Reactive oxygen species involved in apoptosis induction of human respiratory epithelial (A549) cells by Streptococcus agalactiae.

Streptococcus agalactiae (Group B Streptococcus; GBS) is an important pathogen and is associated with pneumonia, sepsis and meningitis in neonates and adults. GBS infections induce cytotoxicity of respiratory epithelial cells (A549) with generation of reactive oxygen species (ROS) and loss of mitochondrial membrane potential (ψm). The apoptosis of A549 cells by GBS was dependent on the activation of caspase-3 and caspase-9 with increased pro-apoptotic Bim and Bax molecules and decreased Bcl-2 pro-survival protein. Treatment of infected A549 cells with ROS inhibitors (diphenyleniodonium chloride or apocynin) prevented intracellular ROS production and apoptosis. Consequently, oxidative stress is included among the cellular events leading to apoptosis during GBS human invasive infections.

Ultrasound assessment of diaphragm and quadriceps muscles and its relationship with handgrip and respiratory muscle strength in patients with systemic sclerosis: a cross-sectional study.

BACKGROUND: Muscle dysfunction may cause disability and reduce the quality of life of patients with systemic sclerosis (SSc) when compared to healthy individuals. However, the literature on the topic is scarce and uses several criteria for assessing muscle dysfunction in this population. OBJECTIVES: To compare diaphragm and quadriceps muscle thickness, diaphragm mobility, and handgrip strength between patients with SSc and healthy individuals. METHOD: This cross-sectional study included 16 patients with SSc and 16 self-reported healthy individuals matched for age. We assessed quadriceps and diaphragm thickness and diaphragmatic mobility (ultrasound), handgrip strength (hand-held dynamometer), and respiratory muscle strength (manovacuometer). Patients also responded to the Health Assessment Questionnaire Disability Index and the International Physical Activity Questionnaire. RESULTS: Patients with SSc presented lower quadriceps thickness (p < 0.0001), diaphragmatic mobility (p = 0.01), handgrip (p < 0.0001), and respiratory muscle strength (p < 0.0001) than healthy individuals. A moderate positive correlation was observed between handgrip strength and quadriceps thickness in patients with SSc (rho = 0.576; p = 0.02). CONCLUSIONS: Patients with SSc presented reduced quadriceps thickness, diaphragmatic mobility, handgrip, and respiratory muscle strength when compared to healthy individuals Also, handgrip strength was correlated with quadriceps thickness in patients with SSc, suggesting that loss of muscle mass accompanies loss of peripheral muscle strength group of patients. Key Points • SSc patients presented reduced quadriceps thickness and diaphragmatic mobility • SSc patients have reduced handgrip and respiratory muscle strength • Lower handgrip muscle strength correlated with lower quadriceps thickness.

Prevalence of Group B Streptococcus serotypes III and V in pregnant women of Rio de Janeiro, Brazil.

GBS serotypes III and V were the most prevalent in pregnant women and exhibited resistance to tetracycline, clindamycin and sulfamethoxazole/trimethoprim. Serotype III showed high sialic acid content and PFGE analysis discerned 33 heterogeneous profiles. Phenotypic and genotypic characterization could be relevant to control GBS infections unaffected by intra-partum chemoprophylaxis.

Effect of chelating agents on the growth, surface polypeptide synthesis and interaction of Streptococcus agalactiae with human epithelial cells.

In the present study, the influence of the chelating agents of ethylenediaminetetraacetic acid (EDTA), ethylene glycol-bis (ß-aminoethyl ether) (EGTA) and 1,10-phenanthroline (PHEN) on growth rate, cytoadherence ability and surface protein expression was examined in a clinical strain of Streptococcus agalactiae isolated from a blood sample. EDTA and EGTA at 10 mM did not inhibit the growth of S. agalactiae, while PHEN significantly arrested bacterial proliferation in a concentration range of 10-0.01 mM. The in vitro interaction between S. agalactiae and A549 cells was a time-dependent process; adherence and bacterial intracellular viability were more pronounced after 3 h of contact. The pre-treatment of bacterial cells with EDTA adversely influenced the adhesive properties of S. agalactiae to A549 cells after 2 and 3 h, whereas EGTA only blocked this process after 3 h. Viable intracellular bacteria were just detected after 3 h of interaction, and EDTA and EGTA inhibited intracellular viability in a similar fashion. Conversely, PHEN inhibited neither the adherence nor the intracellular viability of the microorganism. Furthermore, EDTA robustly suppressed surface polypeptide synthesis, suggesting a decline in the possible bacterial ligands responsible for S. agalactiae adhesive properties.