Judul: Isolation and Antimicrobial Resistance  Detection of Staphylococcus aureus from Pondok Ranggon Dairy Farm, East  Jakarta
Abstrak: Infeksi yang disebabkan oleh Staphylococcus aureus dapat ditularkan dari seekor sapi ke sapi lain dan dari puting yang terinfeksi ke puting yang normal atau sehat melalui tangan pemerah dan lingkungan. Keberadaan S. aureus berkaitan dengan manajemen higiene dan sanitasi yang buruk. Penggunaan antimikroba yang tidak tepat berpotensi meningkatkan resistensi bakteri terhadap antibiotik yang menjadi ancaman serius bagi kesehatan hewan dan masyarakat. Penelitian ini bertujuan mengidentifikasi bakteri S. aureus dari tangan pemerah dan permukaan puting sapi serta mendeteksi resistensi bakteri S. aureus terhadap beberapa antibiotik. Pengujian diawali dengan isolasi dan identifikasi bakteri dan dilanjutkan dengan pengujian resistensi bakteri terhadap antibiotik menggunakan metode Kirby-Baurer disk diffusion. Antibiotik yang digunakan terdiri atas sepuluh jenis yaitu penisilin,amoksisilin-klavulanat, streptomisin, gentamisin, eritromisin, tetrasiklin, siprofloksasin, asam nalidiksat, trimetropim sulfametoksazol, kloramfenikol. Keberadaan S. aureus yang diisolasi dari tangan pemerah maupun dari puting sapi di Peternakan Sapi Perah Pondok Ranggon, Jakarta Timur masih cukup tinggi. Berdasarkan pengujian isolasi S. aureus dari sampel tangan pemerah diperoleh sebanyak 77,3% dan dari puting sapi sebanyak 72,9%. Hasil penelitian menunjukkan 44,2% isolat S. aureus yang diisolasi dari swab tangan pemerah dan puting sapi telah mengalami multi-drug-resistant (MDR). Kejadian resistensi pada S. aureus perlu menjadi perhatian karena berpotensi sebagai ancaman kesehatan pada hewan maupun manusia karena memiliki potensi zoonosis, Infections caused by Staphylococcus aureus can be transmitted from one cow to another and from the infected cow’s teat to the normal and healthy teat by milker’s hand and the environment. The presence of S. aureus is associated with poor hygiene and sanitation practices. Improper use of antimicrobials has the potential to increase bacterial resistance to antibiotics which are a serious threat to animal health and society. This study aims to identify S. aureus from milker’s hand and the surface of cow’s teat and to detect the resistance of S. aureus to several antibiotics. Testing begins with the isolation and identification of bacteria and continues with testing for bacterial resistance to antibiotics using the Kirby Baurer method. The antibiotics used consisted of 10 types, penicillin, amoxicillin clavulanate, streptomycin, gentamicin, erythromycin, tetracycline, ciprofloxacin, nalidixic acid, trimethoprim-sulfamethoxazole, and chloramphenicol. The presence of S. aureus isolated from the milker’s hand or the cow’s teat at Pondok Ranggon Dairy Farm, East Jakarta is still quite high. Based on the isolation test of S. aureus from milker’s hand sample, it was 77,3% and 72,9% from the cow's teat, with 44,2% of them showed multi-drug resistance (MDR). The incidence of S. aureus resistance needs to be a concern because it has zoonotic potential to human and animals.
Keyword: puting sapi, resistensi antibiotik, Staphylococcus aureus, tangan  pemerah

Judul: Antimicrobial Resistance of Escherichia coli and Staphylococcus aureus in Raw Milk from Peternakan Sapi Perah Pondok Ranggon
Abstrak: Penggunaan antibiotik berlebih dapat menyebabkan resistansi antibiotik pada ternak yang dapat disebarkan ke manusia dan lingkungan. Penelitian ini bertujuan mengisolasi bakteri Escherichia coli dan Staphylococcus aureus dari susu segar dan mengetahui sifat resistansinya terhadap antibiotik. Pengujian diawali dengan isolasi dan identifikasi bakteri berdasarkan SNI 2897:2008 tentang Metode Pengujian Cemaran Mikroba dalam Daging, Telur dan Susu, serta Hasil Olahannya dan dilanjutkan dengan pengujian resistansi antibiotik menggunakan metode Kirby-Baurer. Antibiotik yang digunakan yaitu golongan β-laktam, aminoglikosida, makrolida, fluorokuinolon, antagonis asam folat, kloramfenikol, tetrasiklin dan cephems. Dari 36 sampel susu segar didapatkan 16 sampel (25 isolat) positif tercemar E. coli dan 13 sampel (13 isolat) positif S. aureus. Sebanyak 24/25 isolat E. coli resistan terhadap 15 jenis antibiotik dan 13/13 isolat S. aureus resistan terhadap 14 jenis antibiotik. Sebanyak 20/25 isolat E. coli telah mengalami multidrug resistance antibiotic dengan pola yang paling sering ditemui yakni penisilin-aminoglikosida-tetrasiklin-kloramfenikol. Sebanyak 8/13 isolat S. aureus mengalami multidrug resistance dengan pola yang paling sering ditemui yakni penisilin-aminoglikosida-fluorokuinolon. Bakteri yang telah mengalami resistansi antibiotik dapat menjadi ancaman bagi kesehatan ternak, kesehatan lingkungan, keamanan pangan dan kesehatan masyarakat., Overuse of antibiotics can cause antimicrobial resistance in livestock which can spread to humans and the environment. This study aimed to isolate Escherichia coli and Staphylococcus aureus in raw milk and determined their antibacterial susceptibility. Bacterial isolation and identification based on SNI 2897:2008 about Metode Pengujian Cemaran Mikroba dalam Daging, Telur dan Susu, serta Hasil Olahannya were followed up with an antibacterial susceptibility test using the Kirby-Baurer method. The antibiotics used in this study are β-lactam, aminoglycoside, macrolide, fluoroquinolones, folic acid antagonist, chloramphenicol, tetracycline, and cephems Out of 36 raw milk samples, 16 samples (25 isolates) were contaminated with E. coli and 13 samples (13 isolates) were contaminated with S. aureus. As many as 24/25 of E. coli isolates were resistant to 15 types of antibiotics and 13/13 of S. aureus isolates were resistant to 14 types of antibiotics. As many as 20/25 of E. coli isolates were multidrug-resistant with penicillin-aminoglycoside-tetracycline-chloramphenicol as the most common pattern and 8/13 of S. aureus isolates were multidrug-resistant with penicillin-aminoglycoside-fluoroquinolone as the most common pattern. Antimicrobial resistance can be a threat to animal health, environmental health, food safety, and public health.
Keyword: antimicrobial resistance, Escherichia coli, raw milk, Staphylococcus aureus

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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