Jurnal Kedokteran Hewan March 2022, 16(1):6-11 P-ISSN : 1978-225X; E-ISSN : 2502-5600 DOI: https://doi.org/10.21157/j.ked.hewan.v16i1.18944 6 Revised 15-07-2021, Accepted 10-08-2021 MULTIDRUG-RESISTANT Salmonella sp. ISOLATED FROM SEVERAL CHICKEN FARMS IN WEST JAVA, INDONESIA Aprilia Hardiati 1 , Safika 1 , Fachriyan Hasmi Pasaribu 1 *, and I Wayan Teguh Wibawan 1 1 Medical Microbiology Division, Department of Animal Disease and Veterinary Public Health, Faculty of Veterinary Medicine, IPB University, Bogor, Indonesia *Corresponding author: fhpasaribu@gmail.com ABSTRACT This study was aimed at isolating and identifying Salmonella sp. and then conducting an antibiotics susceptibility test in order to detect resistant genes. One hundred and five chicken cloaca swab samples were used in this study. 30 samples were taken from a layer farm in Bogor, 45 from a broiler farm in Sukabumi and 30 from a broiler farm in Cianjur. In order to isolate and identify the bacteria, a tetrathionate broth was used, which was then cultured in a Salmonella-Shigella agar, and finally a Gram stain and biochemical test was conducted. To confirm the presence of Salmonella sp., a pair of primers were used for the polymerase chain reaction (PCR) method to determine the presence of the i nvA gene.. An antibiotics susceptibility test was used with the Kirby-Bauer disk diffusion method. Nine antibiotics were used in this study. Each primer pair was used for the detection of tetA, blaTEM, aac(3)-IV, gyrA and ermB genes, and for genes encoding antibiotic resistance a PCR test was used. Eight (7.6%) Salmonella sp. were isolated in this study. All isolates showed positive results with PCR confirmation. The results of the antibiotics susceptibility test showed that Salmonella sp. isolates were resistant to tetracycline (75%), oxytetracycline (75%), amphicillin (75%), gentamicin (12.5%), nalidixic acid (100%), ciprofloxacin (12.5%), enrofloxacin (0%), erythromycin (100%), and chloramphenicol (0%). The distribution of antibiotic resistance genes in Salmonella sp. were tetA (33.3%), blaTEM (100%), aac(3)-IV (0%), gyrA (100%) and ermB (0%) positive. In conclusion, Salmonella sp. was isolated. All isolates showed positive results in the PCR confirmation. Salmonella sp. isolates were resistant to tetracycline, oxytetracycline, amphicillin, gentamicin, nalidixic acid, ciprofloxacin, and erythromycin. Only the tetA, blaTEM, and gyrA genes were detected in Salmonella sp. isolates. ____________________________________________________________________________________________________________________ Key words: antibiotics, chicken, resistance gene, Salmonella sp. ABSTRAK Penelitian ini bertujuan isolasi dan identifikasi Salmonella sp., melakukan uji kepekaan bakteri terhadap antibiotika dan deteksi gen resistensi beberapa antibiotika pada isolat Salmonella sp. Seratus lima sampel usap kloaka ayam digunakan dalam penelitian ini. Sampel diambil dari 30 peternakan layer Bogor, 45 peternakan broiler Sukabumi dan 30 peternakan broiler Cianjur. Isolasi dan identifikasi bakteri menggunakan kaldu tetrationat, kemudian dikultur pada agar Salmonella-Shigella, pewarnaan Gram dan pengujian biokimia. Konfirmasi isolat Salmonella sp. menggunakan satu pasang primer untuk metode polymerase chain reaction (PCR) bertujuan mengetahui keberadaan gen invA. Uji kepekaan bakteri terhadap antibiotika dilakukan dengan metode difusi cakram Kirby-Bauer. Sembilan antibiotika digunakan dalam penelitian ini. Masing-masing 1 pasang primer digunakan untuk deteksi gen tetA, blaTEM, aac(3)-IV, gyrA dan ermB, gen penyandi antibiotik resisten, menggunakan PCR. Delapan (7,6%) Salmonella sp. dapat diisolasi pada penelitian ini. Hasil uji kepekaan bakteri terhadap antibiotik menunjukkan bahwa Salmonella sp. resisten terhadap tetrasiklin (75%), oksitetrasiklin (75%), ampisilin (75%), gentamisin (12,5%), asam nalidiksat (100%), siprofloksasin (12.5%), enrofloksasin (0%), eritromisin (100%), dan kloramfenikol (0%). Distribusi gen resistensi antibiotika pada Salmonella sp. yaitu positif tetA (33,3%), blaTEM (100%), aac(3)-IV (0%), gyrA (100%), dan ermB (0%). Kesimpulannya, Salmonella sp. terisolasi. Semua isolat menunjukkan hasil positif pada konfirmasi PCR. Salmonella sp. isolat resisten terhadap tetrasiklin, oksitetrasiklin, ampisilin, gentamisin, asam nalidiksat, siprofloksasin, dan eritromisin. Hanya gen tetA, blaTEM, dan gyrA terdeteksi pada isolat Salmonella sp. ____________________________________________________________________________________________________________________ Kata kunci: antibiotika, ayam, gen resistensi, Salmonella sp. INTRODUCTION Antibiotics have saved humans against disease infections for almost seven decades. Animals that are used as food sources are also given antibiotics in an effort to fight harmful bacteria or to increase production. The use of antibiotics for increased production is considered to be a very controversial practice. The use of low-dose antibiotics has a positive effect according to farmers, namely by increasing 4-5% of the average growth of livestock. However, the use of antibiotics also carries with it a negative impact which is an increase in the incidences of bacterial resistance (Diarra et al. 2007). The use of antibiotics on farms plays a major role in the development of commensal and pathogenic bacterial resistance to antibiotics. Risk to humans can also occur due to the developed resistant bacteria (WHO 2010). Deaths due to bacterial infection are estimated to increase every year from 700.000 to 10.000.000 by 2050. Not only do these resistant bacteria pose a threat to human health, but also the worldwide economic cost of fighting these bacteria is estimated to reach US$ 100 trillion (O’Neill 2014). The occurrence of resistant bacteria complicates the treatment process of bacterial infections due to the antibiotics being ineffective at treating the illness. Antibiotic resistant bacterial infections in humans increases material losses in the form of life quality loss, increased death, and reduced health improvement programs (WHO 2010). Several studies on bacterial resistance to antibiotics have been carried out in Indonesia. Salmonella species have been found to be resistant to nalidixic acid (44.4%) and ampicillin sulbactam (11.1%) (Aprilian et al. 2015). According to Loisa et al. (2016), Salmonella sp. has been found to be resistant to erythromycin (66.7%), streptomycin (33.3%) and chloramphenicol (33.3%). Salmonella sp. is still relatively susceptible to enrofloxacin, tetracycline, and gentamicin. The emergence of bacterial resistance to antibiotics is a major concern to the world. Programs to monitor