DOI: http://dx.doi.org/10.14334/Proc.Intsem.LPVT-2016-p.434-440 434 Colibacillosis and Antibiotics Resistance Patterns in Broiler Chotiah S, Damayanti R Indonesian Research Center for Veterinary Science Jl. RE Martadinata No. 30, Bogor 16114, West Java, Indonesia sitichoti@yahoo.co.id ABSTRACT Colibacillosis is considered important in the poultry industry because it generates economic losses due to the disturbance of growth, the decline in production, an increase number of culled chicken, and reduced quality of carcasses and eggs. Study of colibacillosis and antibiotics resistance patterns in broiler was conducted at the Indonesian Research Centre for Veterinary Science. The aim of the study was to provide the latest information on the status of the presence of Escherichia coli in broiler farms in four districts in West Java Province as well as its antibiotics drug resistance patterns and their pathogenicity will be studied. A total of 196 samples of the intestine, liver, heart, egg yolk, air sac that showed gross abnormalities were sampled and feces were collected and used in this study. Escherichia coli was isolated for characterisation and antibiotics drug resistance patterns and their pathogenicity were investigated. Escherichia coli were recovered from 149 (76.02%) samples out of the total samples collected. In this present study, one (7.7%) E. coli isolate was serologically typed into O 78 and 12 of them were untypable whereasthe other 7 (4.93%) isolates were serologycally typed into O 157 and 135 were untypable. In vitro pathogenicity indicated that 91.55% of the isolates were positive for Congo red binding assay and 4.93% isolates were positive for haemolysine production. Antibiogram profiles indicated that 98.70, 79.30, 75.10, 61.40, and 57.70% isolates were resistance against to amphicillin, neomycin, streptomycin, sulfamethoksazol trimethropim, and kanamycin, respectively. A total of 149 (76,02%) histopathologically had consistent colibacillosis lesion with various degree of severity. Key Words: Colibacillosis, Broiler, Resistance, Antibiotics INTRODUCTION Escherichia coli (E. coli ) is one of the most economically important bacteria which is responsible for early chick mortality in poultry farms. Escherichia coli is normal microflora in the digestive tract of animals and human, but certain strains that are pathogenic in birds are called avian pathogenic E. coli (APEC). They are able to spread to various organs and cause systemic and fatal colibasillosis (Barnes et al. 2013). In general, pathogenic E. coli in poultry has specific serotypes, mostly consisted of serotype as follows: O78, O1, and O2, and under certain condition includes O 15 and O55 (Barnes et al. 2013). Colibacillosis in poultry industry is worldwide (Delicato et al. 2003; Ewers et al. 2004). The disease remains a major problem in the poultry industry because it generates economic losses due to the disturbance of growth, the decline in production, an increase in the number of culled chicken, and reduce quality of carcasses and eggs (Barnes et al. 2013). Accordingly, APEC needs more attention as several studies have shown no association with extra intestinal pathogenic E. coli (ExPEC) in humans, especially uropathogenic E. coli (UPEC) and neonatal meningitis E. coli (NMEC). This indicates that some APEC strains could be considered potential zoonosis as gen (Ewers et al. 2007; Moulin-Schouleur et al. 2007; Johnson et al. 2008). Colibacillosis in Indonesia was first found at a farm in Bogor attacking 27.3% broiler aged 5-32 weeks (Poernomo 1988). Purnomo & Juarini (1996) have isolated 950 E. coli isolates, and have been classified into serotypes: O1K1: 85 cases (9.0%), O2K1: 489 cases (51.5%); O78K80;101 cases (10.6%) and other serotypes: 275 (28.9%). Recently, it has