Judul: Resistance Test of Escherichia coli Pathogen from  Feces Sample of Bornean Orangutan (Pongo pygmaeus) at Taman Safari Indonesia-Bogor
Abstrak: Orang utan merupakan salah satu primata dan satu-satunya kera besar yang hidup di Asia. Gangguan saluran pencernaan pada orang utan biasanya berupa diare yang disebabkan oleh bakteri enteropatogen E. coli. Pengobatan dengan antibiotik pada orang utan harus mempertimbangkan sensitivitas bakteri terhadap antibiotik. Penelitian ini bertujuan mengetahui gambaran resistansi Escherichia coli patogen pada sampel feses orangutan kalimantan (Pongo pygmaeus) di Taman Safari Indonesia – Bogor terhadap beberapa antibiotik. Sebanyak 10 sampel diisolasi dan diidentifikasi keberadaan E. coli patogen dan sebanyak 10 isolat terdeteksi sebagai E. coli patogen. Uji resistansi dilakukan dengan metode Kirby-Baurer Disk Diffusion Test menggunakan 7 antibiotik yang berbeda. Hasil uji menunjukkan 20% isolat telah resistan terhadap tetrasiklin, 30% isolat resistan terhadap antibiotik streptomisin, trimetoprim dan trimetoprim-sulfametoksazol, dan 90% telah resistan terhadap ampisilin. Sementara itu 100% isolat sensitif terhadap kloramfenikol, 70% sensitif terhadap trimetoprim dan trimetoprim-sulfametoksazol, serta 50% sensitif terhadap siprofloksasin. Antibiotik yang menunjukkan hasil resistan tidak direkomendasikan untuk pengobatan infeksi oleh E. coli pada orang utan., Orangutans are one of the primates and the only great apes which live in Asia. Gastrointestinal problem in orangutans usually characterized by diarrhea which comes from enteropathogenic bacteria E. coli. Moreover, treatment with antibiotics in orangutans should take into account the sensitivity of the bacteria to antibiotics. The aim of this study is to describe the resistance of pathogenic Escherichia coli in fecal samples of the Bornean orangutan (Pongo pygmaeus) at Taman Safari Indonesia – Bogor to several antibiotics. A total of 10 samples were isolated and identified the presence of pathogenic E. coli and as many as 10 isolates were detected as pathogenic E. coli. Moreover, the resistance test was conducted by using the Kirby-Bauer Disk Diffusion Test method using 7 different antibiotics. The test results show that 20% of the isolates were resistant to tetracycline, 30% of the isolates were resistant to the antibiotics streptomycin, trimethoprim and trimethoprim-sulfamethoxazole, and 90% were resistant to ampicillin. Meanwhile, 100% of isolates were sensitive to chloramphenicol, 70% sensitive to trimethoprim and trimethoprim-sulfamethoxazole, and 50% sensitive to ciprofloxacin. Antibiotics that show resistance are not recommended for the treatment of infections by Escherichia coli in orangutans.
Keyword: antibiotic, Escherichia coli, orangutan, resistance

Judul: Identification and Resistance of Salmonella sp. from Feces Sample of Bornean Orang Utan (Pongo pygmaeus) at Taman Safari Indonesia, Bogor.
Abstrak: Orang utan merupakan satu-satunya primata spesies kera besar yang hidup di Asia. Seluruh spesies orang utan dikategorikan ke dalam kelompok Appendix 1 yakni kelompok satwa yang dilindungi penuh dari segala bentuk perdagangan karena terancam punah oleh Convention on International Trade of Endangered Species of Fauna and Flora (CITES). Status orang utan sebagai hewan yang terancam punah ini menjadikan masalah kesehatannya perlu mendapat perhatian lebih, salah satunya adalah penyakit gastrointestinal yang disebabkan oleh Salmonella sp. Sejauh ini, data mikrobiologi terkait gangguan saluran pencernaan dan kejadian resistansi antibiotik pada orang utan belum banyak dipublikasikan. Penelitian ini bertujuan mengetahui keberadaan bakteri Salmonella sp. serta pola resistansinya pada feses orang utan kalimantan (Pongo pygmaeus) di Taman Safari Indonesia, Bogor. Sebanyak 10 sampel feses diambil dari orang utan dengan kondisi sehat dan tidak sedang mengalami gangguan pencernaan. Hasil isolasi dan identifikasi menunjukkan sebanyak 6 dari 10 sampel menunjukkan hasil yang positif terhadap Salmonella sp. Uji resistansi antibiotik dilakukan dengan menggunakan metode Kirby-Bauer Disk Diffusion Test menggunakan 7 macam antibiotik dari golongan yang berbeda-beda. Hasil uji resistansi menunjukkan bahwa Salmonella sp. 100% masih sensitif terhadap trimetoprim-sulfametoksazol, kloramfenikol, trimetoprim, dan tetrasiklin. Sementara itu, sebanyak 83,3% isolat menunjukkan resistansi terhadap ampisilin dan 33,3% terhadap streptomisin., Orang utans are the only primates of the great ape species that live in Asia. All orang utan species are categorized into the Appendix 1 group, which is an animal group which is fully protected from all forms of trade since it is threatened with extinction by Convention on International Trade of Endangered Species of Fauna and Flora (CITES). Furthermore, the status of the orang utan as an endangered animal makes its health problems need more attention, one of which is gastrointestinal disease caused by Salmonella sp. To date, microbiological data which is related to digestive tract disorders and the incidence of antibiotic resistance in orang utans have not been widely published. This study aims to determine the presence of Salmonella sp. and the pattern of resistance in the feces of the Bornean orang utan (Pongo pygmaeus) at Taman Safari Indonesia, Bogor. A total of 10 stool samples were taken from orang utans in healthy condition and they were not experiencing digestive disorders. The results of isolation and identification indicate that as many as 6 of 10 samples show positive results on Salmonella sp. Antibiotic resistance test was conducted by using the Kirby-Bauer Disk Diffusion Test method with 7 different antibiotics from different groups. In addition, the results of the resistance test show that Salmonella sp. 100% still sensitive to trimethoprim-sulfamethoxazole, chloramphenicol, trimethoprim, and tetracycline. Meanwhile, 83,3% of isolates show resistance to ampicillin and 33,3% to streptomycin.
Keyword: antibiotik, orang utan, resistansi antibiotik, Salmonella sp.

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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