Resistensi antimikroba (AMR) merupakan ancaman kesehatan global, dengan Escherichia coli menempati peringkat pertama sebagai bakteri penyebab kematian akibat resistensi obat. Salah satu alternatif penanganannya adalah pendekatan sinbiotik menggunakan probiotik Lactobacillus acidophilus penghasil bakteriosin dengan prebiotik jamur kuping (Auricularia auricula-judae) yang kaya akan polisakarida β-glukan. Penelitian ini bertujuan untuk mengetahui pengaruh formulasi sinbiotik tersebut sebagai agen antibakteri dalam menghambat pertumbuhan Escherichia coli.
Metode penelitian eksperimental laboratorium ini menggunakan variasi konsentrasi ekstrak jamur kuping hasil maserasi etanol 96% sebesar 0%, 0,1%, 0,2%, 0,4%, 0,8, dan 1,6%. Sediaan uji dibuat melalui fermentasi sinbiotik di media MRS Broth, lalu disentrifugasi untuk memisahkan bagian supernatan dan endapan sel. Supernatan diproses menjadi suspensi bakteriosin melalui netralisasi pH menggunakan larutan NaOH dan disaring menggunakan filter 0,22 µm. Uji aktivitas antibakteri dilakukan dengan metode difusi sumuran pada media Mueller Hinton Agar (MHA).
Hasil uji pada kontrol positif dari supernatan Lactobacillus acidophilus menunjukkan adanya aktivitas antibakteri terhadap Escherichia coli dengan rata-rata zona hambat 13,5 mm. Namun, pada pengujian suspensi bakteriosin di seluruh variasi konsentrasi 0% sampai 1,6% maupun kontrol negatif tidak menghasilkan zona hambat sama sekali (0 mm).
Kesimpulan penelitian ini adalah formula sinbiotik tidak menunjukkan aktivitas antibakteri terhadap Escherichia coli pada seluruh kelompok perlakuan, sehingga nilai konsentrasi optimal tidak dapat ditentukan. Hal ini disebabkan oleh tidak tertariknya senyawa prebiotik saat ekstraksi, ketepatan durasi inkubasi fermentasi, serta kepekatan peptida antibakteri yang terbentuk.

Kata Kunci: Lactobacillus acidophilus, Bakteriosin, Auricularia auricula-judae, Escherichia coli, Zona Hambat.

Antimicrobial resistance (AMR) is a global health threat, with Escherichia coli ranking first among bacteria causing deaths due to drug resistance. One such alternative treatment under consideration is a synbiotic approach, which involves the use of the bacteriocin-producing probiotic Lactobacillus acidophilus in combination with the prebiotic wood ear mushroom (Auricularia auricula-judae), a source of β-glucan polysaccharides. The objective of this study is to ascertain the effect of this synbiotic formulation as an antibacterial agent in inhibiting the growth of Escherichia coli.
The present experimental laboratory study utilised varying concentrations of wood ear mushroom extract, obtained through maceration in 96% ethanol, ranging from 0%, 0.1%, 0.2%, 0.4%, 0.8%, and 1.6%. Preparations for the tests were conducted through synbiotic fermentation in MRS Broth medium, followed by centrifugation to separate the upper layer (supernatant) from the lower layer (cell pellet). The resulting mixture was then processed into a bacteriocin suspension through neutralisation of the pH with a NaOH solution, followed by filtration using a 0.22 µm filter. The antibacterial activity of the samples was evaluated through the implementation of the well diffusion method on Mueller Hinton Agar (MHA) medium.
The result for the positive control of Lactobacillus acidophilus strain showed antibacterial activity against Escherichia coli, with an average inhibition zone of 13.5 millimeters. However, the testing of the bacteriocin suspension across the entire concentration range from 0% to 1.6%, as well as the negative control, produced no inhibition zones at all (0 mm).
The conclusion of this study is that the synbiotic formula did not exhibit antibacterial activity against Escherichia coli in any of the treatment groups. Therefore, an optimal concentration could not be determined. This outcome was attributed to three factor, the inability to extract prebiotic coumpounds, the inaccuracy of the fermentation incubation duration, and the concentration of the resulting antibacterial peptides.

Keywords: Lactobacillus acidophilus, Bacteriocin, Auricularia auricula-judae, Escherichia coli, Zone of Inhibition.