The accessory gene regulator (agr) controls Staphylococcus aureus virulence in a murine intracranial abscesses model.
BACKGROUND
Intracranial abscesses are associated with high mortality. Staphylococcus aureus is one of the main pathogens that cause intracranial infection. Until now, there is no report to identify the key effectors of S. aureus during the intracranial infection.


METHODS
The murine intracranial abscesses model induced by S. aureus was constructed. The vital sign and survival rate of mice were observed to evaluate the infection. Histological examination was used to diagnose the pathological alterations of mouse tissues. The sensitivity of S. aureus to whole blood was evaluated by whole-blood killing assay.


RESULTS
In murine intracranial abscesses model, it was shown that the mortality caused by the accessory gene regulator (agr) locus deficient strain was significant decreased compared with its parent strain. Moreover, we found that RNAIII, the effector of agr system, was essential for the intracranial infection caused by S. aureus. In the further investigation, it was shown that restoration the expression of α-toxin in agr deficient strain could partially recover the mortality in the murine intracranial abscesses model.


CONCLUSIONS
Our data suggested that the agr system of S. aureus is an important virulence determinant in the induction and mortality of intracranial abscesses in mice.
Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing Neurosurgical Institute, Beijing, China.
Jian
J
Gong
Ningxia Medical University, Incubation Base of National Key Laboratory for Cerebrocranial Diseases, Yinchuan, China.
Dongzhi
D
Li
Beijing Institute of Basic Medical Sciences, Beijing, China.
Jun
J
Yan
Beijing Institute of Basic Medical Sciences, Beijing, China.
Yu
Y
Liu
Beijing Institute of Basic Medical Sciences, Beijing, China.
Di
D
Li
Beijing Institute of Basic Medical Sciences, Beijing, China.
Jie
J
Dong
Beijing Institute of Basic Medical Sciences, Beijing, China.
Yaping
Y
Gao
Ningxia Medical University, Incubation Base of National Key Laboratory for Cerebrocranial Diseases, Yinchuan, China. Electronic address: suntao6699@163.com.
Tao
T
Sun
Beijing Institute of Basic Medical Sciences, Beijing, China. Electronic address: yanggg@hotmail.com.
Guang
G
Yang
D000818:Animals; D001922:Brain Abscess / Q000382:microbiology* / Q000401:mortality / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D005798:Genes, Bacterial; D005809:Genes, Regulator; D008810:Mice, Inbred C57BL; D013203:Staphylococcal Infections / Q000382:microbiology* / Q000401:mortality / Q000473:pathology; D013211:Staphylococcus aureus / Q000235:genetics / Q000472:pathogenicity*; D014774:Virulence
Agr; Intracranial abscesses model; S. aureus