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 Pattern of Klebsiella sp. Isolated from the Feces of the Bornean Orang Utan (Pongo pygmaeus) at Taman Safari Indonesia, Bogor
Abstrak: Orang utan merupakan satu-satunya kera besar yang masih bertahan di Wilayah Asia Tenggara. Saat ini, populasi orang utan di habitatnya terus mengalami penurunan. Diperkirakan selama 60 tahun terakhir populasi orang utan berkurang sebanyak 50%. Data mikrobiologi yang membahas resistansi bakteri Klebsiella sp. terhadap antibiotik pada feses orang utan kalimantan (Pongo pygmaeus) belum banyak dilakukan. Penelitian ini bertujuan untuk mengidentifikasi keberadaan bakteri Klebsiella sp. serta mengetahui pola resistansinya terhadap beberapa antibiotik pada feses P. pygmaeus. Metode penelitian terdiri dari isolasi, identifikasi, dan uji resistansi antibiotik. Hasil isolasi dan identifikasi ditemukan sebanyak tiga isolat (37,5%) yang positif bakteri Klebsiella sp. Berdasarkan uji sensitivitas, isolat Klebsiella sp. yang berasal dari feses P.pygmaeus sehat di Taman Safari Indonesia, Bogor, berhasil didapatkan dua pola resistansi berbeda yang memberikan gambaran adanya sensitivitas dan resistansi terhadap beberapa antibiotik. Klebsiella sp. telah mengalami resistan terhadap antibiotik golongan β-laktam dan masih sensitif terhadap antibiotik golongan aminoglikosida, tetrasiklin, dan fluorokuinolon., Orangutans are the only great apes that still survive in the Southeast Asian Region. Currently, the orangutans population in their habitat continues to decline. It is estimated that over the last 60 years, the orang utan population has decreased by 50%. Microbiological data discussing the resistance of Klebsiella sp. against antibiotics in the feces of the bornean orangutans (Pongo pygmaeus) has not been widely carried out. This study aims to identify the presence of Klebsiella sp. as well as know the pattern of resistance to several antibiotics in the feces of bornean orangutans. The research method consisted of isolation, identification, and antibiotic resistance testing. The results of isolation and identification found that three isolates (37.5%) were positive for Klebsiella sp. Based on the sensitivity test, Klebsiella sp. isolates which come from the feces of healthy P.pygmaeus in Taman Safari Indonesia, Bogor, two different patterns of resistance have been obtained which provide an overview of sensitivity and resistance to several antibiotics. Klebsiella sp. has experienced resistance to β-lactam class antibiotics and is still sensitive to aminoglycoside, tetracycline, and fluoroquinolone antibiotics.
Keyword: antibiotik, Klebsiella sp., Pongo pygmaeus, resistansi

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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