2011;77:47-51.
17. Mouchtouri V, Velonakis E, Hadjichristodoulou C. Thermal disinfection of hotels, hospitals, and athletic venues hot water distribution systems contaminated by Legionella species. Am J Infect Control 2007;35:623-627.
18. Rakic A, Peric J, Foglar L. Influence of temperature, chlorine residual and heavy metals on the presence of Legionella pneumophila in hot water distribution systems. Ann Agric Environ Med 2012;19:431-436.
19. Bagh LK, Albrechtsen HJ, Arvin E, Ovesen K. Distribution of bacteria in a domestic hot water system in a Danish apartment building. Water Res 2004;38:225-235.
20. Gagnon GA, Rand JL, O’leary KC, Rygel AC, Chauret C, Andrews RC. Disinfectant efficacy of chlorite and chlorine dioxide in drinking water biofilms. Water Res 2005;39:1809-1817.
21. Kim BR, Anderson JE, Mueller SA, Gaines WA, Kendall AM. Literature review--efficacy of various disinfectants against Legionella in water systems. Water Res 2002;36:4433-4444.
22. Goldstone RJ, Popat R, Fletcher MP, Crusz SA, Diggle SP. Quorum sensing and social interactions in microbial biofilms. Sensors (Basel) 2012:1-24.
23. Bodet C, Sahr T, Dupuy M, Buchrieser, Héchard Y. Legionella pneumophila transcriptional response to chlorine treatment. Water Res 2012;46:808-816.
24. Buse HY, J Morris B, Struewing IT, Szabo JG. Chlorine and monochloramine disinfection of Legionella pneumophila colonizing copper and polyvinyl chloride drinking water biofilms. Appl Environ Microbiol 2019;85(7):e02956-18.
25. Farhat M, Moletta-Denat M, Frere J, Onillon S, Trouilhie MC, Robine E. Effects of disinfection on Legionella spp., eukarya, and biofilms in a hot water system. Appl Environ Microbiol 2012;78:6850-6858.
26. Żbikowska E, Walczak M, Krawiec A. Distribution of Legionella pneumophila bacteria and Naegleria and Hartmannella amoebae in thermal saline baths used in balneotherapy. Parasitol Res 2013;112:77-83.
27. Gast RJ, Moran DM, Dennett MR, Wurtsbaugh WA, Amaral-Zettler LA. Amoebae and Legionella pneumophila in saline environments. J Water Health 2011;9:37-52.
28. Tsuchiya Y, Terao M, Fujimoto T, Nakamura K, Yamamoto M. Effects of Japan sea proper water on the growth of Legionella pneumophila, Escherichia coli, and Staphylococcus aureus. Environ Health Prev Med 2005;10:233-238.
Files
IssueVol 13 No 4 (2021) QRcode
SectionOriginal Article(s)
Published2021-08-11
DOI https://doi.org/10.18502/ijm.v13i4.6973
Keywords
Biofilms; Legionella pneumophila; Disinfection; Sodium chloride; Water-borne diseases

Rights and permissions
Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
How to Cite
1.
Assaidi A, Ellouali M, Latrache H, Zahir H, Mliji EM. Role of biofilms in the survival of Legionella pneumophila to sodium chloride treatment. Iran J Microbiol. 2021;13(4):488-494.