Judul: Identification and Antimicrobial Susceptibility Test of Gram-Positive Catalase-Negative Cocci in Horses (Equus caballus)
Abstrak: Kasus resistansi mikroba terhadap antimikroba sudah banyak terjadi di dunia salah satunya pada kuda. Bakteri coccus Gram positif katalase negatif dapat menjadi bakteri patogen yang menyerang saluran pencernaan kuda. Belum ada penelitian mengenai resistansi bakteri coccus Gram positif katalase negatif pada kuda di Indonesia terhadap berbagai jenis antibiotik. Penelitian dilakukan dengan mengidentifikasi bakteri coccus Gram positif katalase negatif dan menguji kepekaannya terhadap 6 jenis antibiotik dengan metode difusi cakram. Data hasil penelitian dianalisis dan disajikan secara deskriptif melalui perbandingan dengan tabel standar diameter zona hambat atau kepekaan antibiotik Clinical and Laboratory Standards Institute (CLSI) tahun 2021. Hasil identifikasi ditemukan 7 isolat bakteri coccus Gram positif katalase negatif dari dua puluh sampel feses kuda sehat dan dewasa di Jakarta International Equestrian Park. Dari 7 isolat bakteri coccus Gram positif katalase negatif tersebut, 4 isolat teridentifikasi sebagai bakteri Enterococcus sp. sedangkan ketiga lainnya teridentifikasi sebagai bakteri Streptococcus sp. Hasil uji kepekaan bakteri coccus Gram positif katalase negatif menunjukkan isolat bakteri resistan terhadap sefotaksim dan asam nalidiksat. Kepekaan bakteri terhadap amoksisilin, oksitetrasiklin, dan kloramfenikol masih relatif peka. Saran yang dapat disampaikan penulis mengenai penelitian ini yaitu diperlukan adanya penelitian lebih lanjut mengenai faktor ras yang mempengaruhi terjadinya infeksi bakteri. Selain itu, diperlukan identifikasi lebih lanjut berupa identifikasi secara molekuler dengan PCR., Many cases of antimicrobial resistance have occurred in the world, one of which is in horses. Catalase-negative Gram-positive coccus bacteria are pathogenic bacteria that attack the digestive tract of horses. There has been no research on the resistance of Gram positive catalase-negative coccus bacteria in horses in Indonesia to various types of antibiotics. The research was conducted by identifying catalase-negative Gram positive coccus bacteria and testing their sensitivity to 6 types of antibiotics by disc diffusion method. The data were analysed and presented descriptively through comparison with the standard table of inhibition zone diameter or antibiotic sensitivity of the Clinical and Laboratory Standards Institute (CLSI) in 2021. Seven isolates of catalase-negative Gram-positive coccus bacteria were found from twenty faeces samples of healthy and adult horses at the Jakarta International Equestrian Park. Of the seven isolates of catalase-negative Gram positive coccus bacteria, four isolates were identified as Enterococcus sp. while the other three were identified as Streptococcus sp. The results of the sensitivity test of catalase-negative Gram-positive coccus bacteria showed that the bacterial isolates were resistant to cefotaxime and nalidixic acid. Bacterial sensitivity to amoxicillin, oxytetracycline, and chloramphenicol is still relatively sensitive. Suggestions that can be conveyed by the author regarding this research are that further research is required regarding breed factors that affect the occurrence of bacterial infections. In addition, further identification is needed in the form of molecular identification by PCR.
Keyword: Enterococcus, Streptococcus, negative catalase, horse, antimicrobial susceptibility

Judul: Identification and Sensitivity Test of Salmonella sp. Bacteria in Horses (Equus caballus) to Several Antibiotics.
Abstrak: Kuda memainkan peran yang semakin penting dalam kehidupan manusia. Sistem pencernaan kuda mengandung berbagai jenis bakteri, seperti Salmonella sp. , dan dianggap sebagai salah satu penyebab utama penyakit zoonosis. Tujuan dari penelitian ini adalah untuk mengisolasi dan mengidentifikasi bakteri Salmonella sp. dalam tinja kuda, serta menguji sensitivitas bakteri Salmonella sp. terhadap beberapa antibiotik. Metode penelitian yang digunakan terdiri dari koleksi 20 sampel, isolasi dan identifikasi bakteri, serta pengujian sensitivitas bakteri terhadap antibiotik menggunakan metode difusi cakram atau metode Kirby Bauer. Hasil identifikasi menunjukkan bahwa 9 isolat Salmonella sp. ditemukan dari 20 sampel tinja kuda. Hasil uji sensitivitas bakteri Salmonella terhadap antibiotik yang digunakan menunjukkan bahwa 89% isolat sensitif terhadap gentamisin dan kloramfenikol, 55% terhadap asam nalidiksik, 44% terhadap amoksisilin dan oksitetrasiklin. Hasil intermediat ditemukan untuk beberapa jenis antibiotik seperti amoksisilin (22%), oksitetrasiklin (11%), asam nalidiksik (22%), dan kloramfenikol (11%), sedangkan Salmonella menunjukkan resistansi 100% terhadap sefotaksim. Penelitian ini dapat disimpulkan bahwa Salmonella sp. yang terdeteksi dalam tinja kuda menunjukkan resistansi terhadap sefotaksim namun masih sensitif terhadap amoksisilin, gentamisin, asam nalidiksik, oksitetrasiklin, dan kloramfenikol., Horses play an increasingly important role in human life. The digestive system of horses contains various types of bacteria, such as Salmonella sp. and is considered one of the main causes of zoonotic diseases. The aim of this study was to isolat and identify Salmonella sp. bacteria in horse feces, as well as to test the sensitivity of Salmonella sp. bacteria to several antibiotics. The research method used consisted of collecting 20 samples, isolating and identifying the bacteria, and testing the sensitivity of the bacteria to antibiotics using the disk diffusion or Kirby Bauer method. The identification results showed that 9 isolats of Salmonella sp. were found out of 20 horse feces samples. The results of the bacterial sensitivity test on horses to the antibiotics used showed that 89% of the isolats were sensitive to gentamicin and chloramphenicol, 55% to nalidixic acid, 44% to amoxicillin and oxytetracycline. Intermediate results were found for some types of antibiotics such as amoxicillin (22%), oxytetracycline (11%), nalidixic acid (22%), and chloramphenicol (11%), while Salmonella showed 100% resistance to cefotaxime. This study can be concluded that Salmonella sp. detected in horse feces has shown resistance to cefotaxime but is still sensitive to amoxicillin, gentamicin, nalidixic acid, oxytetracycline, and chloramphenicol
Keyword: Antibiotic resistance, Identification, Horses, 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.
Keyword: