Judul: Identification and Pattern of Antibiotic Resistance of Pseudomonas spp. Isolated from Orangutan (Pongo Pygmaeus) at Bogor Indonesia Safari Park
Abstrak: Pseudomonas spp. is a lactose-negative gram-negative bacteria that contributes to several infections including air sacculitis in orangutans due to its having the largest air sac compared to most nonhuman primates. This research was designed to study and analyze the identification and the pattern of antibiotic resistance of Pseudomonas spp. Identification of Pseudomonas includes KOH 3% test, oxidase test, TSIA test, urea test, IMViC test Indole, Methyl-Red, Voges-Proskauer, and Citrate) and carbohydrate fermentation test. Pattern of antibiotic resistance includes five different types of antibiotics from different antibiotic classes which are ampicillin from β- lactam, gentamicin from aminoglycoside, tetracycline from tetracycline, enrofloxacin from fluoroquinolone, and chloramphenicol from phenicol class. As the results, identification of Pseudomonas spp. showed three suspected isolates of Pseudomonas spp. Patterns of antibiotic resistance was carried out by using Kirby-Baurer method which uses agar disk diffusion resulted in two of the isolates that were mostly similar in pattern, resistant to only ampicillin and are sensitive towards tetracycline, enrofloxacin, chloramphenicol, and gentamicin meanwhile the other one of the isolate differ, resistant to ampicillin, tetracycline, enrofloxacin, and chloramphenicol and is sensitive towards gentamicin. In conclusion, feces samples of orangutans revealed three suspected Pseudomonas spp. and showed resistance on ampicillin and sensitive to gentamicin. The study of antibiotic resistance patterns is crucial for future antibiotic selection.
Keyword: antibiotic resistance, gram-negative bacteria, Kirby-Baurer method, Pseudomonas spp.

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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