[Composition and distribution of TCBS bacteria groups from sediments of Jiulong River estuary]

Abstract

Objective: To investigate potential pathogens in waters of Xiamen from Jiulong River, and to provide useful information for the prevention and control of potential pathogen infections.

Methods: All samples were spread on Thiosulfate Citrate Bile Salts Sucrose (TCBS) agar plates, and then incubated at 26 +/- 1 degrees C for 24 +/- 2 h. In total 158 TCBS strains were isolated from TCBS agar plates and pure-cultivated on 2216E agar plates. All strains were identified using the 16S rRNA gene- Restriction fragment length polymorphism (RFLP), 16S rRNA sequence analysis, GenBank database Basic Local Alignment Search Tool (BLAST) and phylogenetic analysis.

Results: The results show that 158 TCBS strains from the sediments of Jiulong River estuary were classfied as 7 genus, which were Pseudomonas (28%), Aeromonas (24%), Pseudoalteromonas (19%), Shewanella (13%), Bacillus (11%), Vibrio (4%) and Psychrobacter (1%). The composition and distribution of TCBS bacteria groups varied with stations. Non-halophilic or haloduric bacteria groups were dominant in the upper area of Jiulong River estuary, and halophilic and haloduric bacteria were dominant in the lower area, which characterized a typical estuary feature. The salinity played a key role in the distribution of TCBS groups. Vibrios did not constitute a significant proportion (6% - 19%) of the total TCBS strains at different stations, and most of the them distributed at the lower region.

Conclusion: There were a lot of potential pathogens in Jiulong River estuary. Aeromonas, a typical genus of halotolerant bacteria, was the potentially terrigenous bacteria contamination to the waters of Xiamen. Most Vibrio specieses were marine aborigines, which was not directly contaminated from the runoff of Jiulong River.