Kaihu Yao, China
Beijing Children's Hospital Lab of MicrogiologyAuthor Of 1 Presentation
FURTHER IDENTIFICATION AND MOLECULAR EPIDEMIOLOGY OF ROUTINELY DETERMINED STREPTOCOCCUS PNEUMONIAE WITH NEGATIVE QUELLUNG REACTION (ID 1090)
Abstract
Background
Some Streptococcus pneumoniae isolates identified by routine clinical methods have negative Quellung reaction which may contain other species of viridans group streptococci. And these Streptococcus pneumoniae probably possess distinctive characteristics.
Methods
A total of 105 isolates were involved in the study. Using multi-locus sequence analysis (MLSA) as the standard to determined the species, the identification capacity of the multiplex PCR method were evaluated. The sequence types (STs) were determined following multi-locus sequence typing (MLST) and antimicrobial susceptibilities were tested.
Results
For all 105 isolates, 81 were identified as S.pneumoniae by MLSA, and 24 were S.pseudopneumoniae. Meanwhile, 91.7% (22/24) S.pseudopneumoniae and only 21.0%(17/81) S.pneumoniae isolates were identified correctly by multiplex PCR. In addition, 31 STs were detected from S.pneumoniae i.e. non-encapsulated S.pneumoniae(NESp), 20 of which were new STs. The dominant STs were ST-bj12 (16, 19.8%). The tested antibiotics non-susceptibility rates of S.pseudopneumoniae were comparable to S.pneumoniae.
Conclusions
Some S.pneumoniae isolates with negative Quellung reaction identified in clinical routine work could be S.pseudopneumoniae. Common used methods could not accurately identify the species of them. Most of NESp were determined new STs which revealed heterologous genetics with the encapsulated S. pneumoniae. The resistance S.pseudopneumoniae against common antimicrobials was comparable to NESp.