Deteksi Gen Pengkode Resistensi Antibiotik Staphylococcus aureus Isolat Asal Sapi Perah dan Hewan Kesayangan

Alyaa Rifqoh Putri Yosyana, Prof. Dr. drh. Siti Isrina Oktavia Salasia; drh. Fatkhanuddin Aziz, M.Biotech., Ph.D.

2024 | Tesis | S2 Sain Veteriner

Antibiotik berperan penting menangani infeksi bakterial, namun terancam tidak efektif akibat fenomena antimicrobial resistance (AMR). Staphylococcus aureus telah resisten terhadap berbagai antibiotik sehingga deteksi gen pengkode resistensi antibiotik S. aureus asal sapi perah dan hewan kesayangan penting dilakukan. Penelitian ini bertujuan untuk mengidentifikasi fenotipik, mengetahui sensitivitas antibiotik, serta mendeteksi gen resistensi antibiotik S. aureus asal sapi perah dan hewan kesayangan. Sampel susu berjumlah 30 dari peternakan sapi perah di Boyolali dan 62 sampel swab klinis asal hewan kesayangan di Yogyakarta dan Semarang digunakan dalam penelitian ini. Isolasi S. aureus dilakukan pada media plat agar darah dan mannitol salt agar yang dikonfirmasi fenotipik melalui pewarnaan Gram serta uji katalase dan koagulase. Uji sensitivitas antibiotik dilakukan menggunakan metode Kirby-Bauer disc diffusion. Konfirmasi secara molekuler dengan mendeteksi gen 23S rRNA dan nuc serta karakterisasi gen coa dilakukan pada seluruh isolat. Gen tetK, tetM, blaZ, mecA, linA, msrB, ermA, aacA-D, dan norA sebagai gen pengkode resistensi antibiotik dideteksi pada penelitian ini. Hasil identifikasi fenotipik serta genotipik diketahui 80% (24/30) sampel asal susu sapi perah dan 19,35% (12/62) sampel asal hewan kesayangan positif teridentifikasi S. aureus. Berdasarkan uji sensitivitas antibiotik diketahui isolat S. aureus asal susu sapi perah resisten terhadap penisilin G (50%,) oksasilin (25%), tetrasiklin (21%), ampisilin (17%), gentamisin, cefoxitin, dan amoksisilin (13%), klindamisin (4%), serta masih sensitif terhadap eritromisin (100%). Isolat S. aureus asal hewan kesayangan resisten terhadap oksasilin dan eritromisin (13,3%), tetrasiklin, penisilin G, dan klindamisin (6,67%), namun masih sensitif terhadap gentamisin, ampisilin, cefoxitin, siprofloksasin, dan amoksisilin (100%). Gen tetK (100%), tetM (75%), linA (70,83%), mecA dan norA (62,5%), msrB (54,16%), blaZ (50%), dan ermA (4,17%) ditemukan pada isolat S. aureus asal susu sapi perah. Isolat S. aureus asal hewan kesayangan terdeteksi gen tetK dan tetM (100%), norA dan linA (91,67%), mecA (83,3%), blaZ (58,33%), aacA-D (50%), serta msrB (41,67%) dan tidak terdeteksi gen ermA (0%). Hasil penelitian ini mengindikasikan adanya mayoritas strain multidrug resistant S. aureus pada susu sapi perah dan hewan kesayangan yang membahayakan bagi kesehatan masyarakat sehingga dapat digunakan sebagai dasar strategi pengendalian multidrug resistant S. aureus.

Antibiotics play a significant role in controlling bacterial infection, however, will no longer be effective because of antimicrobial resistance (AMR). Staphylococcus aureus has become resistant to various antibiotics, so detecting and analyzing genes encoding antibiotic resistance is important. This research aims to identify phenotypically, antibiotic sensitivity, and detect antibiotic-resistant genes in S. aureus isolated from dairy cattle and pet animals. Samples from dairy farms in Boyolali were used for 30 samples and 62 clinical swab samples of pet animals in Yogyakarta and Semarang. Isolation of S. aureus done on blood agar and mannitol salt agar media phenotypically confirmed by Gram staining, catalase, and coagulase test. Antibiotic susceptibility test used by Kirby-Bauer disc diffusion method. Molecular confirmation by detecting 23S rRNA and nuc gene also characterization by coa gene were performed on all isolates. Gene encoding antibiotic resistance such as tetK, tetM, blaZ, mecA, linA, msrB, ermA, aacA-D, and norA were detected in this research. Phenotypic and genotypic identification results showed 80% (24/30) dairy milk samples and 19,35% (12/62) pet animal samples were S. aureus positive. Based on antibiotic susceptibility test, dairy milk S. aureus isolates are resistant to penicillin G (50%), oxacillin (25%), tetracycline (21%), ampicillin (17%), gentamycin, cefoxitin, and amoxicillin (13%), clindamycin (4%), and still sensitive to erythromycin (100%). Pet animal S. aureus isolates showed resistance to oxacillin and erythromycin (13,3%), tetracycline, penicillin G, and clindamycin (6,67%), but were still sensitive to gentamycin, ampicillin, cefoxitin, and ciprofloxacin and amoxicillin (100%). Antibiotic resistance encoding genes such as tetK (100%), tetM (75%), linA (70,83%), mecA and norA (62,5%), msrB (54,16%), blaZ (50%), and ermA (4,17%) genes were detected on S. aureus dairy milk isolate. Pet animal S. aureus isolate showed positive for tetK and tetM (100%), norA and linA (91,67%), mecA (83,3%), blaZ (58,33%), aacA-D (50%), and msrB (41,67%) but no ermA detected (0%). These results indicated there are majority of multidrug resistant S. aureus strains in dairy milk and pet animals threaten public health. These results can be used as a basic strategy for controlling and preventing multidrug resistance in S. aureus.

Kata Kunci : Antibiotik, Hewan kesayangan, Multidrug resistance, Sapi perah, Staphylococcus aureus