Isolation, Identification, In Vitro Antibiotic Resistance and Plant Extract Sensitivity of Fire Blight Causing Erwinia amylovora

Background: Erwinia amylovora is the causal organism of fire blight. The fire blight is widely spread in bacterial disease of plants from both epidemiological and economic points of view. Furthermore, the situation is worsening by the advent of increased antibiotic resistance in these bacteria. The study was aimed to determine the in vitro antibiotic and herbal sensitivity of E. amylovora isolated from plants available in Sylhet, Bangladesh. Methods: In this study, bacterial isolates taken from five fire blight infected plants like apple, pear, lemon, orange and olive plants were identified based on morphological, cultural and biochemical characteristics. All the isolates were tested for antibiotic sensitivity against five commonly used antibiotics and herbal sensitivity against five plants extract. Results: Morphological, physiological and biochemical study of pure culture of suspected organism revealed E. amylovora bacteria which was found 100% resistant to Cefotaxime and 81.89% to Bacitracin. Chloramphenicol was found most effective as all the isolates were sensitive to it. Besides that, most of the isolates were susceptible to plant extracts and found maximum sensitive to Allium sativum and Syzygium cumini whereas resistant to V. amurensis. Conclusion: It can be concluded that the investigation of herbal treatment can be implicated for fire blight disease in contrast of antibiotic test in future.