TY - JOUR
T1 - Accessory gene regulator (Agr) functionality in Staphylococcus aureus derived from lower respiratory tract infections
AU - Gomes Fernandes, Meissiner
AU - Laabei, Maisem
AU - Pagan Maldonado, Natalia
AU - Hidalgo, Jessica
AU - Molinos Abós, Sònia
AU - Villar-Hernández, Raquel
AU - Domínguez Villanueva, Dídac
AU - Jenkins, Andrew Toby A.
AU - Lacoma, Alicia
AU - Prat i Aymerich, Cristina
PY - 2017
Y1 - 2017
N2 - Objective. Characterization of Staphylococcus aureus clinical isolates derived from lower respiratory tract infections (LRTIs), and correlation between the functionality of the accessory gene regulator (Agr) and genotypic and phenotypic characteristics, clinical variables and clinical outcome. Methods. S aureus isolates derived from LRTIs and control groups (nasal carriage and bacteraemia) were genotyped using StaphyType DNA microarray. Agr activity was evaluated using the CAMP synergistic haemolysis assay and the Vesicle Lysis Test (VLT). Discordant strains were analysed by quantitative reverse- transcriptase real-time PCR (qRT-PCR). Results. Agr was functional in 79.7% and 84.5% of strains according to the CAMP and VLT assays respectively. Higher concordance with RNAIII expression measured by qRT-PCR was observed with the VLT assay (76.2%) compared with the CAMP assay (23.8%). No statistically significant differences were observed in Agr functionality between the study groups, nor the phenotypical/genotypical bacterial characteristics. No association between increased mortality/respiratory complications and Agr function was observed. Conclusions. Agr activity was high (82.2%) in isolates from LRTIs suggesting the importance of this global regulator in lower respiratory tract colonisation and infection. However, equally high Agr activity was observed in isolates derived from nasal carriage and bacteraemia, contradictory to previous observations. Agr functionality measured by the VLT assay was superior to CAMP assay.
AB - Objective. Characterization of Staphylococcus aureus clinical isolates derived from lower respiratory tract infections (LRTIs), and correlation between the functionality of the accessory gene regulator (Agr) and genotypic and phenotypic characteristics, clinical variables and clinical outcome. Methods. S aureus isolates derived from LRTIs and control groups (nasal carriage and bacteraemia) were genotyped using StaphyType DNA microarray. Agr activity was evaluated using the CAMP synergistic haemolysis assay and the Vesicle Lysis Test (VLT). Discordant strains were analysed by quantitative reverse- transcriptase real-time PCR (qRT-PCR). Results. Agr was functional in 79.7% and 84.5% of strains according to the CAMP and VLT assays respectively. Higher concordance with RNAIII expression measured by qRT-PCR was observed with the VLT assay (76.2%) compared with the CAMP assay (23.8%). No statistically significant differences were observed in Agr functionality between the study groups, nor the phenotypical/genotypical bacterial characteristics. No association between increased mortality/respiratory complications and Agr function was observed. Conclusions. Agr activity was high (82.2%) in isolates from LRTIs suggesting the importance of this global regulator in lower respiratory tract colonisation and infection. However, equally high Agr activity was observed in isolates derived from nasal carriage and bacteraemia, contradictory to previous observations. Agr functionality measured by the VLT assay was superior to CAMP assay.
U2 - 10.1371/journal.pone.0175552
DO - 10.1371/journal.pone.0175552
M3 - Article
C2 - 28410390
SN - 1932-6203
VL - 12
SP - 1
EP - 14
JO - PLoS ONE
JF - PLoS ONE
IS - 4
ER -