Project description:Staphylococcus hominis is frequently isolated from human skin and we hypothesize that it may protect the cutaneous barrier from opportunistic pathogens. We determined that S. hominis makes six unique auto inducing peptide (AIP) signals that inhibit the major virulence factor accessory gene regulator (agr) quorum sensing system of Staphylococcus aureus. We solved and confirmed the structures of three novel AIP signals in conditioned media by mass spectrometry, then validated synthetic AIP activity against all S. aureus agr classes. Synthetic AIPs also inhibited the conserved agr system in a related species, Staphylococcus epidermidis. We determined the distribution of S. hominis agr types on healthy human skin and found S. hominis agr-I and agr-II were highly represented across subjects. Further, synthetic AIP-II was protective in vivo against S. aureus-associated dermonecrotic or epicutaneous injury. Together, these findings demonstrate that a ubiquitous colonizer of human skin has a fundamentally protective role against opportunistic damage.
Project description:The features of Mycoplasma in human organ such lung and urinary tract are enigmatic. Here, the role of M. hominis in regard to biofilm formation of uropathogenic Escherichia coli (UPEC) strain CFT073 was investigated. Although M. hominis were inferred to not impact on UPEC bacterial fitness including growth and productions of signaling molecules as autoinducer-2 (AI-2) and indole, we found that the presence of M. hominis dramatically decreased biofilm formation of UPEC CFT073 as well as slightly repressed attachment and cytotoxicity of that. Importantly, this activity was observed on UPEC strain specifically, not enterohemorrhagic E. coli (EHEC) strain that exists on intestine. Whole-transcriptome profiling and quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed PhoPQ system and anti-termination protein (encoded by ybcQ) participates on the reduction of biofilm formation by M. hominis (corroborated by qRT-PCR). Furthermore, collaborating with previous report that toxin-antitoxin (TA) system involved in biofilm formation, M. hominis increased on the transcriptions of toxin genes including hha (toxin gene in Hha-TomB TA system) and pasT (toxin part in PasT-PasI TA system). Hence, we propose that one possible role of M. hominis is to influence bacterial biofilm formation in urinary tract. Only fourteen genes were induced (2.5-fold) by the presence of M. hominis in Uropathogenic Escherichia coli (UPEC) biofilm cells. Among upregulated genes, ybcQ (encodes anti-termination protein Q homolog) and phoP/phoQ (encode DNA-binding response regulators in two-component regulatory system), were induced by the presence of M. hominis. Two-condition experiment, UPEC CFT073 alone vs. UPEC CFT073 with Mycoplasma hominis PG21 (10^5 ccu/ml). For preparing the total RNA, UPEC CFT073 cells were grown at 37°C in biofilm cells on glass wool with or without M. hominis for 24 h.
