A Host-Produced Autoinducer-2 Mimic Activates Bacterial Quorum Sensing

Host-microbial symbioses are vital to health; nonetheless, little is known about the role cross-kingdom signaling plays in these relationships. In a process called quorum sensing, bacteria communicate with one another using extracellular signal molecules called autoinducers. One autoinducer, AI-2, is proposed to promote inter-species bacterial communication, including in the mammalian gut. We show that mammalian epithelia produce an AI-2 mimic activity in response to bacteria or tight-junction disruption. This AI-2 mimic is detected by the bacterial AI-2 receptor, LuxP/LsrB, and can activate quorum-sensing-controlled gene expression, including in the enteric pathogen Salmonella typhimurium. AI-2 mimic activity is induced when epithelia are directly or indirectly exposed to bacteria, suggesting that a secreted bacterial component(s) stimulates its production. Mutagenesis revealed genes required for bacteria to both detect and stimulate production of the AI-2 mimic. These findings uncover a potential role for the mammalian AI-2 mimic in fostering cross-kingdom signaling and host-bacterial symbioses

Efektifitas Ekstrak Daun Jambu Biji (Psidium guajava linn) terhadap Jumlah Koloni Bakteri Model Luka Sayat Dipapar MRSA

Latar Belakang: Infeksi luka operasi adalah infeksi yang terjadi pada daerah luka sayat yang dioperasi dan merupakan salah satu infeksi nosokomial yang banyak terjadi di rumah sakit. Infeksi yang terjadi pada daerah luka operasi disebabkan oleh adanya mikroorganisme seperti bakteri methicillin-resistant Staphylococcus aureus. Beberapa penelitian terdahulu menunjukkan bahwa ekstrak daun jambu biji memiliki kandungan yang bermanfaat sebagai penyembuhan luka. Tujuan: Mengetahui pengaruh dan perbandingan pemberian ekstrak daun jambu biji terhadap jumlah koloni bakteri pada proses penyembuhan luka sayat yang dipapar MRSA. Metode: Penelitian ini merupakan true experiment design dengan menggunakan tikus wistar jantan berjumlah 25 ekor yang dibagi menjadi 5 kelompok perlakuan kemudian dilukai sepanjang 2 cm pada daerah punggung dan dipapar dengan bakteri MRSA menggunakan spuit sebanyak 0,1 mL. Pemberian intervensi dilakukan 2 kali sehari selama 10 hari menggunakan gold standar, yaitu mupirocin 2% dan ekstrak daun jambu biji yang berasal dari metode maserasi dengan pelarut etanol 70%. Seluruh data diuji menggunakan One Way Anova dan didapatkan perbedaan jumlah koloni bakteri MRSA antar kelompok perlakuan. Hasil: Pemberian intervensi ekstrak daun jambu biji konsentrasi 5% dapat menurunkan jumlah koloni bakteri MRSA sebesar 50,8 CFU/mL. Kesimpulan: Ekstrak daun jambu biji konsentrasi 5% memiliki pengaruh paling efektif dalam menurunkan jumlah koloni bakteri MRSA pada luka sayat yang diinfeksi MRSA. Saran: Menurunkan tingkat konsentrasi ekstrak daun jambu biji pada luka sayat agar mendapatkan penyembuhan luka lebih optimal, karena semakin kecil tingkat konsentrasi maka semakin optimal untuk penurunan bakteri MRSA

A Host-Produced Autoinducer-2 Mimic Activates Bacterial Quorum Sensing

Host-microbial symbioses are vital to health; nonetheless, little is known about the role cross-kingdom signaling plays in these relationships. In a process called quorum sensing, bacteria communicate with one another using extracellular signal molecules called autoinducers. One autoinducer, AI-2, is proposed to promote inter-species bacterial communication, including in the mammalian gut. We show that mammalian epithelia produce an AI-2 mimic activity in response to bacteria or tight-junction disruption. This AI-2 mimic is detected by the bacterial AI-2 receptor, LuxP/LsrB, and can activate quorum-sensing-controlled gene expression, including in the enteric pathogen Salmonella typhimurium. AI-2 mimic activity is induced when epithelia are directly or indirectly exposed to bacteria, suggesting that a secreted bacterial component(s) stimulates its production. Mutagenesis revealed genes required for bacteria to both detect and stimulate production of the AI-2 mimic. These findings uncover a potential role for the mammalian AI-2 mimic in fostering cross-kingdom signaling and host-bacterial symbioses