LONTAR KOMPUTER VOL. 12, NO. 2 AUGUST 2021 p-ISSN 2088-1541 DOI : 10.24843/LKJITI.2021.v12.i02.p03 e-ISSN 2541-5832 Accredited Sinta 2 by RISTEKDIKTI Decree No. 30/E/KPT/2018 91 The Classification of Acute Respiratory Infection (ARI) Bacteria Based on K-Nearest Neighbor Zilvanhisna Emka Fitri a1 , Lalitya Nindita Sahenda a2 , Pramuditha Shinta Dewi Puspitasari a3 , Prawidya Destarianto a4 , Dyah Laksito Rukmi b5 , Arizal Mujibtamala Nanda Imron c6 a Department of Information Technology, Politeknik Negeri Jember b Department of Animal Science, Politeknik Negeri Jember Jl. Mastrip PO.BOX 164 Jember, 68121, Indonesia 1 zilvanhisnaef@polije.ac.id (Corresponding author) 2 lalitya.ns@polije.ac.id 3 pramuditha@polije.ac.id 4 prawidya@polije.ac.id 5 dyah.laksito@polije.ac.id c Departement of Electrical Engineering, Universitas Jember Jl. Kalimantan No. 37, Kampus Tegalboto, Jember, 68121, Indonesia 5 arizal.tamala@unej.ac.id Abstract Acute Respiratory Infection (ARI) is an infectious disease. One of the performance indicators of infectious disease control and handling programs is disease discovery. However, the problem that often occurs is the limited number of medical analysts, the number of patients, and the experience of medical analysts in identifying bacterial processes so that the examination is relatively longer. Based on these problems, an automatic and accurate classification system of bacteria that causes Acute Respiratory Infection (ARI) was created. The research process is preprocessing images (color conversion and contrast stretching), segmentation, feature extraction, and KNN classification. The parameters used are bacterial count, area, perimeter, and shape factor. The best training data and test data comparison is 90%: 10% of 480 data. The KNN classification method is very good for classifying bacteria. The highest level of accuracy is 91.67%, precision is 92.4%, and recall is 91.7% with three variations of K values, namely K = 3, K = 5, and K = 7. Keywords: Bacteria, Acute Respiratory Infection, Image Processing, KNN 1. Introduction Acute Respiratory Infections (ARI) are included in the list of the top ten infectious diseases whose incidence of infectious diseases (disease prevalence) and morality (a measure of the number of deaths in a population) are quite high in the world [1]. ARI is divided into two, namely upper respiratory tract infections (URTIs) and lower respiratory tract infections (LRTIs). The upper respiratory tract consists of the ears, nose, and throat, while the lower respiratory tract consists of the trachea, bronchi, bronchioles, and lungs [2]. Some examples of ARI diseases caused by bacteria are pneumonia, tuberculosis (TB), diphtheria, and pharyngitis [3]. Pneumonia is an infectious disease caused by an infection that causes the lungs to become inflamed. The causative pathogens (bacteria) are Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenza, Mycoplasma pneumonia, Chlamydophila pneumonia, and Legionella pneumophila [4]. Tuberculosis (TB) is one of the serious health problems in Indonesia. TB is an infection caused by Mycobacterium tuberculosis in the lower respiratory tract. Diphtheria is an acute infectious disease caused by Corynebacterium diphtheriae which attacks the upper respiratory tract [2]. From year to year in East Java, the number of diphtheria sufferers is reported to continue to increase until, in 2019, there were 358 cases [5]. In addition, Neisseria gonorrhoeae is a bacterial pathogen that causes pharyngitis [4], which usually occurs in sexually transmitted diseases (STD) without symptoms (asymptomatic) [3].