Molecular detection of Enterococcus faecalis as a secondary agent of European foulbrood disease in honey samples

Document Type : Original Articles

Authors

Razi vaccine and serum research institute

10.22092/ari.2026.370975.3893

Abstract

Introduction: European foulbrood (EFB disease is the most important bee larvae disease in honey bees which is caused by Melissococcus plutonius (M. plutonius) and then, the larvae are infected with secondary bacteria such as Enterococcus faecalis (E. faecalis), Brevibacillus laterosporus and Paenibacillus alvei. So, the presence of the secondary bacteria can be noted as a remarkable sign for EFB disease. Since preparation of honey bee samples for investigation of apiary health have principal problems, this research aimed to use honey samples to track E. faecalis as the secondary agent of EFB disease in apiaries all over Iran. Material and Methods: Thus, the number of 260 apiaries were selected and honey samples were collected during Autumn and Winter 2023. After the preparation of the honey samples according to the standard protocol, the genomic DNA was extracted from the samples and then, a pair of specific primer was used to amplify the target fragment of E. faecalis using polymerase chain reaction (PCR) technique. For the positive and the negative controls, the standard bacterium and the distilled water were used, respectively. Sensitivity test was performed by specific concentrations of DNA extracted from the standard E. faecalis with the corresponding optimal PCR reaction condition and the appropriate concentration was considered for the PCR reaction for collected samples. Results: PCR results showed that from 260 honey samples, 119 (46%) samples were positive for E. faecalis. Discussion: Findings show that the quick and easy use of honey samples for diagnosing E. faecalis can be introduced as an appropriate method to detect this bacterium. Therefore, honey samples can be recommended as a source for detection of E. faecalis. Also, sever infection of the Iranian apiaries with E. faecalis as an indicator of EFB disease should be noticed as a very significant problem.

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