Judul: Identification of Enterococcus sp. and Antibiotic Resistance Testing in Sumatran Orangutans (Pongo abelii) at the Indonesian Safari Park
Abstrak: Populasi orang utan sumatra (Pongo abelii) saat ini mengalami penurunan sebanyak 80%. Hal ini disebabkan oleh berbagai faktor, diantaranya semakin menyempit habitatnya akibat aktivitas manusia yang tidak bertanggung jawab, perdagangan ilegal, dan juga disebabkan oleh penyakit yang diakibatkan oleh infeksi bakteri. Tujuan penelitian ini adalah untuk mengisolasi dan mengidentifikasi Enterococcus sp. pada feses orang utan sumatra di Taman Safari Indonesia dan menguji resistansi bakteri Enterococcus sp. terhadap beberapa jenis antibiotik. Penelitian ini dilakukan di Laboratorium Bakteriologi, Divisi Mikrobiologi Medik, Sekolah Kedokteran Hewan dan Biomedis, Institut Pertanian Bogor. Sampel feses yang digunakan dalam penelitian ini diambil dari 10 ekor orang utan sumatra di Taman Safari Indonesia. Feses orang utan sumatra diambil kemudian dilanjutkan dengan metode isolasi pada media Enterococcus faecalis (EF) agar, Tryptic Soy Agar (TSA), dan Blood Agar (BA), diidentifikasi dengan pewarnaan Gram, uji KOH 3%, uji biokimia, serta dilanjutkan dengan prosedur uji resistansi antibiotik. Hasil penelitian mengindikasikan bahwa sebanyak 6 isolat teridentifikasi E. faecium dan 4 isolat lainnya teridentifikasi E. faecalis. Hasil uji resistansi bakteri Enterococcus sp. terhadap tujuh jenis antibiotik menunjukkan bahwa sebanyak 9 isolat resistan terhadap ceftazidime dan cefotaxime, sebanyak 2 isolat resistan terhadap streptomisin, dan sebanyak 1 isolat resistan terhadap eritromisin., The Sumatran orangutans (Pongo abelii) population is declining by 80% due to habitat loss from human activities, illegal trade, and bacterial infections. The aim of this study was to isolate and identify Enterococcus sp. in the feces of Sumatran orangutans at Taman Safari Indonesia and tested the resistance of Enterococcus sp. bacteria to several types of antibiotics. This research was conducted at the Bacteriology Laboratory, Medical Microbiology Division, School of Veterinary Medicine and Biomedicine, IPB. The feces samples used in this study were taken from 10 Sumatran orangutans at Taman Safari Indonesia then continued with the isolation method on Enterococcus faecalis (EF) agar media, TSA, and BA, identified by Gram staining, 3% KOH test, biochemical test, and continued with the procedure antibiotic resistance test. The results of the study indicated that 6 isolates were identified as E. faecium and 4 other isolates were identified as E. faecalis. The results of the bacterial resistance test Enterococcus sp. against seven types of antibiotics showed that 9 isolates were resistant to ceftazidime and cefotaxime, 2 isolates were resistant to streptomycin, and 1 isolate was resistant to erythromycin.
Keyword: Enterococcus sp., identification, isolation, resistance, Sumatran orangutan

Judul: Identification and Resistance Test of Enterococcus sp. from Sumatran Orang Utan (Pongo abelii) towards Some Antibiotics
Abstrak: Orang utan sumatra (Pongo abelii) merupakan primata endemik Indonesia yang populasinya terancam punah. Penurunan populasi ini dapat disebabkan oleh infeksi bakteri. Salah satu bakteri penyebab infeksi yaitu Enterococcus sp. yang memiliki kemampuan multi-resistan. Resistansi bakteri dapat menjadi ancaman sehingga perlu perhatian lebih. Penelitian ini bertujuan mengidentifikasi dan menguji resistansi bakteri Enterococcus sp. pada orang utan sumatra liar di Taman Nasional Gunung Leuser. Penelitian diawali dengan melakukan identifikasi bakteri dan menguji resistansinya terhadap 7 antibiotik menggunakan metode Difusi Cakram Kirby-Bauer. Data dianalisis dengan standar diameter zona hambat dari Clinical and Laboratory Standards Institute (CLSI) 2023. Hasil identifikasi dari 8 sampel feses ditemukan 6 sampel positif Enterococcus sp. dengan total 9 isolat, yaitu 6 isolat Enterococcus faecalis dan 3 isolat Enterococcus faecium. Hasil uji resistansi menunjukkan semua isolat Enterococcus faecalis resistan terhadap seftazidim, sefotaksim, streptomisin, serta seluruhnya intermediet terhadap eritomisin. Semua isolat Enterococcus faecium resistan terhadap seftazidim, sefotaksim, serta 2 isolat intermediet terhadap streptomisin. Enterococcus faecalis dan Enterococcus faecium adalah mikroba normal saluran gastrointestinal orang utan sumatra. Antibiotik golongan sefalosporin tidak efektif melawan Enterococcus sp. karena secara alami resistan terhadap sefalosporin. Resistansi pada orang utan liar dapat terjadi karena adanya resistansi intrinsik, lingkungan yang terkontaminasi, dan kontak antar hewan.
Keyword: Antibiotics, enterococcus sp., Antibiotic-resistant, Identification, orang utan, Pongo abelii

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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