Microbial diversity and prevalence of virulent pathogens in biofilms developed in a water reclamation system.
Bacterial biofilm is a common phenomenon in both natural and engineered systems which often becomes a source of contamination and microbially influenced corrosion. It is thought that formation of biofilm in the monoculture of several bacterial species is regulated by acylhomoserine lactone (AHL) quorum-sensing signals. In this study, we investigated the microbial diversity and existence of AHL-producing and AHL-degrading bacterial species in the biofilm samples from a water reclamation system located in a tropical environment. 16S ribosomal DNA sequencing analysis indicated the presence of at least 11 bacterial species, including the frequently encountered bacterial pathogens Pseudomonas aeruginosa and Klebsiella pneumoniae, and several rare pathogens. We showed that only two groups of isolates, belonging to P. aeruginosa and Enterobacter agglomerans, produced AHL signals. We also found that three bacterial isolates, i.e., Agrobacterium tumefaciens XJ01, Bacillus cereus XJ08, and Ralstonia sp. XJ12, expressed AHL degradation enzymes. Furthermore, we showed that P. aeruginosa isolate HL43 was virulent against animal model Caenorhabditis elegans and released 2-6-fold more pyocyanin cytotoxin than P. aeruginosa strains PA01 and PA14, the two commonly used laboratory strains. These data indicate the complexity and importance of biofilm research in water reclamation.
Center for Water Research, Department of Civil Engineering, National University of Singapore, 10 Kent Ridge Crescent, 119260 Singapore. cvehujy@nus.edu.sg
Jiang Yong
JY
Hu
Yang
Y
Fan
Yi-Han
YH
Lin
Hai-Bao
HB
Zhang
Say Leong
SL
Ong
Ning
N
Dong
Jin-Ling
JL
Xu
Wun Jern
WJ
Ng
Lian-Hui
LH
Zhang
D000818:Animals; D018441:Biofilms / Q000254:growth & development*; D017173:Caenorhabditis elegans / Q000254:growth & development / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000472:pathogenicity / Q000502:physiology; D023421:Models, Animal; D015995:Prevalence; D011550:Pseudomonas aeruginosa / Q000472:pathogenicity* / Q000502:physiology; D012988:Soil Microbiology; D014774:Virulence / Q000235:genetics*; D014867:Water
D014867:Water