3.2. Biochemical characterization and molecular identification
of bacteria
Gram staining revealed that the SZ01 strain was red, indicating that it
was a gram-negative bacterium. The specific physical and chemical
characteristics of this bacterium are shown in Table 1. The physical and
chemical characteristics of the SZ01 strain suggest that this bacterium
was Klebsiella pneumoniae . After gene amplification, the size of
the 16S rRNA fragment of the SZ01 strain was about 1500 bp, which was
consistent with the expected size for 16S rRNA. The 16S rRNA gene
sequence(GenBank login No.: MT192711)of the SZ01 strain was
incorporated into the gene library and analyzed using the NCBI-blast
program. The results showed that isolates showed the highest homology
with K. pneumoniae . The 16S rRNA gene sequences of severalKlebsiella species and important aquatic pathogenic bacteria were
selected to construct a development tree based on the 16S rRNA gene
sequence (Figure 3). Results showed that the isolated bacteria andK. pneumoniae (GenBank
login No. is KF733734.1) were clustered into the same branch(Figure
3),and had the highest homology. However, K. pneumoniae(GenBank login No. was KF733734.1) was isolated from the human oral
cavity. Therefore, physical and chemical characteristics as well as gene
analysis of the SZ01 strain all comprehensively suggest that the
isolated SZ01 strain was K. pneumoniae.
Table1. Physiological and biochemical characteristics of the SZ01 strain