Newly Identified Bacteria in Honey: A Hidden Threat to Bee Brood?

Beekeepers know the dangers posed by American Foulbrood (AFB) and European Foulbrood (EFB)—two devastating bacterial diseases that can wipe out bee colonies. However, a recent study published by a Japanese research team Nakamura et al. (2025) has uncovered three new Paenibacillus species in honey that could harm honey bee brood development. This discovery marks the first time in over 100 years that new bacterial threats to bee brood have been identified.

Evaluation of the virulence of honey-derived bacterial strains J27TS7, J34TS1, and J46TS7 under continuous dosing conditions at a concentration of 5 × 106 spores/mL.  Different letters indicate significant differences (p < 0.001) among conditions.

What Did the Study Find?

Researchers found that three newly identified Paenibacillus strains - Paenibacillus sp. J27TS7, Paenibacillus azoreducens J34TS1, and Paenibacillus melissococcoides J46TS7 - had varying levels of virulence, with some being as deadly as Paenibacillus larvae, the bacterium responsible for AFB. The study categorized these strains based on how quickly they killed infected larvae:

• J27TS7 – Highly virulent, killing larvae within 2-4 days.

• J34TS1 – Moderate virulence, killing within 7-14 days.

• J46TS7 – Less virulent, but still found widely in honey.

  
  

Why Should Beekeepers Care?

🔹 New Disease Threats – These bacteria could be silently contributing to colony losses without beekeepers realizing it.

🔹 Hidden in Honey – The study found that these bacteria were present in honey samples, raising concerns about how they might spread between colonies.

🔹 Different from AFB & EFB – Unlike known foulbrood pathogens, these bacteria do not follow the same mechanisms of infection, meaning traditional treatments may not be effective.

🔹 Potential for Global Impact – Although detected in Japan, these bacteria could exist in other regions and might already be affecting colony health worldwide.

What Can Beekeepers Do?

✅ Monitor for Unexplained Brood Mortality – If your colonies show poor brood survival without signs of AFB or EFB, new bacterial threats could be at play.

✅ Maintain Good Hygiene Practices – Preventing cross-contamination between hives and avoiding the use of infected honey in feeding can help reduce risks.

✅ Stay Informed – This research highlights the need for further studies on how widespread these bacteria are and their full impact on bee colonies.

Final Thoughts

This discovery is a game-changer in understanding honey bee diseases. Beekeepers and researchers must work together to monitor, manage, and mitigate these emerging threats. If new bacterial pathogens are affecting brood health, early action will be key to protecting hive productivity and pollination services.

Read the study here: https://www.tandfonline.com/doi/pdf/10.1080/21505594.2025.2451170