Survey on Paenibacillus assamensis infected case

ObjectiveTo identify a suspected Francisella tularensis strain isolated from the joint fluid of a patient in Xingyi of Qianxinan Prefecture, Guizhou province.

MethodsA gram-negative bacterium strain, which was identified as F. tularensis by automatic bacterial identification and drug sensitivity analysis system, was isolated from the joint fluid of a hospitalized patient in a hospital of traditional Chinese medicine of Qianxinan, and inoculated on the selective medium for screening. F. tularensis-specific antigen latex agglutination was performed for the fresh strain, and then the two pairs of primers, including 27f and 1492r, 8-27f and 1500r, were used to identify the strain. In addition, the patient’s serum was used for F. tularensis specific antibody detection with slide and test tube.

ResultsThe strain did not grow on the selective medium for F. tularensis. The fresh strain was negative in F. tularensis-specific antigens in latex agglutination. The patient’s serum was negative for F. tularensis-specific antibodies in latex agglutination by slide and test tube. When the two amplicons involving 1 379 nt and 1 429 nt were sequenced and aligned, the strain showed high homology with 16S rRNA gene sequence of Paenibacillus assamensis GPTSA 11, the query cover was 100% and E value was 0. Moreover, both fragments contained the consensus signature sequence stretches of PAEN 515F and PAEN 862F, which are specific to Paenibacillus.

ConclusionThe result excluded F. tularensis infection and indicated that the case was infected with P. assamensis. This is the first clinical case of P. assamensis infection.